diyAudio

tiefbassuebertr · 2011-10-03 10:14 pm

Fulltilt · 2023-12-30 1:19 pm

Thanks for the add. A friend gave me this amp that does not work, it just crackles when I play. I am a guitarist and dabble in electronics. I attached the schematic. I have +/- 16V after R144 & R145. I plugged the guitar in the poweramp in jack as someone suggested on another thread and nothing happens. The LEDs on the panel work and speakers are good. The resistors look to be soldered OK, no other loose solder joints that I can see. Can someone tell me what I should check next? I'm trying to understand how to check the ICs. This was on another thread: "Check if you have +/- 16V on the IC's pin 8 and 4.". I have 32V across pin 4 and 8 on all ICs. For U7 it looked like I should be getting 16V at pin 1 & 7. I measured across pin 4 & 1 and 4 &7, and got 1.4V and 32V respectively. Am I measuring across the right pins?

Hexhclass · 2024-02-09 7:09 pm

This amp has a very loud hum with no rca jack connected.It increases if I bring the gain up.
Any suggestions?

ggetzoff · 2024-02-09 3:18 pm

Looking for a pair of Lundahl 1692A P-P Amorphous interstage transformers.

Thanks,

Greg

andyjevans · 2024-02-06 5:04 pm

I tried a search and didn't get anything useful, so I'm asking the question here. How close can you mount output tubes? Expressed in either centre to centre or preferably edge of glass to next edge of glass.

I particularly want to know for EL84s, where I have 4mm between them glass-to-glass and 4 in a row.

But feel free to include any tubes you have information for on the thread to make it more generally useful.

Vunce · 2024-02-08 4:56 am

Wooo Wee, inflation hit the Lottery VFET amp bigtime!
https://www.ebay.com/itm/2666616972...sGheTUqSyi&var=&widget_ver=artemis&media=COPY

Hexhclass · 2024-02-07 8:00 pm

Pin 3 on the 494 is high,I think the protection circuit it self is bad.When I force pin 3 to go low voltages look ok.What usually cause that problem on that board?

mot on/off · 2024-02-06 9:09 pm

Hi everybody 😊

I've got a Yoko F-92 CD Player that didn't work at all (made in Korea).

I cleaned everything in the transport mechanism, oiled & greased tracks and gears.
Changed both rubber bands for motors with new ones.
Also gently cleaned head with isopropyl alcohol.

Now it can read instantly all cds (takes 2~3 sec) displaying total tracks, time remaining etc.

But when I push play button it seems that try to focus while disc spins but finally it doesn't play..

It is a matter of adjustment or something with the lens you believe?

I would like to make it play as it has resistor ladder DAC and I'm curious how it sounds 😁

academia50 · 2024-01-28 4:15 pm

One more thread from the AU 4900 and they go....Over the years, this amplifier becomes noisy, generating random crackles. It can work well for a few hours or many days, and at some point begin to generate violent bangs, crackles. It can happen on only one channel, and then appear (or not) on the other.
We usually find the advice on the web to replace the TR 2SA798, pointed out as the only and unequivocal culprit. We will see that it is not so.
It is a differential pair, two TRs in a single package, 5 pins, which is why in the Sansuí manual it is called IC (integrated circuit). These are on the power board, it is the first input TR.
These TRs are impossible to get new, so there are two solutions, build it using two KSA992FB transistors, (the most recommended by the repair community) joined with heat shrink and thermal paste, or use the dual BCM856DS TR, for the latter a adapter for easy assembly. Given the availability here, I chose the BC557B, purchasing 40 units and selecting two pairs with the most similar HFE. I have seen tutorials from repairers who have bought these very damaged amplifiers, only to remove the 2SA798, but it is no guarantee for what has already been said. Of course, I don't believe that the entire Sansui AU4900 production with these TRs failed, but it seems that the failure rate was quite high, they were even used as well.
(maybe the same batch) on Pioneer amplifiers, with the same problems. We are talking about audio equipment from the 70s. There are people who never repaired the AU4900 (or also AU3900) and still enjoy it. Many people say that this amp. It has a "tube sound", something very debatable. But it is very complete, it has tones, filters, loudness, attenuator, two speaker systems, headphone output and also a practical microphone mixer. With good quality speakers, it really sounds great.

Jcris · 2024-02-09 4:45 pm

These are from upgrades. All 4gb , no issues. Will they work for you?

njswede · 2024-02-03 1:55 am

Hi!

I'm a complete beginner at building audio circuits, but I thought it would be fun to design and build a Class D-amplifier. I know, maybe it shouldn't be your first project, but I like a challenge.

Anyway, I went for a self-oscillating design, loosely inspired by a bunch of different designs out there. Pretty simple stuff. I take a ground references signal from an RCA plug, split it up into an inverted and a non-inverted signal, run it through an integrator that's fed back by both sides of an H-bridge, then through a regular comparator and MOSFET driver.

To my great surprise, the thing actually produced sound when I hooked it up to a speaker. However, it has three issues:
1) It takes a couple of seconds, sometimes longer, for it to reach stable oscillation. During that time, it produces awful scratchy noises.
2) The oscillation seems unstable. RV2 can be used to tune the idle oscillation frequency and I have to tune it to a very specific point (happens to be 192kHz) for it to produce a stable signal. Just a 1/16 of a turn on the pot, and it starts hissing and scratching.
3) The output from the MOSFETS has a lot of positive overshoot. Not sure if this affects anything.

Attaching the schematic. And no, I don't expect you to fix my issues, but a pointer in the right direction might be nice!

Biggavelli · 2024-02-08 5:49 pm

I had purchased a box of eBay from a fella that actually put it together with the proper internal room I had bought this six inch sub separately as well as the passive speaker it's a car subwoofer that will be working on a home system so it's connected in series it will be coming from a home cinema source, a sub out.
I've seen these amp class D amp boards on eBay and notice that some of you have used them yourselves you can see the ratings of my sub and I currently have a active Cambridge Audio Minx 200 which works great and does have some good lows for the size of it as it sealed but was wanting to get this other box working as I can totally hide it can anybody recommend any class D amps that would be suitable to power the sub I have in picture many things in advance DIY home audio enthusiast for years and look forward to interacting with some of you in the future thanks for any help in advance

martin155 · 2024-01-28 2:15 pm

Hi,
I would like to ask you for advice what tools will be most useful for my needs.
I want to build several speakers cabinets. Side walls will have approx. between 2' to 4' in length (more types of speakers). I would like to cut the walls under 45° angle. Will I be able to make up to 4' length cut with miter table saw or I will have to use circular table saw, do the right angle cut and then 'fix' the edges to desired 45° angle with milling cuter/router (I am not sure how precise that would be)?

What kind of saw and (if needed) router, grinder/sander would you recommend me? I want to build several speakers so I would like the tools to be precise but at the same time some reasonably priced hobby level equipment. Thank you for help.

batteryman · 2024-02-09 2:25 pm

One pair of hardly used Monacor DT105 8ohm 30watt soft dome tweeters.

These are 98mm dia and are a direct fit to RTL2/3/3se speakers. (crossover may need tweaking)

There is a tiny mark on one but it is not a dent or tear.

£35 the pair + shipping.

batteryman · 2024-02-09 2:21 pm

SOLD

One pair of NAIM SBL original tweeters in working order.
Scanspeak D2008-8511

One has a few tiny dimples but I could tell any difference when I replaced it with a new one. Other one is unmarked.

No cracks in the plastics nor loose terminals.

£50 the pair + shipping.

Artie · 2024-02-08 4:50 pm

While I have this amp apart, I wanted to understand a couple things more clearly. One is a possible mod.

1st: What is the purpose of this resistor (R109) and cap (C61) between audio ground and chassis ground? I've seen this before in other audio circuits. Why the components between grounds? I don't plan to alter this. Just curious why. (The input jack is isolated from the chassis.)

2nd: It seems odd that they provided a DC voltage for the filaments of the 1st 12AX7, but AC for other three. Would there be any harm in just running the DC to all four 12AX7 heaters? I'd sub 1N5407's for the 1N4007's to account for the extra current load.

Thanks all.

Artie · 2024-02-09 1:36 pm

(Moved from Tubes section.)

While I have this amp apart, I wanted to understand a couple things more clearly. One is a possible mod.

1st: What is the purpose of this resistor (R109) and cap (C61) between audio ground and chassis ground? I've seen this before in other audio circuits. Why the components between grounds? I don't plan to alter this. Just curious why. (The input jack is isolated from the chassis.)

2nd: It seems odd that they provided a DC voltage for the filaments of the 1st 12AX7, but AC for other three. Would there be any harm in just running the DC to all four 12AX7 heaters? I'd sub 1N5407's for the 1N4007's to account for the extra current load.

Thanks all.

solderbrain · 2024-02-09 1:38 am

Hi I just have some new guy questions as I troubleshoot a solid state amp I have. I have an amp that has a short I believe, it is pulling a high current shown on my Variac as I increase toward 120V. I have it set to where it only pulls about .1 amp and what I am doing from here is just probing around trying to learn and see what some voltages are in various places across capacitors, resistors, diodes and transistors.

My question is, as I probe around, are there any tell tale signs of any issues for example, would 0 voltage drop across a resistor possible mean a shorted resistor? Same for a capacitor? I know this is a vague question but looking for any advice and/or things I can look for in this scenario.

Thank you in advance!

IWC Doppel · 2024-02-04 8:10 am

I am trying to see if I might be able to solve a problem I have with my AV2 Processor which I only use in multichannel (so as an 8 channel pre-amp)

I am finding there is some digital noise (digital buzzing bee sound) that comes in after 3-4 minutes of play or straight away. When I switch between inputs and then back to multichannel it usually goes, but only to re-occur after a few minutes. It's also having problems locking on to selections as well and you can sometimes find a pause as you hear the relays ticking.

I am very happy with the sound of this processor and have upgraded a fair bit on the analogue power supply over the years.

Be amazing if anyone has any suggestions where to look. Interestingly when I choose a digital input (optical) when it locks on this is noisy the same noise as the erratic digital noise on multichannel but louder. Usually when then choosing direct (2 channel) it goes and then back to multichannel gone but then drifts back. The Noise is on all 8 channels

Any ideas ?

Bluewoldemort · 2024-02-09 11:26 am

I have already built a base enclosure in my car that is the main constraint.
It's about a 250l enclosure for a custom sundown NSv3 18 that I measured with DATS:

Currently the enclosure has a 24cm (10") wide 100cm long round port in it with a 90° bend in it that takes up about 50l of the enclosure and tunes it to about 24-25Hz.
I am not currently able to measure the sub, but I have an old impedance measurement from when it was in an IB setup:

I think it looks exactly like the Zv3 18 impedance, just with an Fs of 20Hz instead of 30Hz, so I used the semi-inductance parameters from here:
https://data-bass.com/#/drivers/5bec9a847950b30004de5b9b?_k=goo6c4

Here is a measurement of the current "trunk wall" enclosure that is sealed off from the trunk:
(This is with a DD715, but it gives an approximation of the cabin gain at the listening position, as there is no moving the enclosure.)

Now I realized I have the room to make a 100-120l front enclosure behind the rear seat:
(This is a pic with the NSv3 18")

I can build all the way up to those round braces on the sides and then a little more.
The third of the rear seat in front of the port can be felled down separately and I plan on keeping it that way most of the time.

So I came upon the HROAR design, which I thought would be impossible to fit in this space with this massive 18", but I came up with this design:

'
This is a drawing of the enclosure with approximated sizes. One square is approx. 10/3cm and the whole enclosure is 40cm tall.
The front chamber has an average depth of 30cm.

Now I still haven't found out if I can model this in Hornresp, because it's not a 6th order, nor an 8th order, nor a tapped horn.
Because I modeled it from the beginning as a tapped horn, but realized the simulated output was at the horn end and not at the front chamber port:

But the output was amazing compared to the current design:

So what if I just added the front chamber in front of the existing enclosure:

It's a lot better, but not as good as the tapped horn...

And one problem with this is still, that at 8kW of power, the 10" port is compressing the output severely, at least based on the port velocity:

So I thought, what if I simplify the initial HROAR design and increase the rear chamber volume and shorten the port, somehow, does it just become a series tuned 6th order bandpass?

And now I have close to the same output as with the tapped horn/ HROAR.

But I'd still have to model it more intricately than what Hornresp is able to do.
I should be able to offset the rear chamber and the "port" between rear line and front chamber and I should be able to model it with an expanding line in the rear, because I can't fit the current rear port any nice way with a constant port area without going into the boot of the sub and without wasting space in the rear. And I wouldn't want to make that many 180° bends as in the initial drawing.

It would have to be a double bass reflex with an additional chamber in front, or an 8th order with the driver between the second and third chamber, not first and second.

Is there any way to come closer with Hornresp or do I have to learn Akabak?

Any help with this or some comments on my design would be appreciated.

Circlotron · 2023-11-15 11:16 pm

Thinking about a bass guitar amp, in particular using a bass reflex cabinet. We all know that the driver becomes more and more unloaded the further you go below the box and port tuning frequency. Seeing the lowest intentional frequency of a bass guitar is 41.2Hz, would it make sense to tune the box at or maybe just a little above this frequency and have a fairly sharp filter to cut everything below this? I imagine the guitar strings being randomly struck while playing would produce subsonic signals that would possibly overload the amplifier and in particular push the speaker unnecessarily seeing it would be nearly unloaded at subsonic.

Would the high pass filter affect the sound much seeing it allows the lowest musical pitch through.
Are bass reflex cabinets considered a good idea for bass guitar or not?

mortron · 2024-01-20 10:53 pm

So I have a few rackmount stereo power amps, a tube guitar head, and a bass amp...

Reality is that for guitar, I'm moving more to modelers and the sort, so am thinking about a small stereo power amplifier than can do maybe like 40wpc at 8ohm, which would still be a lot.

Curious tho, I am always into the Class D chip,s, and have a few boards etc... and wondered... Is that gonna be my best bang for the buck in regards to getting clean watts cheap? I know there are more elaborate ways to go about it, and read that MOSFETs sound better than OpAmps when they overdrive, but believe any FET based amp will be much more expensive and complex, yes?

Any help is appreciated, as I've never given much thought to this before and searches aren't turning up a ton I can go off. Thanks in advance.

RaivisM · 2024-02-09 9:59 am

Dear diyAudio readers,

I am selling a pair of Scan-speak Revelator 22W/8851T00 bass drivers. They have been used once and only for testing. Overall they are like brand new, minor scratches inside mounting holes because of the screws.

Price is 500eur/pair (retail is around 750eur/pair)

I can ship worldwide, however would prefer Europe.

stuartiannaylor · 2024-02-08 6:44 am

Being the heathen I am, I will just twist the L/R wires together and feed the input of a mono amp.
That should be ok? Or are there simpler ways without mixer circuits?

RaivisM · 2024-02-09 9:52 am

Dear diyAudio readers,

I am selling a pair of Scan-speak Revelator D2908/714000 beryllium dome tweeters. They have been used once and only for testing. Overall they are like brand new, minor scratches inside mounting holes because of the screws.

Price is 800eur/pair (retail is around 1200eur/pair)

I can ship worldwide, however would prefer Europe.

GaloDourado · 2024-02-06 12:12 am

Hi all,
I'm thinking of making a 2-way OB using parts from a very old buy order that never were used:

2x Eminence Deltalite II 2515
4x BG Neo10

The initial plan on the day was to make a 3-way using Raal as tweeter (maybe for sale soon), but my hearing today is almost non existent on >9khz, and that's why I'm thinking of using only the Neo's from around 200/500hz and up.

I would be going active with a MiniDSP, so maybe EQ the rising response is not a problem, but I've read about Neo10 beaming on 5-6Khz and up.

Not pretending the ultimate system, but yes something with very good bass and mids (I'm not a bass head and my music preference is mostly vocal).

Open to read opinions. Thanks!

DanielMichael · 2023-06-04 11:40 pm

Hello. Long time reader first time asking for help on a thread.. I have some experience. My father was a master electrician and had me practice soldering In my early teens.. I'm 46. I have previously modified a Xone 23C to rotary years ago but it was a kit so I am not sure which alps Potentiometer to choose for both main channels. I have spare PC boards to replace broken faders that just lock in to the main board so that I don't **** the mixer up. I will drill holes in the faceplate where the faders used to be until I can source a new one minus the fader slots.

Dr. Pepper & Mr. Hyde · 2024-02-09 5:14 am

I'm looking to start on the Sangaku DIY project but as soon as I go to order all the parts I found the potentiometer was out of stock and not expected to be in stock for a while. I am inpatient and would like to see if there is an alternative that could be used. Does anyone here know of a suitable alternative?

maxpalat · 2024-02-09 6:07 am

I have operation problems with PSU battery of my PinkTriangle Anniversary.
In concrete terms, the turntable works regularly when powered by the mains, if the power supply is connected to the batteries the turntable does not work. The good condition of the batteries is obviously beyond question. Probably some passive control component on the battery circuit is malfunctioning, but which does not have the original circuit drawing. The English manufacturer does not have these drawings, and the designer (John Westlake) cannot be reached. I wonder if anyone can give me some useful suggestions.

Thanks
Massimo

lene · 2024-02-09 4:48 am

Hello there!

Say I need to connect 2 drivers.

If I use the dual bridge mode and aim to get 5W for a driver, do I get less distortion than if I use the quadraphonic to draw the same 5W for the same driver?

That's what I understood.

Thanks!

jackinnj · 2024-02-08 12:20 am

I had a message on the screen this evening that Sony will no longer support casting youtube to their screens starting April 2024. Other functions will also be curtailed.

There is probably some revenue stream which Sony is trying to capture.

Disappointed.

deafbykhorns · 2024-02-09 2:38 am

I repeat, do not update the Qobuz application for Iphone or Ipad, update has bricked the application.
Qobuz is impossible to contact

PC997 · 2024-02-09 1:54 am

Hello,
I have an old ROTEL RMB-1076, it is not working (nothing after power on). It is made from 6 ICEPower components (4 power amp units and 2 power amp + power supply). Does anyone know where I can find the internal connection Schematics or the Technical Manual for this amp?

Thanks for any help.

iano · 2024-02-05 8:46 pm

SOLD TransportDigi, MonitorPi, PurePi, Spike set, makeshift top cover from alternative RPi case set. The wooden box is not included (!)

The RPi is an 8GB model.

Works well, and sounds great (as expected). I have been using Moode and Volumio, and then basic LinuxMPD (DietPi) on USB drive - but will the buyer to choose their own platform (I was not planning to include the USB drive)

Asking $200 including shipping in CONUS only and PayPal charges (so buyer is protected)

I have extensive selling history on ebay (iano3), and headfi (iano) - so the buyer can be confident of a good experience. Happy to answer any questions. Pics attached, but can provide others if needed.

I will be shortly selling some more iancanada items shortly (isolatorpi, shieldpi, and another complete setup with the TransportAES instead of TransportDigi, and with an RPi with less memory (2GB)

I really admire the iancanada items, and have greatly enjoyed reading about them, putting them together and listening to them, but have decided to go 100% into an Apple MacMini setup using Audirvana and JRiver.

benb · 2024-02-09 2:08 am

Not surprisingly, they all sound pretty much the same using diode clipping - there's a bigger difference in noise:
Login to view embedded media

smoking-amp · 2024-02-01 5:43 am

I found some "tube rails" for an electronic organ on Ebay. 12 positions with 9 pin sockets (9/10 pin sockets on one) and 3 more empty positions for extra sockets.
12 musical note stickers attached near the sockets. I don't know what brand name organ these were from or what kind of tubes they had in them.

It occurred to me that these could be used for paralleling 9 pin tubes to make a big power tube equivalent, often with unique features. Using plenty of Ferrite beads and grid stoppers of course to prevent parasitic oscillations. Curve tracer matching obviously needed. Probably need to mount them horizontal for cooling. I've got bins of 29GK6, 6HB6, 12HL7, 6197, 6HZ8, 6JH8, maybe some others.

6197 has remarkable curves (pics 3 and 4),
12HL7 has 20,000 gm per tube, 10 Watt and remarkable triode curves too (pics 5 and 6) 12 x 20,000 = 240,000 gm, 12 x 10 = 120 Watts,
29GK6 ( = EL84) at 12 Watts each 12 x 12 = 144 Watts (pic 7),
6HZ8 has a triode driver and 8 Watt pentode,
6HB6 has 20,000 gm per tube, 10 Watt,
6JH8 beam deflection is like an LTP with a CCS tail, all in one tube.

Now, if I could just find another 50 to 100 rails, I could start on the VT-9 AI computer project, that's been on the back burner for decades.

nautibuoy · 2021-10-31 6:49 pm

Today I finished off my 300B Headphone amplifier, a scratch build of the Transcendent Masterpiece preamp.

No output transformers involved of course. B+ uses a Maida regulator and I have DHT specific filament supplies and it is absolutely quiet. I have two outputs, one for my 600ohm BeyerDynamic headphones with a plastic film output cap and the other with a Nichicon FG electrolytic for 32ohm headphones.

I'm Listening to it at the moment with input from one of my DSD decoders - native DSD256 recording of guitar and violin pieces - and it sounds superb.

ungie · 2017-03-12 7:32 pm

I have four unused R-Theta heatsinks from Peter Daniel's Aleph-X group buy. These are 11"x11" and I have attached an image of the extrusion profile. They are anodized black and have a few small electrode marks on the ends of each which is how they came from R-Theta. They are still in the original packaging and were only ever opened for inspection. I'm asking $250 USD for the four pieces, plus shipping within Canada or the US only. For Ontario buyers that are interested, I am occasionally in the Ottawa, Toronto, and K-W areas, so I might be able to arrange to meet for pickup. These are heavy, so they won't be cheap to ship.

pinholer · 2023-11-03 2:09 am

It's been a little while since I finished my last amplifier, so I feel the need to build a new one. My last amp, the choke loaded LU1014D cascode follower was inspired by Nelson Pass's Zen Variations #9 article, and since I still have a bunch of LU1014Ds laying around, I figured, why not do another variation. I have only one common source amplifier, the BAF 2015 THF-51S, and it's feeling lonely among all my source follower amps, so I decided to do a choke loaded variation of the Zen Variations #9. I've got to admit, I was also influenced by the Zenductor.

I did some simulations on LTspice and then put together a prototype using parts that I had in-house. I wanted to test the design before committing to building a finished product. I used a lab power supply and recycled my previous LU1014D follower prototype. For the choke, I happened to have an unused Hammond 193U.

I adjusted the cascode to produce a dominant second order harmonic with decreasing higher order harmonics. With a power supply of 22V, the choke drops 3.4V, MOSFET Vds of 11.1V, JFET Vds of 6.0V, and 1.44V at the 0.7 ohm source resistor, which results in a current of around 2 amps. The amplifier gain is about 9 times.

The THD at 1 watt into 8 ohms is about 0.22% and at about 1.1%, the output is 9.2 watts.

I haven't played any music through it yet, but I will use it to drive one Quad ESL and use my source follower L1014D amp to drive the other ESL. It will be interesting to see how the two topologies compare.

I just received a bunch of aluminum PCBs for my unmounted SMD LD1014Ds and my next task is to get them soldered up and matched with my super-duper FrankenTracer. Then I can test the prototype amp with a variety of JFETs and operating points.

.

dubadub · 2024-01-30 4:02 pm

Greetings Friends. I've been playing around with the EL84 amp I posted about the other day and got to wondering about the total load seen by the power transformer. Obviously the tubes consume power, each power tube dissipates ~11.5w (as per RobRob calculator, 275 plate, 8.5v cathode, 200R cathode resistor, 43mA x 267v = 11.5w) and the preamp tubes eat a couple of mA. But the resistors and choke in the power supply also consume power, as do the cathode resistors. How do we reckon those loses? Is it as simple as applying Ohms law to each component and then adding up all those watts, or...?

Thanks for taking a look.

w

tiefbassuebertr · 2024-01-09 11:15 pm

For realizing various projects like line stage, RIAA stage, active crossover networks etc.) so as evaluation I am looking for PCB's like those under
https://www.ebay.com/itm/255197072218
https://www.ebay.de/itm/202604951103
https://www.ebay.de/itm/255197072218
and
https://www.diyaudio.com/community/threads/vacuum-tube-prototyping-pcbs-of-my-own-design.387959/
but with a single large hole appropriate for tube sockets usual used for chassis mounting (for lower thermal stress on PCB).
The image of PCB from post #2 show this - unfortunately only realized for the power tube and not for the tube for small signal application

Thanks for any advice to suppliers for such prototyping evaluation boards.

P.S.: I will use this as an alternative to the no longer available PCB from the last image in the attachment - go to
https://glass-ware.stores.turbify.net/nostmfbcr.html

ChuckORWC · 2024-02-08 11:47 pm

Hi All,
Planning my next preamp build, for my daughter who just moved into a new (larger) place. It's going to be an H2 V2 board from the diyaudio store. I'm going to include an Arylic Upstream Pro wifi receiver board. Power supply (internal) will be a dual supply using a toroidal transformer with 18V and 8V secondaries, CRC filtered and regulated down to 12VDC and 5VDC for the H2 V2 and Arylic respectively. Chassis will be made out of wood, possibly with a stainless or aluminum back plate, but frankly I'd rather it be all wood.
Everything thus far described is well within my capabilities, but I'm seeking more expert advice on preventing potential EMI noise from the Arylic. The H2 V2 preamp I recently finished is in a wood enclosure (except the bottom and rear which are comprised of a single piece of stainless steel), and has the same power supply as my proposed preamp, but with the 8V secondary left unused. It's dead silent without any additional shielding.
I'm thinking just compartmentalizing the enclosure, with the compartment housing the H2 board lined with copper foil... or would 1/16" aluminum plates between the H2 and the Arylic be sufficient? Thoughts/ideas?

Booger weldz · 2024-02-03 2:24 am

What potentially happens (spitball/theorize/etc) if you offset the driver entry to a Vmax (green arrow) for an even numbered resonance in an open ended pipe?

jwags81818 · 2022-03-30 3:50 pm

A few years ago I built this amp based solely on Andrea Ciuffoli's design (audiodesignguide.com). Over the years I have been swapping parts in and out trying to improve it. I have now finally settled on what I believe is the finest 300B amp I have ever listened to. It is certainly the quietest. I have Klipsch La Scalas at a rated 105db spl and you can not even tell the amp is turned on at 3/4 volume. I am publishing here the schematic and the parts I used in case anyone wants to build a sure thing as far as performance goes. If anyone lives in Oregon Near Corvallis you are welcome to come listen to it. This is not my design. I only made some component choices.

Jeff

jkojic · 2024-02-08 10:45 pm

hi all the cue goes up and down but in real time - i had a look in the post - theres a piston shaped thing but know seals of any kind - any help please

Sergio123 · 2024-02-08 9:41 pm

Hi all!
This is my first post here so please be gentle...
I do not understand what happens to the port of your speaker if you add a (sealed) subwoofer to a ported speaker.
As I understand, port gives you the lowest frequencies that the driver in the sealed box could not produce.
Now of you cut off the frequencies under say 80 Hz because your sub now plays them, does it mean that your port in ported speakers does not have any function any more?
I hope I could explain my question...
Thanks!

sixtyfive · 2023-12-12 3:53 pm

Hi all,

back in 2022 I found out about the Wondom JAB5 and then the freeDSP project and had a with CyberPit-san over in this forum's freeDSP thread. Ultimately I lost interest after finding out that the JAB5 isn't actually fully digital (the ADAU1701 takes analog in and produces analog out) and that any ADAU1452/1462/1466-based boards in the freeDSP board list are basically unobtainium.

Now my interest got rekindled when I found out about the ZOUDIO AIO4CH (not sold anymore) using the TAS5825M. Unfortunately I need around 2x80W + 2x30W. 4x60+ would be fine, but whatever. There's also the TAS5760M, but that has even less output power and no boards with it seem to exist at all.

Now, after an afternoon of wondering more about the ADAU1452 which CyberPit had mentioned and some googling around I'm left wondering about the following:

Have people in the past built a pipeline like what I'm imagining? (HDMI > I²S extractor > ADAU1452 > DAC [which one? Or perhaps a DAC-integrated amplifier chip?] > amp [which one, TDA3116 comes in mind for a first test setup.) And if so, what have your experiences been? Where are the pitfalls? What's difficult about this? Why are not more people doing it? By the way, I'm specifically looking to build an all-the-way-I²S DIY thing, not to buy a 500€-ready-made device.

Looking forward to any responses - and please, if this is the wrong forum, I'd be thankful for a mod moving this thread to somewhere more appropriate 🙂

Cheers,

Jonathan

chienmort · 2023-07-14 11:09 pm

I have a DigiMod 1000 and a Digimod 500. iIs there a design manual? I am wondering how to easily fit a volume control but Powersoft do not reply to my emails.

YundiLi · 2023-03-29 3:14 pm

Post content of sockpuppet removed.

jhb · 2024-02-08 8:56 pm

I looking for the driver, New, used, even if needing repair.

Thanks

roaddogma · 2024-02-08 8:44 pm

CSS LDW7 MidWoofers- 2-Pairs Available
https://www.css-audio.com/online-store/CSS-LDW7-7-Midwoofer-p110079914

These were gently used in an MTM project that saw some casual listening for about 6 months. They were never pushed and performed fine. My father has since become a full-range enthusiast, and is moving on in that direction. Asking $200/pair, or $375for all four, plus shipping

jan.didden · 2024-02-08 11:27 am

As the title says: https://audioxpress.com/news/monolithic-power-systems-acquires-axign

Jan

edmurphy · 2024-02-03 8:21 pm

It seems HFE no longer supports registration for new members, and there's no means of contacting administrators. I'm an apprentice technician for a vintage shop, and a bulk of what people bring in requires a service manual or schematics to get fixed, many of which seem to be available on there.

Does anyone have access, contact, or a throwaway account they'd sell off? Thanks.

profiguy · 2024-02-07 12:30 am

Working on my son's PA cabs. The design is a 15" Eminence KL3015HO, 2× 6" Celestion NTR06-1705B and CDX1-1430 CD on Faital STH100 WG. Mids and HF will be arranged in MTM. Xover is passive at 350 / 2.5 - 3k 2nd / 3rd order. Cab is vented, Fb tuned to 45 hz. I'm using a pair of the Parts Express 15" trap cab flat packs I had left over. They have a good size baffle and decent volume for good low end extension.

My issue here is insufficient baffle height to place the WG between both mids, so I have to compromise by offsetting the WG to the side and place mids right underneath each other. In the past, that's what yielded the best off axis response and performance but I'm wondering if there's a better way to improve off axis behavior.

I know the mid LP is a little high for optimal vertical axis MTM behavior, but I'd rather keep the xover little higher for cleaner CD performance and better HF headroom. The CD/WG combo sounds very good above 2.5k and lowering it ruins the HF clarity. The concern however is creating a problem horizontally off axis by placing the WG to the side of the mids.

Only running one of the mids up to the HF isn't an option due to insufficient upper mid sensitivity. After xover losses and BSC there should be about 97dB sensitivity. I allowed some extra loss for the mid LP inductor series resistance, so running both mids parallel at 4 ohms will end up about 6 ohm in the mids and net a little lower mid acoustic gain.

Any suggestions would be great.

bhjazz · 2024-02-07 1:17 am

Considering taking on the job of coordinating a group buy? Excellent! Not only are you helping our DIYAudio community by making it easier for others, you can help individuals save their dollars by compounding multiple orders into one. You will also meet and work with various personalities within the community and likely even make some friends.

If you are in the US, here are some details you should be familiar with. Thanks to @Chris Jones KS for creating this information:

Our US-based group buy coordinators need to be aware of evolving tax reporting requirements when you receive payments through a payment service such as PayPal. It’s crucial to understand how to report the payments you receive, especially if you're based in the United States. Let’s break down the essentials regarding the 1099-K tax form and what you need to know for smooth sailing through tax season.

Understanding the 1099-K Form

What it is: The 1099-K form is issued by payment processors (like PayPal) to report the total amount of transactions you've received over the year. It’s important to note that this form doesn’t reflect your profit; it simply shows the total payments received.

Key Points for Group Buy Coordinators

Keep Your Receipts: Since the 1099-K form shows total sales or payments without considering your expenses, save all receipts related to your purchases and shipping costs (Cost of Goods Sold - COGS). This allows you to subtract these costs from the total payments when you report your taxes, showing a more accurate picture of any income.
Reporting Income from a Hobby:If you're coordinating group buys as a hobby (not as a business aiming for profit), any extra income should be reported as "Other Income" on Schedule 1 of your Form 1040. This approach helps you avoid the 15.3% self-employment tax for business income that is added if you accidentally report this on Schedule C.
- Hobby income cannot be less than $0.
- If your tax software allows you to add a statement, briefly explain how you arrived at your net income after subtracting COGS from the payments received.

Important Notes on Reporting

2023 Transition Period: For the 2023 tax year, there's a specific threshold for issuing a 1099-K: over $20,000 in payments and more than 200 transactions. This is part of the IRS’s effort to ease into new reporting requirements. The change came late in the year, so some payment processors may issue a 1099-K for a lower amount.
For the 2024 Tax Year:The threshold for issuing a 1099-K will be $5,000. This is an intermediate step before implementing the $600 threshold.
- IRS Form Updates: The IRS is also working on updates to the Form 1040 and related schedules to simplify the reporting process for taxpayers for the 2024 tax year.

Reporting "Friends and Family" Payments

Non-Reportable Transactions: Money received as gifts or for personal expense repayments from "friends and family" through payment processors is not reported on a 1099-K, regardless of the amount. This distinction is crucial for group buy coordinators who might receive payments in this manner.

Summary for U.S.-Based Coordinators

For those in the United States coordinating group buys, understanding the nuances of tax reporting, especially in relation to the 1099-K, is vital. Keep meticulous records of your expenses to accurately report any net income. Remember, hobby income goes on Schedule 1 of Form 1040, helping you avoid unnecessary self-employment taxes. Lastly, stay informed about the evolving IRS thresholds and reporting requirements, particularly the $5,000 threshold for 2024 as a step toward the eventual $600 threshold, ensuring you’re prepared for these changes.

Here is the same information from another viewpoint:

If you are the coordinator for a group buy, you will likely collect the funds from others to make purchases, be it for boards, parts, etc. For example: my VRDN group buy had 30 to 40 people with over 125 boards made. Add in shipping, packaging and a dollar or so for my time and the total ended up well over $800 that was collected through Paypal. I'm obviously not keeping that value as business profit, I'm just getting funds together to make a purchase on behalf of the group. Unfortunately, the IRS doesn't ask whether I was buying something for the group or buying myself a new pair of shoes, so those funds were considered income. (Frustrating.)

If you are taking on group buy coordination: cool! I had a great time doing one myself and I absolutely don't want to discourage anyone from performing this vital function. But since this threshold changes from year to year there is a possibility that at some point someone might unknowingly get burned by just trying to help. A quick estimate on the dollar value of the "income" (even if you keep none of it) may be wise. The easiest way to navigate this, it seems, is to be transparent: if it appears that you are nearing the threshold, then add the tax cost to your per-board or per-order pricing, and inform your group of such. I believe most people here would be okay with it if it were necessary.

Moondog55 · 2024-01-18 1:06 am

Setting up my party system finally.
Robust discussions with my significant other have meant a long delay and the house came first.
Since my first ask a few years ago I've been gifted a few extra bits and pieces and I'm wondering what combination to use.
Inputs are standard home Hi-Fi turntables and CD players.
I've got a couple of used Pro amps now, a Behringer CX 2-channel crossover and a couple of signal processors.
One is an Ultracurve Pro [ The older model DSP 8024] and the other is an UltraGraph Pro which I paid $20- for.
Am I right in thinking that the Ultracurve is a better unit but has a steep learning curve?
And I'm also assuming I use one or the other and not both daisychained. I have a couple of weeks until my birthday party and I'd like to have it set up ASAP

Mark Tillotson · 2024-02-05 6:16 pm

Just a thought I had. Could rail sag be reduced in a stereo amp by inverting one channel? You'd keep correct phasing by swapping +/- output labels on that output, but then the large bass signals common to both channels pull current from different filter caps, rather than the same one. You could also use this to drive a mono speaker in bridge mode.

decommo · 2024-02-08 2:02 am

Hello,

Just asking advice on speaker cabinet for Mark Audio Alpair 12 drivers.

My idea is to build simple vented large standmount speakers. I am thinking 38cm (15") D x 42cm (16.5") W x 75cm (29.5") H in dimension.
I guess that it is not the right way to build cabinet by determining size first then find a matching drivers and wondering how the sound would be like if those drivers onto this sized speaker cabinet.

I checked recommended cabinet design from MarkAudio Website and they are either tall narrow (pencil design) or compact bookshelf type of speaker cabinets.

I believe that there are speaker cabinet design software to simulate based on the cabinet volume and anyone can enlighten me what would sound like if those drivers are in the specific cabinet size?

Thank you very much in advance.

Syd Allen · 2024-01-24 3:40 am

I have just moved house and am having problems with my RIAA phono tube preamp. It is making popping and crackling noises with the old tubes and a new set of tubes installed after my move, this did not happen at my old home with the old tubes.
Plugging the phono amp into a different wall outlet some metres away from the power amp significantly reduces these noises but does not eliminate them. So I guess that I am having electrical interference and should not be using the same power socket for the phono preamp and the power amp.
What is the best solution? Thanks.

d00dz1 · 2024-01-09 11:05 am

Hi all,

i published a C-library to generate commands to control a MUSES72323.

Link to sources

It has no dependencies besides C compiler and library. I'm using it in a project utilizing a PIC18, programmed via MPLABX IDE and compiled by XC8.It should be fairly easy to integrate different Microcontrollers (Arduino, RP2040 etc). To do so you just have to provide a platform-specific send(muses_command) function

I hope it helps to realize some of your projects.

If you have any questions please feel free to ask.

Edit: removed reference to SPI as library does not implement actual GPIO-pin-logic for transmission, but only bit-pattern generation.

Chrisr3521 · 2024-02-08 5:37 pm

I've got a Cyrus Two and PSX, the amp has been recapped except for the large psu caps ( was working before and is working after the recap) bias set as per Cyrus One manual as its an issue 5 board with trimmers for this, its set for 9mv ish both channels. Problem is when testing on 8ohm load with 1k signal after ~14v AC the distortion goes from around 0.003 THD to around 0.05 THD which is out of spec (should be 0.003 to full power) this happens for both channels no matter if powered from the amp itself or via the PSX, I have also noticed that transistor Q46 (shown on attached schematic) does not heat up half as much as the rest when driving a load. Where to look first?

Screenshot_20240208_173714_Adobe Acrobat.jpg

Joachim Gerhard · 2012-09-25 2:15 am

I am designing a two way monitor for SB Acoustics that will eventually lead to a full documented Kit. This thread will show how i work from unpacking the drivers to measuring them, constructing the crossover and the cabinet.
When the speaker is ready it would also like to discuss the subjective impressions how they sound.

east electronics · 2024-02-07 3:25 pm

Been working with a 1090 all caboom due to electric failure in the client's home
Noticed the Vbe multiplier transistor is a darligton (https://pdf1.alldatasheet.com/datasheet-pdf/view/39180/SANYO/2SD1953.html)
recall that i ve seen once more i think in a Marantz amplifier ....

So i wonder why
a BC547 could do the same job a Bd 139 also 2sd600 that was available in stock

Am i missing something here ?

Monrin · 2024-02-04 6:40 pm

Hello everyone,

I would like to turn the enclosure of a vintage radio into a bluetooth speaker. I have a volume of 2.81 liter/0.10 feet3 to play with. Now I wonder, what drivers work best in this situation? Given the dimensions of the radio the driver diameter can't be greater than 65mm/2.5 inch.

Would it make sense to go for a closed setup and use two Dayton Audio ND65-8 2-1/2" full range drivers together with two Dayton Audio ND65-PR 2-1/2" passive radiators for some additional bass? This would also fit my budget.

What do you all think? What would you suggest me?

Best,
Simon

Raimonds · 2024-01-28 5:23 am

Taking into account last developments in loudspeaker`s controlling DSP, the idea to build a loudspeaker with next quality level was borne. It is well known idea to use multi way concept to meet requirements for sound reproduction/radiation of particular frequency band with physical properties of particular driver/loudspeaker unit and to eliminate cross impact of different frequencies , known as the intermodulation.

But what about extreme multi way with so narrow bandwidth of ways that we can use bandpass enclosure almost for all ways. Which increases sensitivity/gain of particular driver and is doing a filtering of out of band components, nonlinear distortion harmonics, as well. Exactly same way as singers are using natural resonators to excite as with a pleasant musical performance.
Here it is. Please meat a 5 way loudspeaker with first 3 ways in bandpasses

schultzsch · 2023-06-01 9:02 am

For sale or trade

Hello,

I have for sale a few 4 layer mirrored(left/right) pcbs that I designed for my UGS Muses preamp.
The schematic is as the one ZM uses except I added some output buffers.

Can offer also the matched 2sk2145 for these

The pcbs are now sold

I can trade the finished modules for 1 pair of matched SJEP120R100 or 1 pair of matched 2sk182es or thf51s

schultzsch · 2023-06-01 8:57 am

For sale or trade

Hello,

I have for sale my blowtorch assembled clone.
It uses matched toshiba vgrade jfets, matched hitachi mosfets and matched toshiba mosfets.
The toshiba mosfets are used as output buffers.
The gain stage pcbs are 4 layers with the left and right channels mirrored.
I have some additional pcbs that can be used to buffer also the input.
The pcbs were designed to be used in the UGS Muses preamp.

The price for the finished pcbs sold
The price for a set of 4pcbs(2 gain stages, 2 dc servos) is 40€

I can trade the finished modules for 2 pairs of matched SJEP120R100 or 2 pairs of matched 2sk182es or thf51s

Moondog55 · 2022-09-29 4:29 am

I just picked up a cheap driver to use for another party box. My computer is still giving trouble with Excel so I'm asking for a little help in the best use of this generic 18"
Re 5.9
Fs 33Hz
Qes 0.522
Qms 5.437
Qts .476
Le 0.7
Vas 250 litres
Looks like 4" voice coil and about 6mm X-Max and I'd guess 10mm X-damage
Driver needs a vacuum and wipe off but it was only $100-
My first thoughts were to mass load it a bit and just shove it in a smallish sealed box and I'll probably need a bigger amp to drive it and near enough is good enough, and I may have to get another Behringer CX unit for it, unless I can find a S/H Hypex amp of course

MysterHawk · 2024-01-28 4:38 am

Good evening,
Recently, I've picked up an electric guitar and I wanted to build a speaker cabinet for it:
Unfortunately, I have neither the budget to buy a prebuilt one nor the tools to build it myself where I live currently, so:

I had an idea in previous days to use the pre-built IKEA Eket cabinet because they were quite accessible for the price (25 EUR or 20 EUR) and easy to build:
https://www.ikea.com/be/en/p/eket-cabinet-brown-walnut-effect-60530577/
or the smaller version:
https://www.ikea.com/be/en/p/eket-cabinet-brown-walnut-effect-30530574/

As frontal panel, I'll use an MDF panel attached to the cabinet with some glue and screws.
I'll probably need to reinforce it internally with some piece of wood and a bit of glue (on the 4 sides).

I planned to have a 2-way design because the woofer is not reaching completely the higher frequencies for the electric guitar, so I thought to add a tweeter.
I think that in the end this speaker will be an open back, but I'll have to see when I build this, actually.

For the drivers I plan to use:
— Woofer: GRS 12PF-8 (12' inch, 120W RMS) [86dB per W] or a GRS 10PR-8 (10'inch, 80W RMS) [87 dB per W]
— Tweeter: Dayton Audio AMT2-4 AMT (15W RMS) [92.5dB per W]
(this is a little expensive, but I have something similar on my near fields monitors [Adam T5V] and they sound quite nice)
You can find their spec sheets here:
https://www.parts-express.com/pedocs/specs/GRS Spec Sheets/292-412--grs-12pf-8-spec-sheet.pdf
https://www.parts-express.com/pedocs/specs/GRS Spec Sheets/292-421--grs-10pr-8-spec-sheet.pdf
https://doc.soundimports.nl/pdf/brands/Dayton Audio/AMT2-4/pdf_Dayton Audio_AMT2-4_1.pdf

For the tweeter, I choose this one presently, but if you know a better choice, please tell me an alternative.
I'm not sure if the tweeter-subwoofer is a good match, for the SPL I've read that it needs to be equal or greater compared to the subwoofer, but what about the Power RMS? Do they need to be equal? I read in some discussion that the tweeter doesn't get that much power at high volume with a crossover, but I could be wrong >.>

What do you think of the frequency diagrams of the woofer-tweeter? They seem good enough for me, flat-ish enough? 🤔

I'll also need to make/buy a crossover, probably the cut-off frequency between the two drivers would be around 2-3Khz for what I can see from the graph (is this okay?)
(I've tried to follow the lines on the frequency response diagram and get a point where the two drivers would converge without changing much in level of loudness for frequency),

Something like this? https://www.soundimports.eu/en/dayton-audio-xo2w-25k.html
If it is not right, I could also make a circuit myself, do you know any calculator to make a simple crossover circuit?

What do you think? Is my plan viable? 🙂

-----

(for future use, at first, I also considered these cabinets, but they were a bit too big, still they could be useful on some occasions)
Theoretically, I could also use these three cabinets also (I'll put it there for future uses):
https://www.ikea.com/be/en/p/kallax-shelving-unit-black-brown-40311873/ (2x 12' woofers)
https://www.ikea.com/be/en/p/kallax-shelving-unit-white-20301554/ (1x 12' woofer)
https://www.ikea.com/be/nl/p/besta-basiselement-wit-gelazuurd-eikeneffect-10247379/ (1x 18' woofer or even 1x 21')

oltos · 2024-02-04 9:12 pm

I count myself very lucky to have this amp. But AFAIK, the stock First Watt F4 never got put through the wringer the way the J2 did.
https://www.stereophile.com/content/first-watt-j2-power-amplifier-measurements

And unlike the J2, no distortion measurements were included in the F4’s manual.

Here's some ("quick and dirty?") distortion measurements from 6L6's first build of the F4 build, post #2.
https://www.diyaudio.com/community/threads/a-guide-to-building-the-pass-f4-amplifier.234355/

Okay, so even a stock F4 is not a low distortion amp. But my speakers are ~ 94db/w, they don't fall much if at all below 7 ohms and only play down to 70Hz, below which my Rythmik F12 subs takeover.

So, with a line stage like the Aikido Rev. F providing plenty of gain https://glass-ware.stores.turbify.net/ainost.html
https://tubecad.com/2018/03/blog0415.htm, how much 3rd or 2nd harmonic distortion would the F4 produce which would likely be audibly offensive?

Biffm17 · 2024-02-08 2:53 am

Hey all new to the group, ive got an pmp1280s that has no signs of life when plugged in it acts completely dead, i need a skematic diagram please i used to repair appliances so i feel comfortable repairing the mixer any help or advice is welcomed

swingarm63 · 2023-03-18 6:08 pm

Greetings all!

I'm in the process of building a pair of these amps. I have several 6c4c=6B4G and several 6a5g tubes. I'd like to be able to use both. The 6c4c are directly heated cathodes and the 6a5g are indirectly heated.Thought maybe i could make it switchable.

I have seen two different schematics of this amp. I'm a little confused by this circuit. Seems the full rectified voltage appears across C1 with less appearing across C2 and the difference being across R17?

If there is a simple way to set this amp up to use both those tubes? I also read r20 r21 and c6 was mentioned somewhere in the past as significant part of the circuit, yet in the circuit redraw it is omitted. I'm not clear on this.

I have done the metal work and installed tube sockets and transformer layout. I am getting ready to do circuit layout and was looking for some help. hopefully some can shed some light on this.

Edit: not both tube varieties at once,

capslock · 2024-02-07 11:24 am

I purchased this on ebay on a whim. It was sold as B&K but it was clear immediately that it is not. There is a Logo on the side that looks like a W and M woven into one. And a number "1220" on the opposite side. On the back side, there is a CE sign and what is probably a serial number, five digit unlike B&K.

Thanks

gab far · 2024-02-08 1:57 am

I'm looking for a design for a 20 Watt RMS into 8 Ohms audio power amp for guitar use. I want solid state -- MOSFET or Bipolar. I'll be using a waveform shaper/ limiter to simulate some of the features of a vacum tube amp, such as soft clipping; consequently, the power amp itself does not need to have nice distortion characteristics, compression, etc. as are sometimes wanted in a guitar power amp. All I want is 20 Watts clean. Other desired features are a reasonably simple design, and ruggedness. No class A please. Remember, guitar speakers only go up to about 10kHz so extremely high speed is not necessary for the amp. Distortion should be low but need not be ultra low.

Anybody know of a circuit that fits that general description?

Oh, and no exotic parts, please: I'd like to be able to get everyhing from Mouser.

oic0 · 2024-02-07 8:32 pm

Building a sealed box for a shallow mount 12 inch sub.

Aside from positioning the bracing for optimal strength and reduction of flex, does it matter where I place them? I wanted them close to the sub on the front side since I don't have enough space to double the thickness of the front plate while still getting the proper internal volume. Do they need to be further from the sub?

Also, does it matter how much they restrict airflow? In the diagram below the red lines represent my hypothetical braces, which would just be sections of the same material as the side pieces. Do I need to keep them small or can I basically section my box into quarters and rely on the open space behind the woofer where the quarters meet to reliably equalize the pressure?

Lastly, do the enclosure space requirements given in speaker specifications account for woofer volume? The specs for this one ask for 0.75.

Backstory:
I ordered all the pieces to do a stealthy sub install in my daily driver, all of it came in except the box, which the order for got canceled. I suspect they may have gone out of business since they don't answer the phone either. Luckily its a really simple rectangle box and the exterior dimensions were listed in the product page. I have access to lots of wood working tools... so... here we go. Plugged the specs into a building calculator and started reading on here to learn about stuff like MDF safety, what kind of caulk to use, etc...

kb2wyl · 2024-02-04 5:09 pm

Hi all. I picked up some Hammond 1650r outputs, because I'm getting back into the hobby and wanted something cheaper to experiment with. 5k P-P, 318ma, 100w, dual secondaries. After I ordered I noticed the part number was "1650Ra". Basic specs were the same, size/weight/imoedance, so I figured it was just a part number change. According to Hammond, the only change was from dual secondaries (R), to a single (Ra) 0-4-8-16.

My question is, no matter how they're measuring, how is the stated primary inductance SO different? I've attached pics. Stated is that the entire primary of the Ra is only 14 Henries, but just one half of the R is 320 Henries? Are they measuring one at voltage and the other not, maybe? Measuring the Ra, P-P, I get the stated 14h.

Thanks so much for any info. Soon I'll start a thread for the build.

electrafixion71 · 2024-02-06 11:36 pm

Hi Everyone,

I just acquired an all original vintage Accuphase C-200 preamp. There are a number of film capacitors (1uf or 2.2uf) on the various audio boards, and I was hoping someone could advise on what type of materia these caps would be made from. The brand appears to be "NTK" but I didn't find anything online from that name. I've seen a couple examples of restorations where some of these caps were changed out for modern poly caps, but I thought I should learn more before replacing the originals as I'm sure they were premium parts back in the day.

Thanks in advance

duvixan · 2023-05-12 9:47 pm

Shouldn't it be an obvious choice?

JR10 · 2024-02-08 1:21 am

Anyone here know if there's a setting for this? I poked around some but couldn't find any internal audio settings to even look at.

This is a simple setup just coming off of an LG widescreen, everything worked out of the box except for the audio.
Owners manual clearly states that the volume control is supposed to work.

brianco · 2024-02-05 11:35 pm

I am very frustrated by the fact that so many post attachments are in .ASC files....these are unreadable on a Mac without installing
3rd party software. Surely .pdf format is preferable to what is a very old security orientated format?

Attachments

WTB Lundahl 1692A Amorphous P-P pair

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For Sale Memory cards

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For Sale MONACOR DT105 TWEETERS

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For Sale NAIM SBL TWEETERS

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Understanding the 1099-K Form​

Key Points for Group Buy Coordinators​

Important Notes on Reporting​

Reporting "Friends and Family" Payments​

Summary for U.S.-Based Coordinators​

Understanding the 1099-K Form

Key Points for Group Buy Coordinators

Important Notes on Reporting

Reporting "Friends and Family" Payments

Summary for U.S.-Based Coordinators