Hello!
Between diagram 1 and diagram 2, which one should be adequate for Shishido LCR Phono circuit?

Thanks!

I thought that contact cement was the way to go with veneer on loudspeakers, but it would seem that PVA glues can also be used with a press. Towards the end of this video, they show how.

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Basically, a PVA glue with a long set up time is applied to the backer of the veneer. The glue is allowed to "skim over" and then applied to the substrate (MDF). A household iron, set to a "medium temperature" is then used as a platten to set the veneer. The author notes that kraft paper should be used between the iron and veneer so as to not discolor the veneer.

Does anyone out there have working Python/Anaconda or Scilab code to read a PCM/wave file and convert to DSD?

For example, start with 44.1kHz 16 bit wave file and convert it to DSD256 or DSD512?

I ask as part of an educational effort related to a discrete DAC project.

Hello,
I have been using the horn folding spreadsheets on diysubwoofers.org to design a tapped horn subwoofer that would fit my particular use case.

Specifically, I'm looking to make a TH that is small enough for permanent residence in my bedroom, but in a pinch can put out enough SPL to occasionally bring out for BBQs and small events (<50 people, anything larger i'd rent). I'd say 90% use would be in bedroom, but for the other 10% would be paired with a single QSC CP12 (HPF @ 80hz), so there's not much needed to outrun the top.

Flat to 50hz or 45 if possible.

Design:
I believe i've some up with something that sims well, but i am new to hornresp and brian's spreadsheets, so i would appreciate if anyone can tell me if there's anything i've overlooked.

I decided to go with the SS15 style fold over the easier to build THAM15. For my bedroom, it's preferable to increase the horn length by adding height rather than depth.

I liked the size of of the POC#3 on diysubwoofers.org, so i decided use the spreadsheets to modify that footprint for a 15" driver.

Would be loaded with Oberton 15XB1200, no particular reason other than it simmed well. I am open to other drivers as well. Thinking of powering and HP/LP with Behringer NX3000DSP

I am selling a miniSHARC + VOL-FP in good condition.
The USB cable, which is described in the manual on page 11, is unfortunately not included.
I can't find it anymore
Plugins (Version 1.12) are included

Shipped from Germany
150€ + shipping

Regards Martin

This might sound a bit like a dumb beginners question.
I now use Titebond PVA glue for building wooden boxes.
Of the three types which one would be the best to use as a paint on paper cone materials?
I've got a quad of really cheap paper coned woofers here for a proposed OB project and I want to play around with them but not completely ruin them by using an inappropriate glue.
I usually use ordinary cheap PVA diluted with water 2:2 and several coats, if I used the Titebond Ultra I think I'd only get a single coat on as it dries waterproof so was thinking 1:1
Thoughts?

OK, so conventional wisdom is that you often need a series cap between one component and the next - or one gain stage and the next - to stop any DC offset passing through from the first to the second component / gain stage.

Sure, I understand that DC offset needs to be avoided at the output of a power amp (or the speakers will suffer). But what, really, is the big deal about 'killing' any DC offset between one component and another ... or one gain stage and another? Why does it matter that the signal is a few 10s of mV - or + of what it ideally should be (if there was no DC offset), when it passes into the next component / gain stage?

Thanks,
Andy

Im trying to figure out faster way to solder thruhole components than with just soldering iron and lead spool.

Im only visualizing it but it seems like solder paste on topside > hot air gun might do the trick. Just dab the paste on vias and blow it with hot air. Most thruhole components im working with will withstand the heat and afterwards i can rework the flow the bottom side with the same method.

Does this seem like a good idea?

Hello,

I have 7 Behringer A500s at home driving my home cinema.
I like the sound of them but they get quite noise at high levels.

I allready bypassed the volume knobs and added bigger filter caps.

I've been reading the old A500 modding thread and they talk about other mods like,
replacing the recitfier diodes, does that make sense for me, also thought about increasing the
capacitance of the Buffer caps in the PSU.

Then i have 20 LM4562MA NOPB opamps at home, would they work as a drop in replacement?

Also thinking about replacing the signal passing electrolite capacitors, but foil caps are expensive and huge,
maybe some suggestions here aswell?


Thankfull Greetings,

Plermpel

Kindly msg me if anyone has it.

Thanks

I have a Carver PT 2400 that is in need of new filter caps that I was given. Its not a large output unit by today's standards. My problem is trying to secure a minimum of 2) 10000/125VDC filter caps that are 2" OD X 5.1" long to replace one channels leaky caps.

The problem is I don't really need it but if its taking up garage space I should make it function or pitch it. The questions are is it worth fixing? Is it possible to find replacement caps for the Philips 3186EG103D125BMA2 Or can I simply do a series parallel arrangement with some smaller sized caps ? It seems to have a 121VDC + and minus supply. The caps are rated 125VDC with a 150VDC surge.
Nothing like running the voltage almost at maximum.

I have a pair of Polk Monitor 5 speakers and really like the bass and midrange but the high grate my ears. Does anyone else have that problem. Is there something I can do about it?

I'm testing a Williamson style input stage with a 6SN7 and the bode plot shows a rolloff of more than 10 dB when the frequency goes up.
Of course I tested the signal generator too and it's flat within 1dB up to 100 kHz.

I measured at the top of the first anode, using a 1 uF capacitor into a 10M probe. The capacitor is there to get only AC for the probe.
The next tube is another 6SN7 with 220K from grid to ground.

What could be wrong? What else should I measure to get a better understanding of what's going on here?

Regards, Gerrit

I have a Marshall Stockwell bluetooth speaker that won't turn on anymore so I want to give it a new amplifier board. Integrated bluetooth is optional as sound quality is my priority. It has 4 full-range driver without any specs printed on them but the speaker specs is 27W RMS audio output & 60W peak power consumption. Can you point me to a good amplier board on aliexpress?

The original unit has a very nice bass/treble control knob, so I thought it would be nice to make use of it with the new amplifier board. However, I see that most of the board on aliexpress doesn't have this control. Do you think I should just put this idea aside and concentrate on looking for a good quality board regardless of having bass/treble control ?

Many thanks for the input.

P.s here is my post on reddit about the the broken speaker with pictures of the inside, if you think there is a chance to repair it please share your idea, I would be much appreciated.
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Hello!
What is the input sensitivity of the Bartola GM70SE?

https://www.bartola.co.uk/valves/2018/03/13/gm-70-se-amplifier/

Thanks!

Hi,
i found on the streets (literally) a TA-AX44, it powers on but no sound comes out from the speakers.

Also a continuous noise comes out from the headphone plug.

What can it be? I already downloaded the service manual and i'm trying to figure out something.

I suspect the STK2240, i read online that they tend to fail often.

Can you help me? Thanks!

In my SIT-3X Amplifier thread I asserted that the common-drain PFET subcircuit of the SIT-3X utilized Schade feedback. Amplifiers described in other threads, in particular some of Zen Mod's designs, have utilized similar common-drain "Schade" feedback circuit.

In this thread I claim that the common-drain Schade-like circuit does not have any feedback other than from the ground, or the input signal reference ground. Thus, the resistor divider performs input signal attenuation rather than feedback.

The first schematic shows a "classical" common-source Schade circuit where the resistor divider formed by R1 and R2 "mixes" the input signal with the output signal, which is inverted, forming a negative feedback circuit. It is easy to verify the negative feedback behavior by both simulation and circuit analysis.

The second schematic shows a common-drain (aka. source-follower) circuit with the appearance of Schade Feedback. If you carefully examine the upper connection of resistor R1 it has the same AC signal level as ground (except for power supply ripple), as shown in the first schematic. Thus the AC signal at the gate of the FET is an attenuated version of the signal of the input IN. There is no feedback from the output.

I'm finishing a power amp design which I will share later after prototyping. It's limited to 20 W into 8 Ohm. I have set a gain to 26 dB just because i't a very common value. Now I started to think isn't it too much? The amp will have a passive volume control attenuator at the front. As sources I have a USB DAC which can provide a full line level and even more and Phono Box E MM phono preamp which has 40 dB gain and its spec says 500mV (RMS?) of an output voltage for 5mV input. So it looks I'm about right as it will give full 20W at maximum volume. Any thoughts?

At present, we can see that the waveform is basically distortion-free at 500hz
How do I need to modify the principle in the diagram to achieve 1-20mhz
Vcc=100 V vi=98 V RL=8.1 Ω
High voltage PNP type triode 2SA1968
General PNP type triode 2SA1013
High voltage NPN type triode BUT11A
General NPN type triode 2SC2328
Standard IGBT FF200R12KT4

Hello Everyone!

If anybody can please assist me in correcting a problem with my Yamaha HTR-2064, which has it's surround speakers stuck on mute.

Everything is working fine except the above. Troubleshooting so far has not yielded any result. So far comparing the voltages, show there is a 3.3v at the base of the transistors Q205 and Q206, which should be approx. minus 12. Other transistors base, of the muting circuit, shows -12v.

I have attached the service manual for reference, so if anyone has come across such a problem, it will be great if they can assist me further on this.

Thank you and have a nice day.

P.S: https://www.diyaudio.com/community/threads/yamaha-amplifier-stuck-on-mute.323545/
I have referred to the above thread, the explanation is good but the cause was not the circuit.

Dear all,

this is my first post, I hope it works.. 🙂

I'm selling 8 pieces of new 13E1 tubes. I bought them years ago because I planned to build an amp with them. However, the project never started and therefore I sell them now.

They are all new and in their boxes. I have two different shapes. 6 piece with one shape and 2 with the other glass. Please have a look at the pictures.

I'm located in Switzerland and I ship from here. Shipping costs from Switzerland are quite high and tax fees may aply from your country if I send them to you. If you are interested, contact me do discuss the shipping options.

Those 6 with the regular glass shape I would like to have € 95.- each tube. Those 2 with the glass that is getting narrower on the top I would like to have € 120.- each.

I don't know if the price is OK and therefore accept also your offers.

Thank you for your interest.

Kind regards,
Bernie

Interested in a pair of Silk RIAA LCR modules, 10k.

Let me know if you have a pair for sale.

Thanks.

Recently I made LM4780(obsolete) chipamp on a hifidiy,net PCB (no further info on this site about schematics, etc.) as per standard BOM values printed on the PCB itself later changed after running into oscillations issues. LM4780 pin 11 was broken (-V) but "patched". As it was lying in my drawer for the past 10yrs, I ordered PCB from Aliexpress to finish these projects. This PCB lacked any place for spk gnd and input capacitors. So I connected spk gnd to supply gnd and somehow connected input DC blocking caps . I have also recv. XY LM3886 PCBs for another pair of LM3886. Any suggestions for improvement will be incorporated in the final build of both chipamps.
During initial testing phase itself the IC would get crazy hot and put out 1.6V DC at both outputs ,with very faint audio and heavy static and weird noises. So I slapped in 18K resistor +47pF ceramic series in feedback, as I had only those available in my drawer. The DC got reduced to 0.75V but still unbearable noise levels. Then I soldered 47pF on both + and -ve inputs each. LM datasheets recommends 200pF between + and -ve inputs and 20K +50pF The amp is now behaving normally with one ch. 18mV DC and other 110mV DC heatsinks runs cool to touch. No zobel was used , I just installed 2.2R resistor just to protect from accidental short. I will be making changes as per datasheets BOM incl Zobel in the final build
I was wondering how could other diyer's iteration of such PCBs would have turned out, as no ceramic pF for reducing oscillations are used in even Audio Sector PCBs too.
My question is -
1. Is 47pF ok on + and -ve inputs? Should I bother to change it to 200pF?
2. Does the large heatsink, directly mounted to metal tab which is connected internally to -V, plays any role in noise or oscillations. Should I isolate it using Mica washer?
I won't be using any boutique parts, this project is just to make a budget biamp, based on single LM4780 configured as stereo / dual for highs, & pair of LM3886 for mids and lows with lower carbon footprint in mind.( +/- 20V ). I will be extensively testing them first on elcheapo speakers and dummy loads for oscillations to avoid damaging tweeters.
Thanks

I buy this few years ago when I owned Unico primo cd player, but on the end I used Siemens crome plate. This are Nos, buyed from tube depot usa. Nice sounding pair. Price 60 eu plus shipping.

Just a quick question. Certain that it's been discussed enough. Not sure how to search for it here.

ampslab-spk projects. The designer is prolific. The designs appear well conceived and executed. There is a broad range of price/performance. The site is lacking somewhat in organization. Subsequent versions of namesake projects, such as versions of the Warbler and the Cardinal, are seldom compared clearly to one another. I've also had zero luck getting any response to numerous emails to the site.

That said I have a difficult time finding much commentary on these designs. Is this simply because they are only 'semi-diy' according to diy ethos since the crossover design itself is pay-walled and cannot/should-not be shared freely? I am expressly not criticizing this enterprise. Just a question about diy ethos.

Posted in the lounge, another cable thread, sorry guys.

http://boson.physics.sc.edu/~kunchur/papers/Interconnect-cable-measurements--Kunchur.pdf

For those that no not, Kinchar has published proper scientific experiments. This one not second sourced yet, but his earlier ones have.

dave

I have a new aftermarket radio I just installed in the car it features carplay/android auto and hdmi in with a rca to hdmi adapter.

I had it professionally installed and everything works fine until I plug in a fire stick to the hdmi input the video and audio work but I get really bad ground loop noises because it needs to get power from a cigarette to usb adapter for power the normal usb ports won't power the stick. I get video and audio but again the noises are really noticeable.

I'm trying to find the right usb isolator for my application but alot of these adapters on amazon say they're rated for 1 or 2v which I believe the stick needs 5v and/or the amp rating is way too low. I'm not an expert and I haven't bought anything yet I just want to make sure I buy something that'll work for this application I don't want to blow the adapter or worse something in the car, any advice would be appreciated.

I stumbled upon this Sanyo msp-5 sound bar that some say it's made in 1981 and believe it or not it works and sound pretty cool for its format.I sent wikipedia this information too as they pretended Altec Lansing was the first to release a soundbar in 1998.They'll probably tell if I'm right or not .If that's not a 2.1 , battery (rechargeable) opperated independent of the signal source soundbar I don't know what is...I dont't have the external power source and I have no ideea if it has charging capabilities.
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Found this lil bad boy reading 8 Ω between bottom 2 legs, found it while looking for a problem that is preventing my LM361 from outputting, it’s getting input on both inputs, looks like a wave trying to start at gates of output FETs but noda :/

so while searching I came across this, searching came up with this “39w” @ Q250, seems to be an “rd3mw” a dot-23 39v .3ma Zener? Never seen a zener like this before. Can’t find any in stock either, left pad on board doesn’t look used but I’m not sure so wanted to check with the Kicker gurus 🙂

if I can’t find a sot-23 package can I use something else since left bottom pad doesn’t look used? Like say a glass zener of similar specs, band side being soldered on top pad? (only zener I knew of, guess they come in all forms 😅)

Thank you 🙏🏻

Hi, I have an ARCAM delta 90 amplifier that needs help. The r58 and R59 resistance of the last stage triode emitter is 0.22 ohm. It is tested that the voltage at both ends of r58 is DC voltage of 1mV. Is the real standard 23.1mv? Is the adjustment adjusted through rv1? Attach the circuit diagram,

I noted in the Alerts that WendyLin was "following me". Also noted in the icon that he/she was banned and had joined recently. Can someone explain what is going on?

Very newbie question so my apologies!

I just picked up an Alps Alpine motorized Potentiometer (100k) for a preamp board I’m working on, but I’m curious how I actually go about incorporating a remote to control the volume pot?

I’ve seen a few PCBs (both digital pots and ones that physically move a motorized pot) on Aliexpress but curious if there are any better options out there

And suggestions or pointers are very appreciated!

Thanks 🙂

I understand a build out resistor is necessary to keep a cathode follower from high frequency resonance or oscillation when driving capacitive loads (like long runs of cable).

However, I've seen a couple different ways of placing that build out resistor in circuit, so I wanted to ask what happens when you move that build out resistor to different places in the circuit. I drew up an example showing the three I've seen:



I usually place Rbo (the build out resistor) as in Ex. A.
I understand that placing Rbo as in Ex. B will add slight additional cathode load, but in use it's pretty much the same as Ex. A.
Will Rbo placed as in Ex. C also act to dampen high frequency resonance with high Cload, as in Ex's A and B? Or will it not work at all that way?

Already addressed the "usual suspect i.e. the 100uf caps on the feedback side of the input long tailed pairs.
That snot it. One channel is about 5v positive, other a couple of volts negative. This is of course triggering
the DC protect to prevent speaker flames. Suspicion is on the input pairs (2 x A1016 and 2 x C2362 per channel )
PITA to get a pile of these things to gain match them.
Any other "usual suspects" I have missed?.
M

Hi All,

I stuble across the forum here and than for years now, and finally registered.
I am an electrical engineer for planing and prototyping industrial machines.

And my hobbies are gaming PCs, home cinema and cars.
But somehow I am just to stupid for electronics, i managed to fix some
dead amps and stuff but can't quite keep up to redesign, modify and especially
improve existing schematics.

Build a phono pre amp a few years ago but it sucked and since then I never really
got into it again until now.


Greetings from austria,
I hope you can help me out with my noop questions here and there.

Hi to all my DIY'ers out there.

So want to do a quick dirty build of this popular amplifier as now there seems to be a number of kits you can buy at a very reasonable price.

I know there are many versions of this amplifier build circling the forums so i'm sure there's a number of you with great experience who can help.

I got these kits from a nice gentleman named Igor off ebay:

Hiraga "Le Monstre" enhanced 8W (15W) A class Amplifier D.I.Y. Red edition | eBay

Hiraga A Class Power Supply PCB D.I.Y. (Aleph , Zen-X) | eBay



Please see attached schematics and pics:
















So far i have bought 16x25v@47000uf capacitors, i also have two toroidal transformers 160va 2x12v 6.67A.

I have a few questions about the power capabilities of this amplifier, now i know it runs at 12V and i know that probably after rectification and going through the capacitors the voltage will increase, so what i want to know is . will this be ok? Can these amp boards take the high voltage? If not what would you suggest i change in terms of components to handle the extra voltages? Or will it be ok?

I'm not fussed if it's 8w or 15w, i just want to learn how to set it all up i.e the bias and to get it sounding as good as i can with what i have.

I need a soft start and speaker protection modules? I will be building the chassis and heatsinks myself!

Can i buy one soft start board and attach both transformers to it? I dont need to buy two soft starts aslong as the board can handle it correct?

The board i am thinking is this:

220V Class A Power Supply Amplifier Board Soft-Start Delay Temperature Protect | eBay

and speaker protection:

Amplifier DC Audio Speaker Protection Board with Delay Partially assembled | eBay


This should be a quick and easy build really! but happy to do some mods along the way.

On the amplifier boards where R12 and R13 are 5W 1R's i was thinking of replacing these for 10w items so they can handle more load as the voltage with be higher then 12v.

Still learning and enjoying about all of this! At present i have parts for Jean Hiraga super class 30w but taking time to build due to expense! The power supply cost is huge.


Any tips would be greatly appreciated especially with bias settings and generally how to warm and setup the amp once built!

Thanks All

Vish

Hi guys,
I'd like to convert linear pitch control to rotary on my beater Technics 1200. Just an experiment.
Is it possible?
What are the general guidelines to do this?
Is it possible to use a rotary encoder and what would this entail (the ones that have no stops)?

Thanks!

Can anyone help me identify or get any information about these compression drivers? I'm trying to figure out whether they are worth doing anything with. They are unmarked other than "Kustom #1" and "Kustom #2".

RECTIFIER TUBES

All tubes come in generic white tube boxes unless otherwise noted. Prices listed for each tube or pair.

Testing data from HIckok tube tester, tested values listed over the tube minimum

Shipping to be decided at time of sale, I will combine shipping.

Tubes are clean and pins cleaned as well.

5AR4 TUBES

ALL SOLD


5U4GB TUBES

-GE PAIR $35/pair $30/pair
date 62-13 92-88/80
date 62-22 92-89/80



5Y3-WGTB (6087)

SOLD

I need to replace the rectifier in an interface circuit from a 1963 Janszen Z-600 electrostatic/hybrid speaker. (see schematic below...6S-1)

The oem rectifier is a Recticon Corp S6350 AB. It is a black cylinder about 3mm diameter and 30mm long with axial leads.

Can anyone suggest the specs for a modern replacement? Thanks!

Hi,

I’m still working on my 2-ways, but in my “spare time” 🙂 I’m thinking about a floorstanding 3-way speaker for “general music listening”.

Concept so far:

• Floorstanding tower shape.
• Sealed or ported, no preference really
• Cabinet size can be large, but not coffin-size large.
• Should have a really good low-end. I will not be adding a subwoofer.
• Woofer 8'' or 10'' probably. Need to keep the baffle width acceptable.
• Passive XO
• Crossover woofer at BSC range
• Crossover midrange 3k or 4k or so
• Sensitivity doesn't need to be super high for the ensemble, I'm probably not going to double the W to go super high-sensitivity.

Because the low end is important, I wanted to start with the the woofer selection. The more I read and look at graphs, the more I’m confused.

These are some candidates I found:

• SEAS Prestige L26RFX/P
• SEAS Prestige L22RN4X/P
• SEAS Prestige CD22RN4X
• Scanspeak 25w/8565
• Scanspeak 26w/4558t00

Sensitivity: not much difference between them. 88dB, 89dB,..

Material: alu or paper or some paper-hybrid. Word on the street is "alu is more precise, clinical. Paper is warmer." Even if that is true, does it matter with a low-crossed woofer? I can still use a paper midrange.

LF response: the SPL of some of these drops faster than others. E.g. CD22RN4X (only 8 inch). But others remaing stronger for longer like the L26RFX and the 25w/8565.

The 25w/8565 is a bit rocky in the low end though. Is that audible?



So given my concept, how on earth do I choose between these drivers? If I were to search more, I'd probably find even more drivers than seem to fit my wishes.

They are too expensive to just buy and test.

Thank you
Vincent

Hi all
I bought a ZERO ZONE Naim NAP200 clone but the materials that included differ from the values marked on the board. So instead of 0.22Ω resistors it contains 0,39Ω. The seller on ebay say to adjust the voltage to 5mV across the 0.39Ω (R13) resistor so the idle current calculated to 5/0.39=12.82mA. It is correct? because I read on some threads that this current must be about 22mA so I have to change the voltage from 5mV to 8-10mV. It's OK?
Best Regards
Spiros

If anyone have a NOS full kit or just the transformers for Joe Curcio's power amp that they want to sell, I am interested in buying.

Hello,

I've been reading posts here for a while now, and now thought to register and ask a few questions.

I have 6 Magnat Monitor 802s in my home cinema and I like them quite well.
They are all driven by Behringer A500s, which I want to modify too.
The thing is I am not quite pleased with the heights.
My dad has two Quadral Signum Towers in his livingroom and the heights just sound
so much better.

Anyone has any suggestions on changing the tweaters on a budget?
Or maybe modifieng the crossovers?

Looking forward to your suggestions.


Greetings from Austria,

Plermpel

Hi folks. Really apologize if this one's been covered ad infinatum, but my poor search skills didn't uncover the answer to my question. I'm building a Morrison Micro 45 and need a "ballpark" value on the 45's cathode resistor. I'm thinking it's in the 4K to 6K range, but power resistors in that range seem to be limited in value, and 25 watts seems to be the go-to. I'll fire it up with a variac to preserve my precious stash, but if the voice of experience would weigh in, that'd be great. I've got all the other parameters covered, and this is the missing piece.

Hi there 😎

It all comes down to Super Audio CD handling / playback using a Sony Bluray player: UBP-X800 and an external DAC:
In my case Topping D90SE which has a HDMI / I2S, which is pin configurable as you can see here:



I intend to buy a 'HDMI to I2S box' and place it between my Sony UBP-X800 / HDMI 2 (audio only) and the DAC, connecting with two 1.4 HDMI cables.
I need to know the HDMI pin config for the Sony UBP-X800 in order to replicate the pin setting to the DAC / HDMI / I2S.

Does anyone know where I can get that information ? (Sony customer service: don't give a camel s... !!)
I am thinking a repair manual: Sony UBP-X800, for technicians, but it might not even be there !

Next question; Which box to buy ? I'm not going for the reputable boxes around 1000-1500 us $...like GEERFAB AUDIO D.BOB and the likes !
Even this one at 79€ (plus shipment) is overpriced : https://www.audiophonics.fr/en/diy-...-hdmi-mhl-to-i2s-coaxial-optical-p-13419.html
This one is more in my price range but a box with less jitter will be nice: https://www.audiosciencereview.com/...-blackbird-review-hdmi-audio-extractor.36478/

I appeciate any box recommandation you have testet with SACD yourself or know about first hand around 30-80 us $

Thanks...all the way 🙂

Partner moved in and her grand piano in the living room (stereo room!) displaced the grand subwoofer and so ... it has to go. :-(

For those unfamiliar with Rythmik, they exclusively make non-accelerometer-based (read: reliable) servo subwoofers using excellent components: spun aluminum cones, shorting rings, cast frames in the drivers, toroidal transformers in the linear amplifiers, or Hypex based for the class D. Really nice stuff.

The unit I have is an older one, comparable to the current DS1502 kit on this page, but with a 370 watt RMS amplifier:
Rythmik Audio 15" servo subwoofer " DS1500 Custom Installation subwoofer

Here's the page for Rythmik describing their servo technology, and why they developed it in the first place.
Rythmik Audio • Servo subwoofer products

And the FAQ page:
Rythmik Audio • FAQ - Frequently asked questions

The box I'm using was built by a fellow hi-fi enthusiast, and far exceeds most anything commercially - it's a sealed box built around a bandpass box, resulting in a thickness of 1.5" (2 x 3/4" MDF), and solid as concrete. That's also why this is strictly pickup only - I can barely push the box on my own, let alone pick it up and load it into a car/truck. It's black, large, and very impressive. The box is 3.6 cubic feet, so ~exactly~ ideal for this driver/amplifier combination.

Looking for $517, locally picked up in Los Angeles (right by Pasadena).

Here are the details for the subwoofer driver itself:
Rigid anodized aluminum cone (black or silver)
* Rigid 12 spoke cast aluminum basket
* FEA designed aluminum short circuit ring to reduce 2nd order distortion
* High linear excursion capability of 1.4" peak to peak (xmax)
* High mechanical excursion capability of 2.6" peak to peak (xmech) to reduce risk of bottoming
* Very low inductance
* 24 ohm ultra thin sensing coil for servo operation keeps moving mass low
* Woven wire lead in the spider to prevent rattling during high excursion
* Gold spring loaded terminals for easy solderless cable connection
* Single 2.8 ohm voice coil
* Available with rubber mounting gasket (15-5/8" outer diameter and 3/4" depth)
* Mounting without gasket (15-5/16" outer diameter and 7/16" depth)
* Two 1" stacked magnets for a total magnet height of 2"
* Cutout: 14"
* 7" clearance in depth
* 350W RMS max power
* Proudly made in USA

I need to add a digital out to above player. The same PCB is apparently used for the 400 and 500 models which have a digital out.

I have located the datasheet of the decoder
http://www.datasheetcatalog.com/datasheets_pdf/M/N/6/6/MN6626.shtml

but it is more than basic.

Does anybody know if the dig out is disabled / enabled by software as in most Philips chipsets?

Why would the digital output interface on the chip have an input named MEMP?


Thanks

Hi All
Recently came across a pair of Dynaco A-10's. Brought them home for a listen and found them to be decent, if uninspiring. Did a little reading and found that Morel made a tweeter (forget the number now) which is a direct drop in for it. Then I started wondering about replacing the woofer too. Just a 6.5 inch woofer.
Anyone ever built anything into these cabinets? Nice simple classic cabinets. I can do speaker building, but I have no where to build cabinets. Any thoughts?
Erik

Hi,

I have an older Def Tech sub and recently it began humming when there was no signal for a short period of time, for example in a movie when there was no bass. I noticed it about 2 months ago and would unplug it from the wall and then plug back in to "restart" it which temporarily fixed the problem. Earlier this week I turned on my receiver which is set to ARC and before anything was even on the TV screen, the sub started blaring a sound that sounded like a tornado alarm. It was so loud I can barely describe it.
I've read through a number of these threads in hopes that someone might be able to shed some light on what is causing it as I would really like to fix this but from what I've read, the solution is not as common as I originally hoped. I am going to call Definitive and know this is out of warranty but if anyone has experienced this and could point me in the right direction that would be extremely appreciated. Thanks

I've got a small little 3W guitar amp I'm building that uses a 6F6 for the power tube. I'd like to try a 42 as an option by adding the additional socket. Most of the 6 pin sockets I see are entirely ceramic and, never having messed with those types, was wondering the best way to mount them? It's seems like they'd be prone to breaking. I see other 6 pin sockets with the regular metal mounting tabs, but its gonna take a month to get any as they all seem to come from China, except the NOS ones which are just way to expensive for this project.

I would like information on the use of the damping material. I know that in a closed box, filling it up all the apparent volume increases slightly. but in the case of a bass reflex, covering the walls with for example 1 or 2 cm of felt and then polyester (as troelsgravesen does) what happens? the volume of the cash register increases, decreases or is it irrelevant?

since my cabinet must be about 5 liters, making a mistake even a little can be significant ... thanks!

This is a new Yarra/M2X format daughterboard that will be used to drive the new 39w LuFo SE Class A amp. I decided to use an OPA454 opamp capable of +/-50v rails and 50mA output. We will power it with a custom +/35v DCDC converter on the lower mezzanine and coupled to the upper mezzanine through a 3pin header. The DCDC converter will take +18v to +30v input from the main amp board. It uses LT8364 converter with SEPIC topology and a coupled inductor. JPS64 has done the beautiful layout and Jhofland designed the DCDC converter. I have designed the OPA454 to provide the LuFo with 22.4dB of gain. This should be perfect when driven by an external preamp with circa 6dB of gain. The OPA454 was chosen since it has capability to handle up to +/-50v rails and can drive up to 50mA of output and had only 0.0007% THD.

We have made provision for a nice Mundorf 2.2uF EVO M cap on the input. It will be DC coupled output and AC coupling will be handled on the main LuFo amp board.

I mistakenly clicked 'unsubscribe' option in my yahoo email (yesterday),
and after that I stopped receiving email notifications.
Is there a way to enable my email notifications again?

Hi!

Could you recommend a USB Stereo DAC that can be plugged into a mixer? Preferably a DAC where I can experiment with different op-amps. Looking for a sound signature that works well on large club dance floors.

Notes: A guest of mine loaned me a custom-built DAC for a few days; after trying several of his op-amps, I found the OP2134 gave a nice result on the dance floor. It had a punchy? aggressive? warm? signature that sounded really good in the club. Wanna get a DAC to experiment some more.

Help please. My Krell S300i volume control had been playing up for a while, volume jumping up and down all over the place. Now the volume is stuck on 35 which isnt too bad but would like to be able to a adjust volume! It also doubles as a switch to changes functions when pressed. Thats not working either. Any idea where I should look for a replacement?

G'day all,

Is it worth to repair a cambridge audio cd 640c v.2? Optical and coaxial output are working but no signal from the analogue output. I have recently replaced laser assembly for $35. I don't know enough to diagnose what is the problem with the analog output.
All fuses are fine, no leaking/bulging caps. Few big ones have brown goo at the bottom, but it looks like a glue.
Local shop wants $100 for checking the player. Repairs up to what they say usually no more than $250.
It works as a transport well, but i need an analog output too. Is this problem a common thing or something unusual?
Thanks for any advice.

Kristof

Where i can find grado ra1 headphone amp pcb layout
I have allready made cmoy and now i am willing to make this little amp for my grado sr80i
greetings from Serbia !

For my next project / for-the-fun-of-it I'm thinking of building John Broskie's Triadtron HP buffer, as shown here: https://www.tubecad.com/2021/12/blog0549.htm

My DAC has plenty of drive and I have a ton of HP amps that are low THD and ultra transparent - this will be more for the single-ended sound and flavour (and because I haven't built an amp for ages).

Before I start slinging solder blobs does anyone have any thoughts? Are there better BJT options than the MJE350 and D44/D45H11G?

when is is too small( too inefficient or needing too much power to get -goodie great- output (need stupid, not conservative)???

one ultimax two sa1000 plate amps or racked version on each coil is possible (have multiples if these and the 15” umax too)

2 ready built versions, fully functional and with “extra all”:
Auricap, Nichicon Muse, Gold
Tune, Caddock TF ultra precision , Vishay resistors.

Price for both 250€, add shipping from Sweden.

https://reverb.com/item/50271724-salas-dcb1-super-pack-kit-with-board
https://reverb.com/item/50271724-salas-dcb1-super-pack-kit-with-board

I had an Audiopipe 2000 watt amp come into the shop that had a very heavily damaged power supply driver card. I just so happen to have an Audiopipe 1500 watt in the shop waiting for parts with an intact driver card. The difference being the the driver circuit was on the main board verse a daughter card like the 2000 watt amp had. The driver circuits were the same so I was able to reference the 1500 to repair the 2000.

Having said all of that, I thought I would post some pictures of the circuit for future reference for anyone else that may need it. I used KST812 PNP for the M6 transistor and KST1623 NPN for the L6 transistor and MMBT5551 NPN for the G1 transistor.

David

anyone can give a thought about that schematic?

thanks

Pairs:
Magnavox, made by Sylvania. 60 shipped conus.
GE - early 1950’s - so actually Ken Rad design still. 60 shipped conus.
I’m keeping the uglier ones as I like these types in a 70’s Princeton guitar amp.

Singles:
RCA. 40 shipped conus.
Tung Sol reissue. 25 shipped conus.
Used briefly in a single ended Vibro Champ.


All in strong working condition and sound great.
Will ship in usps flat rate boxes well packed.

Thanks, Don

I'm planning to build my first open baffle sub as an experiment. I'm scoping out driver options and would like some help understanding what the likely differences are.

This will be driven with DSP equalization and a 100W class-d amp, I'll build a simple H frame enclosure. I'm only going to get 2 drivers to start with and I'll aim for flat response 30Hz~100Hz after correction.

I'm looking at two very different options at a similar price point:
GRS 12SW-4HE, 12", 12.5mm xmax, 84.5dB/W, $60
https://www.parts-express.com/GRS-12PR-4-12-Paper-Cone-Rubber-Surround-Subwoofer-4-Ohm-292-820

GW-1558, 15", 3.9mm xmax, 95.6dB/W, $84
https://www.parts-express.com/Goldwood-GW-1558-15-Pro-Woofer-290-384

Plugging them into Basta with a 70cm square baffle shows me the obvious stuff:
The 12" high excursion driver will take ~3x the power, but will play ~6dB louder at 30Hz.
The high excursion driver will kick out a load more vibration, (MMS 237g vs. 70g).

What else should I be considering here?

HI again. I just had another idea. Feel free to rip this apart. Keep in mind that i will have active EQ and 6 channels of amplification. Ok what i propose is and correct anything i say wrong i can go back and read all the data again till i understand it exquisitly. here is a cheesy picture to clarify my written description.

http://i4.photobucket.com/albums/y121/madmike2/Basic.jpg

i want to take Surgical packing foam, it comes in a grayish black colour and flat sheets of 5/8's thick and sandwich it. Front baffle will be 1/2 inch white pine and the rear support and baffle will be 1 inch mdf that i have. each panel will be 4 x 8 inch woofers wired series paralell to a single channel. In the middle of these sitting side by side will be a 4 inch mid and cd5 fountek ribbon tweeter either wired together to one channel with a simple 12 db crossover since there will be an active x-over removing 400 Hz and lower. Or i can run the tweet on a channel the mid on a channel and the 4 x 8 array on the 100 watt channel with the Dbx doing crossover duty. The front baffle will be in the range of 90 % decoupled from rear as i will use 2.5 inch black mushroom bolts and polyurethane donuts on the back side with wingnuts to cinch the speakers to the front baffle. Almost all the transmission of energy that does make it to the back will be through the poly as the medical foam is CDC certified for vibration absorbtion.

So from what i understood part of the problem with an open baffle IS the baffle. Will taking its effects out or shrinking its footprint in the reproduction picture help ?
Just so you know i just backspaced a whole freaking book back to here, just to ask it in a way i SHOULD have asked it. WIll this design affect or lesson the baffle effect in this design assuming that this array would be valid? Or will it just destroy the point of the open baffle.

I will be reading SL page while i wait for the flaming to begin 🙂

Michael

I've been planning to improve my RCF lousdpeakers (which are being discussed also here,) by adding a tweeter to improve the high range which is somewhat lacking as the current mid/highs have a sensible roll off at the end of the range.
I would like to use a compression driver mated to JBL2404 horns due to the off-axis response of these wonderful horns, of which own a pair, unfortunately without drivers.
I do not want to compromise on off axis response because in my opinion/experience this is a primary requisite to obtain a wide and precise soundstage, which is among my primary requisites. My speakers are not lacking in this regard and I don't want to compromise the high end by choosing any other horn than the 2024.
So I am looking for a compression driver, to be mated to the 2404's exceding 102db spl 1w/1m to match or exceed the current mid/high SPL.
The idea is to cut the current mids at about 5K and let the 2404's manage the rest of the high range.
I am not asking for perfect linearity up to 20k, I would be happy with anything which is (more or less) linear up to 13-14k.
Not being a hardcore audiophile the use of equalizers for mild room correction and/or to compensate for a few db in lack of llinearity of the drivers/speakers is fine for me.

I am planning to use RCF CD1411-M compression drivers, they have somewhat similar dimensional characteristics to the original drivers, except (unfortunately) the frequency response. Also the Mylar diaphragm of these drivers make them better candidate for "Hi-Fi" use than other using stiffer materials.
I have always been an RCF components enthusiast, and furthermore I can get them pretty cheap (about half the average retail price) as I am friends with the area wholesaler. Still the frequency response of these drivers seems to leave some to be desired (at least for my intended use).

I wonder if the amazing linearity of the 2404H was due to drivers response alone, or if the horn design contributed significantly to the final result, because of course this would make the RCF drivers more interesting.
Also, it would be equally interesting to know if the response of the RCF driver can somehow be tweaked (through the crossover ?) in order to make them more linear in the 5-14k range or in order to achieve an overall better linearity of the speakers.

In this regard it should be considered that:
- the current mid-highs are rated 102db w/m @ 800/900Hz, have a similar "slope" to the 1411 (posted below) and, according to the factory crossover design, require an adjustable attenuator to match the 96db w/m of the woofers
-the 1411m drivers are rated at 108db w/m @ 1200Hz, and are about 102db@ 5k, according to the factory datasheet attached below.

As a last resort I may evaluate an alternative compression driver as long as it is easily available in EU and don't break the bank (like importing two of the original JBL drivers...)

Here's the response of the 1411 vs the 2404 original drivers (coupled to the small buttcheek horns).
It shoulf be noticed how the high end slope of the 1411 matches the increasing impedance, hopefully the horn could help in this regard ?

RCF CD1411-M (driver alone, without horns)





JBL 2404H (driver + horn)

Pair of Satori TW29RN-B Tweeters and MW16P Midwoofers

Absolutely excellent condition - with minor imperfection in the mounting holes only.

The tweeters and mids retail for $170/each.

How about $375+shipping (from 20817) for the combined package.

For sale nice build top sounding amp with cerry good parts. Look at pictures. I have build this around two years back and still sounds verry good without hum or hiss. Tubes 12sl7 Tungsol black glass and output matched quad Sylvania 5933 jan wa. Output transformers from Ogonowsky, top sounding better than hammond or edcor. Coupling caps Ampohm Tinfoil pio 0,47uf.Power caps vishay bc and mundorf tube poly. Heater for 12sl7 with Rod Colkeman low nois reg. All resistors are Takman metal and carbon film and power resistors are Milles. On the back is Alps Rk27 blue buaty for volume, if you dont need this just take this out. Wiring is from neotech and sommer. Little capacitors are nichikon Kz muse. Amp is 20watt pro chanel and build on this schematic. B+ delay with sophia electric module. You must made your own front baffle.I try to make this but the sound was so good I never come than to make this and now I have made 2a3 monos and this amp is in not use for about 6 months. Amp is heavy, but the price is 1000eu including registered shipping inside EU,or best offer. Alone all parts have cost a lot more. So payment paypal. More info on contact.

Looking to buy (2) Goat style tube shields that will fit a 71a tube. I'm aware of regular straight shields, but looking for this molded/stamped type. Must fit a 71a.
Here's the data sheet.
Maybe a long shot, but thanks!

I have n.100 nos D3A Siemens tubes. I intend to sell lot of three tubes for €50 but if you want more I accept reasonable offer. Due the lack of time I can't match the tubes.

SELLING SUSPENDED ! Someone is stating that the X on the boxes mean a not conforme product, I was unaware of this, so I'm going to check them with a tube tester, until then the tubes aren't available.

Up for sale are a PAIR of vintage SEAS 8 ohm, 8" woofers from the mid 1980's. Info available on the SEAS site under 21F-WB. Full model number on the back is 21F-WBMX H150.

These drivers were in a transmission-line enclosure and were part of a 3-way system offered by New York Acoustics that I bought back around 1985. Just removed them from the original cabinets to put in a different driver to use as a woofer below 100hz.

They are in VERY GOOD condition. Had them re-foamed maybe 10 years back.
$40 plus shipping - 12lbs from zip 13820 - Email me for a pic

hello everybody,

I am new to this forum and I have made a phono preamp clone of the 834 following the thread on lencoheaven,
I am very happy with the sound and all works fine with the kit I purchased from douk but I want to try another power supply,
I have bought an assembled board trying to upgrade the one coming with the kit but I have a strong hum:
first 4-5 seconds it is silent and then the hum increases for about another 4-5 seconds and gets very loud
with the other power supply it is silent but I want to know what I have made wrong in order to learn a little bit before I begin another project
here is a pic of the wirring



the transformer on the top right is HT 300-0-300, the red wires are 300 v and the black one is 0v connected to the chassis ground along with the brown wire coming from the board ground,
there is one missing wire in the picture: the ground coming from the phono board which is also connected to same point as black and brown, the heaters are also missing for clarity purpose

can anyone give some advise to wire the power supply properly to avoid the hum?

Hi,
I was looking for Hookup Wire online and found the Carol Brand(General Cable) hookup wire from Amazon.com for cheap. Its 14 AWG copper conductor wire.

Does anybody have experience with this brand? I heard for the first time. Below is the link. I got 500 feet for just $15. I checked online the brand seems fine. Didn't understand the configuration much though.

https://www.amazon.com/gp/product/B007IAQPZ4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Spec Sheet - https://www.masterelectronics.com/datasheet/76812.r8.03.aspx?p=10924804


I was just wondering if I can use this hookup wire as a Speaker Cable. I can wound two wires together to create a single wire out of it to get a lesser AWG. Is it fine?

Thanks,
Simar

PCB Kit to make the Singing Bush SIT amplifier. Kit includes 2 Power Supply PCBs, 2 CL60/AC Cap PCBs, and 2 Bridge Rectifier / Snubber PCBs.

The power supply PCB is set up for 50mm diameter Cornell Dubilier Electronics (CDE) 5-pin 382LX/383LX series capacitors.
It has positions for 2 LEDs: 1 for on-board, and one for a front panel LED.
It can be configured as CRC or CLC.
PCB Connections can be hardwired or use 5.08mm quick disconnect spades (e.g. Molex 19708-4013 or similar)

All PCBs are designed to fit on the 10x10mm grid in ModuShop chassis bottom plates.

$25 + Shipping. 4 kits available now. Can make another GB batch based on interest.

PM me, or buy direct here:
Singing Bush Power Supply PCB Kit | Etsy

Hello everyone!
I'm a beginner in the field of audiophilia and I'm taking the first steps to build my first sound system (always according to what my wallet can handle 🤣).
I started with an AB LM3886 50W/8 Ohms amplifier per chip. As I am using two ICs, I will have 100W in total.
Then I bought two used aiwa boxes, they are not in very good condition, but it is the beginning of my adventure, so I think it is ok for that. They are SX-FNV800 model.
My question is:
1 - These speakers are 3-way with front surround, and the information on the back of the box is: Main speaker (6 Ohms) and surround speaker (16 Ohms). Knowing that the box has 4 speakers, how do I find out which wires coming out of the back of the box are from the surround and which are from the main?
2 - Which speakers belong to the main speaker and which ones belong to the surround? (Woofer, Mid-range, tweeter, super tweeter)
3 - To make the connection to any amplifier, even if there is no impedance matching (as in my case), can I ignore the surround?
4 - If I can't ignore the surround, is there a way I can connect them to the main speaker (because I'm limited to 2 channels)?

That's it folks, I'll be following the thread and if you have any questions I'll try to explain it with other words. I hope you understand my situation, one day I will finally get some complete and well-made systems!

NOS Tung-Sol 6550 tubes.
Brand New never used matched pair . New Old Stock.
Both tube mutual conductance measure is 7000 where 6500 maximum.
$300



Made in USA.

Hey folks, I’m looking for a Russco (or Russco rebrands like BE, Micro-Trak, etc.) Studio-Pro turntable for a restoration project. Normal wear OK but must be functional and complete - no tonearm is OK. No stripped out parts tables, please.
Will consider a Cuemaster model but prefer the Studio-Pro.
I’m in the area of Bakersfield, California and can pick up within a 100 mile radius, unless we can work out shipping.

Thanks, Duane

There have been in the past several thread split off's, all dealing with finding answers to the mysteries of MM Carts.
Topics were level dependency of linearity, interaction with the LP, type of mechanical resonance, reason for a dip at 10kHz that most Carts have, etc ,etc.
Since many designs are spread all over these various threads, the idea of this thread is to keep those designs together and not so much as a discussion thread.
Please see it as an technical addendum to the thread "Cartridge Dynamic Behaviour"

One of the tools used for investigation has been the so called Aurak preamp that LD or Luckythedog brought forward.
This a phono amp that goes one step further as replacing the 47k termination resistor by a much lower value of ca 10k creating a 75usec pole.
The advantage of doing such things is that the influence of cable capacitance on the FR becomes much lower, thereby coming "closer" to the sound that the Cart is producing.

The Aurak preamp takes this even one step further by offering a virtual gnd input to the Cart, a so called transimpedance amp with neglectable sensitivity for cable influences.
In principle the FR of an Aurak goes quite a bit beyond that of the 47k//200pF type of preamp, a big advantage when investigating the supersonic properties.

When using a transimpedance amp, a pole is created at Rc/(Lc*2Pi) Hz, resp the inductance and resistance of the Cart, usually somewhere between 100Hz and 300Hz.
This pole has to be corrected to get the Riaa curve as needed.
The basic Aurak version therefore asks to add a resistor in series with the the Cart, who's values is 2*Lc(mH)-Rc. Example: for a 450mH/ 750 Ohm Cart, 150 Ohm has to be added.
This boils down to creating a pole with a 500usec time constant. Internally the Aurak shifts this pole to 75usec, being T3 of the Riaa curve.
Now a second amp stage is still needed for only the 3180usec and the 318usec Riaa time constants, resp called T1 and T2.

There are cases however that the math of this basic version with 2*Lc-Rc is giving a negative result. In that case 3L-R or 4L-R can easily be achieved by modifying the internal correction network.

The image below shows the basic Aurak. First stage shifts the 500usec pole to 75usec. The second stage takes care of T1 and T2 that Riaa prescribes.
Between the two stage is visible a fourth filter, 2k2//1n5. This is optionally the unofficial T4 timeconstant of 3.15usec, creating a pole at 50kHz.
More to follow.


Hans



Erratum:
A somewhat cryptic formulation in the above text might possibly lead to a misunderstanding.
The false impression could have been given that in the Aurak the usual 47K terminationresistor was replaced by a 10K resistor, but that's of course not at all the case.
The intention was to showing several ways how to connect an MM Cart to a preamp along a timeline going from:

1) The original 47k termination, to
2) Attempts by some to reduce the effects of cable capacitances from Cart to preamp, by replacing this 47K with a ca. 10k termination, thereby creating a 75usec pole (f.i. Barney Oliverand Bob Cordell) and
3) A transimpedance as a next step, such as this Aurak, where the Cart is connected to a virtual gnd, completely differing from step 2.

Looking for a 2way project with drivers that can be had from above 2 sites. Since i live in korea the shipping of dayton drivers no longer make them budget friendly so im looking for better (cheaper) alternatives. Preferably 8inch woofer or bigger since theyll be played in my girlfriend's studio...

Thanks for your suggestions