... designed some metal parts for a completely passive cooling for a raspberry pi4 which allows to stack hats ...
Tested with all 4 CPUs at 100% 1.5GHz it keeps the cpu temperature below the critical 80 degree where the cpu starts throttling.

Have fun, Toni

Hello, picked up a MX1571, magnavox receiver, 1976. Having trouble finding a schematic, any ideas?

Looking for a Schematic for a Linx Pulsar power amp
I would appreciate any help, I own this model but it has some things to get fixed.

Hi Everyone,

I'm hoping someone might be able to give me some direction on fixing a problem with my Classe CA-300 power amp.

In short, the amp mostly works fine, and it will sometimes stay on for days (I always leave my SS gear powered on), but sometimes it goes into protection mode, as indicated by a flashing green power light. The amp has been operating this way since I got it used two years ago. I can consistently get the unit to pop into protection mode when first powered up if it hasn't been used in a day or two; after the first power cycle / protection, I can restart it and it will operate.

I'm am completely certain the issue is contained within the amp, as I own numerous components (high end amps, preamps, speakers, and cables) and the behavior is the same no mater what gear is connected to the amp.

A Tech buddy of mine originally thought the problems were related to the input stage, and replaced the input opamps, as also changed the input relays. Bias and DC offset have been adjusted in accordance with the service manual.

Due to the challenges of shipping this unit (no box, and 90 lbs weight) I don't think it's economically viable to send this to Classe for repair.

I'm just about ready to sell this unit for parts, so any thoughts or ideas would be appreciated.

Thanks,
Trevor

Sold - For Sale Salas I-Select PCB plus minikit. This was purchased through the last group buy. $55 shipped.

Hello everyone 🙂 🙂

I play guitar, I like rock music, most of all Pink Floyd, Whitesneake, Dire Straites, Al Di Meola.. 😎 😎

I would try to create a DIY sound system for my house. The system would be consisted of 2 x towers, 1x center speaker for front and 2x bookshelf speaker for rear.
I think a good combination for towers would be a 3x8 '' full range speaker, 1x bigger and 1x smaller tweeter. For the center would be 2 x 8 '' full range and 1 xbigger tweeter. And for bookshelf would go 1x smaller tweeter and 1x 7 '' full range speaker.

All 8 '' speakers would be: Dayton Audio RS225P-8A 8" Reference Paper Woofer 8 Ohm
All smaller tweeters would be: Dayton Audio AMT Mini-8 Air Motion Transformer Tweeter 8 Ohm
All bigger tweeters would be: Dayton Audio PT2C-8 Planar Tweeter
All 7 '' full range speakers would be: Dayton Audio ES180TiA-8 7" Esoteric Series Woofer 8 Ohm

Now I'm interested in the following:
I'm planning to buy everything from partes express site, I'm new to this so i'm interested in the following
1) what DIY amplifier modules do I need to take for my system? I guess I need one towers amplifier and one for the center and bookshelf speaker. Can you recommend which modules would be best for this?
Audio Amplifier Boards & Modules - Parts Express

2) What are Dayton audio speakers in quality, is it worth investing $ 1500 in a system that will be made up of that company alone?

3) Is this DSP good for my whole system?
https://www.parts-express.com/dayto...nal-processor-for-home-and-car-audio--230-500

4) Can you tell me if I need a special 12 '' bass woofer for my system or will this speaker combination cover the bass enough?

5) What crossovers do you need for tower, center and bookshelf speakers, if you could send a link, because I don't understand it.
1) https://www.parts-express.com/dayton-audio-xo3w-700-56k-3-way-speaker-crossover-700-5600-hz--260-156
2) https://www.parts-express.com/dayton-audio-xo3w-500-4k-3-way-speaker-crossover-500-4000-hz--260-152
3) https://www.parts-express.com/dayton-audio-xo3w-625-5k-3-way-speaker-crossover-625-5000-hz--260-154


I'm very good with a soldering iron and can work with wood, so none of this is unfamiliar to me, I would make a solidworks model of every speaker before, copy some famous companies and make good models, I don't worry about that. 😀 😀
What bothers me next is, is it better to spend $ 1500 now on this DIY project or buy a ready-made $ 1500 system that works better? 😕 😕


I ask for recommendations and advice 😱 😱

I've been told to use Deoxit, but not sure how on my amp. Do I pull the knobs and shoot the spray down the shaft? Don't want to screw anything up. Thanks for any assistance!

Hello everyone,
I desperately need some help. Does anybody have the copy of "Tele-tech/Electronic Industries" magazine july 1962 issue? I have downloaded this issue from americanradiohistory.com, but the main problem is that there is missing page from 115-118, 116 and 117 no pages are missing. That article is very important for my project and the main 2 pages that describing the circuit diagram are missing. So if anyone in this group luckily have the 1962 july issue of tele-tech/ Electronic Industries without a missing page, please let me know.The name of the article is"design information for regulating and stabilizing HV power supplies" by donald O. Ward.

Thank you all

Which commercial brand uses Scanspeak discovery drivers ?

In the top diagram, is the basic input of an Audiosource AMP100, which is designed for +4 dBu pro level. The first thing the signal hits is an opamp configured as a voltage follower. (Unity gain.) If I want to convert the input to -10 dBV consumer level, is it as simple as adding the feedback circuit in the bottom half of the diagram? I have it set for a gain of 11, which is close enough to the 11.79 that I calculated.

Thanks all.
Artie

Could anyone tell me if they have used Holton modules with the predrilled UMS heatsinks available on the the DiyAudio Store ?

HPA-NXL300 R4 – Holton Precision Audio

It would make casing up a project much easier if the hole spacings match the spacing of the transistor holes.

I am interested in upgrading my 20 year old Audiolab 8000M amplifiers.

Hello guys, i'm building a stereo crossover from Elliot Sound products
'Isolator' Equaliser


I'm not totally sure hot i have to connect the 2 quad-gang potentiometers which allow me to switch the crossover point. (2 sections of a pot will control L channel, the other 2 will control R channel)

I picked 2 of those dentent pots
https://www.mouser.it/datasheet/2/54/ptd90-777943.pdf



Attached you can see how i would wire it. do you think is correct?
i attach the original schematic from ESP as well.





thanks for any help🙂

Need space for new project therefore selling this Amp :

https://www.diyaudio.com/forums/pass-labs/108683-ugs-power.html

Perfect working condition, asking 1000 Euros + shipping which will be high due to weight ...

Finnish Hi-Fi company Hifitalo has some DIY designs that incorporate their own (as far as they claim) TransFlex enclosure designs.

I've tried searching transflex, and browsed some resulting threads about tapped horn designs and transflex design, which apparently originally is an older idea that has been patented at some point(?) and that seems to incorporate an inward firing driver(?).

However, I'd like to ask if anyone knows how to calculate these "TransFlex" cabinets Hifitalo uses. By drawings they seem to be bass reflex cabinets with an outward firing woofer, but incorporating inner structure of adjacent chambers of increasing volume with ports in between with increasing port area. Hifitalo claims the enclosures have very controlled bass response and reduced woofer excursion.

Hifitalo is a fairly big Finnish Hi-Fi company that for instance is the official importer of Seas drivers in Finland. Hifitalo also bought an established Finnish loudspeaker company OR and continues their manufacturing with some very good results. I've also heard one of their DIY designs incorporating the "TransFlex" (Aw-3 Alu https://www.hifitalo.fi/aw-3_alu_rakennussarja) that sounded really good, especially the bass for that small a speaker. Based on all of this, Snake Oil isn't the first thing I'm thinking.

Does anyone know a way of calculating this kind of enclosures consisting of adjacent chambers that have ports between them? By intuition I'd imagine they might be essentially transmission lines or horns or derivatives thereof.

In the next posts I'll link a few of these designs I'm talking about. Hifitalo has descriptions (or actually marketing speeches) for the designs in Finnish, but I think the detailed blueprints speak more of the actual designs, so I'll link the blueprint PDF's. Every enclosure is supposedly designed for a specific speaker (or a specific woofer), so I'll include driver name and any essential info provided (as well as the original sales speech page as a link as well).

Bought this amp knowing beforehand that it didn’t have no output. Upon getting it on my test bench I confirmed it had rail voltage and the plus and minus regulated voltage. I checked the outputs and there were no shorts. I replaced both A3120 optocouplers and both NE5332 opamps. Upon replacement I had rail to rail oscillation on the outputs and produced clean audio on the bench. Upon installation in a vehicle and setting the gain on the amplifier I got full voltage on the speaker terminals and a deformed square wave. Removed the amplifier from the vehicle and installed on my test bench and couldn’t replicate the issues in the car until turning the gain to the max. I’ve repaired a few MTX’s but never had this issue before.

Hi, does anyone have experience of, or comments on, this particular kit. It's the right size and sensitivity for my first time build. Thanks.

Kit enceinte 2 voies, haut-parleur coaxial, TLHP X17-1460, avec caisse en kit CP 24 mm

Heya,

I searched high and low to see if I could find the exact issue I'm running into with the exact kit.

I've assembled the China 6J1 tube preamp that's a fairly popular DIY kit. I've tried everything that I can think of, but I cannot get it to function 100%. There's a rhythmic popping noise that comes through the speakers. I turn the preamp on, everything's fine (music comes through perfectly), but after around 10 seconds, there's a POP, POP, POP noise that starts up and never stops. The noise is constant, regardless of where the volume knob is set. Oddly, the popping cadence increases slightly the higher the volume knob is turned.

The power adapter is AC 12v 1200mA, right on the money. I've already tried replacing both tubes and re-flowing all the joints. Nothing is helping, and there is no change in the behavior.

I'm at a loss. Do you have any ideas as to what may be causing this? This is my second DIY kit so I may take some moments to get the right info for any followup questions you might have. Thanks!

After reading numerous posts on XLR grounding I am now thoroughly confused.

The pro's say that pin 1 should be connected to chassis and not 0V.

Have I got this right ?

Hello Folks

First post - I joined 10 years ago and every so often I end up back here for an answer - but, this time I can't find an answer. Please bare in mind I can just about remember Ohms law and understand a capacitor but when it gets all wiggly I tend to get a bit confused...

I see this topic crops up across the net and here every so often: why can't I use a mic pre-amp with my turntable? I know there are reasons why not - RIAA, impedance mis-match, capacitance mis-match, level mis-match.

I've read some discussion about the merits of pre or post pre-amp RIAA correction - but, to use the mic-pre amps I will be using post-pre amp software RIAA correction.

Requirements:
1) Impedance match from 3.7KOhms to 47KOhms;
2) Capacitance (variable?) match to present between 200-500 uF to the cartridge;
3) Balanced;
4) Possible amplification (5 mV MM Cart to 10mV Mic - What's that in db...?);
5) If amplified, then phantom powered.

The mic inputs I'm trying to drive take a minimum input of -45dBu for max output, which my 4mV cartridge will just/ almost meet according to analog devices db conversion tool - but, it's not good to drive an amp at maximum - or is it?

I first looked at this:
Phono Transfer System Bare Flat Preamp PC Boards
Following a discussion on using a mic amp for a phono cart here:
Mic preamp as phono preamp? - Gearslutz
So I assumed it was for mic level input, but it's not. It's for line level input and so negates the mic pre-amps I'm trying to make use of, uses up a couple of live level inputs I want for other things and I suspect it's rather more amp than is necessary.

I then found these:
Groove Sleuth Adaptors
At the other end of the spectrum - they're very expensive and I suspect are nothing more than an XLR with a resistor inside...

So, does anyone know of a diy project that fits the requirements of 1-5 above? Or, any other comment... 🙂

(Also, have I posted this to the best forum - there's so many on this site!)

Thanks for listening.
Morgan

I need one Beryllium Tweeter for my Focal Utopia Be speaker. It's a TBU model used on Utopia Micro, Diva or Alto Be speakers. I need one in working condition (whether new or used) without cracks or holes on it. I'm willing to pay decent money for it. Even your tweeter has some small blemish, you can contact me also. I hope can receive your message ! Thank you so much !

Phantom Focus Cube12 Subwoofer

Hi, I have my PCB and right now I soldered a lead from one of my common ground v0 to the chassis.

Is there a way to design the PCB with a via/hole attached to the ground plane and then use a metal screw or some kind of post that screws in to the ground of the PCB and then run a wire to a ground post to the chassis?

I am rethinking the amount of Voltage I shall supply the Mooly amp, Mooly has written 45V-0V-45V as a possible voltage to his great amplifier but I am thinking if it would be of some advantage to supply even more.
I am not doing that to play louder but to have even more power so I can use that amplifier to test and drive future speakers.


The gain is 47 times or 33.4dB, And max input from a CD-player should be 2V
You could say that it's 47 gain X 2V, or 94V, but that sounds insane much to me.

How do I dicide on max voltage and ampere?

Hi
Have to replace some final stage bjt, sanken sa1294/sc3263.
I do not have any idea how closely each pair should be matched, maybe it requires rhe hole 6 pairs per channel to be matched, do not know...
Any knowledge anyone?
I do see all are siries y, which Sanken state have hfe 70-140.
Also emitter resistor is 0.22 ohm 5%
Thanks

I just picked up a R&S UPL on eBay for a good price, but it suffered from a shipper that just didn't care if the item made it in one piece to its destination. Some pieces have broken off the case, mainly feet, however the LCD isn't right either. Only the upper left corner is illuminated, the rest is pretty dark and hard to read with lights on in the shop.

I am trying to decide whether to keep it, break the cal seal and attempt repair, or just return it.

When it first arrived, it would not even boot up. After several hours of poking around in DOS, I finally got the UPL software to start up. I also found and loaded a diagnostic BASIC program and ran all tests. They passed.

The issues are:

Broken feet
Noisy fan bearing
Dim/unevenly illuminated display

If that display could be repaired with a new backlight, or replaced entirely with something equivalent but maybe a bit better, I think the instrument could be servicable.

Does anyone have photos of the inside of a UPL? Has anyone repaired the LCD display on this particular unit?

I have a pioneer 9100 that I would love to resurrect, but one of the issues is a broken volume pot assembly

The original has 2 gangs (two with a ground, six in total) with an additional two prongs coming from the bottom of each gang (what are these?).

I was able to retain the first part of the volume assembly and attach a new double gang pot to the back (keeping the volume limiter (0-30-60db), but I don't know what to do with the extra wiring. There are no pots available which have the same configuration as the original pioneer.

I took many pictures, and looked at the schematic, but I'm not sure what to connect/disconnect so that I can retain (at the very least) the main L/R volume functionality. Can you easily tell what the wires do by their colors?

The link is to a folder with some pictures of the pot. I also have some addiitonal photos if these aren't enough10.0.0.0.1 192.168.1.254 hotmail.com

This is an active crossover for the Duntech Thor self-powered Subwoofers circa 1986.
I'd like to move the crossover point (3dB down point) from 110Hz down to 90Hz or so.
I sent John Dunlavy a fax inquiring how to change it to 160Hz (1987), and he sent me a fax of the schematic and some suggestions on what to change, both on the active circuit passthru to the midrange power amp, as well as in the subwoofer's equalization circuitry. He suggested .086uF instead of .1uF which is the value of the caps in both places he told me to change. I forget why I wanted to raise the crossover point, but in hindsight, that's the wrong direction!
I never actually took his advice. Instead, I simply bypassed the active pass-through circuit which drives the power amps [to the mid-range speakers] with a .047uF MIT Multicap (which turns out to be the 3dB down point of 60Hz). (As calculated for a 60,000 ohm input impedance of the Amp).
I lived with that for 25 years. But now I want to also shift the 3dB down crossover point in the circuit which drives the subwoofer down to 90Hz or less.
I began by changing the .1uF cap that John suggested I work with - to a .147uF.
It is indeed starting to shift the 3dB down crossover point downwards but it's also reducing the output at say 40Hz and 30Hz as well by a small amount - 1dB or so. Not exactly the direction I want to go with my bottom Octave! So, I am looking for ideas as to where in the circuit to start modifying the crossover point without reducing the bottom Octave's output at all! I have the schematic and can email it to you, if you need to see it. thanks in advance. -TMack

Hi all,

I'm about to start putting some passive xo's together for my 1st time.(I've always used digital xo's before but want to learn how to do passives for speakers that I don't want to use 2 or 3 amps per channel for)

Can anyone recommend me some cheap but good brands, and maybe a range of component values that will let me buy a few in so that I have a 'parts bin' to hand if I am experimenting.

I don't mind if they are not the 'best in the world', if my projects end up being successful I'd happily buy more 'audiophile' quality ones.

I usually build with pro drivers / compression drivers if that makes a difference to the power handling of the parts.

Thanks for any help,

Rob.

Hi guys🙂,
last week I started to design an active crossover an I just finished. Now I would like to create two transistor amplifier boards, one with about 100W@8ohms and the other one with 70W@8ohms, both powered with a toroidal transformer. Normally I find the schematics online and I modify them for my purpose, but this time I haven't found anything😱.
Can somebody recommend me something😕?
Best regards
Ben

Here's a new mini streamer/DAC project I recently completed. It's currently being used in my shop and I'm listening to as I write this. I wanted this project to include subsystems I already owned, but weren't using. For the past year or so, I've been using RaspPis and DAC HATs configured as roon end-points, so I've gotten a fair bit of experience getting these DAC/streamers up and running. But, I wanted something more contained with all cables coming off the back panel rather than 3 sides of most RPi setups. From a software standpoind, I've been a big fan for over a year now of the roon digital audio, whole-house streaming eco-system. This software is a pleasure to use. Once you have your digital library online (NAS), and capable roon server hardware, you're ready to go. Plus, it's pretty painless to configure and get it up and running too. Roon allows you to purchase their customized back-end server, that runs on a variety of hardware platforms. It also has what they call end-points. These are streamers and DACs that play the music from your network. If you build you own end-point (like this project), also available is 'roon Bridge' which will configure the end-point(SBC) running Linux to work with roon Server. Another Linux solution for an end-point is to use DietPi. It offers an option to automatically configure 'roon Bridge' with from a single software selection.

This project is a hybrid of hardware/software subsystems matched to provide a very small footprint that can be used wherever you have an amp, speakers and network access. It can easily be setup using a USB WiFi dongle for access as well, if you'd rather go that route. You'll see how I've mixed and matched the various hardware systems below. Now that I have a fully assembled unit, I thought I would share the project with the DIY community. The following are the individual hardware/software pieces I used and necessary links.

Hardware:

(1) For the DAC I chose a Toneboard (TB) from Khadas. This little DAC is based on the Sabre, ESS9038Q2M chip, and has been designed well, and provides excellent sound for only $99USD. It can be used as a stand-alone DAC with USB, or coaxial input. I'm using the 'generic' version, but I ended up soldering an extended 40-pin header to it as it was a prototype for using their SBC (VIM 2) - which I am not using at the moment. The 40-pin header is not needed for this project.

https://www.khadas.com/tone

(2) As I wanted streaming capabilities, I need to pair the DAC with an SBC that had ethernet capability and USB. I could have used I2S, but opted not to for this streamer. Besides, the USB-in on the TB DAC uses the well-known XMOS chip so you're getting a well-established interface from the get-go. The SBC I chose was the NanoPi NEO2. This little guy has a very small form-factor and works perfectly for this project. It has all the necessary elements required for streaming duty. The following link is to the newer 'black' version than the one I had (a couple years old), but is essentially the same PCB using Allwinner’s 64-bit H5 quad-core SoC (ARM Cortex-A53) SoC. The NanoPi Neo2 costs $20USD. More information can be found here;
http://wiki.friendlyarm.com/wiki/index.php/NanoPi_NEO2

https://www.friendlyarm.com/index.php?route=product/product&path=69&product_id=273

As you can see from the web-page for the NEO2 there are a couple extra parts I used, and you may find them there to purchase along with the SBC.

(3) Since I was going for a complete, single and fully self-contained unit, I needed a suitable and reasonably attractive looking enclosure that could house both the SBC and DAC, and still looking good sitting in a rack, or shelf. So, I had remembered a year or so ago, FriendlyELEC was having a sale on an enclosure that was designed for a single 2.5" harddrive NAS box, using the NEO2 SBC. At the time, I was intrigued enough to buy one as they were only $12USD for the PCB and aluminum case! Quite the bargain I thought. In addition, it was specifically deigned for the NEO2 form factor and connectors! Voila. I had a solution. Now if I could get everything to fit into the case, along with a minor amount of modding - necessary for the DAC and some RCA jacks on the back panel. You simply plug the NanoPi into the dock and you're ready to go. You get a 12VDC power jack, an extra USB (2.0) port and an on/off switch. If you don't have a suitable 12VDC PSU, you can purchase one for $10USD on their website. Here's the link to the enclosure.

https://www.friendlyarm.com/index.php?route=product/product&path=89_93&product_id=222

As of late Feb 2020, looks like they are still available on their site for $13USD each. A bargain even if you didn't get the included electronics that turns into a little NAS box. But we're not using it for that purpose. As I write this I'm testing a good 12VDC linear wall-wart from Jameco. This should help to improve the sound. I think it sounds better than an iFi PSU.

Software:

As I mentioned above, I chose to use roon as my digital streaming software. Actually, roon is a whole eco-system for digital streaming. However, with a little bit more effort and other software, you should be able to get any Linux version that runs Volumio, or Moode functioning as the MPD, if you setup a backend server like LMS (Logitech Media Server) to access a NAS library. I started out trying to get Volumio working with an LMS a couple years ago prior to discovering roon. It worked, but not reliably so I abandoned that approach. Now I use roon exclusively and have an Intel NUC running the server and end-points throughout my house. I will say roon is expensive at $600 now for a lifetime license/subscription. This offer may be going away at some point too. Now is the time to pop for it if you can. Here's the link to everything roon.

[COLOR="blue"]https://roonlabs.com/[/COLOR]

The second piece of software we'll be using is Dietpi. I discovered it a couple years ago, and if you like to play with SBCs and Linux, Dietpi is where all the action is. It's free to use and allows the Linux noobie like me to configure just about any kind of software/application using a menu system! And, it's available on just about every SoC SBC board on the market from Raspberry Pis to ARMs and other CPU based boards. Why is it important for this project? One of the options it provides is to turn your SBC into a roon end-point with about 3 keyboard strokes. Literally? It's that easy, so that's why I chose it for this ARM SBC end-point. I believe this is the correct/latest version of DietPi for the SBC (Cortex A35).

https://dietpi.com/downloads/testing/DietPi_NanoPiNEO2-ARMv8-Buster.7z

Attached below are some pictures of my build at various stages.

What do you thing? The general idea is to use ax7 half for gain stage and au7 half for cathode follower which is more fit in for that approach. The concern is to low current for au7 half than.

Hi all,

Just looking for good advice.

Is it good form to XO @ a drivers natural rise of impedance if not using a zobel, or @ new impedance with zobel installed, or is it of no consequence?

Thanx, Mick.🙂

I have a Ciare HWG 160-4ohm that is really more suited in a vented enclosure.
I have a 3 way cabinet design that has a sealed mid chamber of only .275 cf after all displacements (including this speaker). My question is is this going to be too damped in this small enclosure? Calculator is showing about .95 cf for sealed alignment of .707. Since the Qts is lower than the Qtc and the xmax is not too small I think it will work but just looking for opinions. I tried to model this driver on winisd but did not work will, the frequency curve was way off(not even close to linear) from what the manufacturer shows which is very flat +-3db!!

I will probably be crossing to allow usable frequencies of 200 Hz to 2k Hz. I am using a dsp with a few different crossover options so it's easy for me to play around with different xover points.
I am using a Morel CAT378 Tweeter and still playing around with
8" bass drivers, not a giant fan of Dayton but they have an 8" sub( RSS210HO-8) that
will tune flat to around 34 Hz in a 1 cf enclosure, which is what I have in
my cabinet...not as low as what I would like but my project started off very small and now it is twice as large as I was hoping!! 😱Why can't I fit a 3" x 60" port into a matchbook😱 PLEASE PARDON MY TANGENT

I am fond of the lateral mosfet OPS power amps and after building two successful examples:
Assemblage Power Amp

and the bigger lin type:

Very HQ power amplifier (Assemblage VII)

I want to build another one with hopefully even better high frequency response.

Recently read this paper by Bob Cordell http://www.cordellaudio.com/JFETs/LSK489appnote.pdf
where I found a DOPA using a folded cascode IPS and decided this would be a good start for my new power amp.

Allready simulated one possibility but have some doubts about it's viability.

My sim indicates this design is stable even without compensation.....
I can not reduce 1khz distortion below 0.015% THD....
I am not sure about the best ccs to use for the folded cascode IPS....

Hope my design captures enough interest and discussion so I can improve this solution.

Please find the schematic and asc file in attach

Best
Ricardo

Hi everybody,

I'm desperately looking for a replacement part for an Accuphase C-200V preamp - a tape input/output selector switch, which is no longer available from Accuphase or its authorized distributor in Germany.

It's an Alps rotary switch, 1 pole, 5 positions, 18 tooth serration.

The Alps part no from the current catalog is SRBM150500.

It is impossible (for me) to source this component in Germany, but it might be quite easy in other parts of the world. Maybe someone even has such a switch in his junk box. Please drop me a line if you can help!

Thank you 🙂

This is your chance to own a pair of GAUSS CETEC 4081 2" compression drivers.
These are in nearly new internal condition, the diaphragms are in pristine condition and are phenolic, 4 1/8 inch. 8Ω , 119dB, 300-12000Hz, 17kgr monsters. These are rare as hens teeth and fabulous sounding devices!

Yes in the first pic it is the one on the right, the biggest one...24cm in diameter and 15cm height.

I'm looking for metal can equivalent transistors of the following:

MPSA42
MPSA92
BC182B
BC546B
BC556B
BC449A
BC449

Any help will be appreciated. Thanks!

Sold, thank you for your interest.

Brian Oppegaard, President of SpeakerPower sent me one of his Torpedo SP1-4000 amps for evaluation. Brian spent 11 years as Director of Engineering at QSC Audio Products, Inc. and seven years in the same capacity at Renkus-Heinz before starting Speaker Power in 2002.

SpeakerPower has a wide variety of “plate” amps for use in powered speakers.
The SP-4000 is presently their most powerful amp, and the first amp in which the company makes every circuit board used.

SpeakerPower - Home

The amp is rated 4000W/2 ohm, 2400W/4, 1300W/8, it weighs only 7 lbs.
Front panel has one input, a balanced XLR input with a looping XLR output.
One detented volume control, two push switches, one selects full range response or a 30-80 Hz sub filter, the other a polarity reversal.
A Powercon locking AC input, and a Speakon locking looping speaker output complete the “user interface”. The internal speakers are connected with a latching polarized six pin connector.

The amp itself takes up very little internal volume in a speaker cabinet, and produces almost no heat, critical features for a powered speaker amplifier.

When compared to other amps, the lack of heat produced by the 90-95% efficient SP-4000 was striking. The cool operation also uses less power from the AC power service, very important when using the amp with marginal power. More power delivered to the speakers with less from the wall is not only green, but louder!

So how loud does it go, how does it sound ?

Sounds just like the signal going in, until the clip light goes on. Even after the clip light goes on, very little change in sound quality, the clip light is tied to a very fast limiter. Pushing the amp another 6 dB harder after the clip light illuminates, little harsh clipping sound was generated.
This could actually be a problem for some users who will crank the input until high average power smokes the speakers, since there is very little audible tell tale clipping sound.

The SP-4000 has enough power to cause thermal compression with a pair of Eminence Lab 12 six ohm speakers in a matter of minutes using band limited pink noise run just up to clip. Speaker tests were done with both horn and bass reflex cabinets.
Pink noise has a crest factor of 12 dB, more than some heavy duty compressed dance music, users may exceed the average level of pink noise.
The amp did not heat up even with a nominal 1.5 ohm load, but the speakers sure did!
Without some external limiting to keep average power in check, the SP1-4000 does have enough juice to burn speakers in the 400-700 watt continuous range.

So the amp was able to make the Eminence Lab 12s and a 4015LF sound distressed when hit hard, what about “big gun” speakers?

Just about the time the amp arrived for evaluation I was testing new cabinet designs for the B&C BC18SW115-4, a four ohm 18 inch speaker that handles 1500 watts with around 15 mm Xmax.

I used the SP-4000 for much of the speaker testing, it was nice to not have a noisy fan blowing heat into the shop while the speaker was getting the equivalent power of a space heater.

The BC18SW115-4 speaker could probably take every watt the amp could produce without a strain, so from a “bullet proof” powered speaker application, the amp would be a good choice.
That said, for operators that wish to take advantage of the huge peak potential of the latest crop of super speakers, more power could be used.

Brian is working on an export/high mains voltage version of the SP1-4000 which will do 110 V in to 2 ohms, 6000 watts, using a buck regulator to reduce 180-240 VAC mains to a 190 VDC rail for the amplifier. The SP-4000 has a 170 VDC nominal rail.

Power of the high mains voltage version will be approximately 2000W/8, 4000W/4, 6000W/2. The 2 ohm number is tentative and depends on AC line voltage and quality.

This will also apply to the SP1-2400. At higher mains voltages it will do 2000W/8 4000W/4, but no 2 ohm rating.

Brian is also kicking around the idea of doing a 100-120VAC boost regulator version which will do the same numbers.

He asked me if people will pay the extra $100 or so for the higher power.
I can only answer for myself, if using speakers in the power range of the BC18SW115-4, definitely yes.

Having looked at trends in speakers and amps as they chase each other’s power ratings for almost four decades now, I think the new crop of speakers that can handle 1500 (real) watts and peaks of 3 to 6K will only grow larger, a super power plate amp will be welcome.

Using music and pink noise I tested the SP-4000 against all the amps in house, a Crest CC2800, a Crest CA-9, an old Crown PSA 2 (weighs 8 times more than the SP-4000 !) and a QSC PLX-3602.

All the rack amps are capable of 4 ohm bridged mono operation, so a single four ohm load was used.

With music and pink noise into a BC18SW115-4 loaded bass reflex speaker, the Torpedo equaled the SPL output of the CA-9 and the PLX 3602 (though one 3602 died during testing) put out about 4 dB more than the PSA 2, and 5 dB more than the CC-2800.

Notably, when the SP-4000 was loaded at two ohms, (one speaker and a dummy load) the speaker level only dropped by 1 dB.
None of the other amps could put out as much level as the SP-4000 driving two four ohm loads.
As it stands, the SP-4000 is the highest power commercially available plate amp I know of.

Art Welter

I am looking for some opinions....

I recently acquired a commercial Leach amp: The Leach Amp manufactured by LSR&D back in the 80's. It is based on the Leach Low TIM amp design. The specs are fairly impressive, and the power supply is massive. I have had the opportunity to listen to a Leach Double Barrelled amp in a fairly high end system and was impressed with the sound. Listening to this amp for a short period left me disappointed. The sound was veiled and undetailed. The sound stage was almost non existent.

I am driving a pair of Martin Logan Aerius electrostats, but it shouldn't be a problem for the amp. My source is a McCormack CDP and a Curcio Daniel pre amp. My system amp is a Radford ESA225 tube amp (25 wpc Class A) and the basis of my comparison.

So, are the Leach and Radford in two different classes and should I move on in my quest for better sound? Could the Leach be out of spec (it seems to have had a hard life before coming to me!).

Comments and suggestions welcome.

thanks,

Paul

I have a (non-working) Lenovo Ideapad Z580 15" laptop running Win7. I pulled it out of storage in response to THIS thread. I messed around with it for a couple hours today and seen some sign of life (lights came on), then nothing. It seems a shame to throw it in the trash, but that's where it's going soon. Your's for the cost of shipping. I may advertise it for free locally as well.

I'm just building an input selector / RCA - balanced convertor.

The case is quite tight but it does all fit.

Should I mount the meagre mains transformer at the front of the case away from the XLR connectors or just leave it where it is ?

I don't really want any more holes in the chassis than absolutely necessary.

EKTA

Used set in good condition

Scanspeak Revelator R2904/7000 - sold
ScanSpeak Revelator 12M/4631G 4.5" Midrange -sold
ScanSpeak 18W/8531G 7" Revelator Woofer - Sold

with premium crossover. ClarityCap, Goertz Copper Foil Inductor, Mundorf Metal Oxide Film Resistors

Asking USD1xxx, adsorb paypal by me.

I am an experienced in wood working, but I have mostly worked with solid wood. When I have used veneer, it is in the form of veneer plywood... used for table-tops and as the panel in frame-panel cabinet doors. Speaker construction is somewhat different than normal cabinetry (obviously).

I am planning a project using 20mm (3/4 inch) Baltic birch plywood, and there will be many countersunk screws on the outside of the cabinet due to the bracing. Before I veneer the outside of the cabinet, I assume I must fill those screw holes and sand flush so that the veneer has a smooth flat face to bond to. I am using peel-and-stick veneer.

What is the recommended filling material? spackling compound (used in gypsum board / drywall construction)? automotive "bondo" body putty? I can think of several materials which might work, but what is the best practice ?

Jim

Up for sale are two high quality M6 core 280H @ 20mA (DCR 5K) 70H @ 40mA (DCR 1250 R) made in Germany.

Item location Slovenia EU.

Shipping worldwide.

Price: 80 EUR + shipping

Since a week hificollective does not respond to emails; phone is not answered.
Anyone has a clue what might be going on?

Hello,
just wanted to ask wether a push-pull Langevin 311C could be used for a cathode follower parafeed 600 Ohm output for a preamp project?
Just want to replace the Triad HS 50 for a Langevin 311C in the circuit shown attached.
Many thanks in advance.

I have 2 pairs of older EAW DS123Hi speakers that are being used as front and center channels in my home theater.

They use RCF N479 (EAW CD2520) 1" compression drivers with phenolic diaphragms, and they seem to quickly roll off the treble around 13Khz. My Yamaha preamp always turns the treble way up when I use the YPAO auto setup mic. These were used commercially before I got them, so I'm not surprised that the tweeters seem tired.

It looks like I might be able to use the B&C DE250, and mount with 2 of the 4 holes, but I'm not sure. If anyone has any other suggestions it would really help. I also see a couple models by Celestion, Peerless and LaVoce that might fit.

These speakers also have new midrange drivers made by B&C, model 6/033B-8. That's one of the reasons I was leaning towards a compression driver of the same brand.

Another option I considered was putting aftermarket titanium diaphragms on the existing magnets, but I wasn't sure how well those work.

I normally get my speakers from Parts Express, so I'd prefer it to be something they carry.

Hello
I just salvaged this IC and tried making this circuit :


TDA7297 Audio IC - Electronic Circuits, TV Schematics, Audio



However only output 2+ (pin 15) works and the sound is very very low, very distorted. Is the IC dead or did I make a mistake somewhere, is there a way to test the IC ?
Current is about 0.1A. Signal ground and Power ground is connected.

Thanks

I am cleaning out my capacitor supply. Many of these caps are new and the rest are used but in working order. 10 day money back guarantee (less shipping).

PRICE: Make me an offer on individual caps, multiple caps or the whole lot.

here is what I have (quantity x description)

14 x Russian PIO 50uF 1000V (1KV) (large brown box w/ white terminals)
10 x Russian PIO 30uF 160V (brown box)
4 x Russian PIO K75-10 2.2uF 250V (green small)
2 x Russian PIO K75-10 10uF 250V (green large)
8 x Russian PIO K40Y 0.47uF 600V (silver)
2 x Arcotronics MKP 5uF 1200V
6 x Juniper Copper Foil Paper & Wax 0.47uF 600V
8 x Mojo Dijon 0.47uF 630V (yellow)
1 x WIMA FKP 4 1uF 1000V
1 x WIMA MKP 4 DC Link 20uF 1100V
4 x WIMA MKP 10 4.7uF 400V
2 x WIMA MKP 4 1uF 1000V
4 x WIMA MKP 4 4.7uF 400V
2 x WIMA MKP 4 2.2uF 100V
2 x Rike Audio Audio S-Cap 0.068uF 600V
2 x Rike Audio Audio S-Cap 0.033uF 600V

Built a pair of F4's paralleled as monoblocks. Lots of time on my hands these days (ha!) -

They are killer -- almost imperceptibly less transparent than my OTL's - and those take a massive amount of power (and money) to run. Quicker than my OTL's, not as liquid as my SE amps -- but more far slam than them, even with 25W (solid state watts, which ARE different)......

Hey, this wasn't meant to be a review......sorry.

Got a small (teeny - tiny) hum from one of the monoblocks, only noticeable at close range to my Lowthers - (not with my other speakers).

hey, we all know how sensitive Lowthers are -- and I've got a choice, since I'm assuming there's a less than perfect PS cap in there somewhere. Anyone think it could be something else? (bad ground?)

I can swap 'em all out, or just forget it. I'm anal, and like I said, got lots of time on my hands these days. Once the music's playing, at any level, you can't hear it.

What would you do?

Looking at a Holden and Fisher toroidal transformer, the label says "Rating 30". Its a 15-0-15V transformer, not to big and I was wondering whether the 30 means 30VA or 30 amps???

hey all

i have the creative soundworks 740 cd radio , the display has gone dim on one side only

ive broken it down so far in the hopes i can fix it

a,would this screen be custom to the unit or likley i can source a replacement ?

b, are there any replacable parts inside the black screen ?





any help apreciated

Hi,

I just built my new amp yesterday, using a nc122mp module and a ghent audio case.

When I first powered on the amp, I got a very loud hum in the speakers. (>10m audible)
As soon as the preamp was turn on, no more hum noise.
Then I tested the amp alone (without any xlr plugged in, only speakers out) and still had the noise.

So I once again checked my solders, and notice a little lug on the xlr socket, near the pin 1.



After some readings, I decided to solder the pin 1 with this chassis lug, and the noise mostly disappeared, when no XLR cable is plugged.
If I plug the XLR cable again, the noise is back, and if I "move" the xlr cable, the noise changes.

Now, I've a few questions:

• when I compare with same ncore/ghent audio builts pictures on the net, nobody solder the pin 1 with the chassis lug. Is it needed ?
  
• I used thermal compound between the case and ncore module (not the full area). Maybe it "breaks" the ground connection, so it's why I needed to solder pin1 with chassis lug ?
  
• when reading the "Legacy pin 1 problems" whitepaper on hypex site, I understand the good solution is to solder the pin 1 to chassis, and no connection between audio circuit and pin1.
  But in the ghent audio case kit, the pin 1 should be soldered to J4.3 and J4.14 (GND).
  Do I need to bypass it, and only connect pin 1 to socket ground lug ?
  
• Do I need to soldier pin1 to chassis lug in the XLR cables too ?

Thanks for your help

After a few patches the RPI4 USB audio class 2 gadget supports the maximum 1024bytes packets size in USB2 microframe (i.e. 8000 x 1024 bytes = 65Mbits/s duplex throughput) now. Good opportunity to test how common software analyzers deal with high samplerates.

Tested in linux which accepts any samplerate reported by the USB audio device. I configured the gadget to use 1536kHz/24bit/1ch (36.9Mbits/s), with sox generating 700kHz sine signal on the RPi. The USB host was capturing from the USB gadget and analyzing .

Arta in wine - fixed samplerate at 192kHz, not working

REW - not tested yet but definitely will require low-latency garbage collector of the latest java.

Audacity - while it accepts files with any samplerate (I have tested 10MHz files), its soundcard backend is limited by portaudio samplerate range, probably could be changed and recompiled. Stock version not working.


VisualAnalyzer in wine - did not offer the device samplerate, but could be configured at any samplerate. Would require some work (from its author as it is not open source) but its potential is quite good. Screenshot taken.


jaaa - a simple open source FFT analyzer in linux, works OK. Unfortunately only 128k FFT length which is quite little. But this could be changed in the source code. Screenshot taken.

Hi,

I'm all new to this forum hoping for some help with me trusty amp.
I bought this amplifier from Dubai where they have 220 Volts with 50Hz cycles, but i'm now moved back to Canada where it's 110V with 60Hz cycles electricity.The unit does have the voltage selector to select the voltage like 220V-240V and 110V-120V and i'm using 110V-120V.

For some reason when i turn on the unit, it turns ON with all the lights etc but it's the Speaker protection Relay is not Clicking (not completing the circuit to pass the current).

Is the because of the more Voltage Hz cycles as it was made to get 50Hz but here in Canada it's 60Hz or is the Relay unit itself which is now faulty for no reason all of the sudden ? I could be wrong but the unit was working perfectly fine in Dubai before i moved back. I have attached the pictures of the circuit and the Relay as well as the the service manual with diagram.

Your time and help would be appreciated.

Service Manual Link :
Pioneer SA-1040 - Google Drive

Hello
I am thinking of getting some second hand Sennheiser Momentum 2 headphones and wondered what people think of them. I will be running them from an Audiolab M-Dac phone output.
What are they like for the money.
Thanks
thyristor44

Hallo forum members,

My name is Paco and I live on Aruba since 2003.
I have started a Pro Sound rental & sales company in 2015 and I build speaker systems for almost 30 years.

It's a pleasure to be a member of such a large database forum full with amazing projects and knowledge!!

I hope to do my share to this forum!

Have a wonderful day!

Hi everybody,
Nice to have a discussion with everyone. Although, I have registered to participate in the forum for a long time, but due to my work, I am currently returning to the forum.

Hello you all

Lived in the USA (NYC) for 7 years but moved back to Denmark.

Trying to figure out what to build, that is not just a two way but also not a crazy project that will never be finished or get me divorced.

Currently thinking to build some beautiful 3 way speakers for living rom that can be paired well with some powered subs.

Best,
Oscar

I am novice/beginner speaker builder.
I have built a subwoofer with built in amp and a pair of 2 way bookshelf speakers. I followed a YouTube video for the sub so those components should be ok.
Here are all of the components I used:
Subwoofer - Tang Band W5-1138SMF 5-1/4" Paper Cone Subwoofer Speaker
Amp - TPS3116D2 Class D 2.1 Bluetooth 5.0 Amplifier Board 2 x 50W + 100W with Filter and Volume Controls
Tweeters - Peerless by Tymphany BC25SC06-04 1" Textile Dome Tweeter
Midrange driver - Dayton Audio RS100-4 4" Reference Full-Range Driver 4 Ohm
Pre built crossover - Dayton Audio XO2W-4.5K 2-Way Speaker Crossover 4,500 Hz

My issue is over powering bass both from the subwoofer and from the speakers/drivers (the larger issue is the overpowering bass on the drivers because I can turn down the sub channel bass on the amp). I have an old pair of one way speakers and when plugged into the amp the bass is not overpowering in either the subwoofer or speakers. This is why I am assuming it is the crossover that is causing my issue. Should I have used a woofer and a tweeter with this crossover is stead of a mid range? Are you not supposed to use crossovers with midrange driver? Is this the wrong crossover to use? ( I chose a crossover with the highest frequency so it would give more range to the driver) The two channels are 50 watts and the wattage needed for both tweeter and driver is 50 is this ok? Thanks.

I have a set of audio files rescued from a source of phonograph record like a gramophone. Very old family stuff records from my elders back in year 1946. A relative has digitalized these with a turntable and gave the records to me in lossless WAV Format. The audios are just conversations of my relatives in cotidiane situations. So it is just vocals materials but mixed with a heavy quantity of noise. Noise is mostly concentrated in the mid-high frequencies, like 1Khz-10Khz. So the records are VERY noisy. SNR is like 0dB or worst. My mission is to filter out the noise.
One advantage is that noise exhibits a cyclical pattern. I tried some classic vinyl restoration stuff like decracking o declicking with Sound Forge, DART 24 Pro. Results were unsuccessful. The best result I had is the "Noise reduction" effect in Audacity, which did output relatively good. But this last one just filters the frequencies where the noise is with narrow FFT. So the vocals content loses the high-mid frequencies. Leaving only mid or mid-bass content. The noise got down but voices are unintelligible.
So I think perhaps I could turn to a Artificial Intelligence solution?. but I have no clue from where can I start. I have some understading of theory of AI, the Perceptron, neural networks, Backpropagation, but I never applied them to audio. Perhaps a Convolution Neural network could be a solution, but how could I train it?. If helps, I have programming skills in C# and knowledge about digital linear filters like IIR and FIR. But equalization based solutions *are not, what I need *.
Below I offer an example track for your consideration.


Pista de CD 3.wav - Google Drive


What can I do for filter this kind of cyclical pattern noise?

Just acquired this amp last night for a project. Was told that the amp had a low power symptom but to no surprise it pops the combination fuse breaker and on off switch. It was powered up using a light bulb on the power cord. Bulb was bright.

The right channel has newer outputs MJ15023/MJ15022. Appears to be an older replacement. Doesn't appear to have anything smoked.

Advice?

I work for Stillwater Designs/Kicker as the Manager of the Electronic Repair Department. I am still working at the Kicker facility! Here is my Bench.

Hello Everyone,

I am new to this forum and I have found some good advice and information already on troubleshooting my technics amps for this OVERLOAD condition. It was mostly other models but it looked like they shared a lot of the same components and design so I was mostly extrapolating to understand how the different circuits worked and tried to apply it to mine.

I did manage to get my hands on the service manual for this specific model so I have some schematics and some voltages to check. Although I am a bit confused as to what the voltages are in reference to. I checked both chassis ground and points that the power modules (IC601,602,651) are connected to on Pin8 (gnd). I figure that's probably the gnd I should be referencing, but I could be wrong.

I was able to find that the common cause of OVERLOAD was either:
1. cooling fan not working
2. cooling fan circuit faulty
3. shorted spkr terms
4. DC offset on output lines (pins 3 and 6 of power modules)

What I have done so far:
1. Tested fan with a 12v battery and it turns on so that seems to work. It's a brushless DC I believe.
2. haven't checked the cooling fan circuit yet as I don't have proper probes to reach all the little tiny spaces where the transistors are and dont want to accidentally short anything out while it's ON.
3. Spkr terms are not shorted - spkrs aren't even connected. The terms measure 20-30kOhm between +and - of each terminal.
4. I wasn't able to find a DC offset, if I measure between pin 3 and 8, and 6 and 8 of the power modules (IC601/602/651).

I read about the solder joints and how they can become bad over time due to heat and board stress. Since the OL would come on after some time of being ON (no spkrs connected and in tuner mode), when it did go into OL, I pushed on the heatsink and the spkA relay would click back on as well as the fan turn on briefly (about 1 sec) and then turn back off and the relay clicked back off). Definitely seemed like a solder joint. The IC602 was replaced under warranty years ago and I could tell the solder points were different and pretty healthy. I re-did some of the joints on IC601, and same problem. I suspected it might be faulty based on what I had read so I pulled it out and tested with 601 missing.

The OL didn’t come back after the amp was on for some time, no spks connected, and in tuner mode like before. Since all power modules are the same number I thought I would try the 651 chip (center channel) in the 601 place to see if it really did go away. I soldered it into place and turned it on and no OL. However at this point, the spkr relays don’t click on. It didn’t click on before either but I figured that was because the 601 was missing and pin 15 seems to drive that output. I then noticed on the schematic that Q651, Q652, and Q653 look like they all need to be triggered to close the relay drive circuit to ground (I could be totally wrong here in my assessment). So, I installed the ‘suspect’ IC back in the place of the IC651 location to see what would happen. Well, OVERLOAD doesn’t appear but the relays still don’t click on. I am not sure if I maybe damaged something else in the process, which is possible, although I am generally pretty careful with stuff like this and haven’t blown any circuit boards yet.

If anyone has a good method to go about troubleshooting this problem that would be amazing. I would love to get any input on this or ideas on what to check and what to expect to see. Im at a point where I don’t really know where to beginning or what to check anymore.

Thanks in advance,

I'm not sure if this is the correct form for my question but it deals with a multi way speaker. I have an amp with 50 watt channels and I have a pair of two way speakers consisting of a full range driver and a tweeter. The full range driver requires 30 watts of power and the tweeter requires 20 watts of power. I added the values together for my amp to get 50 watts. Should I have not done this? Are both my speakers over powered or powered correctly? Thanks!

Hello,

I've been looking to buy an electric car for my kids. Hopefully a new learning experience for them. But i literally can't decide on which car to buy for them . It has been a difficult decision to make for a mere electric toy car. Driving a car is an wonderful and important combination of responsibility and pleasure for the kids. To do this at such an early age would hopefully help them grow better. But a car that is safe for the kids without obstructing their learning is hard to find. The electric car will also help them understand how they can protect environment at a young age.Here are my top 2 choices for thr future purchase , please help me with this decision. Also , if you have any new suggestions feel free to recommend .

1. Power Wheels Dune Racer

Key Features.
Two driving modes in the forward direction- 2.5MPH and 5 MPH.
Power Lock Braking System.
Monster Traction system helps in driving even on Wet grass and Rough Terrain.
2.5MPH in Reverse direction.
Storage area under the hood for other toys.
1 Year warranty for the car.
6 Month warranty for the 12V Battery.


2. Peg Perego John Deere Ground Force Tractor with Trailer

Key Features.
2 speeds (2.5MPH and 4.5MPH) plus an additional reverse mode with speed-lock technology.
Adjustable seat with armrests.
High Traction Farm Tyres for better grip on different surfaces.
In-built FM Radio
Light Weight Body
Full size-Detachable Trailer
Free second-year warranty.

Hey People

Hope your all well!

Thanks for all the great info, learned a lot here over the last few years. First post so any assistance greatly appreciated! Hope its in the best thread?

Repairing/Upgrading amps in my ADAM S2.5A powered studio monitors. Still sounding amazing and mostly working well, feeling they have lost some definition over their 15 years of good use. Would really appreciate some advice so apologies about the many (sometimes lacking in knowledge) questions below!

One speaker repeatedly clicks when tuning off, the other clicks once. Could the be the C5468 Transistors (found some very close replacements, only difference in specs is Pd of 500mw vs 625mw on originals, is that an issue?

On inspection one of the power supply storage caps felt loose, desoldered and better but probably the snap-in on the actual cap is loose. Hot glued in place until I can find some good replacements, haven't tested yet.
There are 2 installed and 4 spaces, would there be any point replacing the 2 10,000uf 50v's with 4 suitable caps, or best stick to the 2? some 380LX103M050J052 from Mouser will fit nicely (381 too wide).

Will do all caps on all boards (smaller caps on power board done).

What else to upgrade or replace with new on the amp board?
Any point doing resistors after 15 years? The big green ones are marked 0R10 5W 5%, .1 ohm yeah? Maybe some Mundorf MOX replacements?
Do transistors degrade much over time? Have some On Semi 5200/1943 in stock, should be ok to match pairs on both speakers.
MJE 340 and MJE 15030, well out of my knowledge spectrum as to worth of replacing/upgrading these..

Crossover/EQ/Protection Board. NE5532, a bunch of there there, replace with fresh 5532's (if so best brand?).
Flim caps, all the Whima and Visays I have are branded and nothing on these guys so maybe worth upgrading?

Flim resistors to SUSUMU RS? Put some in a Resonance circuit of a very nicely build synth (Vermona) and did improve stability and creamy sound quality.

Also feeling it would be good experience to do a few parts at a time to learn more about what difference I get from each upgrade. Either that or just get it done and get back to writing music!

Thanks for reading 🙂

Cheers

Hugo

Got a request from a friend of a friend about a dead Genesis Stealth amp. Can't seem to find any real info about it, other than it takes a bloody forklift to move it.

Honestly, I have to turn him down as far as helping to fix it unless I can get at least a schematic, or preferrably a service manual.

Anyone know anything about this amp? Is it possible to get service data? (I know the co. is belly-up, but maybe someone, somewhere has some info in their collection...)

I'm investigating the possibility of doing a LW style amp with an EL34 for the output stage. I have a pair of Transcendar 5k:8/4 7W OTs that are somewhat under utilized in their current project as well as an Antek AS-1T200 for power. The OT's can only handle 75mA, and 5K is a bit high for the 375v voltage in most datasheets (For SE triode), but going up to 400v looks like a good fit at 5k for about 7W. With the primaries in series the Antek should do about 565 @ 150mA. I'm thinking I drop about 140v across the cathode circuit to power a single triode stage (either ECC99 or E88CC) with a choke load. TubeCad has an article I pillaged all the basics from:

Loftin-White Amplifier

Attached is a screen shot of my current plan. About 60ish mA of bias current (max), a 3k cathode resistor (Dissipates a hefty 6W) and a 1k 2W bias pot (currently set to 350 ohms in the screen shot). The idea being that the voltage drop across the pot (trim-able) plus the drop across the DCR of the choke (fixed with bias current of the preamp stage) sets the -Vgk at the grid. The EL34 cathode current minus whatever gets diverted for the preamp stage sets the drop across the 3K, which becomes the preamp stage's supply.

I'm still shopping for a choke. I suspect I'll end up with a Lundahl from the LL1668 series. There's an outside chance I try a CCS version but for now I like the idea of trying a choke.

I didn't start out planning a DC coupled amp, it's just that the parts I have seem to work out just right. Thoughts?

I'm making the box of this speaker with 15mm multilayerwood for Unique Back Loaded Horn + Bass Reflex Hybrid Enclosure with speaker FE126EN. I would like some advice whether to apply inside of the all walls, material sound-deadener (anti-noise) or leave the natural wood.

When I measure the voltage on the base of Q501 on the power amp boards, I can hear the amp buzz/oscillating through the channel I'm measuring. The test leads aren't touching anything they shouldn't be and I'm using the small clip on leads that have a small hook that is spring loaded. I turn the amp off before disconnecting/connecting the test leads.

Measurements are what the schematic shows for each pin on the transistor, second photo.

DC Offset and bias adjust and hold, the amp sounds fine, waveforms on the o-scope look good.

Am I showing symptoms of having OCD? Should I change the diff pair to matched BC550C's? Or, should I button it up and use it, get drunk?

My Lazarus Cascade Basic preamp needs some TLC. Anyone have any insights about rebuilding one?
What schematics did you use?

TIA!


.

Retail pricing:

JBL 2262HPL - $309
2206H - $450
Faital 12fh500-8 - $273

Why is JBL 2206H much more than the neo version (2262HPL) that seems to do everything better than the 2206?

I'm looking to make a 3-way with RS52AN-8 and Ribbon tweeter.
I'm already listening to this with Dayton RS270S-08 woofer and there just isn't enough woofer. I have to turn the ribbon tweeter down to max possible attenuation with the attenuator. And the mid almost to the max down level. I just don't care fore highs and mids, I guess.

I listen to speakers that are flat FR and I turn the treble way down and bass way up in my computer and then turn the bass way up on the receiver (if I have one and can) and treble way down and then it sounds normal.

I guess I'm between the Faital and 2206.
I know the 2206 has build quality that I like because I've held them, the faital looks cheaper in the pics (casting and some nuances), but I think it will sound better.

I also have a pair of ScanSpeak Revelator 22W/8857T, but they don't have the efficiency to mesh with the RS52 with no resistor on the RS52 obviously. And the ribbon would need a large resistor. Also I'm not really a fan of home style woofers in a ported box to be honest, the bass never sounds right/natural.

Faital looks like a winner, I just prefer the best possible build quality (and durability/longevity) in a woofer.
I also have a HiVi ribbon I want to try (Hi-Vi RT1C-A Isodynamic Tweeter, 120mm, 94dB).
I'm not sure if I like horns, but they don't sound offensive to me, like most dome tweeters do. I know the "standard" design with a 12 inch pro woofer is a 2-way horn (maybe with "super-tweeter) or 3-way with 6-8" pro midrange and dome tweeter.

I believe I will have a lot of room gain with the Faital woofer in the bass region BTW.

I'm contemplating building an Aleph J (or BA-3 - can't decide), and I'm looking to maximize heatsink area for a given footprint.

I'm looking at the Aleph 0 case design for inspiration (attached). Four identical heatsinks, one on each face, makes for easy construction compared to the later Aleph models with the different heatsink on the rear containing the inputs (attached). I'm considering four of the 5U/300mm Dissipante heatsinks.

However, since the inputs on the Aleph 0 are pushed to the bottom of the casing (attached), which is where the transformer is located, the input signal wiring is very close to the transformer (attached). In contrast, the traditional Dissipante layout puts the transformer relatively far away from the input wiring (attached).

Would the Aleph 0 layout result in unnecessary amounts of noise? Is the additional footprint worthwhile? I'd also have to scale back the heatsinking to the normal 4x 5U/200mm - certainly doable, but I'd like heatsink temps as low as possible.

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