Can anyone point me to a replacement power transformer for a Heathkit W5M.
I'm not a tech, so any information on repair or replacement would be much appreciated.
Hate to see one of these become a doorstop.

for days, I've wanted to compare the sound of a ported box and turbo box for open show

Hello, I am urgently looking for a service manual for a Thorens TCD2000 CD-Player - can someone help? Best regards, Peter

I'm seeing some behavior that I don't understand, and I'm hoping someone can explain it to me.

I'm using an 815 tube (dual beam tetrode with shared screens and cathodes) in class AB1. The data sheet specifies a maximum grid resistance of 15K per side. That's all well and good.

Plate voltage is 500V, idle current is 37mA per side. Screen voltage is 190, dissipating ~1.5 mA total at idle.

I've got 10K grid stoppers, and I'm experimenting with a dual-ganged pot in place of grid leaks, to better understand the behavior at different values. From 0-5K ohms on the pot (10-15K total grid resistance), screen current stays steady. But when I go beyond that, it climbs quickly; by 25K total grid resistance, the screens are dissipating 9mA, and by 40K they're at the 32mA max spec.

I get that I'm abusing the specs. But what I don't get is why screen current would increase with higher grid resistance. Higher grid resistance shifts the bias down, which if anything should reduce screen current, not increase it.

Could it be caused by the big disparity between plate and screen voltage? The tube has a 225V limit on the screens, and I'm at 190 because that was a really convenient voltage to regulate with a simple series pass regulator with VR tubes for reference.

What am I misunderstanding?

My water-flosser died yesterday, and of course I couldn't dump it without attempting to fix it.

It responded to the controls, at least with the LEDs, but the main motor wouldn't run.

The motor is controlled by two paralleled MOSFETs (SMT code A27K, thus should be AO3402).
They act as PWM controllers and power switch (the motor/MOSFETs are directly connected to the Li cell).

Shorting D-S made the motor run, and when in the ON state, a PWM waveform was present on the gate, but the amplitude was ~1Vbe, too small to turn the FETs on.
Upstream of a 330R gate stopper, the signal had a normal amplitude, ~full battery voltage.
I immediately suspected that one of the gates was damaged, and had a parasitic junction behaviour.
To ascertain that hypothesis, I connected a component tester in low-voltage, high-current mode between the G and D, and this made the motor run immediately.
The tester only showed a linear resistance between the terminals, probably the 330R and subsequent logic output in a low state.
When I attempted to start the flosser normally, with the control button, it turned on as it should: connecting the tester cleared the defect in some way.

Apparently, there was something like a parasitic SCR behaviour active, and since the power was always on (via the drain), it couldn't clear by itself.
Connecting the component tester forced a negative/positive gate excursion of several volts, and unlatched whatever parasitic device was present.

Not a completely outlandish behaviour for some ESD protection junctions, but the mystery is why an unprotected device, as the AO3402 is supposed to be, shows such a weird behaviour?

Looking for a PDF of the manual for a Hafler P-125.


Also wondering what a reasonable output fuse size would be to provide some protection to the amplifier. Has a 0.2A which opened when I unplugged the input. Back panel says 5A max, which is probably too big. Will replace with a 0.2A in the mean time. (Usually people who have some experience with the equipment have a good idea of what provides reasonable protection so that's why I ask.)

Hey guys hows it goin? I have built quite a few speaker kits this year. I have built the overnight sensations, Hivi 2.2DIY, a custom active crossover driven 4'' with planer tweeter bookshelf, parts express Da-Wave speakers, and the Hivi DIY 3.1 (swans speakers) but none of them are any better than the HIVI DIY 3.1 that I built last year!

Any recommendations for a good 3 way build for around $500 ??? monitors or floor standing would be great 🙂

Unfortunately there is no other than the Amplifier-Power Supply section at DIY-A.

I give it try over here with this topic.

***

I'm looking for a very good (DIY-) 5V SMPS ( and/or tweaks) out there. Yep - no linear supply!!!

Applications are endless for these.

RPI, HAT devices, routers, PC peripherals, you name it.

Right now I'm quite happy with the iFi iPower. With 2.5A it also delivery plenty of power.

iFi claims 1uV noise. Which obviously can be considered quite a low value. However. iFi excludes mains and switching related noise. Hmmh. And they limit it to the audio band. Hmmmmh I'd be interested to see what's left of that 1uV - if you take the exclusions out.

Anyhow. I still think and know from experience that the device performs really well.

I tried to put a Meanwell RS15-5 (@5.5V) + TPS7A4700 up against the iPower. That combo didn't perform on the same level.

Any ideas for approaching the subject are welcome. Maybe also ideas of how to get e.g. the Meanwell noise (80mV) down would be good starting point.

Cheers

BTW: I added some mods to the iPower. I shortened the cable down to around 12 inches and I also added a large buffer cap at the end of the cable.

Hi all

I have decided to build a DAC based on the ES9038 and to this end would like a very simple controller to set the DAC's various options.

Dimdim's software & overall solution appears to be quite attractive:

Universal Signal Isolator shield for the Arduino DUE | Dimdim's Blog

... however, since I probably will be using a remote control for the PC's audio software anyway it would make things a bit simpler if the ES9038 could be set via something like what TPA has done with their new Buffalo, i.e. using switches:

The Buffalo-IIIse Pro (Stereo Edition) 2-Channel DAC

Also, it might (just might) be relevant for me to be able to run the ES9038 as a dual mono and to my knowledge Dimdim's software cannot set this option ... But this is optional.

Anyway, I have been searching for a simple controller for the ES9038 yet have not found any ... Might one of you know of one that is also not that expensive?

Cheers & thanks for any help here 😉

Jesper

Have a pair for sale in very good working condition.
The caveat is their tweeters are not working.

My plan was to use the SB Satori beryllium in waveguide with them but there's been a sudden change of plans. Essentially I want to cash out all my spare bits
to go field coil.

If i recall these are $5k new, asking USD750 for the pair shipped worldwide.

Msg for pics, pm to deal, thanks!

Hello,

I have a PPI pro mos 450 that a friend bought used then sent to me to check.

I connected the amp, and checked all four channels - seemed fine. About 30 seconds after playing, the sound cut out, and the power led started pulsing.

I can connect ground and +12V without any apparent issues, but when I connect the remote to +12V the amp just pulses with the power led flashing.

I can't see any obvious signs of damage, short circuits in power supply devices, etc.

Any ideas are appreciated, thank you.

Hello Folks,

I'm bringing back to life a little Carver TFM-15 and so far so good, the amplifier section is all functional now but I'd like to make the VU Meters work then install some good looking LEDs on them, the problem I'm having is that, since I don't have any knowledge about VU Meters I don't really know what to be looking at.

In the Carver site I found a couple of threads where they talk about similar issues where a couple of 2.2Kohm 2W resistors where getting hot and they had to change the TA7318P IC and voila!

In my case I have already tried that and nothing, same thing, I have checked the voltage coming from the power supply and it matches to what's in the Service Manual, I have removed and measured every component in the board and they are all good, so I don't know what else to look at.

Again, I don't know how VU meters are supposed to work, all I have done is momentarily apply some DC voltage and they move, then apply same voltage with opposite polarity and they move back so I'm assuming they are OK?

I have measured their internal resistance and one is 260 ohms and the other is 270 ohms.

I notice that when I turn the Amplifier on and apply an input signal the needles move just a tiny bit but over time as I increase the input signal amplitude they keep going higher in the scale and never come back down to 0, so I have to manually return them back and start all over again, they will again creep up little by little until they reach the top.

So with all that being said, can anybody share some experience?, what should I be looking at?, what to measure?

Thanks in Advance and Happy DIY!

Hello DIYr’s-

I’m new to building amps and I’m looking for some help on a slight hum/buzz issue I’m having with my new VTA SP14 Khozmo build from Tubes4hifi. We can take a step back and I’ll give as much info as possible about me. A few weeks back I built a pair of M125 mono block amps from Tubes4hifi/Bob Latino. They are dead quiet, transparent, open and clean. I was using my Bluesound Node 2 as my preamp to stream music. Love them! I was so impressed how they sounded I wanted to compliment them with a Tube preamp therefore opting to build the VTA SP14 from Tubes4hifi. I opted to upgrade the standard SP14 to the Khozmo design which incorporates a digital display and remote control. I also upgraded the output caps to the Muldorf’s and went with the NOS Sylvania tubes.

The project went very well. It is completed and it sounds really nice except for the issue I’m now getting an annoying buzzy/hum coming through my speakers. I’ve been working back and forth with Roy from Tubes4hifi and I’ve tried different things including powering everything into the same power strip (which I hate) but for the sake of testing did and because my voltages were on the high side, I changed the HV tap on the tformer per Roy from the 280vac tap to 260vac. The buzzy/hum persist. I have attached some pics of the SP14 builds along with the mono blocks. Looking for any suggestions from some of the experts out here. This thread is in no way to bash this product or seller. The seller Roy has been very helpful to this point.

I have $1500 into this project but this preamp is also boasted to compete in the big arena’s $4k-$6k price range. That is why I’m trying to get it right to be able to use it to its capabilities. Thank you in advance.

Ive seen couple of products are using pcm1795 instead of 1792A supposed to be the flagship of TI DACs. What is so unique about this chip is there any sonic advantage?

I have a test jig for amplifiers with croc clips to apply power to pcb's.
It also has a DC protect circuit on the output.
So I connected up my Maplin 50 watt hi fi amp tonight.
It still sounds very good.

wanting to put back into service my gfp-1a along with my gfa 555 both of which I purchased new in mid 80's.


Both units worked perfectly for decades, then put into non climate controlled storage for ~10 years. Temperature range while stored was 40 to 90 degrees F.


Hooked up to test speakers and using a CD audio input there is no discernible source audio... only a hum from both speakers.

Disconnect the 555 and with headphones on the preamp there's nothing but loud hum (volume setting makes no change) even with no source and even with the signal processor loop open.


Will open the case and look for obvious, but any advice for this neophyte repair fogey?
Only testing eq on hand is digital and analog volt meters

I find this version seems a bit weird, do you have any comments? I wonder if the chip is fake or real.

I've started a new project of building a pair of floor-standing speakers. They're 3-way with 4 drivers per cabinet; 2 x 8" woofers + a 3" midrange + a 1" tweeter.

Tweeter: Scan-Speak D2604/833000
https://www.scan-speak.dk/datasheet/pdf/d2604-833000.pdf

Midrange: Vifa D75MX-41
https://audio-hi.fi/download/pdf/Vifa_D75MX41-08_dome_midrange.pdf

Woofer: ADS 308RS (automotive subwoofer)
fs = 34.3 Hz
Vas = 1.02 ft^3
Qts = 0.35
Qes = 0.42
Qms = 2.20
Sd = 33.9 in^2
Sensitivity = 92 dB
Re = 4.3 Ohms each (8.6 Ohms in use with series wiring)
Im = 4.0 Ohms each (8.0 Ohms in use with series wiring)
Xmax = +/- 0.32"(linear) to +/-0.47"(peak)
Volume of air displaced by woofer = 0.048 ft^3

Cabinet dimension: Height = 110 cm., Width = 26.5 cm., Depth = 30 cm.

Each woofer has its own sealed chamber, dividing 2 rooms by halving the height of cabinet. Resulting in about 1.5 cu.ft. for each woofer and Qtc = 0.34.

Crossover network: 2nd-order in every section, see attached picture.

The problem I found now is poor tonal balance. The sound was too bright and pronounced midrange, and the woofers had too low SPL. I'd tried to put the larger resistors on midrange and tweeter but it didn't help. The measurement is on attached. Could anyone help to suggest me please?

Note 1: Reference level is so low due to the woofer's SPL. 😕
Note 2: Peak at 100Hz is due to room acoustics, please ignore it.

DIY / Ikea Parts Storage Hacks

Sometimes, this just doesn’t cut it:



(For me at least)

After a big move and realizing the practical issues involved with moving a bunch of half finished projects, PCBs, transformers and so on... a generally disorganized workbench, I’ve thought quite a bit about more optimal storage solutions for parts storage.

Since ikea is available all over the world and is generally thought of as affordable, I figured it would be a good place to start to share ideas on different storage methods and perhaps alterations to existing ikea designs. Of course, if you have helpful ideas not sourced from ikea those are also welcome.

While the traditional parts drawer is useful, it isn’t always ideal for all sizes or amounts of parts. For me it doesn’t represent a full picture of a storage solution. So, how do we fill in the gaps?

I’m wondering: who has done some DIY parts storage and what does it look like? Pics appreciated!

——

For myself I’ve begun with some of the Sockerbit series. By no means a complete solution it was more of a triage to deal with packing, but I like them quite a bit.



The open bins are quite useful for parts sorting and assembly. They also hold most of my tools and other frequently used things when not in use. The closed bins are easily labeled with a piece of tape and marker over it or if you’d prefer right on the box.

They are fairly unobtrusive looking, stack well and fit nicely on most shelves. They are not transparent, which some might find to be a mark against them however I look at it as a big plus. I’d rather use labeling and have a solution which looks more tidy.

Anyhow, just one option amongst many. Quite curious to see what the rest of you have done.

Picture is not my own- taking one of my current disarray would be embarrassing!

On the markets, the output power on the spec sheet is quite confused. From 1x w to 16xx w, when I learned electronics, my lecturer told me that the power output in cinema is about 1xx w only. How come does a power amplifier for normal consumers deliver thousands watts? Too big power for the house of normal customers and too costly. In the past, FTC and EN standard govern to quote the RMS output power in spec sheet. Do those rules become invalid? Any new standards to replace the previous ones? 😕

Hi there DIYAudioers,

I’m hoping I could get some advice on wiring, phase, impedance and amplification choices for a stereo subwoofer pair (2 drivers per side) that I’m planning. (I checked existing threads and couldn’t see an answer.)

Basically, I have two main options I’m considering and I would like to understand their likely relative performance.

In both options, I intend to mount the drivers firing inward toward each other, so I understand I need to wire one driver per side out of phase so there is no cancellation.

However, I’m unclear on how to wire one driver out of phase when also wiring up two dual voice coil subwoofers per side.

I’ve set out what I see as my two main options below, with four questions at the end. The drivers are Dayton UM-18-22s and the amp is a Behringer NX6000. Some advice would be very appreciated! Thank you 🙂

Option 1 (per side)

• 2 x Dual 2-ohm Voice Coil subwoofers, each driver rated at 1000 watts RMS
• Voice coils and drivers wired in series, resulting in 8-ohm impedance
• Single mono amplification @ 1600 watts RMS into 8 ohm (powering both drivers, ie 800 watts RMS per driver)
• Question 1: If this option is preferable, how do I wire one driver out of phase when wiring these drivers’ dual voice coils together AND wiring the drivers together in series? A diagram (or a link to one) would be great.

Option 2 (per side)

• 2 x Dual 2-ohm Voice Coil subwoofers, each driver rated at 1000 watts RMS
• Each driver has its voice coils wired in series, but drivers are not wired to each other - resulting in 4-ohm impedance per driver
• Dual mono amplification @ 3000 watts RMS per mono channel into 4 ohms
• I would use a balanced splitter to duplicate the signal coming out of my active crossover to feed identical signals into the dual mono amp
• Question 2: If this option is preferable, how do I wire one driver out of phase when wiring its dual voice coils in series? Again a diagram/link would be appreciated.

Question 3: Does wiring the drivers in series and powering them through a single mono amp (Option 1) provide any performance advantages over wiring them individually, and powering them through dual mono amps (each amp receiving an identical mono signal from a splitter) with lower impedance (Option 2)?

Question 4: Are there any additional options I’m missing?

Thanks again!
Tom

I am thinking of building these for my next set of speakers mainly for music listening. This is going to be my first multi-way build so I am looking for a proven design. I want to know your opinion how much they would differ in sound & performance. See link below:

SEAS-3-Way-Classic

SEAS-3-Way-Classic-mkII

Both are using the same mids (MCA12RC) & tweeters (27TFFC) with a slight difference in model for the woofers (CA22RNX for MkI & CA22RNY for MkII). Troels' said that the crossover & stepped baffle changes he made for MkII yield better performance. BUT the Mark 2 version is a "closed kit", he doesn't share the crossover values unless you buy the kit from his partner audio store. While the data for the Mark 1 version is available for everyone.

I am leaning towards the Mark 1 version because the shipping & duties cost to my country is going to be a significant amount, I am confident I can get the drivers & other parts locally or in Singapore where I frequently visit. I want to know if I will be missing out on the "better" performance of Mark 2 version & will regret it later on.

Would greatly appreciate if you can share your thoughts. Thanks!

Hi All


Several weeks ago, I bought a Bluetooth Receiver+DAC,
the xDuoo XQ-50 Pro.



xDuoo XQ-50 Pro - xDuoo official store


It uses a CSR8675 chip for Bluetooth 5.0,
an ES9018K2M DAC chip,
and a JRC 5532DD Op-Amp.

It supports LDAC.


As can be seen in the internals picture, the Op-Amp is socketed:





So my question:
I am curious to try other Op-Amps, to see how the sound will change.

Can you recommend other op-amps to try listening to?


And do you have a trustable source for buying them from, rather than eBay/Ali?


Thank you

To run these specs on the old RS 40-1354 and come up with cab dimensions and vent size. I'm using two drivers back to back, side firing and using them for LF duty. Any suggestions on stuffing would be great. I was gifted with a small stash of these and want to do something with them. No knowledge of design software. Thanks for any help you can give.
Specs that I can find:
RE = 7.09 ohm
f0 = 56.0 Hz
SD = 0.0083 m^2
Mmc = 6.16 g
QM = 3.46
QE = 0.537
QT = 0.46
Vas = 0.013 m^3 = 0.457 ft^3
eta (2 pi) = 0.414%
Sensitivity 88.7dB/2.83v/m

In my new house, the living room + kitchen is in 1 volume.
(Panorama pic taken from dividing line).
It's tiled, apart from a rug at the TV area. There's also a rug on order for under the diner table.

There's terrible echoing just while talking normally, and audio listening is not very enjoyable.

What could I do to improve this, without drastically altering the visuals?

Hi all,

Another 'lockdown job' - just taken my A85 apart as it had blown the main input fuses. One channel of the SAP15s has blown, quite literally (surprise surprise), but my question is does anyone know what the turquoise heat sink sheet is ? The sheet is well and truly stuck to both the heatsink and transistors and will be destroyed when they are removed. I'd like to replace it like for like if possible so does anyone have any ideas who makes it ? It seems to be a turquoise plastic top layer with a grey under layer. Google has thrown up nothing.

Cheers,

Jon

Hai all of my friends,, please give me information about my PCB Aleph 5 MKII i dont have shcematic,, 😕

thank,,

I saw quite often on ebay, aliexpress different parts pcb and so on in order to build a psu and i wish to build my own. Should power a hybrid amp which requires a 26v/0.8 and as well a topping d50 dac 5v/2. I never did anything like this therefore i really need you're help. The only sure thing is that the solder is already in HOT 😀

Regards,

OK so thanks to the gentle hands of DPD - this has been returned non-working after selling. I've tested it and there is power to the board but nothing from the speaker outputs. As my technical knowledge finishes there and my friend who built it hasn't the time to look at it I'm offering this for sale as spares or repair. Personally I think it's probably the cable harness so someone could potentially fix it.

This is the stereo NC500 version and puts out an extraordinary amount of clean power (when it works!) I have a custom set of cables made for use with a Naim Pre Amp to the XLR inputs on the Hypex and these are included.

Asking £350 to recoup the cost of the case and the custom XLR to DIN cable (included) so the Hypex module is therefore gratis.

Specs:
Power (2Ω) 2X 450W
Power (4Ω) 2x 500W
Power (8Ω) 2x 350W
Channels 2
Weight 1055g
Dimensions mm 230 x 115 x 47
Mains voltage input 230V / 115V
Automatic input voltage selection

Maybe a huge advertising effort by the company all synth lovers seem to love to hate?

Eurorack Synthesizers

So I was making plans to build horn speakers and I was going to make them out of wood, and for whatever reason, I've decided to 3d print a mould and cast some mono body epoxy-resin horns with pretty rose petals . . .. but how would I get something like that 4'x4'x5' de-gassed? I can't find anything commercial or industrial and I suspect that options would be exorbitant. The only thing I can think of is welding up some sheet steel myself. Is anyone aware of any tutorials on building a vessel? Am I taking the wrong route? Are there epoxy resins that tend to dry clear?

thx

Google has a new Nest Audio speaker that looks like it's a two way.

"Nest Audio adapts to your environment and whatever you’re listening to. So music sounds better. And news, radio, and audiobooks sound even clearer."

Nest Audio, Amazing sound at your command - Google Store

Jason & Co.:

The Sponsors page is filled with problematic and/or outdated links. A complete update appears to be in order.

Thank you, by the way, for the work you're doing!

Regards,
Scott

Hi,

I'm not sure how long this problem has been there, but I guess about two or three weeks. My right DIY esl (a 68cm x 200cm full range panel) has much lower sensitivity than the left one: I measure 8.5 dB less at all frequencies. This is too big of a difference to be ignored. In the first months after completion there was not such a big difference. From what I remember, 1 dB difference.

I use second hand AudioStatic HV bias power supplies for the diaphragm. Not sure if this can be translated in a bias voltage by the schematic alone? Or is this also dependent on other things like diaphrahm coating? Because I would like the forumula posted by bolsert to calculate theoretical SPL to get an idea how efficient my esl is and how much possibly is leaking:

https://www.diyaudio.com/forums/pla...ns-low-sensitivity-range-esl.html#post3006565

Things I already tried

I connected my own bias power supply from a previous model as this one has a neon flash light in order to see flashing rate / leakage. I swapped everything: audio transformer, amplifier channel, HV bias power supply, segmentation resistor circuits, but the right esl stays much quieter. (the difference stays at 8.5 dB)

So yesterday I disassembled the right esl panel and cleaned the diaphragm on the outer edges with alcohol just to be sure it's not leaking here to the wooden frame. I checked the HV bias wire solder point where it contacts the copper charging ring because when putting one ear close to this point I heard a hissing noise. After coating that area the hissing disappeared and neon light flash rate decreased considerably. But as soon as I put both frames together (one frame has the copper charing ring and silk damping screen, the other has the mylar diaphragm) the neon light starts to increase flashing frequency.

I checked for dust, hairs etc. I found a little insect and removed it, but no difference.

I'm wondering what could be the cause - or what method would work to find the cause? Right now I used the neon flash light.

Hi there, I'm attempting to understand altering the B+ output from the regulator section of the M2x power supply in my ANK Kit DAC. It looks very similar to the 1993 Sound Practices circuit here: A One-Tube Regulator Article By Mike Vans Evers Of Sound Practices Magazine

The schematic below is designed to produce 260V which can be adjusted to between 230-300 by changing the value of R2 from 0-50K. **(I have amended this circuit diagram as the original showed the junction to R4 between R1 & R2, which does not seem to match how it is on the board itself.)






However, in a previous version the R2 position was originally a 50K pot, presumably for easy adjustment of the output voltage.





My confusion is, in that configuration, wouldn't the combo of R1, pot & R7 always be 300K total with only the voltage to R4 changing when the pot is turned (or is this a misunderstanding)?

Also, what might be required to reduce the voltage below 230V in the first schematic? Set R2 to 0 and shrink the value of R1 as well? Plus change out the zener diode to a 75V part, as suggested in the Sound Practices article?

Any help would be much appreciated.

Anyone have a schematic for this amp ?

Or a pic showing the area around the driver ic’s for the outputs ?

Is there an easy way to cut a mini-DSP unit out of the picture for making an active digital crossover, by using the front/rear outputs of a typical sound card instead? If so, is there good/easy to use filter design software to be had? I want to do some experiments with basic crossovers/notch filters/eq on the computer with some speakers, and then use an analog board with appropriate filters using jet or opamps buffers to do the final box that will be run with the speakers/amps in day to day use.

I already have computer and sound card, was looking at saving myself buying an extra piece of hardware for now, but allowing some projects to go forward without having to buy more stuff at the moment.

i used a 12.6 vac filament transformer with center tap. With line voltage at approx 122.vac the secondaries are about 15vac and 7vac.



Can someone explain why its bucking 15 volts instead of approx 12.6?

Hello,

have any of you used this Media Player? I didn't understand if the coaxial output can read FLAC FILE up to 24bit / 192Khz, or is it limited to 48Khz? of course I have to connect a DAC to it ..

Opened up some 2402 bullets today for cleaning and general tidy-up. Found the diaphragm looking like the enclosed. I bought drivers second hand and have never heard them but these diaphragms look original. However someone in past has damaged the disc. Just wondered as these are original, should I keep. I assume musically they are toast...but...

Pair of Fostex FF125WK Planet 10 EnABL'ed speaker drivers in Fonken cabinets.

Great little pair of speakers, very musical and transparent. Full range drivers,
no crossovers, efficient enough to use with moderate powered tube amps
(e.g a push-pull 6BQ5) or small solid state amps like a GainClone or Mini Aleph.

Each speaker measures 9 inches deep, 9-1/2 inches wide, and about 13-3/8
inches tall. This particular Fonken cabinet was designed by Dave Dlugos at
Planet 10 specifically for these FF125WK drivers, so they're tuned to this
driver's parameters. The cabinets are made of high quality baltic birch ply,
and were built by Jon Parkhurst. I bought them from this forum when I had
just moved in to a new house and before my workshop was setup. Cabinets
have some imperfections, please see pictures for details.

Fast shipping and bullet proof packing, sent from Saint Louis, MO 63108.

The EnABL'ed Drivers currently sell for $220.
Asking $300 for drivers plus cabinets, not including shipping costs. No fees.

I'm considering building a Pass Pearl II Phono preamp and I noticed that a majority of builds put the power supply in a separate enclosure.

How essential is this? For space reasons, I would prefer not to do that, but I will if it will have a discernable effect on sound quality.

Is it possible to use internal shielding and divide one larger chassis in half to separate the power supply? Also, I noticed that many people who build a separate power supply often stack the two enclosures, doesn't that defeat the purpose?

Hello to all reading this,

I would like some guidance on the design decisions that follow in my 6l6 amplifier build:

Two years ago I decided that I would like to build two Monoblock 6l6 based amplifiers. At the time (with a certain budget restrain) I ordered components that would allow me to build "Williamson" Ultra Linear style amplifiers with bias points slightly adjusted for a somewhat lower supply voltage. I completed two chassis, each with a power supply transformer, OPT and 5 tube sockets installed.

Then came the quite naïve realization (after carefully reading many articles on the Williamson amplifier) that my choice of output transformer might become a severe design limitation. At the time (again due to budget limitations) I chose the Hammond 1620 output transformer. My reasoning was that the 20 Watt power limitation was not going to be too big of a deal as my B+ supply voltage was going to be somewhat lower anyway (and thus the resulting output power).

After reading up on the specifications required for a Williamson output transformer I concluded that the frequency bandwidth of the Hammond transformer (30Hz --> 30Khz -1db) and leakage inductance might become a severe issue.

Also the inductance of the primary winding was unknown, so I decided to contact Hammond in order to get some numbers on the primary inductance in Henry after the realization that the output transformer needs to be one of a certain high quality in order to stabilize the Williamson design. Williamson stated in his article that the primary inductance must be no less than 100H in order to function well and Hammond confirmed that the 1620 could achieve an 106.5H inductance (under certain conditions of course).

I started looking all over the Internet to find people that have pulled off a Williamson build with somewhat inferior OPT's. I found one instance where somebody used the Hammond 1620 in a successful build by reducing feedback and some other (somewhat peculiar) design choices [img1]. It strikes me the the first half of the input 6SN7 seems to be starved and the concertina anode/cathode resistors seem to be quite low in resistance and thus allows for a higher current. Another "unique" aspect seems to be the grid stopper resistors on the 6SN7 drivers and 10k grid stoppers on the KT66. The rather high bypass 1nf capacitor across the feedback network also strikes me as odd (any comments?).

The second design I found was not a Williamson type per-se but a design by Acrosound using (correct me if I am wrong) a floating Paraphase type design [img2]

My questions then would be:

* 1: who can say (from experience or knowledge) which of these two circuit designs (Williamson or Acrosound) has the highest chance of being stable with the given OPT?

* 2: Can somebody with more experience comment on the design [img1] and what the key aspect is that makes it work and keeps the phase shift in check with the Hammond 1620. Also can we improve upon the design (to simplify it somewhat again)?

Thanks in advance,
Pim

Hello all,

I've found schematics for almost every version of the FET-10 except the FET-10/PC (not PE). I'm trying to figure out whether the yellow "Wonder-Cap" things in this picture are 1uf or 1000uf. Any help much appreciated.

Also if anyone can tell me what the little yellow parts are...I know the picture isn't great but maybe someone just knows!

Thanks very much!
Ross in Denver


If image doesn't load, it's here: Dropbox - FET-10PC large pic .jpg - Simplify your life

I've underestimated my heatsinks size so now I'm looking at mounting a couple DC fans to my heatsinks to prove my theory. I'm looking at mounting the fans to the external vertical fins so my question is..............are there any clips available or mounting hardware designed for just such a purpose?

Regards,
Dan

Hi,

I had some buzz in my 63's. Happily, it would appear that the noise came from wrinkled and loose dust cover. By tension the dust cover the noise was gone.
Now I want to secure the stators before the grand old English glue cracks.

Question: I will secure the stators by tiny strips of glue "fillet welds" without dismantle the membrane. (i.e. from the rear side of the lattice).
Which glue is most appropriate for this purpose?
Epoxy ? Superglue (cyanoacrylate gel) ?

Hi there,

I've just recapped and replaced various resistors in the first of 2 1950s Quad II amps. I checked voltages just after after C4 and I'm getting around 375V DC where the schematic suggests 340V is to be expected - I'm using a DMM rather than the AVO meter the schematic was put together with, so is this about right?

I haven't gone any further yet, but I noticed one of the KT66s was too hot to touch after just 30s of operation, which I'm guessing suggests a fault somewhere, so I'm leaving it off for now!

Hi,

up for sale is D3 board with tda1541a chip with bisesik IV transformer. this will come with the I2s2sim v1 board and CMx ps and transformer. All the boards were assembled by Ryan.
With the bisesik the output voltage is about 1V.

Selling to offset a recent purchase.

I have over $650.00 usd invested on this. I am asking $450 for the set

thanks

Hello,

I'm new to DIYaudio. Please excuse if this question is in the wrong area.

Does anyone know what Hypex is charging for the NC2000 modules as well as the required SMPS3KA700?

I am considering this amp to drive my ATC SCM50s.

Thanks

Ищу спайс модель сдвоенного силового igbt ключа

What would happen if having the Caddock TF020 for R32 975K?

The outer shell/chassis of each of these amps is demolished. I found both of them at work. They have alot of water damage on the structural parts, and ive been soaking them in vinegar for days. Just finished cleaning up the shells. The boards however are intact. They look nearly untouched inside. No sign of age or even use. Shockingly out of the all the amps i have these 2 are the cleanest even though their exteriors are wrecked.

After cleaning them, they are getting a coat of ceramic paint and ill be trying to add the stickers back, or similar ones to the originals.

However, id like to maybe modify these beauties alittle. maybe try to squeeze some more watts out of them. Im considering changing the mosfets and transistors, and maybe caps, but im not entirely sure on the process. Ive asked friends who have knowledge in this field and they are unsure of what to do, without looking at it.

Where do i go from here?

Someone (in here) recently wrote that 'knowledge is the devil'.
I find this to be true when it comes to low-fidelity wives and high fidelity amplifiers.
The first problem has been solved (no, she is still alive), but the second is a bit more difficult.
I happen to be the (very) happy owner of an early Threshold S/150.
However, I recently stumbled across a document (attached) that in fine detail describes what my amplifier does NOT sound like.
Very disappointing, especially since the first problem has left me unable to simply buy something better, so... dear pa... could you please
A: Send more money.
or
B: Search the most remote storage-spaces for a pair of (un)populated opto-boards.
or (considering the amount of Zen, F, BA and Aleph-variations that has emerged over time)
C: Design a schematic for the 'Stasis Traps' (To Rule All Previous Stasis).

I would seriously love to have my S/150 sound better than my friends SA/2's.

PS: Forget about A. The b***h takes half anyway!

At the risk of asking the impossible 🙂 I'd be happy to take a ε21 backplane of your hands for my 2-channel passive-ground β22 build.

Hi,

Can you guys recommend me a DAC or D/A converter solution that is affordable?

Preferable a DIY kit.

Im currently using an rme adi-8 ds and its quite good but Im just wondering if there is something better and affordable?

The use would be for music production.

Thanks!

I bought a pair of lundahl LL1627/140mA for parallel 300B but i decide to build 300B PP.
Does anyone want to trade them for a pair of 1620PP ?

Not sure if or how it happened but assuming I accidentally got negative voltage on the positive rail in a trad AB amp what would the damage be?

Recently there has been some email interest in Bride of Zen (BOZ) and
a request for the Gerbers.

So I put a little work into a double sided version and set up the Gerbers
for compatibility with China PCB Prototype & Fabrication Manufacturer - PCB Prototype the Easy Way

PL45AR0 is 8.00" by 4.60"

PL45BR0 is 4.50" by 4.60"

I've done many amplifier simulations in the past but all were into resistive loads. It was time to do the same into something that looks like the real World, a loudspeaker. The speaker simulator circuit I used is what I actually use on the bench during real time tests. The 60 mH inductor is a Hammond choke, The 220 Cap is a non-polarized motor starting cap.
More later, the triode will look much better.😀

Ive always been into car audio, but never really put much into it even though i had a passion for it. Over the years ive done some wild setups, but now im wanting to take it further. I recently stumbled upon a cache of oldschool amps, and ive searched every crevice of the internet looking for information.... then i found this forum.

ive never built my own circuit before but i can read a wiring diagram, and i and decent at soldiering. I have a extensive past in computer electronics.

Hello

I have a Krell Showcase Processor I use as a preamp.

It is not turning on (goes back to standby) and if it does turn on it either plays for a bit and turns off or it makes an off clicking noise. Someone thought this may be the protection circuit thing, relays clicking, is that likely?

Anyone know a good electrician in West London, UK?

Best wishes Edward

Linn LP12, Naim NAT02, Revox PR99, Meridian 557, Sonus Faber Domus Grand piano floorstander, Primare D20

Bought these pretty but not so hi-fi full rangers online, they came out of an almost unused stereo cabinet and are in good shape. Range is 75-18k hz., no T/S parameters given in the original literature.

Looking for fun builds/suggestions, so if you've build something with these fullrangers, please let me know! I'm not expecting these to offer earth-shattering performance over what I have now, so I might just go for something like an interesting omnidirectional concept.

I'm also mulling an "akoestische box A5" as it is called in the original Philips build plans. The 8080 is not mentioned as a recommended driver for this box (a tallish, square column, no ports), but the famous 9710 is; maybe I could just build the boxes and hope for a pair of 9710's to show up.

IMG_6070 by ctjr

IMG_6071 by ctjr, on Flickr

Hello.

The goal is woofer for boombox with class D 24V power supply (circa 70W 4Ω 1% THD).

Please considere size, weight and price.

Actually, i cannot find better choice than Faital 5FE120-4 or 5FE100-4.


Tang Band W46-1316SM is expensive and less maximum SPL.

Faital 6FE100-8 is 8Ω and bigger but more SPL.

Is there any better choice?

I have an AV rack/cabinet I built about 20 years ago; free to anyone that would like to pick it up.

All the shelves are constructed from three layers of 12mm MDF; the center of each middle layer being cut out and filled with dry sand. As such; it's fairly heavy and well damped.

It's approx 168cm wide and 42cm deep. It sits on a set of recessed castors, and is about 53cm tall from the floor to the top of the top shelf.

The internal height between the top and bottom shelves is approx 42.5cm. The middle shelves (one fitted in the photos, one removed) can be adjusted in height. You can fit two items around 19cm tall with a middle shelf fitted.

I originally had it holding four items of AV kit, with a center speaker in the middle and a TV on top - to give an idea of the capacity.

PS Ignore the lengths of brown material - it's something separate.

About 15 years ago I made a set of acoustic room treatment panels, and some bass traps; with useful guidance from Ethan Winer of RealTraps.

They've not been used since a house move a few years ago, and reluctantly I've accepted I'm not going to get chance again - so I'm offering them to anyone that would like to take them.

I recorded the original build here, with plenty of photos: Making Acoustic Panels

Each of the flat panels is approx 61cm wide by 121cm tall, and 8cm deep. There are 4 that were used on the ceiling, and 6 more that have legs (for use freestanding). There are also a few blocks of the denser material for corner bass traps.

From tests when they were installed they did make quite a difference to reflections and room modes (both subjectively and from a number of measurements).

They've been in (dry) storage for a few years (see attached photo) so they aren't cosmetically perfect, but they'll still work (and it would only be a few hour's work with a staple gun to re-cover them in new fabric should you want.

You'd probably get all the flat panels in a large estate car, but it'd likely require a couple of trips to get the bass traps too. Free to collect from north of Leeds - just send me a PM if you're interested.

I have a TNT 2 which has the square motor cut out. I need to replace the 600rpm hurst motor as it has stopped working. I can get the original but was wondering if there is any upgrade that will work.

What a lucky guy Romain Grosjean is!!

Unbelievable fireball.
Nearly decapitated by the armco but saved by the HALO device.

And to escape with minor burns and possible fractured ribs.


Unbelievable !!

https://www.bbc.co.uk/sport/formula1/55124967
https://www.bbc.co.uk/sport/formula1/55122594

SOLD!
10 x A123 ANR26650M1B, 2500mAh 3,3V LiFePo4 batteries
Never used
40 EUR

Picture: Dropbox - IMG_8193.jpg - Simplify your life

Regards
Micke, Sweden
SOLD!

Most of the class AB amps i have built seem to have a parallel L R output filter. Say a inductor of 10 turns and a 1R resistor. i was wondering if any one could tell me :
a) Why is it there?
b) Can one recalculate the turnover freq, and make the inductor smaller?

Clean Dynaco ST-120 Amp and PAT4 Preamp.

Forgot I bought these years ago and found them in my back room collecting dust. Thought about gutting them and putting in some class D Modules, but after connecting up on my variac and having no issues, and listening to them, I cannot help but want to just leave alone - sound great with slightest hum on my somewhat efficient speakers.

I never did any mods to them - looks like previous owner had power supply caps replaced...amp has slight rust pitting while preamp looks to be very clean. All preamp functions work fine.

Anyway, hows $275 + Ship (or pick up in West sub of Chicago) for both?

Matisse Fantasy Tube Preamp - has both power transformers and 5670 tubes and input / output jacks...ready to go.

Bought this years ago - works quite nicely with 5670 tubes...

How's $90 + ship or pickup in West Sub of Chicago?

For Sale Pro-Ject RPM4 Turntable - all stock with Ortofon OM10 cart. Very clean with 9" arm.

Upgraded to an RPM5....

$350 + ship

Please help me out guys.
If a headphone is in essence a pair of speakers on your head, how are they different than regular speakers. I'm not talking about the types of speakers but the supply to speakers. Those that make and sell aftermarket cords for headphones tout balanced, balanced, balanced and yet I've never heard or seen any push to make bookshelf or tower speakers balanced. Does not speaker cable run the same current as a headphone cable?

Thnks
Don

We all know these FFT graphs with a noise pattern. I see them all the time in Forums and other websites. The term Noise floor always is close... But is that also the Signal to Noise ratio (S/N ratio)? Or is this the noise voltage output from a voltage regulator for example? NO it is not... Some times I see crazy low values like -160dB and it is called noise floor. Well in some way that might be correct. Sometimes the equipment is at its limit here and cannot measure deeper in the noise. But is might well be a true measurement...

I just posted a blog entry "what is going on and why is this?"
Link to blog site post

have a read if you are interested and do the poll please ?
The poll will help me on my future posts 🙂

.

I have some replacement parts that have a little larger leads on - can I just remove all solder (as much as I can) and then open up with a slightly larger drill?

Thanks,