Hello all,

I traded an Bel Canto integrated amp for this ST70 Project with a member here a few years back. I managed to get most of the hard work done in the first couple weeks, and then there it sat for the past three years as you see it, when work and life got a bit crazy.

Has custom wound transformers for ST70, and the Triode Electronics Input and power supply boards fully populated. Base is a beautiful Mahogany.

The boards need to be wired up, Bias circuit needs to be added (for pairs or individual tubes), and Choke (Triad C-24X) needs to be installed inside base (not the exact C-354 choke, but should be close). Includes all you see - but no tubes....

I have all the schematics, wiring diagrams and directions. Should include all info needed to complete the build...

Just need to offload some projects I will likely never get to - including refurbing Apogee Scintillas, two pairs of Acoustats, Hammond AO tube amp Monoblocks, etc).

How's $650 + ship? Or pick up is west sub of Chicago?

Hi guys,

I started my HiFi hobby in about 1978 with a pair of Realistic Optimus 5B speakers I bought with money from delivering newspapers. I soon sold those for Bose 601s, I was inexperienced. I became interested in DIY in the early 80s and sold the Bose to finance a Dynaudio build around 21W54 woofers and D28 tweeters. A nice improvement. Lately I started looking for the 5Bs to see just how far I progressed or just how much time and money I wasted. Today I started that re-evaluation with a $40.00 pair from facebook marketplace.

I hooked them up to the Onkyo 886 preamp and Ashly amp and sat and listened for a while. First impressions was "not bad". I put the mid and tweeter levels at the lowest setting. I attached a screen shot of the response with distortion. Bass and vocals sound open and smooth but highs sound like someone banging on a pie tin. tonal balance is bright and that's easy to see why. This is despite the measurements showing distortion on the highs to be very surprising low. I'm measuring mid and high distortion well under 1% at the given level. This is on par with my best tweeters but mostly 3rd order where the others are mostly 2nd.

Bass distortion is about as expected at above 1% rising to 6-7% about peaking at 10 times my favorite woofers.

I would put the frequency response at 38-18khz. Sens at 84db with the mids and highs at 89ish db. Not terrible for era, devices, cost and design.

Sound stage and imaging fall short of any other system in the house.

The plan is to give them a fair listen, dissect the crossover, match the levels and decide after that.

Background: Had done some work on my Audio Research D70, and was getting some odd results, so I started testing and measuring with my Scarlett Solo. I had the output of the Scarlett connected to the input of the amp, and the output from the amp was connected to my speakers, and I had clips on the + and - terminals going to the input on my Scarlett. I was making connections and checking my software, when I smelled the blue smoke smell, and observed that my Scarlett seemed to be on fire. After opening it up, I saw serious black burned/melted PCB around one of the ground pins on the output jack I was using.

I wasn't running a signal into the amp during this time. The output voltage from the amp at idle was nominally zero. I didn't observe any weird voltages coming from the input jack.

I have been messing around with the output wiring in the power amp, and at least once got my signal/ground pair mixed up. That led me to wonder if improper grounding could have caused this failure? I don't fully understand why the output jack would fry like that.

Hi,

I am looking for a DIY project based on LM3886 which could deliever 100W @8 ohm per channel.
There are some projects out there (for example: https://electronics-diy.com/100w-lm3886-power-amplifier.php), but they refer to 4 Ohm and 100W.

Is it even possibe to use LM3886 in some configuration which would be able to deliever requested output?
Apologies if this was already discussed here. I checked, but didn't find it.

Thanks in advance!

Best regards,

Mario.

I am planning to connect my Ares Ii DAC via differential (balanced) connection to my home-build power amplifier (which is based on a TPA-3251 board from 3e Audio).
As the differential output of the DAC is rather high @ 2.4KOhm, I was thinking to use a 100KOhm 4-gang potentiometer (Alps RK27). My reasoning: a 100K pot delivers worst case a minimum of 25% of it's rated resistance (at 12 o'clock setting a 100K pot has a resistance of 2x 50K in parallel = 25K. And 25K is a little over 10 times the output impedance DAC, so the DAC's output doesn't experience voltage drops due to excessive loading of its output. So far so good, I guess.

Because the input impedance of the power amplifier (balanced input) is 20KOhm, I thought it would be wise to place a buffer between the 100K pot and the 20K input of the power amplifier.
However, the buffers for balanced signals I came across had rather low input impedances themselves: the one with highest input impedance was 48K, which is about half of the 100K potentiometer that is on the buffer's input side.

Finally my question: is this a problem and does this defy the sole purpose of the buffer, or does this combination still make sense?
Should I take a 50K pot instead, or 20K even? What would be the best trade-off?

I recently bought an old PA amp (a Champion) and it came with some valves I had not encountered before, EL12 and EF12. They use the Y8A base, which is apparently quite common on older European electrical equipment.

EL12's can be bought NOS for quite reasonable money, especially on the German version of a certain auction site, but the only reference I could find for them here was a big thumbs up when used in a guitar amp.

Does anyone have any experience of their use in hifi?

Hi there,

I am trying to fix an old Marantz PM250. There is no amplified sound, although there is a very quiet, distorted sound from both channels. As both cannels behave in the same way, I suspected common circuity to be at fault, e.g. power supply. I used oscilloscope to check the signal at the input of the Volume module PG00 - looked great and the output - the waveform is distorted. The output is connected to the input of pre-amp stage, so I suspected that the power supply for pre-amp was faulty. Sure enough, the emitter of Q812 that supposed to be -11.4V shows approx 1V positive. I immediately suspected burned Zener Q805 or regulator transistor Q812, however both of them, as well as the capacitor C804, were fine. More to it, when I disconnected emitter of Q812 from the PCB it shows -11.4V as it should. It points to the issue somewhere else.

The question I was going to ask - are there any obvious candidates to be checked? I could start cutting PCB tracks trying to find a culprit, but before that wanted to ask if there is a better approach...

Thanks in advance,

Sold sold sold sold. Please remove. Here's the opening paragraph for the owner's manual of the Simaudio W10 amps:

"The MOON W-10 was a fully balanced differential mono-block amplifier that produced 750 watts into 8 ohms, 1400 watts into 4 ohms and was capable of driving virtually any loudspeaker. Employing our "Advanced Renaissance" technology featuring a "no overall feedback" circuit and bipolar output devices, the W-10 produced a warm, grain free sound common to some of the very best tube amplifiers, but had the reliability of solid state designs. With respect to external cosmetics, the MOON W-10 was similar to the W-5, the main exception being the rear panel connections."

(You can find the entire manual here: https://simaudio.com/en/guides/w-10/ )

Here's the sad story on this pair. I bought them on ebay from an idiot who knew everything...including how to pack a pair of amplifiers that each weigh 70 pounds... NOT! He did a crappy job of packing the amps and several of the front faceplate corners got dinged up. And one of the amps doesn't work.

THese amps cost $12,000 in 2001.

The other one works fine.. Amps look OK, put they are far from perfect.

I think the problem could be a speaker relay, BUT I AM NOT A TECH. Far from it.

I'm going to attempt to attach files, including two short videos of the non-working amp but if that doesn't work, shot me an email to kolle1@comcast.net and I will send the pix and vids. As you can hopefully see in the vids, the inoperable amps plays music very briefly when turned on then LCD1 illuminates and the amp shuts down. At the same time, the relay clicks off.

BONUS: When you pick up the amps in Bethel, CT and pay my asking price I'll give you a Simaudio Eclipse CD player and power supply. This unit cost $5295 in 2001. I bought it from the aforementioned idiot who packed the amps. I told him that before shipping the CD player transport locking screws had to be installed. Of course he said he knew all about that too. But he didn't put in transport screws and the CD player arrived broken. It weighs about 50 pounds. No remote.

Please bring help to load this beasts. I had a heart attack two months ago and it my cardiologist knew I'd lifted one of these amps up onto a bench to take photos, she'd pitch a fit.

$1000 cash at pick up.

Thank you.

Jefferson Kolle

****
****
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I understand that idealy we want all of our grounds wired to one spot or star ground...

In my build every terminal strip has a tab thats supposed to be at ground, and is always the same lug connected to the mounting tab for obvious reasons...

Aree we supposed to lift that terminal strips mounting tab with associated nuts and bolts off thr metal chassis or is running a hookup wire from that ground tan to the main star ground enough?

The web is full of mentoring for victims of so called narcissists. Did they replace micro aggressors and I haven't noticed ?

Hi guys, long time lurker first time poster. This is a little hobby project I am doing. I am basically wanting to hook this CSR 8675 BT transceiver board variant up to this SA9227 USB interface. I have got sort of halfway into researching everything I need to make it happen but am now feeling a little lost. I figured you guys will likely be able to figure it out in minutes what is taking me days to make sense of.

The SA9227 Interface seems to have SPDIF in and out. As well as I2c. The driver that installs gives me "Speakers" and "Line in" I assume this is related to the SPDIF in and out at the front of the board.

The CSR 8675 based BT transceiver board is actually quite a nicely done bit of kit with the major drawback of having no USB functionality apart from an SPI interface and potentially the ability to use it as a BT module. What I am hoping to do is to get it to talk to my PC as an audio interface. I do not think that doing that is possible without adding an interface chip such as the SA9227 (please correct me if I am wrong + the SA9227 was not specially selected so much as what I had laying about).

I guess my question is, is there any obvious way for me to patch the SPDIF or I2C on the SA9227 into this CSR board so I can use it as a playback and recording interface from my PC? Or is there perhaps an easier way to get the CSR board to function as an USB sound card that I have not thought of?
I am really hoping to take advantage of the OPT and AUX connectors and the DAC/ADC/DSP in the CSR chip.

Hi everyone! My project is a Pinnacle Classic Gold Tower upgrade which uses two 8 inch woofers with the lower woofer using a 1st order coil at 150Hz. Crossover point for top woofer and new tweeter is no higher that 2K. I will be building new crossovers to meet the needs of the new tweeter. If this was your project, what tweeter would you consider. My budget is <$70. I have had good experience with HiVi and Peerless dome tweeters in the $20-$30 range but would like to consider a tweeter considered a step up.

I'm attempting to covert my speakers' crossovers from passive two-pole Butterworth to active four-pole Linkwitz-Riley characteristics. I've successfully calculated the corner frequencies with the aid of VituixCAD2 software. However, there's a problem to decide whether the polarity of either driver should be inverted or not, after converting them to active.

Here are the FR and Phase of the original passive crossovers.


FR and Phase of active crossovers WITHOUT reversing polarity.


FR and Phase of active crossovers WITH reversing polarity.


Finally, the comparison


Please advice which way between inverting and non-inverting gives the closet behavior to the passive crossovers.

Selling following pairs of PCBs surplus to requirement:

SMD LT4320 a pair for 2eur
THT LT4320 a pair for 4eur
LT4320+CRC a pair for 14eur
CRCRC PSU a pair for 18 eur

selling in pairs, payment via paypal f&f, shipping at cost from Italy

Hi.

I have a Node 2 that have been working very well, but my unit stopped working completely and while measuring on the connecter between the built-in power supply and the main board, it is completely dead. So this is something more then just the standard issue with the two 1000uF caps.

Is there by any chance someone here that knows what supply voltages that the mainboard expects? My thinking is to build something in line with the upgrade PSU that I have seen some companies sell, but I of course needs to know the voltages. A fair assumption is that there is +/-5V and maybe also 3.3V? Unfortunate needier the mina board or the power supply board gives any clues.

Best regards,
Johan Christensson

Using DACT Type SMD Stepped Attenuators I am repairing a NAD 3500 volume control. The control has dual concentric stereo stages, the front one is a 20K audio taper with a loudness tap at 5200. The balance is a 50K MN control. The following is what I have done.

1) I had to make a MN control, so I took a 21 step SMD attenuator and removed the SMD resistors, and soldered in 4.7K SMDs up to the mid points and shorted the remaining contacts. Make sure to do the right sides (these are NOT mirror images for stereo).

2) The 20K audio taper stepped attenuator is easy to get. I took it apart, and filed the side of the case so the center tap can come out. I used twisted wire-wrap wire to make the tap at the 5.2K step. Strain relief with some super glue.

========
To get the concentric control to work, I need to file the front wiper to accept the outer control shaft. Tolerances are a bit close, but not to hard to do.

The only issue is I don't have detents on the unit, since the concentric shaft is too large for the detent part of the control..

To solder the surface mount parts I used low temp solder paste. I placed the part in a cast iron pan and heated it on an induction stove until the solder reflowed. A little solder paste goes a long way, and the parts will self align if you get them close to being in position.

Fun!!

Let me know if you need more details.

So I'm Buying a this mic as i need to make frequently response of 2 woofers that I'm going to use for a 3 way build I'm doing.

So i need a 1watt output of i think pink noise at a distance of 1 meter.
Can the Dayton audio DATS do this as i have one on the way. ( the 12in woofers I'm using don't have a spec sheet anywhere as there from 2001)

what is the proper way of measuring frequently response. is it the same 1 meter away at 1 watt?

and how do i import that data into a software like Xsim (every video i watched kinda just skips past it).

and what programs you you guys recommend for box and crossover calculation.

and here is the link to the other post on the speakers that I'm building (HERE)

just a short list of what im going to use
Vifa d27, peerless SDS-P830657 6½ and 2x Vifa M30wo-15 (and ovs x2 as that's just one speaker)

idk what the sensitivity is for the Vifa M30wo-15 the closest spec sheet said 93DB

Any help would be largely appreciated.

Are these adjusted to take into account woofer response?:

Says 90bd - 96db - 102 dB , but is this throughout the frequency range or at a specific point?
https://www.dibirama.altervista.org...k-26w-8534g00-woofer-10-8-ohm-150-wmax-2.html

Some other tests:
https://hificompass.com/en/speakers/measurements?page=2
http://zaphaudio.com/8test/

This guy I can understand; he has relative measurements:
https://feleppa.com.au/speakermeasmid.html

Having trouble figuring out which driver(s) has the lowest bass distortion.
Trying to "eyeball it", but doesn't seem that easy. And I don't know where the SPL is referenced from or if they might be relative?

Hello,

I am planning to build a DIY grounding box. I am planning to connect my DAC and Integrated amp to this grounding box by connectig the unused RCA input terminals on the both. For this I need to create two cables with Banana at one end and RCA at the other end so that I can connect them via speaker binding post on grounding box.
I need help with how & where to attach (solder) the cable on RCA socket.

I also need help in understanding if I can connect both L & R RCA input sockets on same amp to same grounding box (assuming I am going to solder the wire on the shell/-ve part of RCA connector)? Also Can I similarly connect all unused inputs on DAC/Amp to grounding box.

I understand attaching multiple inputs to grounding box is not going to amplify the effect & I just want to do it for protection of those input terminals.
Regards,

audio_phool

Hello
I'm just trying this new player but I can't make it work.
I'm using one RPI4 with ES9038 hat and one USB flash drive with 300 DFF files.
After configuration and reboot, the configuring window is frozen, the library shows radio stations but I can't see anywhere my music folders.
Where is the error ?
Until now, I was using Volumio and it' works great with one exception : there is a random POP when changing track.
So I wanted to give Moode a try.

A stalled project, now at a bargain price!



This is the "Square Basket" version of SB Acoustics' 4-inch coaxial driver.

BUT WAIT, THERE'S MORE! It comes with two separate (tweeter and woofer) fully assembled Madisound crossover boards, made to the SB Acoustics factory schematic. This project started out with "Fair Hopes," and I love working with coaxials. But when the shipment arrived and I saw that Madisound had not combined both crossover circuits on one PCB, that made packaging more of an issue and I put the project aside. The driver, crossover boards, and shipping cost me $136. You can buy these parts, buy or make a small cabinet, test it out, and see if you want to build the other of the pair.

My asking price is $60 plus the actual cost of shipping.

john

Just picked up a pair of old "Fried" - Bud Fried - Signature A/6 speakers.
Both speakers work, but the left one has a slightly muffled sound. What gives?
So, have tested out by exchanging the wires – I.e by switching L&R wires on the Amplifier. Making one speaker the L, which was earlier R, and vice versa.
One speaker , speaker X, is definitely voicing EVERYTHING with lesser volume and strength as compared to the other speaker in the Pair. Tweeter is working, but plays fainter. Midwoofer is working, but again fainter. Thus both the tweeter and midwoofer of speaker X are playing fainting as compared to the other of the Pair

Do note that the M.A.R.S system cable is NOT present :

FYI:

The m.a.r.s.® technology requires a two-conductor interconnect between the two loudspeakers. In order to maintain proper polarity Fried has supplied you with a twenty (20) foot cable for this purpose. The two-bladed plug on each end of the cable can only be inserted one way. If you wish to use a different cable, it is necessary to solder the plugs on the two ends so that the conductors are, in effect, crossed. In other words, one conductor should be wired to the larger blade on one end and the smaller blade on the other, and vice versa with the other conductor.

NON-m.a.r.s.® OPERATION:
Your A/6 loudspeakers may also be used in a non-m.a.r.s.® mode. Included with each loudspeaker is a short jumper cable that should be attached from the m.a.r.s.® socket to the negative (black) binding post to operate in the non-m.a.r.s.® mode. One may completely remove the knurled cap of the black binding post and place the ring connector of the jumper on the post. After replacing the cap, you are ready to conveniently switch between m.a.r.s.® and non-m.a.r.s.® modes by either using the m.a.r.s.® cable or the non-m.a.r.s.® jumpers.

Opened up the Crossover and found the below - it's supposed to be a SERIES Crossover (not parallel)
These are 23-24 year old speakers.

Can someone help me with finding best crossover details for AIWA HIFI SPEAKER MODEL : NSX-V900

I'm a massively huge fan of vintage analog synthesizers, effects and musical instruments having grown up in the 70s and 80s. I have a soft spot for the music of that era, specifically British pop, old school hip hop and RnB (the REAL kind WITHOUT AUTOTUNE). My son and I frequently try to quiz each other which synths, drum machines and samples were used in various music back in the day.

I'm not a regular YT watcher, but I needed to share this video I came across, which is beyond excellent and incredibly well done. I hope you enjoy it as much as I did.

Login to view embedded media

Want to buy a pair of Focal, Sonus Faber or Scan-Speak 6.5 inch bass woofers, 8 Ohm impedance.

Thanks.

I am trying to replicate the Revel M105 copy project from ASR, but with a different tweeter. I built the cabinets, the waveguide, mounted the speakers and am ready for the next step (crossover design). I have taken horizontal measurements of both the tweeter and woofer while mounted in the enclosure (driving each one separately).
In the case of the woofer I have collected near field measurements and the same for the port. Microphone placement was about 0.2" from the cone center, and in the case of the port, the microphone was pretty much inside. I used REW, a UMIK-1 to collect measurements all driven from a yamaha amp without changing the output volume (near field measurements were at a lower volume due to clipping).
I combined the port and woofer near field measurements and adjusted the port SPL using the appropriate formula (20Log(portdia/woofereffectivedia). I then adjusted the near field for the baffle diffraction. Once I had a cleaned/combined/adjusted near field I blended with the far field 0deg measurements to get the response shown below.

The woofer is a Scanspeak 15W/8530K00 and the tweeter is a Morel ST1108 supreme.

I have a few questions and am looking for some expert advice.

1. How do I determine what the port tuning frequency is at right now? (Jeff bagby paper references a drop in SPL, which should occur at the tuning of the enclosure, but I don't really see it). I am targeting about 40hz for enclosure tuning and cut the port length appropriately (2" diameter port).
2. What is going on with the scanspeak at the 250-3550hz range. Why is SPL dumping out? Should I be concerned? Where should I be looking to try to address this?

The enclosure is made from 1" MDF walls (2 pieces of 1/2" glued) and the front is 1.5"MDF (3 pieces of 1/2" glued). The internal is braced and I glued some melamine foam to the interior.

Here are some pictures. I appreciate any help you can provide.







Here is my attempt at a crossover.

I've built almost any kind of exotic loadspeaker: planars, ribbon, Rubanoid and of course AMTs.

My last endeavour will start with four of these:


This will be a real time adventure as usual, so there will for sure be bumps on the trip.

First I got rid the net and its fasteners:


More later...

Hello diyAudio forum,

I'm a first time owner of an amplifier, as I've just bought two passive speakers. I wish to connect it all to both a record player, and my TV.

I'm having issues with the NAD T743, and I apologize if I can't explain it well, because I'm really not technically gifted.

The speakers are connected to the right places with the wires.
The red/white cables are put into the "CD" input on the back.
I turn it on and put it on CD, and connect my phone. But I can only hear a VERY low sound of the music playing, and that's while the amplifier and phone is at maximum.

I've pressed all the buttons and I don't know what to do. I've tried to factory reset, but it doesn't work per the guides I found online, and I don't understand what the user manual describes. I have a remote, and it can turn the amplifier ON, but it can't do anything else than that. All the buttons just light up red when you click them.

I hope someone wants to help. I was really hoping to have this set up by now, but I've spent 4 hours playing with it and have no results.

Thank you.
Best regards,
Anders

4 channel amp not powering on
I checked voltages on mosfets
Drive voltage and 12v are present at left and middle leg but led of power or protection not glowing
I suspect pwn ic as faulty
Can anyone tell me all voltages of kia494ap at each pin and how to verify that it is serviceable
In my case voltages are
1 nil
2 5v
3 500mv
4 220mv
5 2v
6 1.7v
7 gnd
8 12v
9 4.7v
10 4.7v
11 12v
13 5v
14 5v
15 2.5v
16 0.2v
Kindly assist to clear fault
Thx in advance

I've just registered on this forum so please forgive any errors in procedure in my request for help.
I have a CD880 and a good while ago it seemed to require some time from switching on to read a disc. I thought that perhaps a deteriorating component needed some warm-up time. The problem got so bad that I decided to leave the machine switched on all the time. Eventually, this approach failed and it ceased to read a disc at all. Somewhere, I have seen a reference to replacing the 33uF capacitor on the pcb on the underside of the disc mechanism as being a possible solution. I have gained access to that capacitor and would like advice on the specification of any suitable replacement; 33uF, yes, but what else should I be aware of - voltage rating or build type, for example?
Grateful for any advice to keep this vintage device alive, which can include other possible solutions to the problem in case the capacitor change fails to do the trick.

Hello, I have consulted this in another forum specialized in Sansui, but I did not receive answers, maybe someone here can help me, thank you.

"Hello everyoneI have this tuner that has some drift in the FM tuning, it is not much, but it is annoying, when the tuning changes, listening in stereo it activates the mute, you have to correct a little to hear well again, the power supply is correct and it lacks ripple, I even tried changing it and the tuning does not change when doing this, I replaced the TC3 trimmer, the C8 capacitor of type NP0 and Q6, and the problem persists. Use a freezing spray but its influence is very powerful, I'm not sure the temperature is the problem either. Any opinion or suggestion is welcome."

Czy ktoś budował taką konstrukcję? Dwa głośniki Acoustic Elegant TD10S w zamkniętej obudowie. Dodatkowo Bliesma 34b, Audax po modernizacji. Wiele osób dodaje oddzielne wzmacniacze dsp. Mam monobloki o mocy 250 W/8 omów. Pokój 20 m2
Czy ktoś ma doświadczenie w budowie głośników 3-drożnych z głośnikami TD10s?
Mam problem z dokonaniem wyboru. Czy powinienem wybrać 2x 8-calowy grafen Seas Excel czy AE td10s. Wiem, że te dwie mniejsze są szybsze, ale nic nie brzmi tak dobrze, jak duża membrana. Pozdrowienia.

---

I have 2 new SMPS boards from the DENON PMA60

These boards are well made and have multiple voltages available

Dual rail set for +27v 0 -27v at 5A

Also +12v -12v rails to power opamp circuit.

220~240V supply

Voltages available on board:

+5V 1A

+12V 0,35A

-12V 0,3A

+19V 0,05A

+27V 0 -27v 5A

size is 16,5 x 9 x 5 cm
Postage Australia Only
$40 ea. + postage

How is this for an excuse for applying brakes to a few thousand dollars of new audio gear, boards, components and drivers?


Hello all, please allow me to introduce Randhir Jagawar Lal, two and a half months old now











So, how are your projects progressing. Any interesting excuses? 🙂

Hello everyone, I am getting into the world of electronics applied to the field of music. I have built a pre-amplifier circuit for an electret microphone controlled by a PTT that closes with GND, and I am facing the following problems:

• I have to get the microphone too close to my mouth for it to work.
• Without pressing the PTT, when I speak excessively loud with the microphone close to my mouth, it can be heard through the speakers.
• We have tested to change R99 to 1k and R96 to 100k but it doesn't work.

The model of the headphones is as follows: Sennheiser GSP 302.

Attached is my schematic, thank you very much.

One of my power transformers developed a short - firsthand knowledge of how important is a good ground!
Since I had a bit of mechanical hum from the old ones, I want to mount them on a rubber pad. I installed grommets in the mounting holes and was planning on using some rubber washers under the bolts to help with eliminating the hum. The hum is purely mechanical and the transformers have a history of this. As a matter of fact, the company sells a rubber sheet specifically for this purpose.
So how can I safely rubber mount these transformers while insuring a safe electrical ground? I was thinking of running a wire from one of the mounting bolts to the chassis. Does that fulfill safety requirements? The end-bells bolts are insulated with plastic shoulder washers and cardboard sleeves so electrically seem isolated from each other. Should I use one wire from each end-bell mounting bolt to the chassis?
Thanks for any help
Dave

SOLD

Happy Holidays All!

Over winter break I plan to build a pair of B&C Sub 15s I'm going to slightly modify the design to incorporate an extension around the enclosure about 40mm to countersink a flush grill. I want the vents covered also as these will live in my garage when not in use and I live rural so rodents are a real thing. Given that the enclosure is on the smaller side and the vent is fairly sizeable, small differences in length seems to make big differences in tuning. The flange will extend the vent on 3 sides, since it is only 3 sides, how do I account for/calculate the amount if vent I have to leave off internally?

Thanks!

Chad

Just finished building my Aleph J and when adjusting the bias and offset, I got some possibly concerning results. Once powered on, I set the bias to 0.35V for both sides, then let it sit for 30 minutes. I then adjusted to 0.40V. I started measuring the DC offset and got 0.011v for the left channel and .021v for the right channel. I put the top cover on let it cook for another 30 minutes. After 30 minutes with the top on, the bias voltage on both sides dropped a little bit under .40V. so I boosted them back up to spec. The DC offset then rose back up to the aforementioned values.

I cannot seem to get a lower DC offset voltage while having the bias set to 0.40v. Is 0.011v and 0.021v okay for both channels? I did some research and it seems it will be, but I wanted to get some opinions from people much more experienced than me. 🙂

Thanks!

I can post pictures if needed

Finally a Bluetooth speaker worth buying!
Coming soon to a listening room near you (Free shipping and free returns (at least here in Australia))

Buzzword compliant - AirPlay, BT, wifi streaming via Chromecast, Spotify and Roon ready etc





Teeny tiny skinny floorstanding cabinets your born in 21C partner / children would like.

for the DIY audio nerds- it’s an
active 3 way with a 5” wide baffle with 4” coaxial midrange/tweeter closely surrounded by four 5.25” woofers crammed into only 12.5L of cabinet volume.

500/100/100 Watts (4ohm) for LF/MF/HF
Uses DSP for baffle step compensation, delays, crossover, equalisation and +/- phase correction, and limiters for woofer protection.
The coaxial is part of KEF’s recently released ranges, albeit smaller, with acoustically tuned damper for the tweeter.

Each pair of midwoofers share a common magnet (!) , but optimised for low rubber surround radiation distortion: the white paper suggests a very flat and symmetrical Kms(x) & BL(x) curves.

The woofers also use voice coil current negative feedback for reduced bass distortion, which is advantageous when using small woofers in small boxes.

Here is the White Paper with the details:
https://us.kef.com/pub/media/ls60-content/LS60W_WP.pdf

Now, I know what you’re thinking. Big deal.
And they’re €7K/US$7K/AU$10K a pair.
Let's forget about the price for a moment, or whether you can afford them, and even if you could, are you in the market for one.

I'm glad that not all wireless speakers are $100 BT speakers... I'm looking at you Apple, Google with more resources for R&D than anybody else. This is a problem that Sean Olive commented on- how do you get people to be interested in acoustic excellence; there’s not much captured in the specs or reviews that indicate why a large high performance speaker (the size and weight of a person and the cost of a small automobile) is better than a $100 speaker with essentially the same frequency response? Of course; that is, without having to sell them a piece of (audio) furniture?

Come on, let’s make an easy-to-use wireless speaker that the kids and spouse can use with their voice / phone, but us audio nuts might also enjoy listening to...

K E F
Make Speakers Great Again

@Galu
@AllenB
@newvirus2008 u
@Andrew Eckhardt
Good evening guys here I am then, this new thread is true because the project has changed, I will use 2 lower frequencies (5khz) to be able to overcome the impedance. Their interference will produce a 10khz wave, which is not ultrasound, but I'll start from there. However, for now I believe that the important question is the mathematical formulas, such as how does the frequency and amplitude vary based on the materials they pass through? I hope to make it with your help

For those who aren't aware, HiVi sells completed speakers, and I just wanted to make a post saying that they're pretty good! At least the ones I bought.

HiVi-Swans OS-10 HiFi Stereo Speakers, Bluetooth 5.0 Active Computer Bookshelf Speakers - 4'' Dynamic Woofer, Powered Desk Speakers 62w RMS with Touch Control for PC/Phone/TV https://a.co/d/cMzKvAA

These are on sale right now, so I bought a pair for a friend in need, and I'm quite impressed with them. Seems to be the T20 tweeter and B4N midwoofer? And they are powered with RCA, coax, optical and Bluetooth inputs. All of the cables you might need are included with the speakers, and they even come with a remote (and batteries!) I don't have any of my equipment to take any measurements, but subjectively the sound is very full bodied for their size, with impressive bass and a very calm (almost subdued) top end that does not call attention to itself. I think this laid back sound signature fits these speakers quite well, as most speakers I've heard in this size range have sounded shouty and anemic.

Anyways, if any of y'all are in the mood for gift giving, or just need a set of TV speakers or something, check these out! I think you'll be pleasantly surprised

Given how common Zoom is today, I'd thought it would be fun to have occasional Zoom meetings to chat about audio. Whenever someone wants to host a meeting, post a link here. I'll go first: https://us05web.zoom.us/j/88169974953?pwd=izSjEbvblrglQ4jSs5CjyZ7ev8LdhK.1

Any experience with Tang Band W8-1808 in sealed box?

Massive NAD surround receiver for parts. I don't have the time to fix it, but transformer and heatsinks appear to be in good condition. Xform is approx 2x45V loaded. Guessing 400-600VA. Weight 20kg.

I think local pickup or shipping in Dk is the only realistic option.

300DkKr?

Hi. I am trying to figure out the best impedance match between a passive attenuator, and a unique old amp.

The amp in question is an Onkyo M-505. It has an input impedance of 100k. There was a matching preamp (P-303) with an output impedance of 600 Ohms.

The designer says that this is to ensure for the least amount of voltage loss.

I am not aware of any quality 1K audio pots, and I am not sure that one could build a stepped attenuator that could achieve or maintain this value.

I thought about trying a 10K pot, but this may skew the sound of this special amp.

https://audio-database.com/ONKYO/amp/integram-505-e.html

Where can I buy the "Power & Shorts" Lamp/lights for the B&K 747B

I have single ended triode and pentode amps and push pull pentodes, so got to thinking about building a push pull triode amplifier.
Target output: 15 - 20 watts no feedback.
Ideally something just a little bit more exotic than trioded el34, 84 6L6 etc.... and got plans for PL36s EL500/4/9 already so not them. UK based which seems to limit the (cheap) availability of a lot of American triode sweep tubes that would be suitable. 🙁
Don't want to spend much money if possible.
Seems the days of super cheap tubes are gone, initial thoughts, in an ideal world, would be something like a 2A3 amp, but even 6B4G quite expensive nowadays.
Initially the 6P21s seems like it could provide some DHT goodness, but I hear reservations about the longevity of the filament. It is a "relatively normal" tube though? so if that was a problem it would not be a total loss to redesign the amp with say a 6L6 type of valve. I could use a fairly normal 6k ish A-A output transformer.
I also have some 12E1 tubes. I get the impression they are not the happiest in triode mode though, but they are more powerful than I need so some room for flexibility, but seems moving towards lower voltage lower Z transformer.
And then there are the (Russian) regulator triodes, and 6080s. On reflection I could imagine paralleled 6080s (2) into a carefully chosen toroidal mains transformer, although not aesthetically what I am after, could have the potential to deliver the kind of sound I think I would like, clean and tight...
any thoughts.

I want to know where to allocate funds when specifying transformers for a tube amp build (read: what corners to cut).

At the risk of oversimplifying things... From what I understand the output transformers make the most difference sonically; however, I know that amps are the sum of their parts and each typology would stress different aspects of each component. To get the best OPT possible, would you go with a slightly lesser quality choke or power transformer? I'm leaning toward cutting corners on the choke but I would like to get a second opinion.

When I imagine cutting corners, it would not be on choke specification... more on overall quality (I guess???)... for example, forgoing the Hashimoto choke for an Edcor or Hammond. Obviously, there will be a difference...

I'm heading to Japan next month and specifically wondering if I should get some nice big ISO OPTs and General Transformer (formerly Noguchi Transformer) chokes or get slightly lesser ISO OPTs and ISO chokes. Am I overthinking this?

For sale is a Hypex power amp built and purchased from another diyAudio member a few years ago. I have used it but never opened the enclosure, so I only have exterior photos. Amp modules are Hypex UcD400 with HxR, and the power supply is SMPS400A400.

3-pin XLR inputs only.

Dimensions: 10"W x 12"D (not including speaker terminals) x 3"H.

I am told the chassis has not been internally grounded.

$350 shipped to lower 48.

Hi All,

I have a strange issue with my beloved NAD 208 THX, it kinda loops into protection mode with bad bangs to the speakers ... here is a video of it :

nad 208 thx problem - YouTube

It happened from time to time but now does all the time. I checked a few caps, found they were out of specs so recapped the whole power supply board & input amplifier unfortunately to no effect.

The protection IC (IC 601), a TA7317P, seems to have commonly been a source of problem. Might it be the culprit ? Have some of you ever seen that ?

Thanks for helping !!

Since I deal with Solid-State power amplifiers 99% of the time, I thought this was the appropriate forum. If it should be somewhere in the design and build forums (Equipment and Tools was a close 2nd), mods, please feel free to move this.

I've had the good fortune to have enough time to search and scan the diyAudio threads for some time. I have not yet put together a 'final' list of tests that a skilled hobbyist with a reasonable bench should conduct to ensure the proper operation of an amplifier against either published specifications and/or the designers' expectations. I've also popped over to ASR and read a few magazines / reviews (non-scientific publications) to see what is commonly published for amplifier testing.

On to the point. I've read posts from skilled technicians, amplifier designers, EE's, and knowledgeable hobbyists. What do you all do to make sure "the thing works properly" before it goes out the door and you consider something "done"?

Perhaps there is a reference I've missed, and if so, I don't want to reinvent the wheel and have people type and re-type. My angle is completely as a hobbyist. I'm trying to learn more refined / consistent measurement techniques and create a better process for checking things out before I connect them to my system. Think of a "binder" of results on my computer for comparative purposes and personal interest also.

Let's say you get a random amplifier dropped in your lap. What would the skilled among you be sure to check before hooking it up to your own favorite speakers or pre-amp/source?

Please for the love of all that's holy, don't turn this thread into a subjectivist / objectivist thread. I'll report any posts that stray in that direction and have them deleted. Let's keep it in the spirt of understanding the 'objective performance' of the amplifier. What tests would you run on an unknown amplifier to see how it performs against others?

Here's what I've come up with so far.

Basics / Essentials

• THD / THD +N at 8R and 4R loads (1kHz seems to be the norm, and I've continued to wonder why not at 20Hz and 20KHz or more points).
• Noise (A and C weighting)
• Power delivery at 8R and 4R loads (I have never done a "formal" sustained sine test / thermal test at 50% power or other standard tests)
• Voltage Clipping Observations / Recovery - Check voltage at clipping on both positive and negative 'halves'. What does clipping "look like"? Any sticking?
• Frequency response. At a minimum determine the -3dB point (if present) at 20Hz through 20kHz and observe plot for "flatness".
• DC Offset at output

Additional Tests -

I don't have the foggiest clue around some of these, but I generally understand why they might be important / meaningful.

• IMD - I am still trying to learn how to run this consistently, and more importantly what it means / tells me. I see 19kHz 20kHz referenced. Any tips would be greatly appreciated.
• Observable characteristics (if any) of the residual / distortion.
• Stability with various capacitive loads? I see references to gain and phase margins. This is pushing the edge of my current brain power. Trying to grasp phase makes my head hurt.
• Slew Rate / Rise / Fall Times / Square Wave Performance and Observations - I have a 'proper' signal generator that's now become part of the bench. Now... what to actually do with it and my scope vs. just look at pretty waveforms? I see square waves commonly run at 10kHz, and some out to 20kHz and beyond.
• Crossover distortion. This is a brand new term to me. I've taken it to mean, what do things look like at the 0-Crossing?
• Check for oscillations (under what conditions?). I've just learned that oscillations out into the MHz range can affect performance and stability.
• Output impedance

Any thoughts / links / corrections / additions / "Read this book" are welcome and greatly appreciated.

Hi everyone, I have on my bench a pair of old Japanese DIY monoblocks. They are fairly standard with 6189 input, Sylvania 6350 LTP phase inverter and 2A3 push pull output. Built with Lux kit transformers that are very common in Japan. Only one thing really has me stumped. The power supply is diode rectified, but the unused 5V 3A winding on the mains transformer appears to be connected to the secondary of the output transformer through a 3K resistor like this:

0----------16 ohm

3A Secondary of OT

5---3K----0


I am completely stumped as to why this has been done, I have worked on a lot a tube amps and never seen this arrangement anywhere. Can anyone explain? Many thanks in advance

Hello.im interested in buying a stereo Mosfet power amplifier 2SJ162/2SK1058.

If you have any board, fully populated board or fully built unit, please, let me know.

Pretty familiar with building kits/soldering/fixing basic stuff but this is a new level for me. Always wanted to five deeper into understanding more. Unit powers on and left channel is fine but right channel sign very low. I want 2 way channel stereo. I am pretty sure this unit was setup 3 way mono for decades and kinda stuck. LOUD clicks on the LOW on/off switches and mono LOW. Got some contact cleaner coming. No visible issues upon inspection but can post pics if needed. Also have schematic. Anyone willing to help? Many thanks in advance!!!

Hello

I'm experimenting cardioid implementation.
The basic principle seems self-explanatory.
You place the same woofer in the front and back of an enclosure, and feed an inverted signal delayed by that distance to the woofer behind it.

A practical problem arises.
Due to the radiation characteristics of the enclosure, the frequency response of the front woofer and back woofer is not the same.
It can be fixed by applying PEQ to the rear woofer to match the frequency response.
But the position of the microphone becomes an issue.

Should it be right in front of the rear woofer?
Or should 1 meter to the rear of the enclosure?(I'm measuring directivity at 1m)

My intuition is that it doesn't matter either way, as long as the effects of reflections are properly eliminated.
However, if I use the rear woofer as a reference, it doesn't cancel properly at the 1m position,
If I use the 1m position as a reference, it doesn't cancel properly directly behind the enclosure.

It was easy in the sub-bass band, where the enclosure has little effect, but seems not so easy in the midrange.
I would appreciate any help.

Anyone successfully implemented the Henk ten Pierick DEM reclocking for the TDA1541 ?
I've tried, but I can't get it working. Get noise & distortion, guess the active divider isn't working.

I'm using 4*fs (non-oversampling application),
and BC557B's for the PNP's
The negative voltage is -6.1V
I measured -10V DC voltage on pins 16 & 17.

The FF indeed has the 4fs signal on it's outputs and there is some sawtooth on the DEM pins (noisy), but no luck.

Anyone ?

For sale 4 pcs of the beautiful CRCRC PSU PCB byPrasi ideal for class A amps. 15eur/pcs
6 pairs of the LT4320 SMD RECTIFIER 2eur/pair
2 pairs of the LT4320 THT RECTIFIER 4eur/pair

Paypal F&F/fee + shipping.

All items are in the EU

Hi to everyone,
I'm new here and I've read here something about Switching Power Supply for tube amplifiers.
I'm finding since a lot of time a schematich for a good and safety power supply for a full tube amp and when I've seen that Blackstar announched the St. James amps series with a complete switching power supply, it blow out my mind.
There is a video on their youtube ( Login to view embedded media ) in which describe the system adopted and there are few frames with the power supply board.
After this I think that a full SWPS for tube amp is really possible and not so hard to build, so now I ask to you:
Has nobody token that amp and seen how the power supply board is made? Or anyone has a schematich of something similar?
Thank you all for the comment and help.
Here there are some frames from the video.

Possibly a silly question, but given say for instance a Williamson amplifier or an amplifier with balanced input, is there any real disadvantage to running feedback off of each side of the transformer secondary?

Like so-



Ignoring the parts values, zeners, etc, what would be the disadvantages to running it this way? It seems like it would avoid the phase shift inherent with looping an additional stage inside, with maybe less THD reduction than the traditional way, assuming that you could keep phase shift in line? Might be better for lesser quality transformers?

Good morning all ,
Id like to swap out the speaker on my Dewalt work radio -Dcr020 as it sound muffled and dull compared to my previous standard kitchen radio .
im not sure if this existing speaker is multi range but It sounds too bassy so I need something that gives more midrange and treble .

Can any recommend anything ? I’ve had quick look online and there’s plenty out there inc ebay but I’m not sure about the ohms and wattage that I’ll need to abide too ?
Or if just go for a midrange like for like Will I achieve anything?
Thanks in advance , Scott .

Dear Friends ,

Does anyone know if this particular amplifier " Infinity Primus 6004a " can introduce any significant delay even if in ms at the Speaker Output .

I am using this amplifier and have a strange observation that my output at the Speaker is delayed .

Anyone knows why ?

Hi,

In one of my projects I will add a DC-blocker according to this article from Rod Elliott:

https://sound-au.com/articles/xfmr-dc.htm

See Figure 8 - Recommended Design

I’m wondering if it’s possible to add LED’s to light up when DC is present (and blocked by the bridge).
Is this possible?

Regards, Gerrit

SOLD

Price: $40 shipped
My hope is that someone can appreciate this because I don't want to throw it away.

This is a DIY kit from Power Physics that contains multiple amplifier boards, a power supply board, and various interconnects and accessories. I do not have spare time to dig into this kit myself, and I am not sure what the condition of all these parts are. I have every reason to believe they work, but I have not tried any of them.


Kit includes:
-one P500PFCR4 PN.368 power supply circuit board
-one A-404R5 amplifier board
-two A-404R6 amplifier board
-one A-1004 amplifier board
-aluminum headsink and chassis
-various interconnects and hardware
-two PDF files (attached to this post)

I do not post much on this board, but I have tons of references in the 12volt community and some other forums if you would like.

I have a TON of electronics and other stuff that I'm trying to clear out. See pictures of everything here:
https://www.smugmug.com/gallery/n-tqJ8QR/

Hi, a friend of mine has recently purchased the above speakers, that were made by someone.
They have the modded fostex drivers in.

Couple issues.
1. Hardly any bass
2. They don't seem that loud (tested and quieter than some standard 91db speakers)

Are there some simple obvious issues to address this problem.
Thanks in advance.

Hello, I'm trying to build a simple mono system on a budget. This far I have managed to find these parts quite cheaply:

Altec 416-8A
Altec 291-16A

and a Heathkit AS-101 crossover

The Heathkit AS-101 is supposed to be same as N800-8K that was ment for Altec Valencia speakers.

The N800-8K was designed for the valencia speakers and they use the Altec 416-8A with 806-8a compression driver. So both of the drivers where 8-ohms and I have a 8 ohm woofer and a 16 ohm compression driver now. I guess I could order a new 8 ohm diagram for the compression driver but since it seems original now I wouldn't want to spend extra on a new diagram now.

So my question is, would there be a simple way to mod the crossover so that it would work with the 16 ohm compression driver. Or is there even need or would it work as is with these drivers?

Heres the schematics:



Thanks!

Im building a 5-channel amp based on Purifi 1ET400 modules.
At absolute max it will need to deliver a total of 1000 W.

The Hypex SMPS1200A400 should in this case be sufficient?

Hi all, first post so apologies if I have the wrong area of the site or am asking something which has been asked before.

TLDR: Is there a sticky or list of available diy designs that are active? By active I mean able to be created today?

Searching through a lot of designs I see that various components are discontinued and hard to find. I live in NZ so getting my hands on parts is a bit of a nightmare although I can import from aus easily, US too although shipping can get costly..

I have good woodworking skills and can solder like a champ but i do not have thorough speaker design experience apart from a few subwoofers that i have designed myself using winisd. Hence why I want to explore tried and tested designs.

I have an array of subwoofers so do not need so much the low low end but I do like the idea of a 3 way design to cover the low end from 80hz up.

In terms of price range and performance I have been looking at the statements II. But as it is an older design I can't find all of the components easily. The mid driver is also discontinued.

So. I have a few questions.

1. Is there a list of diy designs that can still be made stickied somewhere that i can look through?
2. Are there any other designs similar or better in performance to the statements 2 that I can build? I am assuming that in the last 10 years speaker components have improved. So should I be looking at more recent builds?
3. Is there a woofer I can drop in for the discontinued NE123W-08 mid driver to be able to build the statements 2 speakers? Or do I need to remodel the cabinet and crossover?
4. Similar for the tweeter. Although it is available it is costly to ship from the stores with it in stock. Are there any alternatives worth looking into to upgrade the tweeter that are newer and more widely available? Again, do I need to remodel the cabinet and crossover if i replace?

Thanks all for your help. Look forward to contributing more over the coming years.

Chris

Have 24 hours to decide.
Should I get the

Dayton Audio DATS V3 Computer Based Speaker & Audio Component Test System
Or the
Calibrated Mic.

Budget is tight have been saving up for the mic for some time. Now. But then I see that Dats V3 can do what a calibrated Mic can do and more.
But I was really keen to get started with using REW and I dont think Dat V3 works with REW.

My application ?.
Testing drivers that come with flakey at best TS.
Building a 3 way speaker setup and box for my own use and entertainment as a hobby. And testing various builds like open baffle, sealed / ported etc.
I thought I would look into just getting a regular 5$ USB mic and using it with REW. Maybe create my own calibration file. Nothing Im doing needs to be super accurate. As this is just a hobby. But now I dont have the time. Have a friend returning from the US in a few days. And have to pick something like today.

Hello,
I am looking for someone that Lives in Berlin that can help with a Heavy eBay purchase. the seller only ships to addresses in germany and I cannot even bid in i believe. I would need someone to bid on the item on my behalf. pick up the item from the seller or, the seller might be able to ship to you. and then I would need it sent to the USA. I am willing to pay for someone's time and effort plus all cost's etc.
If you can help, please send me a PM and lets talk about it.


Zc

Hi
I am looking for either a board (dam) or a finished dac by Soekris. Would appreciate any offers.

SOLD



price: $40 shipped
My hope is that someone can appreciate this because I don't want to throw it away.

This is a matching set of power supply, a BASH 2.1 amplifier board, and a premplifier board with basic controls like subwoofer level and crossover frequency, volume, etc. I do not have the time to dig into this and I do not know the condition of the parts, but I believe they worked when I acquired them a while back.

Kit includes:
-one Indigo 620019 power input board
-one Indigo 640033 power supply board
-one BASH multimedia 2x100w and 1x200w amplifier board
-one Indigo DV2202F multimedia 2.1 pre-amplifier test module
-aluminum plate

I do not post much on this board, but I have tons of references in the 12volt community and some other forums if you would like.

I have a TON of electronics and other stuff that I'm trying to clear out. See pictures of everything here:
https://www.smugmug.com/gallery/n-tqJ8QR/

SOLD

Price: free, plus shipping

My hope is that someone can appreciate this because I don't want to throw it away. Maybe the parts might be worth something to you, even if the whole thing is not?

This is a mono plate amplifier with minimal markings on it. I know it's from Portland Audio Lab but I'm not sure what model it is or what the specs are. There appears to be a tone control or filter daughter board. The person I got this from was a tinkerer so I'm not surprised to see the granddaughter board too.

My best guess is this was in the low hundreds of watts range like maybe 200-400w based on comparing it to the Boston Acoustics V2000 plate amplifier that I have.

I do not post much on this board, but I have tons of references in the 12volt community and some other forums if you would like.

I have a TON of electronics and other stuff that I'm trying to clear out. See pictures of everything here:
https://www.smugmug.com/gallery/n-tqJ8QR/

Can someone please tell me which fuse holder I need for this IEC inlet?? Also explain why Schurter wouldn't include this with the IEC inlet 😕. Thanks in advance!

Schurter 4304.6091 IEC

Hi everyone,

I've recently started messing around with FPGAs, and, though this is possibly very naive, wanted to try my hand at digital class D. I found an IEEE paper titled A Class-D Amplifier with Digital PWM and Digital Loop-Filter using a Mixed-Signal Feedback Loop that I wanted to implement on an FPGA. However, the paper prioritizes power efficiency over fidelity, and (from what I can tell) neglects post-filter feedback. I've attached a block diagram illustrating essentially what the paper describes, but with post instead of pre-filter feedback. Though it still requires a high sampling rate for stability, the paper's approach relaxes the distortion requirements on the ADC, to a point where it seems hi-fi digital class D might be accessible to us DIYers, instead of being firmly locked behind expensive, proprietary chips like Axign's. I have little formal background in EE or control theory (I'm currently a Comp Sci student), so please call out any basic mistakes I've made or fundamental misconceptions I have. I would appreciate any feedback on the theory and, if its sound, further development of this project as the thread progresses.

I got the Alpine amp stated in the title from a family member and was told that he didn't know if it worked or not. After wiring it up and trying to turn it on the amp went right into protection mode. Yes my wiring was right I opened it up and a mosfet labeled N0D C25P20FR on spot D607 and one labeled N0E KCF25A20 bon spot D606 were busted. Would it be posible to bypass the protection circut or should I replace the part.

If I do replace the part the replacements I found only had the C25P20FR and the KCF25A20 labeled on the data sheet, would these work?

Hello, I'm a student in major electronics. I've learnt about amplifier already. I want to ask my circuit design below is correct or not, and are there any problems? Thanks for helping.

I have four completely unused connectors. The price I listed is a 20 percent discount from the listed price online. Will ship anywhere. I am new to this forum but I have a headfi account of the same name with some ratings and feedback.
A little bit about the connectors:
Duelund has developed a new RCA paper plastic-free Phono Plugs with a Gold plate. To complement their incredibly popular range of wires the RCA plugs marry amazingly well.
They are constructed from UP-OCC copper, UP-OCC stands for Ultra-Pure, Ohno Continuous Casting so you really cannot buy a better purity material when it comes to copper. They then go through cryogenic and demagnetizing treatments. The outer shell comprises of a natural fibre vacuum compressed paper similar to that used on their capacitors.

Hi, I have two SS D2905/9500 tweeters and I bought DATS V3 few days ago, so I'm quite new to measuring.
One of the tweeters is loud and clear and let's call it good (impedance peak around 900Hz so not really as it should be) and the other very quiet and no impedance peak.
Zma files in attach...any ideas what to do?

Hi folks,

I'm progressing a 4-way speaker design with dig. x-overs and DACs placed in each stereo speaker box. To feed them the digital signal, each Box is supposed to receive a coax stereo SPDIF signal sourced from a pre-processing DSP unit. The current (industrial) design only provides one (not reclocked) 75Ohm SPDIF Output using the SRC4382 TX+ signal from pin #32.

I want to do two things and am not certain if my implementation idea will work:

1. Reduce Jitter of the Output signals by reclocking (the TX+ output signal) with the available 24.576MHz low phase noise clock.
2. Feed the reclocked signal to two BNC-75Ohm koax outputs (one feeding each box).

So the question really is: (How) Can I do this with the TX+ signal from the SRC4382? I've read the data sheet and it seems as if the TX+ signal is TTL compatible, but I am still unsure if my idea would work:



Just for completeness: The sample rate is 48 or 96ks/s, the SPDIF input (driven by the buffer and a 75Ohm coax cable) has the same transformer in the input.

Thanks a lot for feedback, advice and recommendations!
Winfried