I've been trying to figure out why there's car amplifiers that use 12-16vdc and produce 1,000+ watts rms easily but there's no easy solution to power class d amps boards in a car? I want to be able to power some class d amplifiers that require 32-36vdc in my car. If a car amplifier can do it why aren't there any power supplies available to boost 12v to 36v for this purpose? The only things I've seen even close to working are the cheap boost converters on eBay, Amazon, and AliExpress but the quality, lack of directions, and even worse the believability of the specs are less than ideal. I would have tried them anyway if I thought there was a chance they would work without introducing noise or other headaches.

I plan to use a Hypex SMPS400A400 to power a stereo AB100 integrated amplifier. My question is: has anyone added additional capactitance on the amplifier boards with this SMPS? I contacted Hypex and they just said "Our SMPS’s have sufficient capacitance for the power they can deliver. Adding extra capacitance may be possible but it is not required and not supported. Doing so will be at your own risk." Not very helpful. If you aren't familiar, the AB100 boards have places for four capacitors on the board. I have 4700uF 80V capacitors to put in those spots if it can handle it.

Hello,

I am looking for a service manual for KEF TDM45B.

Any help?

abandoning a project , i have a brand new pair of VOLT VM527 2inch dome driver to sell , never mounted , never used.
my loss is your gain .

wanting 450€ for the pair including shipping to E.U only
thanks for looking.

SOLD !

I'm selling off some speaker parts that I'll never use. I hope someone else can use them. Brand new condition, open box but never used or mounted together or mounted on a baffle. I never did anything with them.

1. Pair of EOS-8 waveguides. 2-bolt pattern mounting holes. 1-inch (2.54 cm) diameter throat opening. $30 for the pair, plus shipping (they're light and not very large).

2. Pair of DNA-150 HF compression drivers. 1-3/8" T-18 thread screw-on mount, as for Eminence 10CX, etc. $35 for the pair, plus shipping (small and don't weigh much).

3. Pair of 1-3/8" screw mount to 2/3 bolt mount horn throat adapters. $15 plus shipping.

Prices are US dollars.

Hi, I have a Mark Levinson 31.5 cd transport which works well for a while and then appears on the display: SERVO RESET. the reader does not obey to stop or change the track, it has to be turned off completely. Has anyone had a similar situation that could repair it? Thank you very much.

I have for sale the following evaluation boards from Tripath.
RB-TA3020-96€
RB-TA0105-160€
I do have more Tripath amplifier boards that you can check here:
https://www.ebay.de/usr/rocksandsound
Payment by Paypal tracked shipment,shipping to US on request.
For more information PM

I recently rebuilt a pair of ESL-63s, and printed some 5 degree tilt back feet, but I don't like having the sound beamed up at my ears from close to the floor, so I designed and built some stands using 1"x1" and 1"x2" t-slot. The stands lift the speaker about 350 mm off the floor, and they are sturdy and center the weight so they aren't easy to knock over.



Details and link to CAD file here. Extra bonus: they are high enough that my cat will probably stop using them as a scratching post.

Yeah, looks like a clickbait but I had such a design target.
Analog Processing Unit contains two devices in the same housing. THAT1510 based preamp-LNA 34/60db gain, 10Vrms max output level, and 48VDC phantom power, just in case if need to work with a condenser mic. The input impedance is 47kOhm 100pF in case it needs to use as a MM phono-preamp without RIAA(Cosmos ADC has internal DSP and may handle RIAA EQ online accurately). The input noise of the LNA is about 130nVrms(A) i.e.
5-6x times fewer than APx555 which, for instance, is not capable to measure the dynamic range of $13 Meizu HiFi DAC, APx555 result is 123-124db(A). Cirrus promises AES17 DR 130db(A) for CS43131, Cosmos APU+Cosmos ADC result is 130.5db(A) with 12db room to APU's residual AES17 DR for 2mV. The LNA's balanced inputs are clamped at 5-6V by TVS thru the 10ohm 0603 resistors in serial to each input i.e. an overvoltage with a good enough current rather may burn the resistors than TVS but that's safe for THAT1510.
The second and biggest half of Cosmos APU is the 1/10kHz active notch filter with -30db ratio(Q about 50) at the fundamental frequency and nearly 0db at 2nd and 3rd harmonics i.e. you can simply divide by 30(or subtract 30db) the THD/THD+N result to get a normal value. Also, with REW or Arta, you can use a calibration file to normalize the notch's frequency response and observe FFT results directly. The max balanced input level is 10Vrms, it is also clamped but by the active clamp with opamp's rail voltage-1V, hence, 10ohm 0603 again may be burned like a fuse. The residual harmonics of the distortions are <-150db@1kHz or <-130db@10kHz, that's probably isn't too spectacular but still better than APx555. The residual THD+N, practically achieved one, -132db@1kHz@10Vrms(DAC+LPF approach), calculations based one is -134db but I can't confirm that so far because of can't find a perfect-zero-noise sine for that 😉 It is clear that APU is kinda a microscope for your ADC, even any laptop audio input with APU gets the ability to measure a tiny noise of DACs or LDOs, and distortion levels are perhaps lower than AP SYS2722 or even Cosmos ADC.
The best way to power Cosmos APU with a power-bank(or a good smartphone charger), is to minimize GND loops issues.
The device is quite simple and inexpensive, strange that's not on the market already. Especially inexpensive(~$70) would be a version without the case as a PCBA which any DIYer can adjust by 4pcs trim-pots(2pcs for the 1kHz Twin-T -30db or -40db, another pair for 10kHz -30db).


REW with the calibration file DAC+LPF->CosmosAPU->CosmosADC


The residual THD+N of 5 preproduction samples, -101db of reading need to subtract 30db i.e. THD+N -131db@9.5Vrms the same about harmonics -127db means -157db







APU Notch frequency responses:





AES17 Dynamic Range test performs at -60dbfs level by measuring the THD+N A-weighted. That plot shows the residual THD+N (A) of the LNA at 1-10mV level sweep. 2mV corresponds 2V 0dbfs DAC like CS43131, and -82db needs to subtract 60db to get AES17 DR = 142db. A typical high-performance DAC with 5Vrms 0dbfs could be measured down to 150db and so on.




The residual noise of 5 preproduction samples(the S2 using SSM2019 instead of THAT1510), the reading need to divide by 1000 due to 60db of LNA i.e. a uV is actually nV.




The gain of Cosmos APU preamp is +60db(1000x times), hence the scale units are nVrms(A). After the APU unit turns On, you can see 5s of settling,
from 6s the input noise reaches 130nV, about 9s 48V power was turned On, and after 1s reached 142nS. Hence, APU's phantom power adds just 12nV to the preamp noise, that's a nearly ideal result as I think 😉 The test was performed with a shorted preamp's inputs(In+ to In-) and biased to the GND by 2x6.8kOhm resistor as a dummy condenser mic.



and the spectrum 20Hz-130kHz of the same test, units need to divide by 1000 as well, so uV becomes nV. This is a good illustration to killing the myth that SMPS is always dirty 😉 Cosmos APU contains no linear voltage regulators at all, only SMPS with Fswitching > 1MHz.



Finally, I got working Cosmos ADC with internal DSP and RIAA EQ implemented for all Fs from 44.1 to 384. A pair of Cosmos APU was used as a dual-mono phono preamp +34db gain with no analog RIAA, which was applied in Cosmos ADC digitally. The video is a comparison of LP vs CD sound, recorded this way.
The formal specs of such a combo:
THD+N@5mV-40ohm(AP output) -83db, and suddenly it places Cosmos APU to the 2nd position of the phono-preamps ASR rating(and yes, I know his tests are silly) 😉


I remeasured Cosmos APU+Cosmos ADC+RIAA max accurate, AC line hum virtually zero.
5mV 10ohm source APU gain 34db Cosmos ADC 1.7V sensitivity, THD+N -89db or -97.7db(A). Due to H2 and H3 being very low, SNR is also 97db(A).


250uV 10ohm source APU gain 60db Cosmos ADC 1.7V sensitivity, THD+N -66db or -78db(A). Due to H2 and H3 being lower than the noise floor, SNR is also 78db(A).


The real SNR i.e. APU source is a cheap MM cartridge AT3600L, the LP record is digitized by Cosmos ADC@32/384, normalized to fit max peak to the -6dbfs, next, the stylus is up to the air, Pioneer PL-300(made in Japan 1980) turntable keeps 33.33rpm. This way the SNR = 91,2dbfs-6db=85.2db(A), that's looks decent if the LP "silence" between the tracks shows SNR = 65db(A) and less.


Of course, both these functions, mic and phono preamp, are features just for the feature list, but I think both are decently implemented and virtually for free so I couldn't call that a marketing 😉

https://e1dashz.wixsite.com/index/cosmos-apu
https://archimago.blogspot.com/2022/05/early-look-cosmos-apu-high-performance.html#more
https://www.l7audiolab.com/f/e1da-cosmos-apu-2/ APx555b measurements
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Hi there. I have enjoyed a fine Rega Elicit mk2 amplifier for several years. However, recently I noticed that at a certain position of the volume control (or rather the LED track, as the knob has no fixed position) the sound from the left channel disappears, if I turn the control knob (or remote control) a few clicks clockwise the sound reappears, although it is slightly muffled. I checked different inputs, different sound sources - the problem does not disappear, the sound from the left channel disappears exactly in this position of the LEDs. I need your help.

I have twelve (12) brand new 22,000 uF, 80V capacitors. Ordering error from Mouser and I'm stuck with them. I'm trying to recover some funds. Asking $35 each, plus USPS shipping from zip 17402.

4.125 inches tall and 2.5 inches in diameter. Great for all your power amp projects! Send me a PM if you're interested.

Mouser part number: 598-CGS223U080W4C

Am I missing something? I can't seem to save the filter settings for the forum so I end up re-entering them every time.
Any thoughts? Problem Exists Between Keyboard And Chair?

Background – I’ve built speakers in the past but my most recent build was in 1999. So I am trying to read and catch up with current speaker building trends.

A lot more attention is being paid to off-axis performance these days. I gather that consistent and as wide as possible directivity are said to give a more realistic sound. That said, I am seeing two different approaches to off axis in tweeters. I have borrowed a couple of normalized off-axis curves from hificompass.com to demonstrate. Many thanks to them for their fine measurements.

Some folks are trying to keep the widest directivity to as high a frequency as possible followed by a smooth narrowing at higher frequencies. An example of this is the BlieSma T25S-6 where there is no narrowing of the off-axis curves until about 6.5k Hz. Then it narrows linearly until a break-up in the 17k – 20k region.

Others prefer an early but smooth narrowing, often accomplished with a wave guide. An example of this philosophy is the Satori TW29BNWG-4 which uses a wave guide and starts narrowing about 1300 Hz. As it happens, hificompass.com offers 3D printer plans for a the BlieSma T25S-6 which changes the T25S-6 into something like the Satori.

My question is which kind of directivity pattern is preferred and why? If it’s just preference, what are the advantages and disadvantages of each.


Thanks.

I'm adapting an existing ps to supply +/- 15-20 vdc to preamp boards that draw zbout 55ma per rail. I'm planning to use an existing transformer and have a simple PSU board to adapt with spare parts to provide the vdc to the boards I've built. Once the AC from the transformer (23-0-23vac) has been converted to VDC via a bridge rectifier it then has some bulk caps. The output voltage is, however, 31.8vdc (unloaded) and I'm looking for a simple way of reducing this to 15-20vdc bearing in mind the 55ma draw of each board. What would you good folk recommend to achieve this? I have a simple option on the existing board to insert a through hole component... The boards have regulators so I just need stable raw power supply that can handle the current draw without smoking...

Building the Pass/Firstwatt F4

This is a fantastically good sounding amp - read more about it here before staring;

https://www.firstwatt.com/wp-content/uploads/2023/08/prod_f4_man.pdf

The thread at DIY audio -

http://www.diyaudio.com/forums/pass-labs/97540-f4-power-amplifier.html

And this the the corrected schematic (The schematic in the Firstwatt article has a typo, also this one agrees with the PCB)



Here you will find a build guide for the Pass / Firstwatt F4 power amplifier using PCBs and chassis from the DIYaudio store.

The 5U 'BIG Amp Chassis' is shown, because that's the one I have. It will fit comfortably in a 4U 'Jack of all chassis' and have enough heatsink as well.

~~~~~

There are plenty of places that you could start, but for the sake of illustration let's begin with the heatsink assemblies -



This is the heatsink(s) from the 5U 'BIG Amp Chassis' It has a mirror-imaged set of pre-drilled heatsinks and brackets to hole them together and make a mounting point for the rest of the enclosure. The 4U is similar, but the heatsink is a single piece.




This build will also utilize the 'DIY friendly' baseplate, here shown with the feet and hardware, and also the heatsink's brackets.


There is a hardware package available for the pre-drilled back and heatsinks, including input and output jacks, IEC module, and hardware for the PCB and heatsinks.


The contents of the hardware bag.


Using the brass PCB standoffs, install them into the PCB mount holes as shown, to get the following pattern;


Now there is a place to mount the amplifier PCB


Speaking of PCB, it's a very nice layout, plenty of room, and the ability to use many sizes of resistors and caps. This is the front.


Here is the back.


Stuffing the PCB should be done in the usual order, from smallest device to biggest - so that would be diodes and resistors first.

Of note, I got the bigger (Dale/Vishay RN60) resistors to see how they would fit on the PCB. They are the size of the PRP resistors that are quite popular amongst the fancy parts crowd. They are great everywhere except the row flanking the small transistors right in the middle. They don't fit there side by side. You could mount them soldier style, or just mix in a few smaller resistors like I did. Or just get RN55's. They are the smaller size.


Pots and transistors next. (yes, I didn't stuff the input pair when the photo was taken…)


Ah, there they are.
The ziptie is just to help their thermal tracking.


And finally the capacitors.


There is a top and bottom to the Universal Mounting Spec holes, the board mounts as shown


I find it helpful to bend the leads of the transistors first, and mount them (a little bit loose) to the heatsink.


Like this


And then mount the PCB. You can snug all the screws down and then solder and trim.

Ok, now lets move on to the Power Supply.


Here is a photo of the PSU board, I am going to use integrated bridge rectifier blocks, so you need to remove the part of the PCB that mounts the diodes. The new PCB, not quite yet available at the time of this writing, will have a similar feature with the diodes, as well as room for more/bigger capacitors.


As always, stuff the small components first - the light blue resistors are the filter resistors, the darker ones with the teflon are the bleeder resistors, and the small ones are for the LEDs.

This PSU board is the exact same DIYaudio PSU board, just without the top blue soldermask.


This shows the INPUT edge (from the diode bridges)

The capacitors are Panasonic T-UP 33,000uf 35V


Connecting the bridges to the PCB




This is the OUTPUT edge of the PSU - the colors are
Red V+
White GND
Green V-
The black connects the PSU GND to the CL-60 to the chassis.


The wiring from the PSU to the amp PCB is clearly shown.


Here you can see the bridges with the wires attached from the transformer secondary. Remember that the green attached to a bridge must have continuity with the blue attached to the same bridge. (As it's the 2 ends of the same piece of wire)



As long as were are tailing about the transformer, here is a photo of the terminal block shown wired for 120v. The Blur lead is the AC Live, and the clear the AC neutral. The reds and blacks are the transformer primaries.

Transformer is an Antek 400VA 18v+18v, part number AN-4218.



The last bit of the PSU wiring is the chassis connection, the black comes from the PSU GND, and the green is the AC safety earth.

The AC to primary wiring confuses everybody, so;

Let's look at the PSU schematic just to make sure everything is OK... Remember that I am wiring it for 120v operation, so the transformer primaries are in parallel. People wiring for 240 with a transformer like this, please ignore.



Notes in red are mine.

Look at the connections of the transformer primary, through the thermistors and line cap, to the mains.

Hot AC is connected to the "120" (which in my case is the red leads on the primaries) One red primary is connected to AC hot through a thermistor.

Neutral AC is connected to the black "0" leads, one of which is connected to the AC through a thermistor.

AC Hot and Neutral have a cap across the leads.


So, yes, the AC will be connected to the center 2 posts, which is across the cap.


(This photo lifted from my F5 thread, but it's the same PSU…)

Left to right we have post 1, 2, 3, 4

POST 1 - Transformer primary 'B 0' which will be connected to AC Neutral at post 2, through the thermistor between post 1 and 2.

POST 2 - AC Neutral in (not shown in photo), connected to Transformer primary 'A 0" , a thermistor to post 1, and a line cap to post 3

POST 3 - AC Hot in, connected to transformer primary "B 120", thermistor to post 4, and line cap to post 2

POST 4 - Transformer primary "A 120", connected to AC Hot through the thermistor to post 3

If you look at the red and black wires in the photo you will see that the Mains AC must to pass through a thermistor to connect to each of the 2 primaries. And that is the point of them, to keep inrush under control during powerup.

Ok!

Now we need to put everything together -

But first a bit more mechanical assembly.


This is the pre-cut back plate and the thick front plate.


Gather and mount the IEC plug.




The speaker posts.




And the RCA jacks.

Note that the shoulder washer goes on the inside, so the metal of the chassis doesn't touch the metal of the jack. There is a similar washer on the speaker posts.




The inside of the back panel.


And the outside. Looks good, yes?


The IEC module is wired as shown. This will switch both the Live and Neutral. The blue (live) and clear (neutral) go the the wiring block with the thermistors, cap and transformer primaries.


The amp PCB completely wired.


A bit closer.


The top connections labeled.


This happens to be the other channel, but the connections are all the same.

Remember that V- / GND / V+ is always left to right as you are looking at the format of the PCB


I'm not entirely sure what I was trying to show here, other than the screw and washer. It looks cool. I will keep the photo in the guide.





A few notes on bias -
P1 controls the bias, measured across any of the 3W source resistors. Adjust for 0.13v when it's cold, and watch that it doesn't get higher than 0.2v once it's up to temperature in about an hour. Adjust for 0.2v when hot.

P2 is used to adjust the DC offset on the output to zero.


Attach a DC voltmeter across the speaker outputs to measure offset.




If you find that the P1 doesn't have enough range, I.E., you can't turn it up enough, replace R9 with a smaller resistor, I used 4.75K and it works well.



Connect a voltmeter across any of the source resistors. The outboard ones are easier to clip across.

Adjust for about 0.13v cold, and once the amp is up to operating temperature, trim for 0.20v - It takes a long time to warm up, take your time.

Adjust P2 for zero offset, then re-trim P1

Here is a photo of it all connected and working -



I'm driving the F4 with an O2 Headphone amp sourced from an iPod; Driving 85.5db speakers. Although it is a small room, it gets louder than I want to listen. It still can't drive it to clipping, but it does get really, really loud.

One thing worth mentioning, and it speaks very highly to the quality of the amp, is that it is completely non-fatiguing, and more interestingly, very easy to listen to turned up too loud… I don't realize how loud it actually is sometimes. Complete transparency is a word used a lot when describing this amp - but I have to agree. It's fantastic!





Please comment away if you desire.

Also please feel free to ask any F4 questions here, and if you would like to post photos of your F4 completions, old or new, please do!

I have a rather large stock of NOS MOSFETs. New and used.

New are $20/pcs, used $15/pcs.

Ships from Sweden.

Thanks for looking.

R Malmin

CEC (C.E.C) claim by their mostly amplifier models, it's class A (here in Germany even "Pure Class A") The name of circuit topology is "LEF (Load Effect Free). The developer is Mr. Carlos Candeias. Have a look to this URLs: Amp 3300R:
CEC AMP3300R
and Amp 5300R (Amp5300R Amp 5300R Amp5300)
CEC EUROPE WEBSITE
The last model delivers 120W/8 ohms and 135W/4 ohms, as to read in the CEC datasheet
If anybody can posted the schematic of one of both models, I will make an evaluation. I guess, the term "Pure Class A" is concerning the pre-driver stage and driver stage of a push pull complementary CFP resp. Sziklai pair, but I don't know this exactly.
If there really pure Class A by the output power devices, where is a heatsink with the appropriate sizes?
Thank you very much for your posted schematics in advance

Hi everyone,


I’m wondering if anyone could help me identify the capacitors used in the Canton Fonum PC 210 speakers.
Unfortunately, I can’t read all the values on the original capacitors, and I haven’t been able to find any information online about the crossover specifications or component values.


Any help, photos, or schematics would be greatly appreciated!


Thanks in advance!

Hi everyone! I'm passionate about vintage audio and enjoy modifying and upgrading old amplifiers to achieve a rich, warm analog sound. My current setup includes a JVC RX-308 amplifier upgraded with OPA2134PA opamps and a Yyaudio P-037 power cable. I'm running Canton Fonum PC 210 sealed 3-way speakers, which I’ve internally rewired with Neotech STDSPCT-22 silver-plated OFC copper cables using lead-free solder with 3.7% silver content. External speaker wiring is done with 2×2 meters of KáCsa KCE-LS25 cable. For vinyl playback, I use a JVC AL-A151 turntable with an Audio-Technica AT85EP cartridge, an acrylic mat, and Sommer Cable RCA interconnects. I'm always striving to extract the most musical, natural and analog character from these classic components.

My Topping DAC D50 does not power on. I tried different USB charger 5V-1.0A and 2.0A.

Did anyone experience the same problem?

I hear it "click" on, but indicator light (display) does not light up. Has anyone any ideas how to get it working?

Thanks.

Hi everyone,

I’m completely new to the world of hi-fi and DIY audio, and I’m really excited to start this journey. I’ve recently developed a fascination with high-quality sound and have been exploring.

While I don’t have a technical background, I’m keen to learn — whether it’s about amps, speakers, or the basics of audio electronics. I joined diyaudio.com to connect with others, ask lots of (probably beginner) questions, and slowly build my understanding of this amazing hobby.


Looking forward to learning from all of you and sharing my progress as I go. Thanks for having me here!

Sad to hear about Rick's passing. He designed some speakers back in 2007 for me. I was wondering if anyone knows who still has access or owns his designs? I'm looking to build some speakers (RS180 + 27TDFC) that he had designed that tonally match the ones he designed for me (RS150 + Peerless HDS). Does anyone still sell his designs or have access to them?

For sale a very rare pair of Titanium JBL tweeters perfect working condition.
Never been repaired.
250 Euros+shipping.

Came in with blown power supply. Replaced PS fets, gate resistors and ucc27524 driver.

When I apply power, no remote, the ucc27524 shorts its outputs(pins 5 & 7) to ground with 5.4 ohms resistance. This also happens with the fets removed. I tried another ucc27524 and no change. Parts are from mouser and work in another amp I have here with the same driver(stetsom ex6000eq).

With the ucc27524 removed I can see drive signal on both input pins(2 & 4). I get 12volts on the vdd (pin 6) and ground on pin 3.

After a few minutes disconnected from power the short goes away.

I am at a loss.

Is there anything fundamentally better about a discrete r2r DAC as opposed to an IC?

Dear friends!
I am assembling a headphone amplifier. I have a question: how to correctly calculate the value of the potentiometer RV1? I heard that it should be about 10 times less than the input resistance of the amplifier. In my case, the input resistance is determined by the value of R12 and is equal to 33k. Then I need a potentiometer of 3.3k? But everywhere where I studied the circuits of similar amplifiers, they recommend a potentiometer value from 10k to 100k.
How to choose correctly?

PS. Input signal goes from PCM2704 DAC (recommended output impendance 10k or more).

Does anyone know where I might find these or equivalent.
The amplifier is a Sundown Salt-6

Can TIP32C or MJE3055T be used for B631K?
and KTD600K-Y or 2SD600K) for D600K

What would be a good combo?

Thanks

Contracted manufacturer to install 1.0mm pin sockets in Magnoval bases. Tested on 12GT5 Novar tubes.
Money back guarantee if not satisfied with fit. Background link below.
$2.50 each + ship to US, Canada.
Thanks,
Jim

https://www.diyaudio.com/community/threads/real-novar-sockets-inside.397358/#post-7304388

This are my assumptions, and i am not an audio engineer.

This midrange is not designed for bass even if has lower fs. 30hz
The low fs come from the very lose suspension, believe it or not a loose suspension means eficiency, in a way, because it lowers the qes! Also making it good for ported, making it even more efficient.
Thats why they have such low qes qts.
This means that the coil doesnt have to be denser to achieve lower qes, instead the coil can have thinner wires to achieve a bigger bl (more total coil in the gap) better motor force controll. And with the loose suspension mechanical looses are very low.
This gives it very low distortions

Have a PPI A300 amp connected to the front speakers. I am noticing some slight static when the car is off. When the car is on, there is some slight wining as well. I ran both neg/pos 4 Gauge straight from the battery and have made good connections on both ends.

Can the amp itself be the issue? It seems the input is quite sensitive as well as I have a Xover 2XS in front of the input which I had to turn the gain almost all the way down on it or the volume is very loud at low volume levels on the head unit.

Thanks

Hiya,

Looking at SMD components to minimize area on PCBs, but kind of lost in what components to use.

In particular I want to add some caps/ferrites to stop noise/oscillations and wanted to know if I should go for PPS caps for the 10nF/100nF, and what to look for for ferrites. In through-hole components I am using MKP for the caps, ferrite beads on some wire and 150R tantanlum resistors but this takes up more space than I would like (even when using resistors/ferrites vertically.

Not sure what to look for in SMD equivalents. Anyone with experience in SMD components?

Working perfectly and in excellent cosmetic condition .

Bought to compare in my speakers

£60 + shipping ( I’m in the UK )

Who knows the exactly name of very high voltage booster capacitor manufacturer to the logo "db" (see attachement) ?

Hello, I'm a new user of this forum and want to introduce myself...

Just recently got back into "vintage" audio (I hate calling it that! it wasn't vintage when I was originally buying / building my set up, back in the 80's-90's). I've dug out my original gear from college and post college, and sadly, much of it is worse for wear. So I'm building a new set up mainly from facebook market place finds!

Anyway, I'm off to post about my BSR EQ-3000 which just quit on me 🙁 Want to see if anyone has any repair tips. See you over there!

Mab007

All electrolytic capacitors replaced with quality capacitors of equal value ( higher voltage ) including the large power supply capacitors.

Nichicon muse , Elma silmic , Kemet .

Din cables included

New thermal paste

£450 + shipping ( uk based )

Hello everyone,

As mentioned in an old thread from years ago, running this program on newer Windows versions is nearly impossible. Additionally, the original installation files are no longer available on the official website and you can no longer purchase it.

After searching through my dad´s old computers, I found .iso files of the program and was able to make it work NO USB KEY needed. This has been tested and confirmed to work on:

• Windows 11 (64-bit)
• Windows 10 (64-bit)
• Windows 7 (32-bit & 64-bit)
• Windows XP

For proof, I recorded a short video demonstrating all three programs running on Windows 10 (64-bit) -> Video link

Installation Steps​

1. Download the "LinearX Leap5 + FilterShop.rar" uploaded to Google Drive. It contains two folders: "LEAP" and "FilterShop".
2. Extract the .rar file and move both folders to C:/Program Files/.

• Inside the "LEAP" folder:
  • LEAP_XVR.exe → Crossover Shop 5.1.0.334
  • LEAP_ENC.exe → Enclosure Shop 5.2.0.350
• Inside the "FilterShop" folder:
  • Fshop.exe → Filter Shop 3.4.0.808

You can create a shortcut for each executable by right-clicking the file and selecting "Create shortcut" to place it on the desktop.

Important: Fixing the "System Error: Number Decimal Symbol is Not a Decimal Point"​

Before opening the programs, it is necessary to change the decimal symbol in Windows from a comma (",") to a dot ("."), as the software requires this setting to function correctly.

Steps to change the decimal symbol:​

1. Open Control Panel.
2. Navigate to Clock and Region → Change date, time, or number formats.
3. Click Additional Settings.
4. Find the "Decimal symbol" field and change it from , (comma) to . (dot).

These steps apply to Windows 10, but the process is similar on other versions.

To simplify the process for everyone, I decided to upload only the necessary files—this way, installation is as easy as copying and pasting folders.

Greetings from Argentina!

I'm sharing a slightly different kind of post here, hoping it will find its way to the right people. I’d truly appreciate any shares in relevant places.With great sadness, my family and I recently said goodbye to my father after his battle with cancer. My dad was a very special person, and there’s so much I could say about him—but in the context of this group, there’s one thing in particular that stands out: his deep passion for sound and audio.

Over many years, he acquired an impressive amount of knowledge, technical skill, and understanding, which he used to restore, upgrade, and build a variety of equipment—from amplifiers to speakers, turntables, and more. Before he became ill, he had started working on several projects, but sadly had to stop midway, and now they sit unfinished with an uncertain future.

I’ll be the first to admit—I don’t have the expertise my father had. What I do share with him is a deep love for music, which was one of the strongest bonds between us. But unfortunately, he didn’t pass down his technical skills to me.I’m posting here because I feel that my father left me with a mission—his legacy, if you will. And I’ve made it my goal to try and complete the work he couldn’t finish himself.

I’m looking for a mentor, a guide—someone who can help me understand where to even begin with these projects that meant so much to my father. I’ve attached some photos of what he left behind, in the hope that someone might see the value in this and, out of love for this beautiful world of stereo and sound, help me breathe life back into a dream that’s been paused.

(Just a note: all the items shown in the photos, except for the QUAD speakers, are unfinished projects. The QUADs are functional—I included them to give a sense of the level of investment and dedication my father had for this craft.)

*A pair of Quad electrostatic speakers — rebuilt and fully functional



*Sony's VFET R0 Diy Kit


*JVC TT-101

Hello all, I found this forum after looking into a modification project for my stereo. I want learn more and ask questions so here I am no longer lurking.

Hello everyone,

Following the sudden death of my Sherwood R965, which I was unable to repair, I decided to build an ESP P101 Mosfets amplifier.
I'm going to start with two channels, and will probably add three more later.

So I bought a set of boards from Rod, including:

2x P101c Power amplifier
1x P39c Soft start
1x P33b Loudspeaker protection
2x P245a Mosfet relay

I will reuse the Sherwood R965's case and power supply (600W, +/-56V, 2x27000 uF).

Regarding the P245a (mosfet relay), Rod recommends several references, but I already have components that seem suitable, although I don't have the expertise to be certain.

The mosfets I have are : CSD19536KCS from Texas Instruments

Will they be suitable for this application ?

Regarding the P101c, Rod mainly recommends the ECX10N20 / ECX10P20 references, but these components are difficult to find and obsolete according to the manufacturer, who instead recommends the ECX10N20-W6 / ECX10P20-W6 models.

Again, I assume they are suitable, but I want to be sure...

Thanks in advance to anyone who tries to help me.

Good day
Dear gents
After few months of work I make the Nait2 main board to aluminium case

Hey everyone, I’ve been sketching out a 3-way speaker build and wanted to get your thoughts on mixing pro audio components with hi-fi ones in a single design.

Here's what I’m thinking:

• Highs: Compression driver + waveguide (pro audio style)
• Mids: SICA 8 Fe 2.5cp (8" pro midrange)
• Lows: Instead of a typical pro sub, I’m considering the Peerless by Tymphany XXLS-P830845 (12" Nomex Cone Subwoofer, 8 Ohm), which is more of a hi-fi driver with a lower sensitivity (~87dB).

My question is about making the low end "keep up" with the rest of the system. If I run two of the Peerless subs in parallel, would I effectively gain:

• +3dB from doubling the driver count
• +3dB from halving the impedance (going from 8Ω to 4Ω load)

Bringing the system sensitivity from ~87dB to ~93–94dB? Would that be enough to balance well with the higher-sensitivity pro drivers, or am I missing something here? I know there’s more to it than just raw dB—like dynamic response, damping, and matching tonal characteristics—but I’m curious if this is a path worth pursuing or fundamentally mismatched.

Appreciate any insight or real-world experience anyone can share—thanks!

Hi ive been on here for years, enjoying fullrange driver and turntable topics. My old email account expired and can no longer access it. Hence the new account here. Thanks!

While watching a video on the history of Quad, a magazine cover showing an ESL63 atop an SL-6000 dipole sub caught my eye.
Login to view embedded media
I was able to locate the articles online and thought other ESL63 fans might enjoy reading them...if nothing else, for historical perspective.

Enjoy!

Hi everyone,

So I just had my old vibe slick a0 amp die on me. I hadn't realised but it had been running at bridged 1ohm this whole time so honestly surprised it lasted this long. It is rated for bridged 4ohm 200w.

One channel still works but hits protect when you turn it up too much, and the other hits protect as soon as a load is connected (even 4ohm). In bridged it hits protect immediately after being loaded by any speaker even idle.

I've opened it up and the board looks ok, possibly some burn marks on the resistors, or not sure if that's just the black residue that looks like it was there from the factory (attached some pictures)

Anyway I'm thinking to replace the transistors anyway, they are currently k d998 and k b778 transistors. Does anyone know what I can swap them with as I can't find these anymore? I am in the UK. I can find 2sc5200 and it's complement (2sc1943?) for a pretty good price and readily available. Would these work?

If anyone has any other suggestions on what might need replacing or other alternative transistors to use any suggestions would be appreciated!

Thanks
Gershy13

As I just released the DDDAC1794MK3 series (Dac and PSU) I thought it might be a good idea to set up a support thread for technical and background question, discussion and support.

The release post is here: http://blog.dddac.com/the-new-dddac1794mk3-dac-and-psu/

For those already interested in the construction and installation manuals:

DAC: http://blog.dddac.com/wp-content/up...tion-DDDAC1794MK3-DAC-Version-2.6-rev-1.4.pdf
PSU: http://blog.dddac.com/wp-content/up...ction-DDDAC1794MK3-PSU-Version-2.5-rev1.4.pdf

I am not a great photographer, nor do I have a product photobooth, so here is a somewhat lousy picture of my test set-up:

• Power transformer 2x12 Vac
• double DDDAC PSU
• two AE Chokes (my specs: Amorphe 1H 4 Ohm)
• DAC Board DDDAC1794MK3
• Sowter Output Transformers

looking forward to some good discussions 🙂

Doede
http://blog.dddac.com/

Hello, all. I have been a member for a year or so, but mainly to read messages concerning tube amplifiers and also see what Nelson Pass is up to. I have a friend, V Kung who imports and sells Japanese made tube amps. I'm also interested in learning of attempts to build dipole subwoofers. I have a pair of Quad 988 speakers and am always tempted to add subwoofers to them.

-- Alton

Hi all,

i have tried some years ago the switch from BoxSim to VituixCAD but i have massive understanding problems with that, my impression is that i am getting too old for the learning curve of it.

Here the comment of another thread member, probably younger and less stupid than me:


maybe one of the VituixCAD experts can take a look at BoxSim and add here some comments how to switch from BoxSim to VituixCAD for dummies

there are a lot of DIY folks in Europe that are still using BoxSim, but the import of foreign data is difficult and limited to on axis measurements, Visaton started the development of the program many years ago as incentive to buy Visaton instead of other brands and posted the serious measurement with on axis and off axis data in 5 degree steps only for their own drive units

if you look at the new Purifi tweeter you can see that even in the industry VituixCAD is getting more and more relevant, i wonder when the big players like Seas and Scan Speak will start to offer the measurement data in 5 degree steps to import in VituixCAD

many thanks in advance for your help, Stefano

I've been designing HiFi for 35 years. Built my first DIY amp when I was 14 and still love the hobby!
Having spent a few years away from desigining stuff, I've decided to ditch the corporate ladder and get back to the fun stuff. I'm now taking HiFi a bit more seriously and designing some high-end upgrades and accessories for British HiFi brands (Naim, Pink Triangle, Arcam). I'm also starting my own range.

The 3d waveguide printer guys here will enjoy this article

https://phys.org/news/2025-06-3d-device-white-noise-acoustic.html

Greetings!

Here is a link to a German language catalog containing the datasheet for the Roederstein EK Series capacitors. See pages 32-37:
https://archive.org/download/katalo...ektrolyt-Kondensatoren - Gesamtkatalog_v3.pdf

I would have added this to the following thread, but it is closed for replies:

To demystify the detail of its body construction: 'The capacitor winding is mounted in a pot-like plastic cup and sealed hermetically with cast resin.' (original text: "Der Kondensatorwickel ist in einem topfartigen Kunststoffbecher montiert und luftdicht mit Gießharz verschlossen.")

I haven't been around much lately because I was working on a new book, this one about audio circuit design. I don't like spamming the forums, so this is a one-time announcement. My Audio Circuits Cookbook published by Focal Press is now available. This book presents more than 80 audio circuits along with extensive tutorial information. It's meant for anyone who wants to design audio devices, but without needing an engineering degree. Full info here:

https://ethanwiner.com/cookbook.htm

I'm not so much an audio electronics geek, but do dabble in vintage electronics. Found a discussion here about a capacitor that I'm familiar with, and wanted to provide a link to the missing datasheet.

This preamp board has a "GRN" connection between the + and - on each channel. I understand that this is connected to a chassis. But I am only going to mount the board either on a board or in a plastic chassis, so do I need to wire this to anything? Photo attached. Thanks!

Hi All

I just wanted to share this unit gain headphone amp circuit I designed and built it on Sunday.

So far it has exemplary performance and specs considering its simplicity, the built version exceeded my expectations:
Even thought I show a cap in the circuit, if the JFET's are matched the circuit is DC coupled input to output. I built 2 channels and 1 channel has 4mV DC offset andthe other has an 3.4mV DC output offset
The frequency responce is crazy I measured the responce to be almost perfectly flat with 0dB from 10Hz to 1MHz into a 33R resistor.

The specific JFETs isn't critical as long as IDSS is greater than 3mA and they are matched. I simulated with 2sk170GR, 2sk246GR/BL but I built it with 2sk117Y's (the model of the 2SK117 wasn't good).
The output bias current it set by 0.65/R75+R76, in the built version I went with R75 and R76 5R and R50 10R so it didn't run too hot.

I put it in a box last night and listening to Leonard Cohen with it now.

Have to give credit to Nelson Pass for his constant current stage and Erno Borbely for inspiration.

Cheers

Tim

I am trying to use a Citation B power amp (circa 1964) in place of my Marantz 9 tube amps as my "summer" amp here in the desert.
I noticed the sound to be good, but the sensitivity is less. The Harman Kardon is rated at 1.6V input for rated power. Curiously, I can't find the input sensitivity specs for the original Marantz 9's. It is not on the brochures I've seen from the company. The reissue from 1996 does list the input sensitivity as 1.3V into 100K ohms.

Looking at the schematic (attached), I see R2 (left channel) and R36 (right channel) in the input part of the circuit which is 2200 ohms. Would this be a good place to start? What value resistor should I use? I may install sockets on the circuit board to experiment with different value resistors.

My preamps are Marantz 7 and 7T. I would like the Citation B to mimic the 9's input sensitivity as close as possible.

Thanks much!

What is unique is the use of folded cascode.
Simulation shows THD 0.00032% but what the real value is we can not know.
Let us say the distortion should be low.
Folded cascode makes the input pair drive the output.
Because EXICON Laterals are easy to drive, it works.

Hi ive been waiting for over 6 months for some f-18 drivers to arrive. Ive reached out several times by email with no response, but have phoned a few times and go a next week they should be sent out response, for the past few months. Now they have closed operations in canada...
My questions are is anyone else in the same boat? Is this normal for lii Song?

A power transformer snubber is a wonderful thing for reducing or eliminating RFI from rectifier-induced LCR ringing. Unfortunately it's a huge pain to design and optimize a snubber. First you have to measure the transformer's leakage inductance and secondary capacitance, at about 100 kHz, which is not especially easy. Then you have to estimate the capacitance of your rectifier(s), which does not always appear on datasheets. Finally you plug these numbers into a formula that spits out snubber values -- and then you hope it's all correct.

Shown here is a little test jig called "Quasimodo the bell-ringer" which makes this process a great deal simpler. Quasimodo connects an actual snubber across the transformer, smacks the transformer to make it ring, and you observe the ringing on an oscilloscope. Then you adjust a (25 turn) potentiometer on the jig, watching the scope to find the setting which completely damps out all ringing. And you're done! Just use the same snubber values in the end product, as you used on the test-jig, and success is yours. (The 25 turn trimpot is socketed for ease of measuring the final resistance that gave perfect damping).

Attached are some scope waveforms showing a Quasimodo jig driving an Avel Lindberg toroidal transformer (from the Akitika GT-101 power amp). I set the trimpot to 5 different resistance values, and got the 5 traces shown. When the trimpot was removed from its socket (R = infinity), I got the black trace. A setting of Rtrimpot = 109 ohms (red trace) gave "critical damping" with no ringing: see yellow arrowhead.

Quasimodo gave an optimum snubber having critical damping (Greek letter zeta = 1.0), without requiring any calculations and without measuring the transformer's inductance or capacitance. It is a quick procedure, too: set Rtrim to max, observe waveshape on scope while reducing Rtrim, stop when all ringing is completely damped out, remove Rtrim from socket and measure it with an ohmmeter. About 3 minutes from start to finish.

This Avel Lindberg transformer has dual primaries for 115V/230V operation. So I configured the primaries the other way and ran Quasimodo again: figure attached. Not surprisingly, the optimum snubber for 230V operation is (slightly) different than the optimum for 115V operation: 120 ohms versus 109 ohms. Plus or minus the error tolerance of my ohmmeter, of course!

I've also attached a .pdf note that contains more details, schematics, construction tips, user guide, more "Quasimodo in action" scope photos, plus a bit of theory and a list of references.

EDIT 1: I had a small number of extra PCBoards + kits of all parts, which I sold at my cost, in October - December, 2013. They are all gone now, and I have no plans to sell any more. I encourage any energetic and enthusiastic diyAudio member to organize a Group Buy, using the PCB Gerber files and Bills Of Materials I provide in this thread. "CheapoModo" (a low cost version of Quasimodo) kits and PCBs are available in the Vendor's Bazaar, here.

EDIT 2: I have attached the PCB Gerber files and the Bill Of Materials, for both boards (V3_SMD, and V4_thru_hole) right here, to post #1. So now they are very easy to find!

EDIT 3: (April 2022) I just stumbled across this "Yes Math!" application note from Texas Instruments, which calculates RC snubbers to eliminate ringing from switch mode power supplies: (link)

EDIT 4: If you don't yet own an oscilloscope, post #2540 of this thread shows a cheap (USD 40) little scope toy which works for Quasimodo.

EDIT 5: Answers to frequently asked questions:

1. Build guide for V3 (SMD) is found in post #27
2. Build guide for V4 (thru hole) is found in post #103
3. 2 hour build time, quick-and-dirty Quasimodo on solderless protoboard (no PCB!) is found in post #18 and in (the CheapoModo thread)
4. Substitute parts recommendations are found in the Bill Of Materials
5. How to choose a MOSFET besides the ones in the BOM, is found in post #175
6. How to check your own BOM before purchasing components, is found in post #203
7. diyAudio members who have ordered their own sets of PCBoards from a PCB fab, using the Gerbers provided here, include: gazzagazza, luvdunhill, Borges, stormsonic, cwtim01, normundss, dsolodov, EUVL, kissmurphy, stephengrenfell, Piersma, SyncTronX, yoaudio, andrensairr. You can PM them to find out how easy or difficult it was.

. .

After much consideration, I have decided to use the Hypex Nilai platform for my new Class D amp. I was wondering if it’s possible to bypass the internal input buffer or if this is even a good Idea. I believe that they use a type of differential circuit, I probably don't want to mess with this. I will be using a Silver Rock passive TVC preamp and will most likely need more than the 29dB of gain that is offered on the board.

My idea is to use a tube (or discrete op-amp) buffer and gain which will allow for over 30dB of total gain. Is this a good approach? having 2 buffers does not seem to be the simplest solution but bypassing the internal buffer may not be possible or recommended. Any ideas?

Thank you, community!

G

Greeting all, I'm having trouble planning a circuit with a 0-135v secondary 230ma into a voltage tippler and a tube rectifier. I have never used a doubler or a tippler before
and am a little confused how to wire this up with the tube rectifier. Thanks in advance for your help!

I need some brain gymnastics this weekend, so I was thinking of designing (from scratch, of course) a digital sub filter for the sub woofer I'm currently working on. I have a Teensy4.1 with an audio shield that should be up to the job.

My DSP-fu is a bit rusty, though, so maybe someone can do a sanity check?

Filter. I want to use a FIR due to its linear pass band phase (and therefore constant group delay). Unfortunately, very low frequency LP filters require extremely long FIRs, so I'm going to use the old decimate-filter-interpolate trick. I first decimate by 5, apply my filter, but with a 5 times higher relative cutoff frequency. Then I filter it again to interpolate. I experimented a bit it Octave, and it looks like 100 taps for the first filter and 50 for the second one yields decent results without using too much compute power. I'm not too worried about the aliasing bumps in the stop band, as they sit at about -55dB.



Next I need some kind of phase correction. And correct (no pun intended) me if I'm wrong, but it's really the group delay and not the phase I want to correct. So instead of fiddling with all-pass filters, I should just use a simple digital delay, right?

And yes, I know I can buy a perfectly good module for this at AliExpress for less than a the price of a cup of coffee. But what's the fun and learning experience in that?

Hi,

My name is Gavin from Australia. I’ve wanted to build my own speakers for years. Bought a few books, enough to scare myself off a new build for errr decades. Tinkered around converted two way sealed to a 3 way etc. but never built new.

Finally decided I’d build a kit set, but couldn’t find a kit I liked. Almost pulled the trigger on some open baffles with servo sub, but the sub had known issues with 240V. Scared me off, kept looking. Don’t even know if I like open baffles - never heard them.

Finally landed here because of the OSMC. That bought me here. Yes, finished. Thought I’d post the obligatory glory shots, but I’ll add this to the OSMT thread once permitted. But I’d like to thank all those that contributed so newbies like me can tackle their first speaker build. Yep numero uno.

Now I have some awesome speakers I need to an amp.. here I am.

Gavin

Hi,

After 30 years using my JTM45 clone (Echolette BS40 from 1968), I've finally decided to apply all the mods I had in mind for so long.
Since a recap was needed, I had to screw up stock german build anyway, let's do it deeply.

I'm mostly cloning a JTM800 preamp, with all stages chaining in series, cold clipper on V1B, warm stage before the cathode follower and attenuators between stages
Preamp seems working ok on scope with no power tubes.

Next mod in my mind is trying to improve the amp's voice, moving master volume from pre to post tone stack. The stock pre is on the cathode resistor of the cathode follower, it tends to scratch a bit event with a new pot, tone setting gets screwed on volume change, and tone shaping is limited.

Problem occurs when I put a 100k resistor on cathode, and a 650k pot between the treble cursor and the grid from the inverter : amp self cuts off at 20/25W (dummy load), after a short period of sort of self oscillating. On Marshall schematics, vol pot is 1M, I don't have any. I doubt it really solve anything looking at the impedances involved in the tone stack.
I reverted back to pre tone stack master and problem disappears, but I'm not satisfied at all, especially because I don't really understand what's going on. I suspect something related to NB, but don't took time trying to disable it before revert back

Any thoughts ?

Thanks

** Cross-posted on Pink Fish Media **

Just picked up another 2 of these Kodak PCD-860 Photo/CD players to add to my collection (I now have 4). A perfect supply for CDM9/44 laser assemblies, which the laser assembly is identical to the CDM9/Pro laser fitted to my 2 Naim CDIs (and many other high end players).

They are a perfect source of low mileage lasers - a photo cd player was something that never really caught on, so any out there are almost bound to be little used. Three of the 4 I have all displayed the exact same faults;

- Tray belt stretches so doesn't close tray fully
- This means laser mech is not in right position and it slams the upper disc clamp down onto the disc platter off centre, pushing the shitty plastic platter down onto the mech

For the 2 I've just bought I have just forced platter up .2-.4mm, fited a temp belt to test laser - both working perfect. Now I strip the lasers and throw the rest away (a little guilty for the landfill, but apart from laser they're a crap machine!).

Look at these belts - proof of lack of use for a few years 🙂



Sharing this info now as I now have 6 suitable laser head donors for my 2 CDIs - should see me out for my life 🙂 If you're after good 9/44s, keep your eye out for these (recent 2 cost me £17 each, they're always cheap).




Richard

After 20 years I want to upgrade my active crossover (dcx2496). I do not need more functionality but upgrade noise and thd specs.
Looking around I find dbx pa2 and venu360 but they have almost the same specs.

So I decided to build an active crossover/dsp myself with some ready made modules(pcb).
DSP I like to use an adau1467 processor using it for 2 channel in and 8 channel out.

For output dacs I have seen boards below, does anyone experience with them?

• CS4398
• PCM1798

I think the pcm1798 with OPA 161X opamps has the best specs.
For that price I can not build it myself.

John I was wondering if you came to any conclusion about the pink noise from the da-capo DAC from the post on the forum middle of last year.

I also have a Da-Capo which creates the same pink/white noise sound, with a hint of the music behind it, after a period of being powered up (doesn't seem to make a difference if it is in standby or not, just the power being plugged in).

The DAC has the HDCD filter fitted (so isn't the 1307 filter issue that you mentioned).

I have tried re-seating the filter module and moving the Input card to a different slot. Neither have made any difference.

Funnily enough about 4 – 5 months ago a Da-Capo came up for sale that must have been one of your development ones. The serial was no 1 and it had a dedication to your wife actully on the circuit board. If I had seen your name on these forums before now I would have let you know as it sold for silly low money…

Lastly I wondered if by any chance anyone might have a copy of the original Da-Capo instruction manual at all? I would really appreciate a photocopy of it (been trying to get one for ages), I am also looking for a Cardinal instruction manual as well…

Does anyone know the dip switch settings for the HDCD filter (or will I only get intelligible sound if I have used the correct setting)

What transport was the Cardinal based on… Yes I know the drawer etc is some bespoke low vibration material etc… but I guess the laser and motors etc. were taken from a commercially available Transport… It would be of immense help as I could then track down some s/h really cheap units that used the same laser and motors etc for future spares.

John can you remember if the cardinal produced performance figures (jitter etc.) better than most other transports produced, or is it just good figures for it's era?

Lastly is there any other transports that use a compatible clock lock to the Da-Capo DAC? Just wondered because at some point if the cardinal broke and it can’t repaired it would be good to know of any other transports that would work with the clock lock connection on the DAC.

Thanks for any info that can be offered.

John H

PS my Cardinal accepts CD-R’s without any drama (including the cheapest of the cheap CD-R’s), I haven’t tried RW’s but will later tonight.

Here is the method
1) Install Spectroid app on your Android phone from Google playstore
2) Ensure there is relative silence while doing this test, we want to keep the noise floor down.
3) Prepare to run frequency sweep from youtube Login to view embedded media This is a sweep from 25Hz to 150Hz. You may use any other way of sweep if you want to go lower than 25Hz. Pause the video at start.
4) Bring your android phone mic as close to the port as possible keep 1 cm of distance but dont touch the speaker or sub with your phone. The idea is that the mic should mostly catch the audio from port only and other sounds should appear as noise coming from far.
5) Start the app
6) Run the sweep from youtube, when it completes, notice the peak in response in bass in the red curve of the app, that's your tuning frequency
7) Repeat above to be sure.

Note:- Android phone mic is not a good way of measurement but for this purpose, it works

Below is my speaker's 60Hz tuning

Hope it helps.

Warm Regards,
WonderfulAudio

For those using legacy DACs with SPDIF inputs, can you list some good converter boards?

Plenty of Chinese ones, plus JLSounds and no doubt many others....

I'm using 4" full-range whizzer cone speakers in my bedroom. They operate normally. No lack of treble. However, one day, I found the NOS tweeters of the same series with those full-range are being sold. I think what if I buy and add them to the 4" full-ranges.

Of course, the HPF for the tweeter is required. But, how about LPF for the full-range, isn't it required?

If so, the x-over point might be set at around 4-5kHz (no problem). But, if not, which means running the full-range (closed) to 20kHz as usual and assigning somewhere upper frequency for the tweeters to handle, then, what frequency should be set for HPF of tweeters?

PS. I have a DSP in my system so I can actively control x-over.

Hi Everyone. I'm french (nobody's perfect) and new on this forum. I'm sound eng. and I record classical music in churches in my Brittany (France) region with my DIY gear.

ive tried every wiring option but get nothing or a fixed noise - anyone help please

Hi everyone

I've been working professionally with solid state amplifiers for over 3 decades , and have been surprised by the sudden surge of devices going EOL. I believe that traditional class AB amplifiers are not going away, but are transitioning away from the mainstream to a boutique market. Valve amplifiers saw this happen a long time ago. With that said, there are a lot of high end solid state amps being built, and specialized parts sources are out there to supply them. I would like to list a number of sought after device type easily available, in some cases with a different part number.
They are available from Profusion plc in the UK. We have verified samples of everything listed here in pro audio gear made by LAR audio systems.
LAR audio is reason I had to locate some new sources.

KEC DEVICES (Korea Electronics Corp.):

KTA1381 / KTC3503 300V FAST VAS STAGE TO126 Replacement for the EOL ON devices really fast high voltage VAS
They should be in stock by Jan.

KTA1837 / KTC4793 230V VAS / DRIVER TO220 Replacement for toshiba 2SA1837 / 2SC4793 , good VAS and driver , in stock

KTA1700 / KTC2800 160V VAS / DRIVER TO126 Replacement for 2SA1220A / 2SC2690A , GOOD VAS and driver in TO-126
They should be in stock in Jan

KTB2640G / KTD1640G 150V 130W FAST DARLINGTON OUTPUT TO3P N Replacement for Sanken 2SB1647 / 2SD2560 improved SOA, in stock
This is a really nice output device for simple hifi amps

KTA1943A / KTC5200A 230V 150W WIDE SOA FAST OUTPUT TO3P L (TO264) This is an enhanced version of Toshiba devices, almost identical to 2SA1302 / 2SC3281 in every way , but higher voltage rating.

Unisonic This is not the most serious sounding name for semiconductors, but it is an established OEM supplier in Taiwan.

2SD669/A / 2SB649/A The TO126 versions are a good substitue for 2SA1220A / 2SC2690A There is some confusion about power ratings on the data sheets because they come various packages, including SMD, and the rated power is in free air We have verified that the SOA curves for the 2SD669A apply to all TO126 devices when on a heatsink.

2SA1837 / 2SC4793 The TO220 versions are also like the old favorite, but they are available in various case styles.

I may have post this in the wrong area, but searching threads, most appeared to discuss a specific need for a specific project. I hope I have been helpful to continue on with the construction of fine Transistor amplifiers.

Hi all,

KSA1220 seems to be obsolete and KSC2690 is available at the big seller.

Did someone know which can be used as a good replacement for KSA1220 / KSC2690?

For lower power projects like preamps, headphone amps, etc. I like to use power supplies with TO220 voltage regulators.
I designed a universal board for this.
To power a recently built OREAD, among other things, I had some new supply boards made and now have some spare boards for sale.
The board can be used with TO220 voltage regulators like LM317/337 and 78xx/79xx or others with the same pinout.
It also allows the use of: fuses, RC-snubbers for transformer secondary windings, rectifiers like 1N54xx for full 1.5A current, CRC filtering, suitable heatsink,
soft start for output voltage.

The circuit below shows values for +/-15 volts output. A BOM (example/proposal) will be sent to buyers via email.





this version sold out. new version available, see last post.

If interested: Email/PM me

Not sure that it actually needs the servo, but I was not happy with 18mV worst case DC offset at the output.



Seems to simulate pretty well.

We have previously published a Simple Speaker Protection (SSP) for amplifiers with balanced outputs :
https://www.diyaudio.com/community/...power-amplifier-with-balanced-outputs.244157/

But how about Class D amps with single supply and maybe also BTL outputs, or car amps such as TDA7850 ?
This is an attempt to find a single solution for all.
Not proven, but useful basis for discussions.
Hopefully someone has better ideas, or can make it even simpler.


Patrick

.

38 PMT foil caps with 10 uF each, used, with traces of masking tape and soldered together in parallel, were once installed in a crossover for a Manger Wandler, now complete for slim 20 Euros plus shipping

SOLD

Elektor has in time past published two hi-end preamps using MAT02 and MAT03 dual transistors for the differential pair using +-15volts supply; one was with a DC offset nulling preset somewhere in the negative supply line and the other was with a servo using OP77.

I have somehow lost both the Elektor issues but would like to have the schematics. I have three assembled boards of the one with the servo. I would also like to try out the easier offset nulling arrangement.

Could someone please send me a scan of the entire articles OR if someone wants to sell their copies of Elektor containing the above, I will gladly buy them.

Thanks,

Hi.
I need a schematic for SPL Dynamics S-2000D car amplifier. Everybody who can help me, please send the schematic for my email: gyovcsi@gmail.com