For sale matched pair of tubes in nos condition. Verry nice sounding tubes. Price is 50eu plus shipping inside EU it would be around 7-9 euro with tracking. For more info plese contact me.

Good day brothers. I just received this amp B2 mono from a friend but no model written on it. I checked it and found out no gate drive signal at Hi and Lo banks. Power supply section is normal and rail voltage +53 and - 53 are present. Actually the driver chip was located under the blue capacitor which I relocated it and connected it with red wire as shown in the picture. I did this in order to check the drive signal from the Driver chip U9. As I did, tracing backward from Fets gate, there are no drive signal from the chip itself. But my problem is that the part number of the drive chip U9 was erased due to heat I believed as well as the adjacent chip U10. As I traced, the Lo signal out is Pin 1 and Hi signal out is Pin 8. Can anybody tell me the part number of the chips U9 and U10 as shown encircled in yellow. I can not find any model written in it on the amp. . Thanks in advance bros.

Selling a pair of Linlai WE845 Western Electric replica vacuum tubes:

https://www.ebay.com/itm/275281326800

Selling a pair of Beyma 12XA30ND 12" Coaxial Neodymium Speaker Driver Pair New + FD2XA Crossovers:

https://www.ebay.com/itm/275278959959

Selling a pair of Faital Pro HF1440 1.4" Compression drivers here:

https://www.ebay.com/itm/275281311416

Selling a pair of RCF HF99 90x90° 1.4" Throat 9.84"x9.84" Loudspeaker Aluminum Speaker Horns. See here:

https://www.ebay.com/itm/275281303356

Hello friends.
I have a 300B SE amp. I am waiting for new Khozmo stepped attenuators. I put at first tube grid a 70k resistor, for use the amp without potentiometer and protect them a little. Know, i have 2kz noise at both speakers. I put a picture.

Slightly odd question;

When using the PGA series digital volume control IC's is there any noticeable delay in varying the volume, any audio artifacts? or is the behavior much like a conventional resistive control?

My application is that I want to use them in a DJ idolator (type of EQ) but need the response to be percived as instant and smooth. The digipots are attractive as they avoid running the audio signal through the pot and reduce the requirments of the control pots.

For sale holfi cd player Xara, upgreded by Holfi to Xara DC. Player is in top working condition with remote. You can use the remote for volume control by this cd player also. Player hase some scratches on top plate, but face is in nice condition and remote is like new. Player is known for his analogue sound with output in pure class A and battery power operation. The new price was 1590 euro back in 2011.More info on contact. Price is 300 eu plus shipping or best offer.

When my Pioneer DV-535 DVD/CDA player started to fail, after trying to repair it and failing, I went looking for a new CDA player. But, the market (when not!) had already stopped the production of these dual DVD/CDA players, and exclusive CDA players like Marantz had very high prices. Streaming music and Netflix movies were here to stay!
So I bought a product made in China, which had on its forehead a brand that was synonymous with quality at the time. I'm talking about Philco. I remember that after putting together several TV kits in my beginnings as a technician - the ones that copied the original Wells Gardner circuit - and having cursed for that 50 C/S oscillation (here
in Argentina, in the USA and other countries it is 60 Hertz, as you know ) on the screen that refused to disappear after changes of rectifier tubes, filter capacitors, etc. , I bought an original Philco TV for personal use - manufactured here under license and strict quality control - I never saw such a high quality black and white image in those years! (Possibly Westinghouse would have been, but it was never made here).
So the Chinese generic outfit "Philco" manufactured wholesale and with the brand and model "on request" that I bought, - DVP-500 -, ultra thin, fashion rules, they call it "slim" has been working perfectly a few years ago Already.
I have to admit that it has an excellent behavior as a CDA player, MP3 player; WMA etc The big drawback is its slow process for selecting tracks and the poor information on the display. And well, for the money it cost, you couldn't ask for more, that's clear to me. As a DVD player, very limited too, but since the Optoma projector blew up, there was no more cinema in my home.
Having said all this, and having used the optical connection from the beginning and coupled the Philco to an Oppo Sonica Dac, - the idea was to use it as a transport and take advantage of the virtues of the ES9038PRO chip of the Oppo Sonica DAC -, I had a doubt.
Lately I have read that to listen to music the coaxial cable connection is better than the optical one ..... and a demanding audiophile like me cannot ignore this just like that!
Delving deeper into the subject, in favor of the optical cable is the null interference of nearby electromagnetic fields, and against its lower bandwidth, also against the fact that the cable should not be bent, and the poor quality of many "generic" cables that in instead of a crystal center conductor they use plastic, which would degrade the entire bit path. Well I use the one that came with the Pioneer.......
In favor of the coaxial cable we have a greater bandwidth, against which it is prone to pick up electromagnetic signals from nearby equipment and that the cable must have a characteristic impedance of 75 Ohms, so common analog interconnection cables should not be used. RCA.
Thinking ? Am I missing some SQ (sound quality) when using the optical connection? I want to do the experience, should I buy a specific "boutique" coaxial cable or is it the same to prepare one with a generic 75 Ohm cable and two RCA connectors?

I’ve built 2, 3, and 4 way speakers but now I’m building full range speakers with 10” drivers. I plan on building ported cabs and while looking at a number of designs I see many have an f3 around 35 to 40 hz.

is that the normal f3 for full range?

on page 8/15 to 10/15 under
https://pdf.dzsc.com/88889/4193.pdf
(save in the attachment) there is to find the circuit description to such an active crossover network.
Colloquially, this term is obviously totally outdated, since I can't find any further publications on the web in this case.

The special feature of this active crossover network is the absence of additional gain stages consist mostly of operational amplifiers.

Who can me send the currently usual term for this topology (maybe to find in the application notes from TI, NS, LT or Analog devices) ?

Thank you very much

Follows the schematics of a 5W amp I have built using the 832A transmitting double tetrode. The original schematic belongs to Ultra Analog whose site is off line for some time now.

Sounds fairly good.

There's my universal smps from parts from pc power supply.If it don't start to oscillate,reverse feedback windings (15k resistor).I'll test it on some amps,and it works great.PCB is without rectifier,I'll finish it later.

Hello Everyone! First time in a forum since the old days of DTMpower (the early 2000s)

I recently have been building DIY audio projects and I have dove deeper into the rabbit hole with this latest build. I did not want to use a prebuilt passive crossover nor rely on an active configuration like mini DSP so I began to research crossover design and ended up taking Audio Judgement's Udemy course on room acoustics and crossover design. 100% worth the 30 bucks I spent.

So I have spent a few days tinkering with XSim for the drivers I have ordered and I get a good response and a good phase correction (i think that is what its called) Then I go to parts express to order parts and the parts I used are not available or super expensive. What I have below is the closest thing I can get with available parts that don't cost hundreds of dollars. This configuration is $51 and has a good phase correction but it has a 3db dip at the crossover point. Will I actually notice that? I know that I can use active to correct and I will use REW for room corrections but I hate it not being as linear as I think it can be, well I know it can be more linear it just costs gobs of money...I'm not paying 200 bucks for a single inductor.

Secondly, the midbass has a pretty nasty dip around 300hz and nothing I do seems to remotely affect that so what is the best course of action there? I come from the car audio world so my first reaction is to add another driver to the equation like a tang band w5 and have like a 2 1/2 way setup and let the tang band handle a bit of the 80-400 bit subtlety to create a more linear response in the room... am I overthinking a 4db dip here or is my train of thought correct?

Anyways thanks for any advice, happy to have found a DIY audio platform to participate in.

SOLD

I have these NOS 3.5mm plugs and jacks for sale, 8 plugs and 10 jacks. Shown are the Digi-key labels so you can look up specs if you need. That lot for $10 + ship.

Also a package of Bourns 1.0K ohm 9mm plastic pots. Again, label shown so you can look up specs. $10 + ship for this package of pots.

Buy both to combine shipping, which should only be about $5 or so for USA.

If you are interested in these, private message me and we can discuss other stuff I want to sell... lots of 1/4 watt carbon film resistors, standoffs and spacers, chip resistors, NOS Digi-key kits of film caps and polyester caps, trimmers, lots of other stuff I haven't had time to photograph and list yet.

Thanks,
Keith

Bass reflex systems have been discussed ad infinitum but speakers systems have changed. Yes, a port offers bass extension but like I said: speakers systems have changed. In its most basic definition a port offers +3dB at whatever frequency you desire.

I'm one of those consumers who have replaced home theatre satellites with 'real' speakers. For example one of my AV amplifiers has a relatively high (160hz) crossover point. The connected fronts are Sony bookshelf speakers with a 5" ported bass driver. There are a couple of phenomena that I struggle to understand, (1) blocking the port reduces SPL (even though the port is tuned to a frequency the cabinet never receives). (2) The port remains 'active'. Even at high volume levels the satellite bass driver exhibits no movement discernible to the naked eye. However, the port remains active, moving air.

It's a ridiculous question: where do you tune the port on a satellite speaker?

not sure if this belongs in the 'Parts' category, my apologies if this is in the wrong place.

i've gotten the attention of someone at Electro-Harmonix/New Sensor in regards to the many confusing, incomplete or absent data points on their KT120, 150 and 170 datasheets. this person is very motivated to rectify this lack of usable information, and make these tubes more accessible to designers.

this is an official open call to the public, for any and all requests for additions and revisions to said datasheets. these requests will be delivered directly to the New Sensor design and testing technicians on April 22nd, so please post before then.

please be exhasutive and state all your requests, even if they have already been mentioned. please also feel free to indicate which requests you would like to be prioritized the most. i will be compiling a final list to send to them, and will be sure to accentuate items that got the most requests and placed the most highly on folx's lists.

please understand this is not a guarantee that any of these requests will procure published data, nor is it a guarantee of the timeline in which this might occur.

please also understand this is not a thread on which to discuss or compare the various merits of these tube models or the companies that make them. there are many other threads for such discussions - this is a thread to collect requests for datasheet revisions and additions, only.

one last note, and single exception to the above paragraph - since EHX/NS seems to be at least somewhat willing to innovate and create new tube models, i am personally taking this opportunity to provide some requests for what sort of tubes they prioritize the development of in the future. i have been told that these ideas are welcome and will be sent to the technicians as well. so by all means, please share your desires for what sorts of new tube models you'd like to see!

personally, i want to see subminiature pencil tubes, especially the frame grid types, see more focus. they were a brilliant idea too soon overshadowed by the rise of the transistor. just think of how awesome a new line of 6111/6112 style tubes would be! less space needed, more flexibility as to placement, less vulnerability to physical damage, high shock tolerance, lower operating voltages...

Hi all, a small problem with my B-2 that i'd like to diagnose before I go replacing un-necessary parts..

It has been cutting out on the left hand channel most days, rhs stays level, just the left drops out - it goes quieter sometimes and then cuts out completely sometimes, no pattern no continuity.

I thought the first port of call might be the front panel switches, so cleaned all these with deoxit. It seemed to help but doesn't solve it - it's still cutting out on the lhs.

So I swapped the rca inputs from one input to the other (controlled by a switch on the front panel) and the same problem persists.

Then swapped the speaker output from speakers A to speakers B and it seems to work perfectly.

So is my problem the speaker A selection switch on the front panel? Or the internal relays??

Thanks!!

hi folks,
a noob question here (should that not be clear from what follows 😱)
I have hooked up a cheap 48V supply to a couple of TDA7293 amps through a DIY voltage divider to get +/-24V:

When I don't hook up the TDA's, I get a nice +/-24V, but as soon as the TDA's are connected, the led on the power supply immediately starts blinking, indicating that the overcurrent of shortcut protection kick in, I guess.
Which beginner's mistake did I make?
Thanks in advance!

Hi All.
A friend of mine brought around a pair of Sansui D-40 Loudspeakers this weekend just gone. He knows I collect speakers.
A very unusual design, the covers are screwed in place from behind. A bad design flaw. I always remove the covers when playing loudspeakers.
I found that the wiring on one of the tweeter had snapped off, and the cap on the other was an empty shell.
I replaced the 0.47µF Tweeter electrolytic caps (old one measured .057µF) with equivalent poly caps, but left the 2.2µF electrolytics inplace (fresh out of spares).
Result. Very acceptable sound. Very listenable.
I think replacing the mid caps and adding inductors might further improve the sound.
My question is:
As I'm trying to stick to a budget (zero dollars so far), I was wondering whether fitting the iron core inductors junked from my TDL RTL3's?
It's a 10" woofer. The Sansui's are 8 ohm, 65w/c , & 93Db/1m.

I have available a very small quantity of PCBs for building the headphone amplifier as described in my article in Audioxpress June 2013.
You can find the article online if you have missed it :
Build A High-Quality, High-Power Headphone Amplifier | audioXpress
If you are interested, send me an email at: gntanavaras@gmail.com

I am looking at this schematic and it is not entirely clear to me what the resistors R21 and R22 are doing in the filament supply.

My best guess is that they are providing a ground reference for the 6.3V winding.

My other question is whether a center tapped 6.3V winding AC coupled to ground through a 30-50uf capacitor would have lower noise.

This is an earlier version of the schematic; the one I am working from omits the 12AU7 stage and has paralleled EL34 power tubes but is otherwise identical. I don’t have permission to post it whereas the above schematic is publicly available.

Thanks in advance.

SOLD

I bought this to refurbish an old B&W subwoofer but it is too deep and I missed the return policy window. It has only been removed from the box for fitment and never used. Currently back-ordered until mid-April. $300 shipped. Thanks!

Dear Colleagues,

I am trying to find out about the availability of 3-phase AC mains supply at the point of installation of High-power Audio equipment (i.e. amplifiers).

I am neither an audio- nor a power-engineer. So, before asking my questions, let me first give my understanding briefly.

Some possible locations for high-power audio amplifier installations are:

• Live Concerts (open air)
• Stadiums
• Concert Halls
• Discotheques/Night clubs
• Cinemas
• Shopping Centres
• Churches (esp. in the USA)
• Music studios
• etc. etc.

The total output power of the installed equipment, and hence the total input power required from the AC supply, can be in the order of multiple tens of kilowatts, even over 100kW in large installations, just for audio amplifiers alone (excluding any other AV or lighting equipment).

Most of professional high-power audio amplifiers come in 19"-rack mountable enclosures. As far as I know, all such commercially-available amplifiers provide only a single-phase AC mains power-supply input (which may accept a universal voltage range: e.g. 85-265V AC 1-ph). I think, this is true even for the highest-power audio amplifiers recently introduced to the market, e.g. 20KW output (music/program) power and ~ 3-5KW input (1-ph AC mains) power.

A similar situation exists with 19"-rack mountable DC power supplies (AC-DC converters in the KW range) for Computer Data Centres (CDC), with such high-power DC supplies accepting only 1-phase AC mains input. However, a recent tendency in CDC installations is to distribute AC power in 3-phase form and make it available to 19"-rack equipment also in 3-phase AC form.

Clearly, at high power levels, power transmission and distribution is less costly and more efficient in 3-phase AC form than 1-phase AC form.

My questions are:

1. For high-power audio installations, why are audio amplifiers not available with 3-phase AC (400V or 200V class line voltage) power supply input?
   
   
2. Is it because 3-phase AC mains supply is not readily available at such installation points/locations (as listed above)?
   
   
3. If 3-phase AC mains supply is available in such installation points/locations, are there any reasons as to why high-power audio amplifier manufacturers do not make amplifiers accepting 3-phase AC mains for their power supply input?

I will appreciate any contributions, suggestions, ideas or feedback you may be able to offer.

what is happening?

when i use the room simulator and set up a perfectly symmetric left and right subwoofer to listener and room layout i get different frequency responses from the left and right subwoofer, why is that?

in a perfectly symmetric layout i expect to have identicle responses from the left and the right subwoofer.

As per the title, I'm looking for a single Raal 70-20xr tweeter. I know that these are normally OEM only, so they're hard to come by for DIY. However I own one already, and it's sitting doing nothing because I don't have a second one. I'm hoping someone might be able to help.

Bought a pair of LK1 kit speakers from Mike at Lenehan Audio.

1st dry run to see how the cabinets go together.

hello at all

I did a multiroom system I like to show to you. All is done with arylic.com diy streaming boards. There are two rooms on the same floor and I apreciate the same music or other audio in those rooms. I had some older passive Hi-Fi speakers and one passive closed subwoofer I did myself.
I apreciate to have the IR-control to do volume changes or to tweak the bass and treble. If a customer is calling I can mute the system suddenly without having to use the App on the smartphone. The freedom to change the sound in detail with the APC-Workbench software is a great feature I don't like to miss. I also did some 2 way crossover stuff in another setup, easy peasy! Everything works nice. What I did here is no rocket sience. But I like the sound and how it integrates to the rooms and my use case. When I had a issue the team of Arylic responded fast and friendly.

Kitchen
A simple but nice sounding setup. The Up2Stream Amp (V3 I guess) is driving a pair of Infinity Modulus speakers mounted in the upper corners of the room. The setup of the amplifier itself is stock, I did not changed anything with the APC-Workbench software. The Up2Stream board is enclosed in the a Arylic case. Before this board was at a different place. That is why it has a volume knop and a 3.5 mm input in a hight nobody can reach.





Material used or mentioned
https://www.arylic.com/products/up2stream-amp-amplifier-board
https://www.arylic.com/products/up2stream-case
https://www.arylic.com/products/2-u...bluetooth-wireless-amplifier-and-pre-amplifer
https://www.arylic.com/products/expansion-boards?variant=32778796105813
https://www.arylic.com/products/ary...mote-control-usb-aux-in-opt-in-wifi-bluetooth
https://www.arylic.com/products/acp-work-bench-audio-effect-tool

Living room
The Arylic Up2Stream Amp 2.1 is enclosed by a low end wooden case with plastic studs I did. A friend of mine sold a pair of JBL TLX 320 floor standing speakers for a good price to me. The are not high end but ok sounding to me. In this 2.1 setup they go up 100 Hz. Some EQ-ing I did to make them better to my ears. The bass comes from a closed subwoofer with a 12 inch hard suspended bass driver (Monacor SP-12/200PA). The subwoofer does 100 Hz and below. All in all the sound of the system is huge, clear, loud enough and goes deep. If I like to practice bass guitar I plug the subwoofer over to may bass amp and jam along the JBL's without the bass support.













Material used or mentioned
https://www.arylic.com/products/up2stream-amp-2-1-amp-board
https://www.arylic.com/products/ary...mote-control-usb-aux-in-opt-in-wifi-bluetooth
https://www.arylic.com/products/acp-work-bench-audio-effect-tool

Hi, some help please! I am running a three way active system with a horn top end. Obviously the cd driver is a distance behind the mid.

When implementing a dsp crossover it is a relatively simple matter to adjust for the time delay caused by the physical offset of the driver voice coils..in this case around 225mm which results in approximately 600micro seconds delay to the mid.

Using arta and Omnimic one can monitor the frequency response at the selected crossover frequency and watch the effect of the time delay dialling in an amount to achieve the flattest response?

But my question is this!! The dsp also has a phase control option in 10deg steps from zero to reverse (180 of course) . The filters are set to 4th order LR which have zero degrees polar tilt at crossover. Is there any requirement for Phase Control adjustment with 4th order LR once the time delay to account for driver offset has been set? I understand the signal can be adjusted to "exit" at the "same time" but may still not be "in phase"?

Is there any way of checking one is both minimum phase and time aligned? Both arta and omnimic will plot minimum phase against FR...but I'm not sure what I'm looking for in regard to this phase plot!!

Anybody help with this!

Hi everyone,

I am a serious (but amateur) classical pianist that no longer has the ability to use an acoustic grand piano due to noise constraints, so I purchased the Kawai Novus NV10 digital piano. This is a hybrid instrument that uses a real acoustic grand action mated to optical sensors and a digital piano cabinet. So, you get all of the feel of a real acoustic without the noise.

There is just one problem - the built in audio is atrocious given the cost of the instrument. The only way I can get good sound out of it is to hook it up to my computer and use it as a midi controller with Pianoteq software and my Sennheiser HD650 headphones. But the speakers are horrendous, so I figured I would open it up and take a look.

Frankly, this sound system seems like a complete afterthought to me from both an architectural and quality standpoint. The woofers feel cheap, there is no real crossover network, there is point-to-point "fix it" wiring on the mainboard, and the system is generally underpowered.

Given the poor design and components of the system, I am wondering if I can simply take the audio output off of the mainboard, run it through something like a miniDSP and then directly to my own amplifiers and replacement drivers?

I spent some time today and drew up a schematic of the way the sound system currently works.



Looking at it, I have several questions:

1. It seems that the mainboard has separate audio outputs for L/R channel and bass. I assume this means a digital crossover for the bass woofer? This is one issue that I may have to figure out that could impact driver selection.

2. I do not understand the pinouts or number of wires used on this system, it does not seem logical. For example, there are five wires coming off of the mainboard for the L/R channel output, which corresponds with five pins in the input of the Amp. But when the output of Amp 2 is daisy chained with the input of Amp 1, there are only three wires. Why?

3. Why does the bass signal need to be pre-amped, but the L/R channels do not?

4. Is there a way I can find out whether or not the signal coming off the mainboard is flat or processed to hell?

Here are some more pictures of the system. I would really appreciate any help!

View of the action with the cover off



Amplifier Section



Bass amp and Preamp



"Crossover"



How the drivers are mounted to the lid of the piano



View with back cover removed



Close up of L/R channel amps



Mainboard



Mainboard 2



Mainboard output section

hi everyone

I want to build Apex amplifier (HV23)(that I founded in page below (thread 44) :
http://www.diyaudio.com/forums/solid-state/162043-mosfet-amplifier-irfp240-irfp9240-5.html

I found all the parts in this schematic except Q9 (2sc4793) and Q10 (2SA1837)

but the salesman suggested me to use 2SC2073 and 2SA940 instead

and I'm so confused😕 that are they right for replacement??????
If anyone could help me I'll be grateful

Hey toute la monde (everyone).
I rig my preamps up so that the phono stage isn't powered until you select it rather than it being lit up all the time.

It seems like a waste of cathode and electric to light and power the phono stage just to save 15 seconds when you need it?
I switch inputs with relays by switching the grounds AKA if you ground it, it turns on (BMW does this - I used to switch positive). I simply add another relay on the phono setting to hit a relay that will connect 12V/B+.

Anyone else do this?

I just received Triode Electronics EF86 input board for for the ST-70. The parts list specifies four resistors at 18K (R3, R6, R9, R15). Supplied resistors are 20K (not high measuring 18K, but actual 20K, as indicated by the bands). I have 18K resistors on hand. Should i use my 18K resistors or the 20K ones supplied?

Carrozzeria (Pioneer) DEH-P01 amp.
Or rather, the amp that comes with DEH-P01 anyway.
(If you don't know, DEH-P01 is a Japanese domestic version of P99, the most high-end Pioneer car stereo currently available, except US version doesn't come with this amplifier)
The actual product name is CWK-1040, it's a 6x50w MOSFET amp
Used condition, good scratch on top, harness included.
It's a very small very SQ amp - only 4" by 7"!
Could be used in a car or as a very compact solution for your active speaker project.

$150 shipped CONUS

Hi everyone and a Happy Easter weekend!
I just wanted to enquire if anyone knew where to point me in regards a re-cap on the NAD C 325BEE?
Here are some factors:
If diy route:
• I can solder but have not yet done smd
• I would need pretty tight instructions as I am not electronically trained but I’m not a ‘monkey’
• I have various soldering apparatus inc a variable temp station & desolder braid etc

if not diy route:
• a reliable person to undertake the above

additional factors:
• I am open to some improvements in the parts spec if it would give some benefit
• I do like the sound of the NAD C 325 BEE anyway l
• there seems to be some light ‘crackling’ in one channel which I have determined to be from the amp after switching source channels / speaker outputs round etc
This is the main reason I enquire about a re-cap + I understand that NAD did not use that good a quality caps to begin with in this amp (understandable given it’s price point when new).

I really want to keep this lovely and musical amp and like the idea of maintaining it and preventing a failure if possible.

many thanks in advance to any/all that may be able to assist.

cheers
Pete

I have an inexpensive Vifa tweet here and have removed the back of its rear chamber......sounds way better. It has a plastic back on it so was easy to remove. You must leave the felt in place or it whistles down the vented pole piece (2K peak). Can other tweeters have their backs cut off in the same way? How about the Scanspeak, Peeless, Morel, Seas, etc. tweets? Do some have a metal back and can they be removed?

Also, what tweets have the most power handling/maximum xmax to be able to be used very low (1000 hz or lower....cut off at 48db per octave via DSP xover). Using tweet in 12 inch customized waveguide.

Any info would be appreciated. I would hate to have to buy tons of tweets and hack them all apart to find out.

Hi all. I've got a Marantz SR4023 (stereo receiver) on the bench in protection mode. PS section. regulators, relays, diodes, resistors - all check out. I haven't found a single suspicious, burnt or discolored component, so I've started to debug the L and R channels amps and the protection circuit. I have removed the transistors for out-of-circuit testing and found weird hfe behavior with these KTC3200GR transistors. The first one, from the left channel measured 40, the second I've pulled out measured 85, and so did the 3rd (more than twice as much than the first). To my surprise, the parallel transistors on the other channel's amp circuit, had nearly the same hfe. It's almost as if the transistors were matched cross channel. The protection circuit has a couple of these too (Q512, Q612). These measured hfe was 435 !!!. Again, the same KTC3200GR trannies appear to be matched, but nearly 10 times hfe as the first two in the amp section.

I'm baffled. Is this normal?

What can substitute KTC3200GR that can be had with Mouser/DK/newark?

TIA.

For the last two days all notifications for threads and messages are send with a day delay.
Is it me or something is wrong ?

I've recently been enjoying watching videos of people fixing/refurbishing things. I find them soothing.
I thought this one might be enjoyed by some here 🙂



Login to view embedded media

I'm trying to help a friend repair a Hammond Organ AO-43 amplifier that uses a paralleled section 12BH7 to drive a reverb tank with a 14 Henry plate choke as the plate load instead of a resistor. The original choke has gone open. Will a choke intended for use as a DC supply filter work as a replacement? I simply don't know if there are major design differences between chokes intended for use in CLC filters and chokes intended for plate loads. The overall specs on this Hammond Mfg. part appear similar enough:

https://www.mouser.com/ProductDetail/Hammond-Manufacturing/157L?qs=o/sL%2BddUClXXlG/JFsor3Q==

Before someone points on that 14H doesn't seem enough for full range signal drive, that's what it says on the schematic. I suspect that one purpose of the choke is less gain at lower frequencies, which is a good thing in reverb drive unless you want a lot of muddy reverb.

And this is a reverb amp, not HiFi, so we don't have to worry about perfect fidelity. It just needs to be good enough to get the job done.

at this time the first watt f8 is my favorite amp and would like to try the f3.

Has anyone heard of output transformers made by a company called Tracy Electronics? I have a pair of 8k PP transformers (model TS-142A) and the quality looks pretty good. Can't find any references to them.

Where is the diyaudio enhanced print view?

I’m working on an amp platform similar to the concept of the NPXP by Anand (poseidonsvoice) https://www.diyaudio.com/community/threads/nelson-pass-experimenters-platform-npxp.373417/

Mine will also be a single chassis dual mono design, using 2 of the xrk SLB dual-rail power supply boards https://www.diyaudio.com/community/...ct-crc-cap-mx-class-a-power-supply-gb.336479/ , and also a single custom Toroidy power transformer with quad secondaries.

I too plan to use this for many of the PassDIY / FW clone amps, which of course are designed to use a +/-24VDC PS. But, I’d also like to use this with the Alpha Nirvana (standard 8ohm version) https://www.diyaudio.com/community/threads/alpha-nirvana-39w-8ohm-class-a-amp.344540/ which prefers a +/-27or 28VDC PS. I’d prefer not to run the AN at +/-24vDC, and I don’t want to use a Variac to boost the primary voltage either. Too easy to accidentally bump the voltage up without realizing, plus a semi-permanent Variac in the living room would never fly with the interior design committee [wife].

After some discussions with Toroidy, I've discovered that they can build a single transformer that can do multiple secondary voltages, as long as you only use one voltage at a time.

So my question for you all (especially those familiar with Toroidy transformers or XRK's SLB) is: what secondary voltages should I get? 20 and 24? 21 & 23? Something else?

For the low voltage, if I go by Anand's experience, I should order 20V secondaries to get +/-24VDC (though his was 800VA, and I'm considering one that's 600VA. Not sure what the price difference is between 600 and 800VA, but I could check if you all think it's worth spending more for the extra 200VA).

But if I go by this https://www.diyaudio.com/community/...x-class-a-power-supply-gb.336479/post-5759699 I need 22V secondaries

And similarly, to yield +/-27VDC for the AN, do I want 23V secondaries? 25? Something else?

My wall voltage is usually 120VAC. It sometimes will drop to 118 during the midsummer peak cooling season, but I'll likely not be using this amp during those hottest summer months anyway, so let's just assume I always have 120V coming into the primaries.

All four heatsinks are in pristine or brand new condition. 11”x11”x2.25”. $45.00 each. approximately 12 lbs each. Would like to sell all four at once. $35.00 shipping FedEx ground with track. USA only.

Retail $66.00 each. 11.5 pounds each. $90.00 for both plus $25.00 FedEx ground USA only with tracking.

I’m planning to use some Lundahl transformers (LL1555, LL1544a, or LL1545a) for a project, and am planning the PCBs now, but I do not have any samples in hand, and the datasheet gives only minimal information on the terminal pin dimensions. These three parts have the same mounting pin arrangement, and I suspect the dimensions of these pins would be the same for any other Lundahl whose pins are placed on 0.1” centers.

The datasheets say that the PCB should use 1.5 mm diameter holes for the PCB terminal pads, but with 0.1” / 2.54 mm pin spacing, a 1.5 mm hole leaves little room for a annulus as well as spacing between the pins. Bob Starr published an old Eagle library for Lundahl parts that can be found online, and in those footprints, he used a 1.27 mm hole for all parts with an oval pad shape. This should probably work fine, but still, it would be nice to know what the pin dimensions actually are, since a 1.27 mm hole still leaves only minimal space for clearance and an annulus.

If anyone has any Lundahl parts out there and a micrometer, can you measure a mounting pin for me? I assume they’re square pins, but again, I have no idea. The length of the pin is unimportant, only the diameter or width dimension is interesting. I’d imagine they would be square pins with a width of anywhere from 0.025” to 0.040”, but the details would be of great use.

Thanks!

Hi,

I was wondering if anyone had any recommendations for drawing software that could be used for working out horn folds. I saw there was a forum from a while back which suggested using sketchup, but it looks like they've updated the software and it's not as suitable anymore.

I have designed a horn model in hornresp, and can export the coordinates in txt or csv form, so I want a sofware that can import these, in two dimensions. Then i can work on the folds from there.

Does anyone have any suggestions?

Thanks

I have a crazy idea that's probably a misguided mishmash of speaker design, and I'm no audio engineer (but am well versed in electronics), so please excuse anything here that sounds idiotic. I'm just trying to filter out what doesn't make sense and make something cool.

That said, I'm thinking of designing a subwoofer with the following considerations:

• As low of response as possible, hopefully 10Hz or less.
• Upper response into 120Hz.
• Multiple drivers (3 or 4) for ability to move big air and get really low while also being smaller (I'm thinking 12") and cheaper with good fidelity into the higher frequency.
• Large, almost infinite baffle tuned to the low frequency response target.

I was planning to use a small storage room for the infinite baffle, but this is in a concrete floored, basement room where I was planning to raise the floor anyway. Then I saw something called Hovereze which is basically a platform for you chair set on rubber tubes with subwoofer drivers firing down to shake your chair, but that sounds goofy to me. But that got me to thinking about building a 2x4 framed floor section big enough for the proper tuning, setting it on a flexible seal of some sort around the edges, and building the box such that it opens into said floor which, with perhaps multiple such subs (I'm thinking one in each corner fed by each surround channel), will shake the floor for tactile effect. With multiple drivers in each "box" it should be able to reach super low.

And yes, subs aren't directional in lower frequencies, but individual floor sections shaking would be, as would frequencies up into 120Hz.

But that's just the low end. I was watching the Tech Ingredients video on Voigt tubes for full range speakers, and thought, what if I made that but tuned it to extend a subwoofer's range in both directions? Now I'm imagining the aformentioned setup with 3 or 4 drivers at the floor on a large, slanted column that takes up the corner up to the vent at the ceiling.

Is this a crazy/stupid idea?

Here's a quick mockup of what I was thinking it would look like. The gray lines are the floor joists set up such that they don't inhibit air movement.

Hey guys,

I’m planning to make an OB PAP TRIO clone. Initially I was thinking of using all Lii audio drivers; the silver 8, and a pair of W15 woofers. But then I realised the AE dipole 15 is very similar to the W15. Both woofers are in the same price range.
the Lii W15 and the AE dipole 15 are both quite expensive (especially when you visited you need 4 to make a pair of PAP trio’s), have a high Qts, and a large Xmax.
Cheaper options for woofers are the eminence alpha 15’s and the SB Bianco 15OB350. The cheaper woofers have a fairly low Qts and a smaller Xmax.

I read a fair bit about the Leonidas speakers, which use a crystal 10 full range, and a single W15 woofer (both from Lii audio). They’re supposed to be very good. So I was planning on basing the design on those speakers, knowing that I need to reevaluate the crossovers based on my own drivers.
I recon using a Silver 15 full range driver and two W15 woofers, would keep the crossovers similar.
Since these will be my first OB speakers (and overall my first speakers), I’m actually curious to know what would be the more important factor to consider for an open bake speaker, And why: Qts, or Xmax?
Note that all be using it on an 18W tube amp, so sensitivity is a bonus

fyi,
The W15 has a Qts of 0.79 and an Xmax of 15mm
The AE dipole15 has a Qts of 0.94 and an Xmax of 15mm
The alpha 15a has a Qts of 1.26 and an Xmax of 3.8
The Bianco 15OB350 has a Qts of 0.57 and an Xmax of 11mm.
The alpha and the Bianco are comparable in price (in Europe), the w15 and the dipole15 are also comparable in price but about 3-4x the price of the alpha and the Bianco. The dipole15 is also hard to get as they can only be ordered from the US and thus import and shipping are extra (which is why the dipole and w15 are similar in price for Europe).

I want to build myself an stereo amplifier with the 5881 tube. Single ended and with ecc88-ish, or 6sl7, or ecc81 as input tubes. Input selector and volumepot in front. Are there someone out there that can give me some good advice. Thanks for a great forum!

Does anyone here have any experience with online IT classes, either for a certificate or an AS degree towards a job in the IT field?

The ones I've found so far don't give out much information, they just want you to give them your phone number so they can make a sales pitch over the phone.

Hi all,
I was wondering if anyone can help me with fixing a very dim VFD display on my NAD 5320? There's lots of information on changing bulbs behind the later NAD's LCD displays but I can't find anything on this problem.
Some parts of the display are brighter than the others. Schematics can be found here.
NAD 5320 Compact Disc Player Manual | HiFi Engine
I'm not very good in reading those.... 😀
I received it not working at all. I changed C601 and C602 but that was easy: they had leaked. Also the voltage regulator was changed. And now it works. Except for the display. All variable resistors are assigned to the Laser and such (I checked that).

Trying to get my LM3886 to work. Three attempts so far no result. Fourth attempt I've simplified the circuit and have only resistors soldered onto the actual chip tags. No circuit board.
Still nothing. I am perplexed, especially since I have built two previously that work well.
So currently I have 30 volt positive and negative supply directly connected. I have input and output directly connected. Pin 8 (mute tag) has 20k to the negative rail. The feedback loop from output to non inverting has 20k connected with 1k to ground. The CD output goes directly to the inverting input with 1k in series and 20k to ground. Thats it. No capacitors.
With the CD input fully open (max volume) I get a faint whispering through the loudspeaker.
Help!!!

For sale 3 pcs of Telefunken RES 164. NOS and NIB! Never open!!!

Send your offer to PM.

Sold

Thank you

hello I want to upgrade my Trace Elliot GP7 7 band EQ pedal so I have more output lower noise
And over all better audio definition

It has two
TL064CN
Is there an OPA equivalent?

I decided to build the Kensho Two – M2 off Göran's website "AudioExcite" after purchasing the ribbon tweeters
from the swap meet and the woofers on sale from Madisound. The crossover caps were also on sale from Parts Connexion.




Boxes were made with 3/4 Baltic Birch ply, also first time veneering with paper backed Mappa Burl wood veneer.

Hi

I looking for ready to install comercial round grilles that fits Alpair 10.3 flange size. 160 diam x 10,5mm. thick Any clue or comments are helpful.

TIA

Lundahl LL4612 inductor set for LCR phono. Brand new.

Attached is the datasheet for LL4611 which is the same as LL4612.

Asking for US$500 o.b.o for the set

Hi all,

Has anyone built, listened to or comapred the new ACA Mini vs the ACA and, if so, can you please share uour thoughts on their relative differeces, strengths and weaknesses?

Many thanks!

Hi
My Marantz cd player has stopped working.
Symptoms;
1. When powered the player
The display says power on but does not go beyond to indicate the no disc.
2. The cd tray has stuck.
I opened the top cover and released the tray by carefully rotating the gears.
When I did that the tray mechanism become very slack and indicates no resistance when I push the tray in carefully.
3. Still the power on position did not go beyond the no power indication.
Anyone who could explain to me the reason for the above issue and how I could get over this issue.

Regards

Mohan

Hi lads,

After some struggle with a corded Mountfield I decided its time to be a real man 😀

I have a small lawn, around 75-80sqm. Main issue with the corded one was I have post lights and a fountain which makes doing about 1/3 of the lawn a bit hard as the cable likes to get stuck on these. Also, when grass is wet this one`s not collecting it properly.

Would you say it makes sense to buy a petrol mower - been eyeing a Honda HRG 466 SKEP but suddenly got slapped by a thought - isn`t a large 46-50cm self propelled mower not going to create other problems in a smaller garden? Or be Clarkson and get all the power & pistons & smoke 😀

I've pretty much completely rebuilt my SCA80Q with parts and help from Dan at updatemydynaco.com; all the big capacitors, fully repopulated both preamp boards, new input jacks, new speaker binding posts, new balance control, new caps and resistors on the front panel switches and pots, and new caps and transistors on the power amp boards (the power amp parts were from an eBay supplier).

The amp sounds better than ever, except for a few vagaries....

1. I have lost the left channel completely on two occasions. Lost, as in, NO output even at full volume. No hiss, hum... nothing. Swapping input channel leads confirms that the issue is internal in the SCA80Q. With volume full up, no inputs connected, there is the expected hiss and very slight hum in the right channel, but absolutely nothing in the left channel.

2. There has always been a significant turn-on "thump," and it is still present; if anything, it's even stronger than it was before the rebuild.

3. Here's where it gets weird. The solution to item number 1 above, on both occasions, has been to turn off the amp, wait a few seconds, then turn it back on. When doing so, the turn-on thump is severe... almost a turn-on "CRACK," meaning not just the "thud" usually heard, but a strong full-range POP. After that, both channels work and the amp sounds pretty good.

Have already received advice to swap the pad 19 leads from the pre boards to the amp boards to narrow down where the problem is, and will do that. Anyone have any further insights/places to look? I had originally thought that the issue may lie in the selector switch contacts, but the fact that turning the power off, then back on, seems to negate that. Who knows.

Thanks in advance for any suggestions.

I dread starting a capacitor discussion as much as anyone, but I've been looking at datasheets on various brands and types of capacitors to use for the +/- power rails on a SS power amplifier. I work mostly on tube amps, so I have years of experience knowing which type and brand to use for a given application. With SS rail caps, I'm not as sure which way to go.

For example, there are the well-known Nichicon Audio Grade lines like LKG and others. But if you look at the datasheet specs by other companies, you see that in recent years, they have managed to bring ESR down in some cases to half that of the Nichicon Audio Grade capacitors and have increased ripple current figures. Companies like TDK/Epcos and United Chemi-con seem to be leading in this area.

Reading sites like the Elliot Sound Projects pages, there's an emphasis on low ESR for SS power supplies, and I've seen some techs using arrays of smaller capacitors to replace single larger capacitors to lower ESR by putting them in parallel. In other words, I see emphasis on this parameter from multiple sources.

On the other hand, Nichicon specifically markets several lines of capacitors specifically for audio, and I've used several of them with good results in signal path applications like KZ and ES Muse types. For the most part, however, other companies simply don't market their capacitors in this way for specific applications. (Elna comes to mind as another company that does, but they are mainly for signal path.) Nichicon doesn't state exactly what it is about their audio grade capacitors that makes them better for audio.

Making comparisons even more difficult, you have to do a pretty deep dive into the datasheets to compare apples to apples since the various companies don't all report their specs in the same way. Math is involved.

So if I'm looking for a 3300uF capacitor, I could go with a Nichicon LKG "Type II" with 120mΩ ESR. But there is also a Vishay/BC Components capacitor from the MAL2056 series listed as having 67mΩ ESR @ 100Hz and 40mΩ at 10kHz. It's also listed as a 12,000 hour part compared to 1,000 for the Nichicon. Ripple current is about the same as Nichicon, but for a longer life.

Then there's a TDK/Epcos cap from the B41505 series that claims 56mΩ ESR @ 100Hz and 55mΩ ESR @ 10kHz. It also claims around 60% greater ripple current than Nichicon or BC Components and a life of 5,000 hours @ 105C, 12,000 hours @ 85C, and 25,000 hours @ 40C. Looks like this line has been around since 2016.

On paper, it looks like the TDK capacitor would win the specifications contest, but does that lead to better sonic performance specifically for a power supply rail capacitor? Would Nichicon's audio grade sound better even though Nichicon is pretty vague on why that would be the case? Or is it simply the case that Nichicon pursues the audio market in a way their competitors do not? I've used Panasonic and Chemi-con capacitors in some power supplies in the past, as well as Nichicon, but I can't claim one sounded better than the other. They were all very good. And is that the answer? Has performance of all modern electrolytics by top companies gotten so good that it's just splitting hairs as to which is "best"?

good morning everyone ! looking at the projects of the aleph amplifier from the KKPCB website I saw that the power supply stage has fast diodes and a pigreco filter formed by 4 capacitors and an inductance for each power supply branch! Have you tried this type of power supply? Would it be possible to replace the coils with resistors?

Hi,

I'm trying to step up my PCB game designing a board for Doug Self's EQ/Preamp from LinearAudio Vol. 5. I know, there is a nice "official" board available here. However, I would love to fit this device into a Modushop Galaxy GX247 case. That's about 220mm wide and 170mm deep.
My expirience with designing my own PCB is limited to much smaller endevours. I've done simple home-made single-layer boards but no professionally manufactured boards of this complexity level. But maybe I can still pull this off 🙂
Since building Bonsai's X-Altra Phono Pre made me realize that soldering SMD isn't half as bad as I had imagined it to be, I think I can get the design to fit into the case by using 805 SMD parts where I can.

I tried to follow the best practices that I'm aware of and came up with the following board. Most tracks are .4mm Some are wider, none are smaller. I treid to set up a good star-ground structure and to make the power supply rails clean and staight. I don't know if I should consider any ground-planes. Not sure where that would make sense.
Also, I still need to work out whether I need heat-sinks for the regulators...

It would be great if some of you with more expirience could take a look and point out any glaring oversights, improvements or other tips.

Here is the PCB so far in what I hope is a high enough resolution to make out things...


Here is the GND network highlighted:


And this is the VDC+/- power supply rails


And finally a 3D view...


Would be great to get some insights on what might be missing to make this work...

Cheers!
Lars

Here I need a qualified opinion from the attending gurus please (as much as possible so pls feel free to just go at it. Thx).

I am listening to LX521s right now (with my 12inch sealed bass units). I used a similar driver/XO arrangement in my home brewed OBs:
https://www.diyaudio.com/forums/multi-way/123512-ultimate-baffle-gallery-259.html#post5670164

I actually liked that driver complement better (Visaton AL200 + SS 10F/4424g00) than the SL drivers. So I am thinking of making a BOX speaker to put on top of the LX521 sealed bass. I really love the SS 10F driver and would like to stick with it if at all possible.

My tentative design goals are:
1) box size around 12 x 14 x24 inch (W xD xH)
2) run one (or two) AL200(s) from under 100Hz up to 700Hz,
3. use 10F from 700Hz up to TBD but:
3.1) use the lower distortion 8ohm version (10F/8424) but get the sensitivity back up to 90dB or better?
3.2) increase the max SPL capability so the drivers run low on displacement and distortion at higher volumes?
3.3) increase directivity and "throw" into the room (listening distance is 12-13ft) if possible, so the direct to radiated sound ratio gets better?
3.4) introduce a super tweeter if necessary to prevent comb effects (may have to experiment eventually to see if that is an improvement).

Combing may present less of an issue at this listening distance but should still be addressed within reason and that is why I am asking the questions.

I am thinking so far something like these arrangements:




Also, an out-of-the box: if a synergy like upper mid is possible with a cylindrical supertweet in the middle:



Does any of this look doable to you?

Btw I am planning on 3-way active here between AL200, 10Fs and the tbd supertweet, so one EQ per amp channel is available. (actually 4-way with the 12inch sealed sub under).

Hi,

I have been compiling a rather comprehensive listing of tubes not found in the latest tube-chart I have for the B&K 607/667 Testers. My B&K setup-chart # is 497-015-0-180 and I don't know exactly when that was published as it doesn't say in the booklet. Living in Europe obviously I come across quite a variety of European tubes and some aren't listed by B&K. I set about finding as many missing European & US tubes as possible and x-ref them to already listed European or US types to obtain setup-data. As you will see it turned out to be quite many. When direct x-ref wasn't possible I still listed the tubes but w/o the LOAD setting. It will enable you to still test the tube to a degree and becomming familiar with using the 607/667 testers you'll soon recognize what LOAD-settings are sane and what aren't.

This list is for NON-Russian tubes but a Russian ditto is on the way and will be posted here as well.

The reason for doing this is that I'm very happy to be using the B&K testers. I have one of each, but they're really the same except for the case. When they arrived I renovated them, replacing ALL resistors as they were out of range. Also the electrolytic cap's needed to go. To finish renovating I bought a 100MOhm resistor to do the required calibration.

Now they're my favorite testers for catching faulty tubes showing grid-current/leak. To my knowledge no other testers are able to do this as well and when dealing with used tubes this is a must. I didn't anticipate that so many tubes would suffer from this problem but they do.

If you spot any errors in the list, and there is bound to be some or if you have any additions I'll be very happy to hear from you.

Wow, I would have thought more people were using the B&K 607/667 testers. Still, those who do knows what great emission testers they are. Especially for detecting grid current/leak ! I'm attaching the latest chart, ver.1.3 which includes additions and corrections. The bulk of compatible tubes are of course already in the chart and now finding more is a very tedious work. Also I need to confirm settings by actual testing of NOS tube-samples on hand. Some few are already done and more will follow. Have a look at the new chart...

rgds,

/tricomp

The chart grew extensively. Now about 60 pages of setup-data for non-listed, non-Russian tubes. As I have a lot of NOS German Steel Tubes, Socket Y8A (EF11 etc.) on hand I made an adapter for testing these as well. An adapter for the European Side Contact Base P8A (EL6 etc.) will follow as I also have a stash of these tube variants. A Rimlock B8A adapter (EL41 etc.) will surely be added too. The B&K works just fine with the adapter-solution for testing real vintage tubes, but of course it should. These tubes aren't any different from modern tubes save the sockets. I'm impressed that the previous chart was only downloaded a single time. I can't believe no-one knows about the B&K 607/667 testers. If that's the case I can say that you don't know what you're missing ! This beauty will tell you about any potential grid leak problem way before any other emission tester imho. And, ..now it has one of the most comprehensive additional setup-charts available for any emission-tester !!

Hi All.

Just came across a pair of 3 Way Loudspeakers which I'd like to freshen up.
Previous owner said the high notes were absent.
Each enclosure has 1 x15" Nisco Woofer, 2 x 3 1/2" Japanese Mids, 2 x 2 1/2" Japanese Tweeters.
Firstly I found a non soldered section of wire feeding the mid drivers had separated.
The other thing, that puzzles me, is that the mid capacitor is feeding the -ve terminal on the mid range speakers.
Existing crossovers:
+ve signal to large air core inductor, then to +ve terminal on woofer.
+ve signal to 8 µF electrolytic cap, then to -ve terminal on midrange speakers.
+ve signal to 2.8 µF electrolytic cap, then split, one going to +ve terminal on tweeter speakers, and another going to a smaller inductor which then goes to -ve return.

Is this correct?
Should the 8µF electrolytic cap be feeding the negative on the midrange drivers?
And, is it normal to have the 2.8µF cap feeding both the tweeters & an Inductor (especially as the Inductor then goes back to -ve enclosure terminal)?
Also, are these drivers of any value(the 15 inch drivers look like they could move some air)?

Hi All!
I'm building an RH84 and have grounded it as follows: AC line green direct connection to chassis very close to IEC socket, all else star-grounded back to PT secondary. Upon checking continuities, I realized my secondary grounds are all isolated from the chassis ground (all my star-ground connections used insulated terminal strips). Is this an absolute no-no? What are the pros/cons of doing this? Thanks!

Hi everyone. I want to build my first own Subwoofer for home cinema and music. I plan to use a TPA3255 for it and chose a "Hertz S 300 S4" (https://hertz-audio.com/product/car-audio-subwoofers-uno-s300s4/) (I know it is a car subwoofer, but thats the one I already had).

My question now though is: How to design the Power Supply? For low frequencies and this chassis I need some power so toroidal transformer are large, heavy and expensive. That's why I chose a switching power supply. The next thing would now to add a filter and for toroidal transformers you would need to filter 100/120Hz very much. But the switching noise of the switching supply would be at i.e. 80kHz or more right? Even if that is not filtered at all, the chassis wouldn't be able to play that frequencies PLUS nobody would be able to hear it anyway. So what filter should I build? No filtering or just the internal filter of the switching supply seems wrong. Maybe there is no way around powering some load and measure the frequency spectrum to see where the noise is and filter that? Or just use a low-pass like it would be a toroidal transformer and that blocks everything above as well?

I get why switching power supplies aren't very popular in audio environments but for a subwoofer which only plays below 150 Hz or less? Why would you not use a switching power supply?

I'd be happy for every helping anwser.

greetings from Germany,
Michael

GR Research has released the LGK 2.0 and I was wondering about whether it would work in FH Lite or any other
of planet10 Hifi's great designs. Specs are here:
https://gr-research.com/product/lgk-woofer/
Thanks.

I am contemplating using an RF beam power tube, the 5763, in a stereo SE amp, because I have them. In very rough terms, I would characterize the 5763 as a souped-up 6AQ5, just to give a frame of reference. Most data sheets only list RF specs for the tube, but the Brimar data sheet gives AF values as well (probably for modulator use). The problem is, I have a hard time believing the SE numbers. In particular, for the DC plate input the claimed output seems way too low. Example:

Plate V: 250 V
Plate I: 45 mA
Power out: 2.85 W
Efficiency: 25.3%

That's a plate input of 11.25W for 2.85W out, or an efficiency of only 25%. A 6AQ5 has these numbers:

Plate V: 250 V
Plate I: 45 mA
Power out: 4.5 W
Efficiency: 40%

6BQ5:

Plate V: 250 V
Plate I: 48 mA
Plate out: 5.7 W
Efficiency: 47.5%

Any thoughts on how the 5763 could have such low power output, with essentially the same plate voltage and current swings as the other listed tubes?

https://frank.pocnet.net/sheets/184/5/5763.pdf

Hi. After a long time of job "grinding", i finally have some time for myself. So next to some serious projects (amp, speakers), i have went on to create something i wanted to do for a long time, and make pio capacitor. Had 20m of copper 0.05mm foil laying around and i wound myself a 0.4uF cap (pics in attachment), since i have access to both machines that can roll it tight, and vacuum chamber. Vacuumed with mineral oil, and encased in wax. Now i have been told to pay attention to inductance of such a capacitor. I have only connected leads to the ends of both foils (each foil is 10m).

Which leads me to this topic and the question at hand. What is the best way to reduce inductance in such a capacitor? How does duelund and the rest do it? What i have managed to pickup from the videos and photos, they leave extra foil on each side (so conductor/foils are not completely parallel, and one side protrudes from one foil, and the other side protrudes with another foil), and i guess they connect somehow those edges on each side (which can't be seen, but it's my best guess).

I picked up a N.E.W. class A amplifier that had a decent amount of damage to one of the boards. The actual board and traces were fine, there were just a few components that had become charcoal.

I replaced all of the components that were damaged and measured the components that were near them in circuit (transistors on a curve tracer, caps with a Peak ESR meter, etc) including the four output devices. Excluding the components that were charred everything measured normal. I then powered it up on a variac/DBT starting at about 50V. Got it up to line voltage, 122-124V and it doesn’t seem to really be drawing anyting, 0.02A and I’m guessing that’s from the LED that lights up on the front panel. Fuses are good obviously as the power LED lights up.

Measuring from ground I’ve got a +30Vdc and -30Vdc rail on each board directly from the bridge rectifier. Measuring the 3 pins on each of the outputs to the chassis, each pin has either a +30Vdc or a -30Vdc. Overall it seems to be a fairly simple design. I find it odd that only one board had damage, yet it seems that the entire amplifier is doing nothing. I’ve had this amp in the past and I remember it got quite warm, it’s been plugged in for at least 30 minutes and it’s still dead cold.

I’m hoping to get suggestions. I’ve worked on and have repairs several amplifiers so not a complete novice, but by no means an expert either. I have many tools and am competent enough that I should be able to do what is asked of me.

What is the best way of biasing a class A amplifier? Generally with A/B I’ll measure across the emitter resistors and set to a certain voltage (mV) if there isn’t available factory instruction.


Thank you,
Dan

Anyone have reccomendations for a pre-amp build to match up with Aleph J, tube or SS, i dont mind

Thanks

Fresh made DIY desktop Speakers named MoniThor (small but great sounding)
Drivers:
Peerless SLS-85S25CP04 - 4 Ohm
Ciare MT200 - 8 Ohm

Xover point: ~3000Hz
FB: 50Hz

Mayht New Speaker Driver Technology Attracts Multi-Million Investment | audioXpress

“Our vision is that Mayht will become the new industry standard for speaker driver technology”, says Mattias Scheek, CEO of the company. “The world will get used to - until now unimaginable - high-quality full range sound experiences including the full bass spectrum, from the most compact of form factors.”

We are in the process of developing our Technology Platform which will bring optimal sound quality to any device in all verticals. We are in close contact with the world leading Tech- and Audio companies, and see their interest grow at every step that we take”. Driver technology has so far remained unchanged for at least 75 years. With Mayht it is finally possible to think of radically new and smaller form factors, with immense sound quality improvements - a true paradigm shift. Phones will sound like bluetooth speakers, small bluetooth speakers will sound like hi-fi speakers, a flat TV will finally have home-theater sound capabilities.

Mayht – Disruptive Transducer Technology

- So it is a double opposing diaphragm bipole system, pumping air in-between with high excursion. A woofer really, they don't say how high it can go.