Time for another clearance:

2x SBAcoustics SB17MFC35-8 midwoofers. NOW SOLD.


2x SBAcoustics SB26STCN-C000-4 tweeters. NOW SOLD.



2x HIVI TM1A tweeter + midrange. In their original box. Never used. Bought 4 months ago and opened just for pictures.
Asking 60€ for the pair.





2x HIFIDIY AL-100 AMT tweeters. In their original box. Never used. Bought 4 months ago and opened just for pictures.
Asking 20€ for the pair.




2x Audaphon MB18-8 midwoofers. Used but in very good condition. An incredible well built unit.
Retail 50€ each. Asking 50€ for the pair.





2x SEAS 27TDFC H1189-06 Tweeters.
SOLD.

Paypal fees and shipping not included.
For several units price will be dropped.
Questions, please, PM me.

These are a pair of woofers from emerald physics top of the line open baffle

carbon fiber
huge spider
largest magent

made by eminence

pictures: Emerald physics 4.4 - Album on Imgur

this ad is for just the pair of woofers

i;m giving the woofers away for free but whether i have to do two boxes or one box you have to pay for all packing and shipping cost via UPS

Hi DIYers,

I am working on an unique directed coupled 300B amp.

All triodes are common cathode configuration.

2 stage 6SN7 amplification, first stage 6SN7 and second stage are capacitance coupled, second stage 6SN7 and 300B are direct coupled.

I don't use high watt resistance to raise cathode voltage of 300B, instead I use negative voltage supply for second stage 6SN7.

I use 866A tube in B+ and EY84 in B-

All parts and chassis are ready for assembly.

Happy to hear your comments!

When further listening to my newly arrived and otherwise good sounding Coral Beta 10Bs, I noticed a buzzing sound on certain bass notes (mainly lower cello and middle electric bass). When I unplugged the buzzing driver and gently pushed the cone inwards, I heard a rubbing sound. Very scary. Only if I pushed it to one side however. I suspect that either the voice coil is damaged, or I need to re-align it. Maybe both. Anyhow, I need to somehow remove/release the cloth surrounds and spider. Anyone done this before? What type of glue can I use to stick the surround to the frame again, if I manage to salvage it? Also, is there a place where I can buy new white cloth surrounds for a 10" speaker?

Those " click to open in full size " never work when I click them could someone tell me why.I have had this problem for at least 2 years.

Hi, 1st post! Got a burning question which has been asked to death. As per title, can't decide on the above. Please help. & it has to be these 2 only strictly from JL Audio.

-1st option is 2 x 12W6v3 subs in a dual opposed sealed JL enclosure powered by an HD 1200/1 amp - JL Audio ProWedge CS212OG-W6v3

-2nd option is a 10W7 sub in a sealed JL enclosure powered by an HD 750/1 amp - JL Audio CLS110RG-W7AE

The car is a Mercedes Benz CLS63 Shooting Brake

Sound Quality is my main priority and saving boot space. I've heard that the 12W6v3-4 sounds better than the 10W7 but others say they all sound good.

I rarely listen at reference loudness - mid volume mostly. I still want to be thumped in the chest or massaged by bass though when in the mood!!

The 10w7 would occupy slightly less space & also cost a bit less. I suspect the 2 X 12W6v3 may have more control and composure as its rated at 1200 watts vs 750watts for the 10W7.

Obviously the 1st option has more cone area and will be working less comparatively. But the 10W7 has 23mm x-max vs 19mm for the 12W6v3

I appreciate that custom enclosures may yield better results as they're bigger than JL Audio's apparently conservative sizes. But it has to be from the above JL's enclosures as I will be changing cars next year. Decisions, decisions, decisions... Thank you in advance 🙂

10W7AE-3

Free Air Resonance (Fs) 30.6 Hz
Electrical “Q” (Qes) 0.578
Mechanical “Q” (Qms) 7.647
Total Speaker “Q” (Qts) 0.537
Equivalent Compliance (Vas) 1.28 cu ft / 36.1 L
One-Way Linear Excursion (Xmax)* 0.9 in / 23 mm
Reference Efficiency (no) 0.17%
Efficiency (1 W / 1 m)** 84.3 dB SPL
Effective Piston Area (Sd) 59.8 sq in / 0.0386 sq m
DC Resistance (Re) 2.75 Ω

12W6v3-4
Free Air Resonance (Fs) 26.919 Hz
Electrical “Q” (Qes) 0.487
Mechanical “Q” (Qms) 9.365
Total Speaker “Q” (Qts) 0.463
Equivalent Compliance (Vas) 1.920 cu ft / 54.37 L
One-Way Linear Excursion (Xmax)* 0.75 in / 19 mm
Reference Efficiency (no) 0.11%
Efficiency (1 W / 1 m)** 85.4 dB SPL
Effective Piston Area (Sd) 75.338 sq in / 0.0486 sq m
DC Resistance (Re)*** 6.493 Ω

Hi everyone,

Anybody familiar with these monoblocks? One of mine keeps blowing the fuse on turn on, so I'm trying to diagnose where the problem is. A schematic of some sort would help but I can't seem to find one. Any help would be much appreciated.

David Tan

Which headshell (Lenco L133)?

My daughter found a Lenco 133 turntable, which is missing the pickup and headshell (see attached photo). I am a total noob with this stuff... what type of headshell do I need, and where do I find one?

Hi there,

I have an 18" Mackie branded (but built by Eminence) driver laying around that I got off a friend a while ago. I would like to build a box for it to put it to use, and so I put the T/S parameters into WinISD. It defaulted to an absolutely massive 17.3 cubic foot box, which does not seem correct - or is it?

The parameters are as follows:

Re 3.20 Ohms fs 38.3 Hz
Le 0.72 mH Mms 145.5 grams
QM 8.03 Mmd 122.0 grams
QE 0.51 Cms 0.119 mm/N
QT 0.48 Rms 4.354 N*sec/m
Xmax 6.67 mm Vas 238.4 liters
Pmax 450 Watts SD 1188.0 cm^2
Bl 14.85 Tm VD 792.1 cm^3
Coil Diameter 4.00 Inches EBP 75.3
Gap Height 0.375 Inches Magnet Weight 109 ounces
Efficiency 2.54 % Winding Width 0.900 inches
SPL 96.1 dB 1W-1m

Could someone please tell me if i'm doing something wrong? Or would you recommend to just get a new driver.

Thanks,
Joe

Hi!

Are there any drivers that can be used for home theater applications?
The driver would be mounted in a on wall box and it has to go down to 80Hz.

Can I expect any current full range driver to reach reference level at lets say 2m listening distance in such a configuration?

Thanks!

Hi all,

I'm hoping there are some generic aspects to this issue that someone can help me out with.
FFW and RW switches are working on my Sony TC-510-2 however when I engage Playback, nothing happens.
I've been looking at the unit, the schematic and the layout and trying to piece together what is going on.

The PLAYBACK know is attached to two switches as below.
S15 leads to the Servo Amp board and S16 is for timing:

The Layout diagram looks like this:
Wire <28> is 14V from the power supply. When PLAYBACK is engaged the little button on the left of the switch is released.
Now the trouble is, when I probe all three pins, whether PLAYBACK is engaged or STOP (i.e. either position of the switch) ALL 3 pins on that switch read 14V (though when I probe resistance there is about 100 ohms or so)

Following the important wire <67> leads to the Servo Amp Board and I've highlighted exactly where that wire goes. Now my understanding of circuits gets hazy here. There's a transistor, but according to what I probed at the mechanical switch, that highlighted yellow wire is always at 14V. So the switch appears to not have any effect. Where I get confused is two things:

I can't tell firstly what the effect of switching between PLAYBACK and STOP should be from the diagrams above? Should wire <67> be 0V at STOP and 14V at PLAYBACK, or is it the other way around?

Secondly, if PLAYBACK should be 14V, and somehow the mechanical switch is faulty and leaving it "on" all the time, why is the servo motor not running?

Thank you for your help!

Hi friends

I just got impressed by both the documentation of the (Aussie) Advisory Circular AC AIRCRAFT WIRING AND BONDING ...
and the bespoke audio passive preamp...

and thought that I should/could do that too. 😀

What thread/string can be used to get there? It seems like it's a bit a specialty material, can it be substituted?

Yes of course I could just try'n err, but probably there's somebody more experienced willing to share a bit of knowledge?

Thanks
david

I found (and ordered) a loudness PCB on which the capacitors (4 pieces of 2nF and 4 pieces of 0 .033 uF) and resistors were "calculated" for a 50k Ohm volume potentiometer.

I am currently using a very good sounding 10K TKD 2CP-2511 log pot in my passive preamplifier.
There is also an Audio Note 100k log pot "in reserve".


My questions are: what happens if I connect the 10k Ohm or the 100k Ohm volume potentiometer to a pcb "designed" for a 50k Ohm pot, without replacing resistors or capacitors?


Or, as far as I know, for a 10k Ohm pot I would have to change the resistors to 1/5 value and the capacitors value to 5x. If this analogy is correct, when I am using a 100k pot do I have to change the resistors value twice of original and the capacitors value to the half?

PSU for TPA3255 : https://www.diyaudio.com/forums/power-supplies/376297-psu-tpa3255.html#post6766724

The forum boilerplate bottom-matter does not render. Nor a Reply box. There is a base64 clog.
(Me: Win7, FireFox 91.0.2)

Digging in, below .."the range is from 18V to 53.5V D.C." there is a humongous Base64 URL at line 738:
"....forums/data:image/png;base64,iVBORw0KGgoAAAAN........"
98,733 characters

And again, below "these are quite cheap when bought on AliExpess for examle:" at line 760:
".....forums/data:image/png;base64,iVBORw0KGgoAAAAN......."
1,135,725 characters

The second one seems to be the choke-point. But neither renders even when opened in another tab/window.

I bought a ML332 recently. During the recap, I noticed that the left side voltage gain board is much warmer then the right side's. ​I probed around and found that the bias of the left voltage gain board seems off, quite off. The picture attached explains. The +/-supply is +/-114v. The differences between the left board and right board are
1. Q12 collector, -45v vs -15v
2. U6 collector, 72v vs 55v.

The bias is very different. Because #2, the bias to the second stage through R110 & 110 are also off. Anyone has experience on that and what might be wrong? I am thinking to replace SSM2220 and 2N6730. They both are obsoleted, Mouser don't carry and I see some people are selling them on Ebay but with 2 weeks shipping time. Other than Ebay, any recommendation on where to buy obsoleted components.


Thanks,
cfy30

After blowing up the crossover and drive unit on one of my Kef Q1s with (i think) my gainclone. well im sure it was my gainclone.

How do i protect my speakers from any other gc mishaps?

would just putting a fuse at the speaker terminals work? what sorta amperage?

btw, what couldve caused the speaker to blow. it was playin at low volume..

thanks
Amit

Hello--

I recently acquired a pair of Stanton Sixty-Five four channel headphones. For whatever reason, all 4 speakers are blown out in them... I am in search of replacement drivers, and have it narrowed down to two different ones (i think). I am just looking for opinions on them, or possibly another suggestion of speaker choice. Original driver diameter is 40mmx17mm(?) (dont remember depth, but there is spare room behind the speakers). I initially tried getting help from members in the diy section of head-fi.org, but apparently no one knows nothing about speakers on a forum about headphones 😕

I havent decided how to wire them up yet either. There is a switch in one of the cables to go between stereo and quad (has two quarter inch plugs for quad usage), though I am not sure if stereo parallels the speakers or just disables two of them.

Also, would it be worth plugging the air ports on these, or possibly adding sound material behind the speakers? On my Sixty's, I ended up replacing the blown 2 way dynamic speakers with 2 way car speakers, and plugged the airports based off a really old forum post that said doing so really helps with lower frequencies. I don't have an unmodified set of sixty's to compare against, so I'm not sure if plugging the air ports helped or not...

#1: http://www.newbdnc.com/wp-content/uploads/datasheets/BFC-D45-7-32-012.pdf
I like these cause they have the lowest Fr, and have the most data available about them Frequency response seems decent as well. If they were paralleled, that should bring the resistance down to a reasonable 16 ohm.

#2. Access Denied
Similar to #1, though the frequency chart is blank :/

I know nothing when it comes to speaker choice, so any and all input on the matter would be greatly appreciated! 🙂

hi- anyone know what the -b - stands for?

Hello,

Just wanted to double check my thinking is sound for a power supply I am working on.

I am building a PCM56 DAC, my first digital design, a simple NOS implementation. I came across the idea of using a balanced isolation transformer prior to the mains transformers to reduce mains-coupled common-mode noise.

I had looked into a custom toroidal for this purpose, but had not found a transformer maker for the job.

Instead, I am looking at an off-the-shelf option. Maximum secondary current draw for my design at 120VAC is ~70mA. I am looking to use this transformer from Triad Magnetics, VPM240-100. It is a dual primary (120VAC, 240VAC) dual secondary (120VAC, 240VAC) medical grade toroidal with electrostatic shield and hum band.

Secondary rating for 120VAC (parallel) is 208mA, for 240VAC (series) is 104mA.

https://www.mouser.com/datasheet/2/410/VPM240_100-844597.pdf

What I would like to do is use both primaries and secondaries in series, as if running at 240VAC, but with 120VAC on the primary and ground the meeting point of the two secondaries (virtual center tap) for balanced +/-60VAC balanced. Again, max secondary current draw for my design is 70mA.

I think this should work, but thought I would run it by you folks, thanks.

Hello

I have try to do a LTspice simulation of this amplifier circuit, but the offset voltage and the bias in this simulation are wrong, anybody can tell me where are my errors in my simulation ?

I include in this post, the circuit image and my simulation file

Thank you

Bye

Gaetan

Someday somebody may trace the history of Carvin guitars/amplifiers.

I have been planning to use a DSP crossover with high quality DACs feeding one amplifier per driver in a 3 way active speaker. My first thoughts were whether to use a MiniSHARC or a NanoDIGI - anyone know the advantages of the SHARC?

Anyway, whilst looking for information that compare these two DSPs, I found myself stumbling over several articles that compare analog crossovers with their DSP counterparts. My target (like most people) is to get the most ACCURATE sound reproduction which would imply that the DSP solution is better. Several people point towards the downsides with a DSP solution (even with good DACs) but I just can't see why - is it just 'fear of the new' or are there aspects that genuinely affect the sound quality. For example, does 'perfect reproduction' sound too harsh or something like that?!!

The 375L is the name of a famous Swiss car... 😎



... That I only have in miniature, unfortunately 🙁



Incidentally, it's the name that I choose for my loudspeaker enclosure project to come - because it's 3-way and 75L. with some Vintage style 🙂



The template :



The wood on the bench :



The start of the construction is scheduled for... Tomorrow 😀

A+!

Has anyone used Pole-Zero placement and Laplace Transform to design the crossover network of loudspeakers? Can you help to briefly explain the procedure? I have some basic knowledges of algebra and calculus. I’d like to try a new experience. Kindly help.

New DH Labs Encore 14AWG shielded, unterminated power cable. New for $2.99 per foot, retail $6.50/ft. 15 ft minimum.

Price is firm. No trades. Buyer pays shipping. PayPal adds 3%. Other fee free options.

Thank you.

Encore A/C Power Cable – DH Labs Silver Sonic

I would like to ask why very large public address amplifiers often employ two complementary input stages? Using two different sub-circuits for the input necessitates that the two sub-circuits behave exactly in the same way. My impression, which may be wrong and that is why I am asking, is that, making NPN and PNP transistors to match to a very high degree, is expensive and difficult.

Anyone have this schematic?

We are looking at one from the 1980s, any opinions on these?

Hey all,

I recently picked up a pair of B&W DM2a's and am in the middle of rehabbing them. Fortunately all drivers work, the crossover is in fine shape with no EC's, and the cabinets are coming along nicely.

Where I have run into trouble is that, yep you guessed it, some previous owner has messed with the T-line stuffing.

Basically once I removed the front baffle I found the cavity behind the woofer has had all the white fiberglass (?) completely removed. I also found the triple folded felt pad had been unfolded and stapled to the top and all the way down into the throat of the T-line partially blocking it.

Another area of concern is that the white fiberglass (?) in the bottom bend of the first fold of the T-line is very tightly packed. This makes me wonder if the PO took the existing teased stuffing behind the woofer and shoved it down into the bend, or if it was originally this tightly packed.

Some other points of interest: I also found strips of yellow fiberglass sheets (similar to what you would find in a pipe insulation wrap package) laid across the top of the stuffed bend of the T-line at both the inlet and outlet. Also, the rubberized open weave bat that is usually seen at the bottom edge of the front baffle board was also inserted down into the throat of the T-line.

Here's a cut away view of the cabinet and stuffing that shows the intent.


I can easily restore the folded felt mat back to the original intent.
I can also move the rubberized open weave batting back to its original position.
The Yellow fiberglass strips are probably not hurting anything.

Where I need assistance is with the following:

1. What is the original stuffing material behind the woofer?
2. What would be a suitable replacement for this material?
3. Is the 1st bend of the T-line supposed to be very tightly packed?

and
4. any other insights or recommendations are appreciated?

I will post more pics in the next couple posts.

I am following several threads about the TPA 3255 and come across a lot of questions related to suitable power-supply-units by less experienced users.

This chip can deliver up to 315 watts per channel and has an efficiency of 90% and better , so if we assume 315 watts x 2 = 630 watts which are equal to 90% then the power required to output this is an input of 700 watts. which the PSU has to deliver .

OR LESS ?

YES because the power required depends on the output power you need or want.
If you look up the datasheet of the TPA3255 at this link :

https://www.ti.com/lit/ds/symlink/t...=https%3A%2F%2Fwww.ti.com%2Fproduct%2FTPA3255

from Texas Instruments you will find a graph of " output power versus supply voltage where you can look up what the voltage you need for the output you want , the range is from 18V to 53.5V D.C.

This is that graph . If you use a slightly higher voltage , say 2 more volts , your output will be perfectly clean provided that your PSU delivers the necesary CLEAN current , which depends on load , type of music played , and a lot of other minor factors .

Now you know the voltage the TPA needs for your output- power.

The current is another story because it depends on the number of channels you have , the kind of music played , but in general terms the PSU should have 20 percent more watts than the sum of the channels to be driven simultaneously , so if you want say 2 channels at 60 watts each which gives 120 multiplied by 120% gives 144 so your PSU should have 150 watts or more , and so on.
This is valid for a class "D" amp , class AB needs a lot more .

With SMPS this should work fine for you provided that it delivers a clean current so consider a filter between the PSU and the amp
With a linear PSU you need high cpacity to avoid sagging rails at 100HZ in Europe and 120HZ in the United States for example.

If you have a linear PSU with a somewhat lower voltage than what you require a good option is to use a boost module to raise the voltage to what you require provided your PSU has the necesary output power and its voltage is between 10 % and about 35 % lowerr than what you need . the allowable booster input current has to be twice the current the amp needs and here as well I recommend a filter between the booster and the amp. Use a booster specified for twice the amps you need as these are quite cheap when bought on AliExpess for examle:

You get this for 10 dollars , or 10,40 euros now .

You can adjust it to the exact voltage you want , and limit the current to whatever you adjust as well.

Hello everyone. There is an amplifier stetsom ex10500. When turned on, 2 short flashes, one long blink. I remove the resistor R127 and apply ground to the Pic, the amplifier starts up normally and works. Power supply unit 30A 14volt. At the same time, even with a resistor, I do not see a high level. Which way to look, what could be faulty? Before that, one bridge burned down. I replaced Irs, logic, checked all zener diodes and gate resistors. Thanks for the help.

Hi guys.

I'm looking to power on my 2x15W JLH from a physical on/off switch in the back and a one-touch button on the front. I want the touch button to turn on the amplifier when I first press it, and turn it off when I press it again.

This is what I've found so far, from eevblog...

https://imageshack.com/i/p9BJywFXj

However, this needs two different touch-buttons, which is both unpractical and uncool. In my head, this modification makes sense and will work, but will it?

https://imageshack.com/i/p3q0gmj5j

I've forgotten enough about electronics, I cannot figure out this myself, therefore I'm turning to you guys, perhaps this can help others as well. 😊

If this is a dead-end, please enlighten me, how can I easily make a simple on/off switch from one impulse switch/touch button. Got relays, bd139/140's, got diodes, caps, resistors... Just doesn't have any dedicated chips or 555's or whatever...

PS: tried to upload the images here first, but was missing a security token of some sort...

Sincerely grateful...

Ben from Norway.

Hello,
I got an Atoll PH100 phono stage and was wondering if upgrading these caps will get me some improvements:


-100 pf input ceramic disk caps (these are switchable and when on noise floor increases noticiably)

-220 uf electrolytic caps

-4.7 nf yellow caps

-15 nf white caps


Are the yellow-white caps polyester?



I have compared it to my Rothwell Simplex. Bear in mind the Atoll is brand new, just a few hours of duty and the Simplex is fully burnt in! The Atoll sounds very good but the Simplex has a bit more weight on lower mid frequencies (maybe between 100-400 hz) wich gives a fuller, more sculpted central image... I wonder if the Atoll will get there when burnt in or the type of caps may have something to do.


By the way, do you know what the 2 variable resistors at the bottom of the picture do? I tweaked one and couldn't notice any difference... but I couldn't listen from the listening position while moving the pot, so maybe that's why.
Thanks

I have just found a really nice pair of EPI 180s and in the interest of diy, I am contemplating building a pair of M201 clones, just for fun.
Even though i have found little in the way of positive comments about the 180, they present a huge soundstage and substantial bass output while having a sweet overall presentation. However they look rather cumbersome in my smallish room and I hear good things about the 201s when placed wide and against the front wall.
The clones can be made from one 4 x 8 sheet of ply or mdf.
Does anyone have knowledge of any internal bracing in the original 201?
Attached is a pic of the 180 which uses the same driver complement as the 201.
Cheers
Peter

Hi all.

One of my first ever valve projects was a pcb-based PP EL34 with a whole bunch of salvaged transformers. For years, I used an underspecc'd pair of power supply chokes. One day, after maybe a decade of heaps of use, one of them sprang a leak and coated everything in thick oily waxy substance.

1) any thoughts about if this is toxic or if it is just mineral oil?
2) any concerns about just washing it off, replacing the chokes with something more appropriate, and then putting her back into service?

Many thanks!!

Hi all,
I have the above mentioned amp for repair. Some gate resistors are 47.5 and some are 60.4ohms. Dont know if anybody interfered with them. I would like to the values of the gate resistors. They used 75344G mosfets. Thank you

Have one which came in with output FETs hardly working. One was almost shorted but not quite. I clipped a few off the board and the amp started to get a little better.

The output FETs are TO247 but are defaced. Anybody know what these are?

Im also going to replace the drivers ICs, as there are two in this amp; IRS20957S as I believe - scratched off as well; that is IF I can find them. Right now I can only seem to source them from eBay.

Does anyone replace the 6-pin ICs? zxgd3005e6ta as I believe. The problem with these is, they're not available anywhere from what I can tell.

This may be the last Brazilian/clone I work on if I cant find parts.

Thank you in advance.

Here's a chart from DSL giving port location horn loading cutoff for the SH-50, a 50x50 conical.


I need the same chart for a 60x60.

(and would really like to learn how to generate them for any size pattern...via math or maybe via hornresp ?)

Thanks, Mark

Amp is stuck in protection mode.

All outputs and power supply fets test fine .

Any ideas ?

Is there a way to improve the grounding of the kit? I just built the kit and followed the 6L6 build guide. If there is a way to improve the grounding, what should I do? I'm thinking make a bare spot on the chassis and run a ground wire(s) to it but where should the ground wires come from -- pot, input, output, etc.?

Hi I have an OLD set of Logitech Z-5500 speakers where its just not functioning anymore. It's the RCA version with a weird PID of 10003301-0445R. I've been searching for a way to resurrect the sub for my own use but I can't find any solutions anywhere. I don't want it to end up in a landfill.

I've bought an adapter meant for PIDS between R200-R635, but the sub just booms and buzzes when I connect it. Mine is obviously wired differently.

I'm not super knowledgeable about hacking electronics, but I have access to tools if I could just figure out what to do. Can anyone help me?

Hello

I am looking for some thoughts on an enclosure for the 7ms driver. I already have a pair of the drivers but am a bit stuck on a design.

Goals / criteria
- Under ~12" x ~12" footprint
- Room size is about 250 sqft
- Able to be very close to / up against the back wall
- Floor standing or bookshelf is ok
- Ideally used without a subwoofer
- FAST / WAW ok as long as a speaker level passive crossover can be used
- Driven from a 50-100 watt home theater type receiver

Any ideas on something that would meet the above?

Thanks!

I have two ACAs. I’ve run them mono with balanced cables and see the discussion on what’s happening: i.e., more power less distortion. I have them in a system that only has RCA hook-ups. What happens running them mono/bridged with a single ended input?

Hi,

Is it OK to use the amp chassis as heatsink for discrete semiconductors like B+ voltage regulating MOSFETs (insulated package, like TO-220F), or should I always put a dedicated heatsink? I'm not looking at extreme cases like 6C33-based amps, which get extremely hot, but something based on 6L6GC/EL34 in class AB. Any advice is much appreciated!

Thanks,

Jose

Hello DIY People,

Can somebody help me figure out what this part is please. There are two of them, one for each channel, and they are mounted to the heat sinks right next to the power and output transistors of a McIntosh MC425 audio amplifier. It looks like a cap but there are no specs on it so even if it is a cap I don't know how to find the specs for it so I can either test or replace it.

I spent the last few days looking for a schematic for this amp so that I could figure out what this part is. But I can't find a schematic for this amp. I found some McIntosh amp schematics, just not for this one.

Here is the picture of the part.

50W/8R Circlotron Power Amplifer

Each channel need active parts:
* OPA2604 x1
* PowerJFET LU1014D x2

passive parts:
* Resistor x12
* Capacitor x3
* Inductor x1 or x2

Power supply:
* ±24V-DC voltage-gain-stage power x1
* 24V-DC circlotron power stage power x2

Selling a pair of professionally CNC'ed Frugal Horn FH3's. The bezel is machined to accept the Fostex FE126En drivers. Includes outriggers, spikes and speaker terminals.
Built from high quality marine grade Baltic birch.
Asking $350. Shipped at buyers expense, local pickup in DFW or I can deliver to Houston next week.

New to Amp boards here and need some suggestions and help!

Plan on building a 2.1 speaker setup, and have got some requirements on mind for the amp:

1- has > 70w x 2 channels
2- has >= 100w subwoofer channel
3- has Bluetooth module

Found https://www.amazon.com/AOSHIKE-DC12V-24V-Subwoofer-Amplifier-Bluetooth/dp/B07BKYL3GC/ref=sr_1_5?dchild=1&keywords=tpa3116+amp&qid=1629042633&sr=8-5 which satisfies 2,3 but its only 50w per channel.

Couldn't find any "Cheap" boards that satisfy all 3 requirements that I have.
Can I use one of this in conjunction with one of that for the ultimate 2x100 + 100w? How would I go about connection both amps to work as one single unit?

Thanks in advance!

Hello good people,

I'm relatively inexperienced at this stuff and a little confused by what i'm running up against. My buddy gave me a JBL floor monitor which was not working. I pulled it apart, the woofer worked fine if i used a tone generator on it, the horn seemed to work fine similarly, so i assumed the two way crossover had an issue. I replaced it with one from amazon, and had the same issue, but i could hear that there was audio coming down that line with an induction wand. I tried several other speakers that should have been able to replicate high end frequencies and got nothing. I then took the leads from the x-over to the woofer and put them to the horn and it made high end noise. At this point i assumed i got a DOA crossover and had amazon replace it. New crossover is having the same issue. If i run full range to the horn, it functions ( i know not to leave it like that) Anyone know what might be going on here?

I did look through the forums for a similar issue, but didn't find one. Apologies if i missed it.

Thanks
telfer

Speaker: JBL JRX100
horn: JBL2412h-1
Woofer: JBL M112-8 (8 Ohms)
original crossover jrx112M
new crossover(s) EMB CX-5

Hello, I have a NAD T775 with some broken speaker terminals. Anybody have or know where I could purchase some replacements? Please see the attached photograph for details. It's the two black ones that are broken. I've tried contacting NAD, but no luck so far. Thank you.

Hi All,

I own a Fender Pro Junior which I have owned for about 5 years. Shortly after purchase, I renewed all the electrolytic capacitors and replaced all the signal resistors with metal film. I also redressed the wiring routing etc. It's PCB shows 2005 so would think it is a series 2. It has always been excellent and has always been without hum and noise (no i/p, no volume) except for a very small hiss if putting an ear to the speaker.

Recently I had the V1 go very microphonic so replaced it with the same make and type (Philips NOS 5751) as I originally bought them as a pair. I was very surprised to find that the replacement valve produced quite a noticable 50Hz hum when fitted. I then visited my valve box and tried 4 different makes of 12AX7's. All but one gave quite a noticable hum at different levels. The one that didn't was a Groove Tube 12AX7 which was virtually silent. Not to be put off I then purchased 2 x JJ 5751 Gold Pin valves from a very reputable dealer as the valves were supposed to have quite a good review. Hoping for great things I tried both in the Amplifier. You can imagine my disappointment when they both had considerable hum, with one a lot worse than the other. I have now re-fitted the Groove Tube 12AX7 and now everything is good.

Question: Are all valves we buy now so unpredictable in their performance? I am now at a loss, as I could buy some more Groove Tube 12AX7's and find they are hummy too.
Roger

One of the springs under the speaker terminal leaf switches on the back of my subwoofer popped out and must be replaced, but I don't know the size or where to find an OEM replacement (I've found springs on eBay, but again, I don't know the required size.)

Any help appreciated. TIA.

Hi,

I have a complete FC100 Kit for sale. I have participated in the FC100 group buy but sadly haven't had the time to finish it. The amplifier boards are completely assembled and tested working. The only missing part is an enclosure for this brilliant amp.

https://www.diyaudio.com/forums/group-buys/293550-roenders-fc-100-buy.html

My offer consists of the following items:
- 2x Fully assembled FC100 Boards with matched transistors (see the thread above)
- 2x Fully assembled Shunt power supply for the preamp stage
- 1x Fully assembled soft power on PCB
- 1x 1x230V/4x34V toroidal transformer for the frontend psu
- 1x 1x230V/4x25V fully encapsulated transformer for the backend psu

I don't know exactly what I payed for all these components but i think it was around 500€. I would sell the complete Kit for 300€ plus shipping.
I hope I can find someone who is interested, because it is a shame that such a nice amplifier is collecting dust in my cabinet.

Hi all!

In a search for popular amplifier circuits in other countries, I discovered the most popular amplifier circuit among Russians. This amp is called "Only Music 2.7". The scheme was found on the Russian site "cxem.net". The author of the scheme is - "Nem0"



Diy PCB - https://cxem.net/sound/amps/files/amp240_OM27LUT.lay
Gerber PCB - https://cxem.net/sound/amps/files/amp240_OM27_01_(2).zip

The amplifier is actively assembled in russia:








I want to build it. I am interested to know your opinion.

I know there’s a lot of members of this forum who are also a member of the FB, Vintage Audio and Tech forum. I hope none of them will feel offended I’m posting here. As a total electronics noob, I need all the help I can get!

I’ve been restoring a B&K, AV5000 S2 that has one problem left to solve to complete the project. Channel 4 has a very faint speaker “hum/buzz” that’s there no matter what is or isn’t connected to the input. All 5 channels play and sound great, but when you turn channel 4’s volume down you can hear the hum/buzz. I’m pretty sure its not the power supply. Channel 4 shares its power supply connection with channel 5 that’s dead quiet. Also the noise is still there if you swap channel 4’s power connection with any of the other 4 channel’s connection. I’ve also checked solder joints, wire routing and ground connection problems and all seem to be OK.

One suggested source could be V+, C2 and V-, C12; 100uF, 100V caps. The caps in it tested as: C2: 97.79uF, ESR=1.18 ohm, Vloss=1.2% and C12: 103uF, ESR=.38 ohm, Vloss=.8%. I also suspected the 10uF, 25V, bi-poplars, C7 which leads between the 4 mosfets and C8 because its the first component from the plus side of the input. They tested as C7: 12.3uf, ESR=1.5 ohm, Vloss=3.4% and C7: 12.6uF, ESR=1.6 ohm, Vloss=3.3%. I’ve read on a “Electronics For Dummies” site the Vloss values might indicate the caps are out of spec and should be replaced. Another suggestion is CT: 100uF, 25V, that’s on the schematic and board, but not listed in the BOM. It tests as 100.uF, ESR=.75 ohm, Vloss=2.0%.

While I’m capable of doing the testing and soldering replacement parts, I don’t have the diagnostic knowledge that would tell me what the test numbers mean and what else could be the cause of the hum. Its been a long summer sourcing and replacing parts (20 mosfets!) cleaning up issues left by previous work. I feel so close to success, but could really use some technical help and guidance finishing up this project.


Thanks

Just want to pass the construction idea past people. To make the bass and treble enclosures, takes the length of carboard tube (bass is 50cm long, mid 47, conveniently) and, using a ply jig, place 4 M6 studs along the outside length, with M6 internally threaded adaptors welded on the end.

Fibreglass the structure, keeping it as round as possible despite the studs.

Then wrap with sound deadening material, again keeping as round possible.

Insert assembly into PV pipe with an overhang each end and fill airgap with builder's expanding foam.

Make two two part bungs, one part fitting inside the PVC, one inside the cardboard tube. One bung will be the baffle, one the back. Route the baffle end so the allen bolts used to attach the ends to the rods are flush. It may be necessary to turn up the bolts for sufficient surface area. This can be done.

Make a rubber gasket.

Fit connectors, fill with foam etc and screw ends onto tube and driver onto baffle.

Add bungs, one with an air conditioning valve in the part that will be cut out for the driver.

Trim pipe.

Run air con pump to check they are airtight.

If so, fit foam, connectors, mount driver off centre in baffle, and assemble.

These can easily be taken apart for further tweaking.

If not, seal firmly and curse, because in future access is only via the driver hole.

Costs to this point are minimal, so the methods can be refined and the process repeated until all four enclosure are made.

Sound reasonable?

Hi,
I would like to have a audio SA, and I am stuck with these three options:


- buy something like a HP3562A but they are old and very expensive, about 80dB dynamic range
(Price 1000+ EUR delivered best case)



- use my E4411A SA (9KHz-1.5GHz) with this:
NEW Spectrum Analyzer low frequency converter bg7tbl Type sa-LF os12 conv | eBay


Still about 80dB dynamic range and possibly need conditioning circuitry

(Price 70 EUR delivered) + conditioning circuitry



- Buy a good enough sound card and specific software, I have found something like these:
Creative Sound Blaster G3
Creative Sound Blaster G3 Amplificatore USB-C DAC per console di gioco PS4, Nintendo Switch, con GameVoice Mix (equlibrio audio per giochi/chat), controllo del microfono/volume e controllo : Amazon.it: Fai da te
(Price 40EUR delivered )


- CREATIVE Sound BlasterX AE-5 Plus Pure Edition
(Price about 190EUR)

32bit/384 kHz
Snr da 122 Db



I don't need exactly high end stuff, still I prefer "real" instruments, so if I will use a computer soundcard it should have way better performance than the 80dB I can have from old hp gear.


I have a HP8903B with very good software from P. Millet already.


I saw software tester that seem way more I may need, do you have recommendation for a good sw/hw audio board combination?


Max budget is 200EUR for the audio board, I would love to build a conditioning circuitry to better use the combination, so I could shell out another 100-150EUR max for it.


TIA


Giuseppe Marullo
IW2JWW - JN45RQ

B579D580-F11A-4C5A-9308-0AFF2937D6FF | Zack Fedor | Flickr

Good day,

I have been thinking about building a low power but good sounding amplifier, I’m either class-A or class-A/B.

I came up with the above schematic from studying a few Germanium Transistor based schematics. The amplifier makes use of a class A preamp and class a/b power amp, which both work on 9vdc.

The goal is to build a nice sounding tabletop music player. Not building the next pass zen, but I want a better sound than what is found on the market from something using low voltage.

I threw the schematic together while at work, so it probably has errors. I will run it in spice later as well.
My limited audio knowledge rests with vacuum tubes, so I would like some assistance, please.
Any advise is welcomed, but please don’t mention how bad Germanium Transistors measure. I know, but I like their sound.

Thank you all in advance.

With a back to back mosfet relay arrangement, can they be used for lifting the ground instead of lifting the amp output? So when they engage they would connect the amps ground to the binding post instead of the amps output to the binding post

The reason why i want it this way is because so that i can implement it in my existing myref amp and also it cuts down the complexity to half.

Hi guys,
Got a Pioneer dj mixer suffering from buzzing on the XLR output. Turns out its a common problem and the culprit is the fuse on the 'hot' signal out. The issue and the fix is shown in the following video.
Pioneer DJM S9 XLR buzzing or no output issues repair fix - YouTube
Same as the owner of the video I also thought what would be the purpose of this fuse. At first I also thought it could a guard against accidental plugin into phantom powered input - but since phantom power is limited to mA range and though its not ideal it could not cause much harm in this situation and its not common to see a fuse on this end in other similar mixers.
Also the exact fuse is hard to source and its sold as 'pioneer fuse' 😱 . Which leads me to think its kind of a manufacturing decision to make the life of the repair tech harder.
What are your thoughts on the possible use for this fuse?
Thanks in advance.
P.S. any suggestion on an equivalent replacement. Its rated as a 1A fuse.

Hi,
does anyone knows tested low noise tested circuit? I want updgrade Bmw HIFI Logic 7 amp. Problem is engine noise if I connect direct RCA on TDA8566Q balanced input. So I decide build low noise pream wich will convert balanced to unbalanced signal.
I dont want to use audio processor is too expensive, Hi-Low converters I dont like too (poor audio quality), so I think the best solution make converter.

There is one big problem, preamps using dual PSU in Logic 7 single... Maybe I`am not right cause I get balanced output from digital section to TDA8566Q?
I did some drawings LOGIC7 - Image on Pasteboard




TDA8566Q input impedance 120Kohm by datasheet.

THANK YOU!!

Didn't know if I should create a new thread or write on an old thread. Hopefully new is ok. 🙂 I've gotten the repair broken things bug and so have been attempting to troubleshoot and fix what I can find on the cheap.

Ok, on to the questions. Powered up this solid state amp on a dbt and the light shines bright. Unplugged and discharged i immediately went for the transistors. All test ok through my dmm at or near 0.500 on the proper legs. Going to need to walk my way back to find the issue. We'll get more into that soon...

After pulling the main transistors i noticed some had mica and grease and a few had just rubber. Is that normal? I also had two that had double mica? Accident or purposeful?

I'm trying to figure out what the best way is to connect the input wires for the toroid transformer to the output wires from the mains input switch/fuse/IEC kettle connector unit.


Do I:

1. solder the wires together and cover only in a couple layers of heat shrink wrapping? (doesnt seem a good idea given 240V mains)
2. use a crimp female to female thing (might be called a "butt splice terminal" but unsure of the name,
   An externally hosted image should be here but it was not working when we last tested it.
   ) with a bit of heatshrink?
3. Use a connector strip terminal block (the 80s/90s style with screw terminals)? Not sure how to mount them - usually I've seen them with self tapping wood screws
4. Use a terminal block for semi circle connectors like: Dual Row Fixed Screw Terminal Block 15A 600V Electric Barrier Connector | eBay
5. use something else?

I'm unsure how much space I have in the case, want to try to make it look neat.


Anyone have any recommendations or tips please? Thank you

I'm working on a Class A Follower power buffer that will use Tokin SITs so I will have a couple of hundred Watts to dissipate.

I have two large heatsinks that are natural anodised finish. To maximise their performance I would ideally like to finish them in black so the choices seem to be black anodising or powder coating. Any thoughts on which finish will be best?

Oh, one other thing, if you run a finger nail along the heatsink fins they 'sing' and I'm wondering if powder coating would give a modicum of damping?

Thanks

Instead of drilling directly into the bottom metal plate of various chassis, I'd like like to commission custom baseplates with custom specified drilled mounting holes. That way I can attach the baseplate to the chassis using only a few mounting holes with it slightly raised above the chassis bottom and screw down the various audio modules and transformers to the baseplate.

Does anyone know of affordable options for something along these lines? Plastic or metal would be fine. I know front panel express will do panels, but I'm looking for a cheap option to potentially try different layouts. Given 3D printing and the cost of plastic, I was hoping something cheaper is available.

The Hifi2000 baseplate doesn't extend the full length of the chassis, the drilled holes don't fit for some modules and the spacing isn't always in line with all PCBs.

I have a large number of surplus Sanken audio output transistors which I'd like to offer to members first here, before they start going on ebay.

These are brand-new current stock, genuine Sanken parts (these were bought from a Sanken distributor so no question about their origin!)

I have:

Qty several 100s of Sanken 2SA1216 (PNP, 180V, 17A, fT=40MHz)
Qty approx 100 of Sanken 2SC2922 (NPN, 180V, 17A, fT=50MHz)

They are in the Sanken MT200 package, PCB mounting, sort of like a wider TO3 style.

I'm asking £2.50 ea, these typically sell for £4.50+ from Farnell, Rapid etc..

Also open to negotiation on larger quantities.

Hi
Some body who can clear it up for me ?

From adire :
3.3 Adire Alignment Design
The Adire alignment design for Tempest is an overdamped vented alignment. This alignment matches a second order roll-off with a Q of 0.577 and an Fc of 20
Hz to within 0.5 dB down to 11 Hz. This overdamped alignment provides a very tight and accurate sound (with the group delay near 17 ms at 20 Hz), while
providing the potential for high SPL output. Overall, it provides the same effortless sonics of the EBS alignment, while yielding higher potential SPL output in
the midbass range. As a result, this alignment is well suited for both home theater and music-only applications.
The Adire alignment design is a net 214L cabinet, tuned to 15.4 Hz. It is stuffed with 64 ounces of polyfill. It’s external dimensions are 37. 5” tall, 22” wide,
and 22” deep. This includes the height from 4” tall legs. It is vented with a pair of FP3 three inch flared port kits, with 11” long center tubes. The Tempest and
vents are mounted on the bottom, downfiring. Three internal braces are used to stiffen the cabinet, and keep the widest panel span to a very good 9.75” or less.
Recommended building materials are void free plywood (such as marine ply, apple ply, or baltic birch), MDF, and particleboard, in that order.


Overdamped sounds nice !

Can some body help me make a Overdamped cabinet for this woofer : Monacor sph-380tc t/s

It is for HT and music

look here and help me : my thread

Thanks 🙂

Has anyone here tried doing I2C or SPI communication between two CSR8675 chips? Is this even possible? 8675 datasheet does not make it clear whether it supports I2C / SPI or not. At some sections it makes it sound like both are possible, at some it makes it sound like it only acts as a master. Does anyone have any experiences with this?

--EDIT:
What I need to do is something like this. I will have an analog mic attached to MIC A of CSR8675, I want to send the words of audio data received from this microphone via I2C/SPI to another CSR8675, collect them into a large buffer in the receiver CSR chip, perform some processing on it (for now, a simple multiplication of bit shift), send the digital version of this audio to the receiver CSR chip, process it further there and then play it out on the DAC of the receiver CSR chip. Is doing something like this feasible through I2C/SPI? I do not care about the delay between sound going into the microphone of the transmitting CSR chip and sound coming out of the speaker in the receiver CS chip, as long as all transmitted data is received.

Is I2S what I should be looking for? I have never done anything with I2S before. Does anyone have any pointers on where to start regarding this?

Performance is on par with the traditional EF-VAS with cascode.
Benefits
1. Current is limited out of box. No extra current limit circuitry is needed.
2. It is stable. The idea is that, at very high frequency, Q5 will be dropped out of the local feedback loop automatically without farther compensation, though I did not prove it mathematically.

I am looking wattage of this tunnel resistor ? Any idea of manufacturer...
1.75in(44mm) long , 3/16 (5mm) inner hole and 3/8 exterior diam. (10mm)
The value is .5ohm and marking is: 119505-1 ZA/CAN 1908

Thanks for your help.

Note: I could be completely wrong on all my assumptions, so please correct me if so 😛

My understanding is the original M2 design was push-pull and produced 25W into 8 ohm. If the Mountain View front end is used, it makes the amp into a SET configuration, right? In which case, the power output should change, right? If so, what is the new output figure with this front end board?

Hello, I've been building speakers for a while now, I've learnt a lot of things and tips.

The only thing I still can't figure out is how to make angled speakers live this design that I've made in Sketchup.
Any suggestions?

Maybe this is old news, but I just saw the LT3092 and thought there might be some clever audio uses for it. Anything from super simple low power class A headphone amps, to better current sources in conventional designs. Anybody else thinking about using it?


LT3092

I have an opportunity to obtain a pair of 805D3's. I was wondering if anyone had experience doing this.

My room is super-small.

My current setup is DAC->Nutube B1->Splitter
Splitter->F6->Woofer of Klipsch RP600M
Splitter->Attenuator->Aleph J->Horn of Klipsch RP600M

Some of you might recall me trying to get this setup humming. I have, and I love listening to it!

A friend of mine is recommending the D3's. I'd like to try them. I heard his 802's, and thought they were quite good.

Hello, I am wanting to learn more about the specifics of drivers for different subwoofer designs (folded horn, tapped horn, 4O bandpass, reflex etc) and its becoming apparent that there are certain T/S parameter values for drivers that make it better/worse for each different subwoofer design. Could somebody either help me understand or link me to a thread explaining what T/S variables could make a driver better suited to a specific design of subwoofer. Thanks

Hi Russ / Brian,
While waiting for the new B II batch to appear “In stock” I read the whole Buffalo II thread here and came upon the Legato announcement.
Well, I was about to happily order the IVY III with BP Placid etc. but I am now hesitating between the two I/V stages.
I know it’s very subjective and down to a personal taste but could you please be so kind and help me to choose the right one for me?
My system is a modified pre Naim NAC 202 w/ local Superregs and NAP 250.2 power going to a pair of 15” Tannoy DMTs. I am mainly a rock music listener (unfortunately, with poor sound quality very often) and I am looking for fast bass with good grip, good dynamics and smooth mids and treble.
So, IVY or Legato will suit better my (rocking) needs, please?
Thank you,
Ivo

Hi folks,

Does anyone know where I could find schematics for TTP 2000F preamp? Emailed Thorens, their answer was that they don't have anything for that anymore.

The peculiarity with that preamp is that it's output level seems to be too high for the TMA 2000 power amps it's paired with - can't turn the volume above around 20% of travel without things getting uncomfortably loud. According to the little information I could find, the sensitivity of the power amps is 0,7 V - seems insanely sensitive to me. Is that normal, or is there anything I can do to lower the output level of the pre-amp?

It started years ago. Decades to be honest. Back in the days of Carver. Ever since I have been building and buying and tweeking. Always trying to get better sound than I could afford. I found out that the real key to achieving stereo bliss is shitcanning the old lady. After 27 years living with a genuine sociopath I am finally free.
So a couple years ago I saved up and bought a set of Lundahl transformers and some 300B tubes and built a really nice SET amp. It sounded great and I continued to work on it. Bought some autoformer volume controls. Tentlabs heater boards, and Deulund caps. It was becoming quite amazing. I was using a pair of transmission line speakers that were magic with this amp.
Well I had the opportunity to buy a pair of La Scalas from the original owner for $1250. I rebuilt the crossovers, hooked them up and have been just floored how great everything is now. It took a long *** time to get here but I finally have the system I want. Only took until I was 56 years old. I still gotta put the amp into a chassis worthy of its parts but for now I just listening to it and loving it. I was amazed at how quiet my amp is with 105 db spl speakers. You cant tell it on unless you stick your head in the speaker. it was those heater boards that did it. worth every penny.

just got new tyre from tascam ninja- i tryed it with no glue- started sqwealing- whats the best glue for this please?

Hello, all
For this little project, I'm using a LM311P. It is has a collector/emitter output. Because my circuit didn't function the way it should, I started debugging.
With the collector unconnected the emitter (pin 1) still sinks (11 mA) and sources (20 mA) current, when applying a square wave input. I measured mean dc amperage to either rail, so the max is higher. I cannot explain this behavior.
Doing the current measurement on the collector (pin 7) with an unconnected emitter I get 14 mA when sinking, and none when sourcing. But not following the input signal.

Any suggestions of this?