Im selling mundorf BS series coils.
2 x BS140 4,7mH
2 x BS140 12mH
2 x BS150 5,6mH
Price for all 6 coils 150 euro plus shipping. Psyment by paypal.

I made this amplifier for test my home DIY speakers (two way TL).

D4 on component layout wrong polarity, in post #253 is corect componenet layout.

I bought these amplifiers from an old man at work.
He brought them in because he heard i love tubes and he wanted to be rid of the heavy turds at 80 something years old...
I offered him $500 for these and the preamp which was also a diy effort.

The workmanship was poor and the amps didn't work. The boards were a rats nest and the builder used 5 different types of green wire.
I bought them for half of what I figured the iron was worth because I knew i could do something with them eventually.
(The preamp has SUTs)

I drew out the schematic and it did not make sense and it also didn't work, so I knew I'd need to overhaul the whole thing in order to make something worthwhile.
Luckily the A-340 dynaco is an extremely easy to use transformer. I could copy the dynaco mk2/3 but I already had 2x small tube sockets.
Instead I went full Williamson.
I am in fact William's son...
I put 6cg7 in the front sockets for va/pi
And driver.
I built a fr4 circuit board with a bias/balance adjustment pot.
I rewired everything using cloth wrapped wire to Retma color codes.
Now they both fire up and bias in and it's time to put signal through them and start fine tuning them.

Hello all,

My Roland Space Echo Re-201 has an issue, and i’m struggling to troubleshoot. When I have an input plugged into the J3 instrument jack, when the SW3 switch is set to ‘Echo’, there is no dry/direct sound outputted. Please can someone help trace where this dry signal goes on the schematic? The echo signal is outputted on this setting, but just not the dry sound. I’ve been trying to trace, but i’m finding the schematic confusing. Ive been inputting a 1k square wave and tracing with a scope from the OP 13 board to the OP 14B board, i will attach.

I have changed all the electrolytics and this hasnt fixed the issue. I suppose it must be simething else, transitor etc. sometimes when i put a loud signal through it, then the direct appears, which makes me think transistor?
Any help or advice is appreciated, Thank you,

Hi team,

I have a K502 with a quad of 11BM8 tubes (similar to the thread kcroy created here https://www.diyaudio.com/community/...unsure-what-tubes-to-use.290013/#post-4684440 but the B version of it). Bought from Antique Electronic Supply in 2008

While moving I managed to loose the schematic that was supplied with the kit when I bought it so wondering if somebody has the same kit as myself and has a copy of the schematic to spare.

I have found the schematics of other kits (3 links below) and as I see the differences are minor to negligible but would be great if I could have the original to be able to compare 🙂

• https://diyaudioprojects.com/Gallery/displayimage.php?pid=99
• https://diyaudioprojects.com/Gallery/displayimage.php?pid=123
• https://diyaudioprojects.com/Gallery/displayimage.php?pid=368

The layout is identical, pretty much all caps have identical values, just certain resistors are different I presume for adjust the gain between the different tubes used amongst the different versions (10GV8, 11MS8 and 6005).
Small project behind this amp is:

• Do some major cleanup + new case
• Replace the power transformer since now it's 110V and I want to be able to plug it straight into 220V (dual output 11v ac for filaments + I presume somewhere between 165V and 200V for B+ but need to measure)
• Replace the output transformers
• Introduce a bias circuit on the tubes

Thanks in advance for any help.

Hello,

I started studying electronics a few years ago and have recently started repairing equipment for local musicians. This weekend I built a stereo ribbon microphone to mount on top of a field recorder.

Hi. Lately i’m working on an old synth and just for test purposes i’m trying to replace some old transistors. Ordered them from china (they will be with me here in Greece in a couple of months) but i may have a chance to find equivalents locally too.

-The “very” odd ones are the k81 ones. I assume they are similar to 2sk81.
Can’t find any info regarding their pinout in english.
Are they jfet, n channel fet, mosfet, or what?
Some people say that they are close to the j113, with different pinout. What is their type and what is their pinout? Is j113 a correct equivalent, or is there anything other equally mainstream more suitable? Any idea?

-i also look for 2sc2785 equivalents. Similar sources said that bc546 is a good equivalent, with just different pinout. Is this correct? Anything more suitable, equally easy to find?

- And lastly there is a 2sa1175 (as a muting switch i guess). Same sources suggested bc556. Is it ok? Better equivalent that can be found as easily?

Thanks in advance

Hi all,

Attached is a preliminary schematic of a return-to-zero FIRDAC I intend to build. No idea when I will find time to design a PCB, stuff it and debug it, but I'll get there eventually. It will be a DAC that can only handle raw DSD. If it works well I may or may not decide to also make a PCM version that uses an FPGA board to convert PCM to sigma-delta modulates.

The circuit with the stacked dual transistors on page 2 is (or at least should be) a low-noise bandgap reference. I have the concept from D. F. Hilbiber's article in ISSCC Digest of Technical Papers from 1964, see https://www.diyaudio.com/community/...ith-ic-voltage-regulators.359652/post-7021353 It should have better noise performance than almost all modern bandgap references, because those almost always amplify a V_BE difference by a large factor instead of stacking V_BE differences. Only half the transistors are needed; I can't predict whether the BCM56DS or the NST45011 stacks will work best and they don't have the same footprints, so I want to reserve space for both.

The reason I can't predict whether the BCM56DS or the NST45011 stacks will work best is lack of information about the base resistance of the BCM56DS. It's a matched pair of medium-power transistors, so chances are that the base resistance is low, but I can't be sure of that. The NST45011 is specified to have a 1 dB typical noise figure at a 1 kohm source resistance when biased at 0.1 mA, which implies a base resistance of about 130 ohm, which is not bad but not very good either. (There are matched transistor arrays from THAT and Analog Devices with good and clear noise specifications, but I find those much too expensive.)

The fifth page has a clock doubler and a return-to-zero circuit, among other things. JohnW doesn't like the RTZ circuit I used in 74AHC02 and 74AHC08 DAC with 97 dB(A) dynamic range because he is afraid that the switching of the flip-flop may disturb the gate output signal when the flip-flop isn't slow enough. To avoid that issue, in this circuit, I split the RTZ logic from the actual DAC.

74LV574A's connected as shift registers on the third and fourth pages are the logic circuits used as DACs, they have low-noise reference supplies that are separate from the RTZ logic supply. As they run on a doubled clock and there are zeros inserted between each pair of data bits, simple shift registers work as RTZ FIRDACs. It's like the DSC2 DACs, but with return to zero. It's a balanced four-tap FIRDAC, balanced to keep the load on the reference supply as data-independent as possible. For matching reasons, I've connected the 74LV574A flip-flops in an ABABABAB style, with a second 74LV574A in BABABABA style.

Regards,
Marcel

Edit, 12 May, 1 October, 14, 15, 22 November 2022, 1 and 12 February, 26 May, 16 July, 1, 3, 6 and 8 August, 17 and 18 September, 15, 17 and 22 October 2023, 6, 10, 21, 29...31 March, 1, 8 and 15 April, 2 and 18 May, 28 July, 26 October, 1 and 7 November, 2, 3 and 9 December 2024 and 9, 11, 15 and 16 January 2025:
See posts #20 and #21 for the version (DAC3_5.pdf) I built and did some measurements on (using NE5532's rather than OPA1678's in the filter because the latter were out of stock), see post #1931, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7483396 , for the latest BOM and schematics, and see post #241 https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7175580 and its links for the latest layouts. The latest schematic versions are DAC3_10_holdtimefix.pdf and DAC3filter_6.pdf. Versions 9 and 10 of the DAC layout (with or without hold time fix - the fix only consists of four resistors with updated values) are meant for 0.21 mm PR7628 prepreg, the earlier versions for 0.36 mm. See post #272 https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7182183 for the (old-fashioned) KiCad files.

I corrected the literature reference in this opening post.

Measurements:
The most relevant measurements are in posts #35, #60 (noise floor), #75, #79, #88 and #764 (distortion and noise floor driven from an Amanero), https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7403333 The measurements of post #764 were done by Hans Polak. Some measurements by bohrok2610 on a variant of the DAC can be found in post #955, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7417293 and post #1090, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7419240 , and an overview of measured noise floors in post #1092, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7419247 It seems that the noise floor is quite sensitive to far-off phase noise and spurious tones on the clock. Later measurements by bohrok2610 on his variant with an improved board layout can be found in post #1928 and a few posts below it, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7481890

See also bohrok2610's measurements on low-signal-level distortion and 10 kHz distortion starting at post #2467, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7635702

For comparison, using the same sigma-delta modulator, the DSC 2.5.2 has low-level distortion with a similar looking spectrum, but about 20 dB worse, see https://www.diyaudio.com/community/threads/simple-dsd-modulator-for-dsc2.370177/post-7407497

On the other hand, ska managed to make a DAC with a similar spectrum but about 20 dB lower distortion products, apparently using a very simplistic approach. The sigma-delta modulator design is different, so the difference might be due to the DAC itself or due to a different dithering scheme in the sigma-delta modulator or both. The information about ska's design and layout is sparse, but there is some information spread out over posts #3834, #3837, #3844, #3847, #3850, #3851, #3863, #3865 and #3887. See also ska's thread about the same DAC, but with a better sigma-delta modulator, https://www.diyaudio.com/community/threads/discrete-fpga-dac-project.407618/

The measured noise of the bandgap reference with BCM56DS is smaller than the calculated noise with the NST45011, so the BCM's are the winner. Hence, in version DAC3_9, the NST45011's have been removed.

Hold time fix:
Measurements from Markw4 showed that the delay of U22, U24, U26 and U27 was only 1.7 ns, shorter than the anticipated typical delay and quite close to the 1.5 ns minimum hold time required by the SN74LV574As. Reasons may be the fact that I designed the circuit using TI data but switched to Nexperia for U22...U27 because the TI parts were not available, and that U22...U27 see a smaller capacitive load than the 50 pF used for the datasheet measurements. To fix this, R124, R127, R129 and R131 have been increased from 39 ohm to 270 ohm.

The prototype is fully functional with the original 39 ohm, with 270 ohm and even with 560 ohm. This last value is not recommended because it could lead to set-up time issues, I just tried it as an experiment. The noise floor with 270 ohm resistors is in post #1927, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7481723

Supply currents:
The measured supply currents of the prototype at 27 Mbit/s are in post #88, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-6999623 Add 50 % to have some margin for exemplaric spread.

Supply sequencing:
There are some supply sequencing requirements, fortunately ones that can easily be met. Again see post #88, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-6999623 , for details.

Alternatives to components:
The TQ2-12V relays can be directly replaced by Zettler AZ850-12 relays, which are sold by Conrad (among others).

The latest filter design has NE5532's instead of OPA1678's in the second and third stages of its schematic, because the prototype also used NE5532's. Both should work, as the filter was originally designed for OPA1678's.

The OPA210 and OPA2210 could be replaced with OPA209 and OPA2209, respectively. They are very similar, although some specs of the OPA209 and OPA2209 are slightly worse. If neither OPA2210 nor OPA2209 is available, OPA1602 should also be usable as an alternative.

Header length:
The headers connecting the filter PCB to the main PCB have to be relatively long because of the height of the capacitors used in the reference buffers. I hope the ones suggested in the latest BOM are the right size, I guess they are as I didn't get any complaints.

Skipping the last filter stage if DC offset doesn't matter:
You can skip the last filter stage if some DC offset is acceptable, for example because the offset is blocked somewhere further down the signal chain. On the filter board, you can then skip U₆ and U₁₃ with the surrounding components and connect the outputs of U₅ and U₁₂ straight to the 49.9 ohm resistors. Ray (nautibuoy) made filter boards without the last stage, see posts from #647, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7365893

Output signal level:
A 0 dB DSD sine wave produces a differential output voltage of about 2 V RMS.

.dsf test files:
See post #762, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7403044 , for .dsf files with repetitive silent patterns, these can be useful for measuring just the analogue circuit noise (without the effects of the ultrasonic quantization noise). See post #2610, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7643831 , for a Pascal program that generates a non-repetitive silent DSD512 .dsf file. With small modifications, the Pascal program can also generate a tone.

The program and .dsf file attached to post #2696, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7652259 , are meant for checking to what extent a DAC generates intermodulation products between idle tones around half the sample frequency.

Variants:
Besides Ray and his simplified filter board layout, there are three others who designed variants:

post #429, PCM variant for Raspberry Pi by Thorp, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7272503

posts #955, #1923 and #1928, single-board version by bohrok2610, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7417293
https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7481890

post #1847, latest version of Markw4's mix and match between my DAC and stuff from Andrea Mori and others, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7455840 See also his summary post #1880, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7457164

bohrok2610 did some experiments with the filter to reduce the harmonic distortion at 10 kHz from about 0.003 % to even less, see post #2238, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7620060 for an overview, and see post #2380 https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7625079 for information that is more recent than the overview, and that seems to refute my hypothesis in post #2238, although a later measurement seems to confirm it.

The schematics of the filters he tried are here: https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7635719 and here (well, a description actually): https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7680453

He also did many most interesting experiments related to distortion at low signal levels as well as 10 kHz distortion. There is a whole series of posts related to this, starting with post #2467, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7635702 An attempt at explaining the results can be found in my post #2485, and an extended and updated version in the pdf file attached to post #3265, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7686002

Markw4 made a DAC board layout with some extra test points, see post #2620, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7645321

Hans Polak suggested making the FIRDAC longer by cascading the two SN74LV574A's. A longer FIRDAC is less sensitive to the phase noise floor (not to be confused with close-in phase noise), but doing it according to Hans's proposal has the disadvantage that the suppression of data-dependent reference current gets worse. A calculation shows that the suppression around odd multiples of half the sample rate (where you need the suppression most because of idle tones) theoretically remains intact, see post #3428,
https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7729904 All in all, I cannot predict whether Hans's version would be an improvement or a degradation.

If you are good at lifting SMD IC pins, it can be made on the original PCB, as Hans pointed out in post #3433, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7730150 He explained in more detail how to lift pins in post #4038, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7887181

2A3SET tried Hans's suggestion and subjectively likes the result, see post #4047, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7896594 More information about 2A3SET's set-up, including a fully passive reconstruction filter, can be found in posts #4052 ... #4060.

Calculations:
The way the original filter was designed is documented in sections 1 ... 5 of the attachment of post #3028,
https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7672339 Section 6 contains calculations on how to combine a passive LC filter with an MFB stage.

The attachment of post #2269, https://www.diyaudio.com/community/attachments/jitterfirdac_en-pdf.1282828/ , might be useful for people who want to design longer FIRDACs.

Quasi-multibit digital sigma-delta modulator:
The low-level distortion products bohrok2610 found do not occur when the digital input signal comes from a properly dithered quasi-multibit modulator. See post #4043, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7895559 for the latest version of an implementation on a cheap FPGA.

Suggestions for further improvements:
Even though the DAC works quite well, there are suggestions for further improvements all over the place in this thread, too many to link to in this opening post. I've commented on some of them in post #3526, https://www.diyaudio.com/community/threads/return-to-zero-shift-register-firdac.379406/post-7747974

As mentioned, another potential improvement would be to make the FIRDAC longer to make it less sensitive to the phase noise floor (not to be confused with close-in phase noise). When this is done by using longer shift registers while keeping all measures to cancel out data-dependent reference current in place, it should reduce the audio noise floor you get with an imperfect clock.

Hello from an audiophile DIYers team who also happen to be metallurgists and have put a lot of energy and resources to produce the purest possible silver conductors for audio. We do not want to breach any forum rules, we just hope to inform the members (and we have some members here in our team) of our presence and answer any questions they may have.

Are you old enough to remember LEAP 4? only the best loudspeaker design program ever written IMHO.

If so and you want to bring back the good old days of DOS, you can now run it on your window machine, cracked and ready to go. Please see my post in the general loudspeaker forum for details and BTW, someone just posted a LEAP 5 crack .... Good times and thank you Chris Strham, you were brilliant and I cherish our many conversations.

Hi everyone,

If you recall, I'm a big fan of XSim, but I'm embarking on converting a 2-way (AMT tweeter + 6.5" mid-woofer, ported) to a 3 way with the addition of a bass cabinet and 3-way plate amplifier. I took my original FRD measurements for the tweeter and mid, and have spliced in the Dayton reference data for the woofer. None of the levels or delays are probably accurate, they are just here to see how far I can get in this design while I consider whether or not to proceed.

Based on my good luck with LR4 in my center channel I'm trying to use that slope again here. Ignore the phase plots, this is VirtuixCAD under Wine/Linux so the graphics are not 100%.

Thoughts?

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!

Over the last week or so I have been working on my 1995 Wadia 16 CD player that stopped working back in 2007 and has been languishing up in my attic for more than 7 years. It worked fine for 12 years then suddenly crapped out. I opened it up back then and poked around, but without the prospect for obtaining any kind of dealer or factory support (Wadia was in and out of being a viable company for years), I quickly abandoned my effort. I remember being really pi$$ed off that a $7000 CD player was essentially junk because some tweaky high end "company" knew how to design, but wasn't so interested in the business aspects of running a company; a hobby run amok. If it hadn't weighed 45 lbs. and was in outwardly mint condition, I might have thrown it out in the trash along with a case of Budweiser to ease the pain of the garbageman.

To make a long story short, the 16 is back up and running perfectly. There were a couple of minor issues including a dirty laser, but nothing that was a show stopper. Troubleshooting analog is one thing, but with the advent of microprocessors and FPGA's, modern electronic equipment is becoming more and more non-user serviceable. Thankfully all of this was in good shape, along with the transport, even after 7 years of zero to 100+ degrees F and wide humidity swings.

I think a lot can be said of Wadia's attention to detail when compares the Teac VRDS servo PCB to the Wadia PCB. The Teac isn't even close.

In the end, the last thing that needed to be done was re-solder the servo board digital output shielded cable that runs to the Wadia digital IO board. I broke it loose at the servo board end when I unwisely attemped to remove the bottom chassis plate which has the servo board mounted to it. You get to the servo board from the top. Since I had no idea where it was soldered to I figured I'd email Wadia last Friday and ask them if they had schematics and assembly drawings for the 16. Based on what I've read here in the DYI forums and elsewhere, I wasn't expecting even a reply from them, but it took little effort to at least try.

Wouldn't you know it, they not only replied, but sent me PDF's of all the schematics and drawings they had on the 16! Now that's customer service!

A while ago, I got similar results from Krell, so I also have complete schematics on the KRC preamp and the MDA 500 amps if anyone needs them.

Regards,
Doug

For sale 4 pairs tube adapters.Like new used verry short time and verry good quality.Buyed by Banzai music Germany and Tube Town Germany.
Price for all 8 is 120 euro or best offer plus 7,90 euro tracekd shipping inside EU!The last pair adapters are for 6sn7 to 6f8g!More info on contact.

Verry good tube amp transformer for sale.Zransformer with copper shild and specifications that you can see on picture.Price 100 euro including shipping to EU with tracking and insurance.Payment by Paypal.More info or offers on contact.

One pair, like new, only few weeks old. Price 50 euro plus shipping.

Hello. I'm a new member here, longtime lurker.
Audio science, snake oil, subjective, objective - it is all of interest to me.
Mostly interested in learning about tube circuits and modifications to said circuits to substitute one tube for another. Too much to learn, not enough time. Thanks

Greetings to all and thank you for giving me access and any guidance you can provide

I didn't find a lot of information out there on this topic. How can I switch out a 30uH inductor for a ferrite bead? I did a little searching and it looks like the low pass capacitor going to ground becomes quite a lot smaller (instead of around 1uF after an inductor, with the ferrite bead that value becomes 0.001uF). But is that all? Are there any other considerations (for it to function)? I did see in the datasheet that layout runs must be compact to the chip. I also saw that it must be able to carry enough current and must go to around 120 ohms at 100MHz.

Welcome to SylphAudio thread!

Our New Product Release Roadmap for 2024



****

SE800 PFFB High Power Class-D Amplifier
Supply Voltage: dual ± 25V min, ± 85V DC max
Unclipped Power (<1% THD+N, ± 85V): 350W-8Ω, 700W-4Ω
Input configuration: Single Ended
Output configuration: Single Ended
Input sensitivity (PFFB): 2.6V RMS
Voltage gain (PFFB): ~25dB
PCB area: 140mm x 70mm
Overvoltage Protect: ±88V to ±91V DC
Undervoltage Protect: none, UVLO @ ±12V DC
Speaker Protect: none, requires external SP

Can be used with a 2Ω load if powered with a lower power supply voltage around ± 60V DC, can reach 800W output (< 10s burst signal).
Designed with PFFB to reduce load dependency and improve noise and distortion. 5W at 4Ω THD+N is around -82dB, with THD at -94dB.
Rugged and super-stable PFFB design based on TI, implementation by SylphAudio.

ETA: Jan 2024

Sample pictures



FB100 and FB360
We've applied the largest feedback factor possible without reducing the output power capability. Which results to exceptional performance.

FBUltra
Under development, composite OPA1612 and LM3886 design.

Sdudio monitor speakers. Simply the best.

Originating from a user of the German HiFi-Forum. Very solid database imo. Includes HiFi and PA. You can also submit your own entries.

https://diyspeakerdb.com/

1pc 2SK180 NOS TOKIN V-FET(SIT) Original, Made in Japan, similar 2SK77 | eBay

watanabetomoaki | eBay

Find this 2SK180 Tokin sit's seller in Japan.

Shipping cost are not high. Any Diyer know & try his batch of hockey puck's ?

EDITORS NOTE: This is the single depletion mode Mosfet amp that Nelson Pass demonstrated at Burning Amp this year. END

Nelson Pass said:

I just opened an unexpected arrival from Jon this morning....

Click to expand...

After seeing this, who can resist?

(Tea-bag, thanks for the photo)

Nelson Pass said:

It's worth noting that I am considering some other tweaks
on this as well.😎

Click to expand...

J-fet CCS? 😎🙂

Uk, need Mylar 4/6/12 um: where to buy ... ??? thank you for any help.

I have some spare parts if someone has a whammy board and they need a good deal on some parts to get them going. This has MOST of what you need to get the power supply completed.

What is included:
- brand new Talema 18VACx2 25VA transformer

- all the heat sinks (low profile)

- 6 Panasonic 3300uf 35V caps

- 4 IN4004 diodes

- 4 5.1 ohm resistors (for the CRC psu)

- red LEDs

- 2 pairs of different 220uf caps

- a pair of Nichicon UEH bipolar 22uf caps

- opa2134 opamp

- a pair of 1uf poly caps

- assortment of Vishay/Dale RN55 1/8th watt resistors.

I am asking $60 shipped and will throw in some Mogami wire.

Unfortunate work circumstances force me to sell of some DIY parts. I am selling the whole setup below for $325 shipped Conus. I did a rough estimate and sourcing these parts brand new would put you around $450. Keep in mind I only have the 3 pairs of daughter boards.

Here is everything you get. Keep in mind some parts have been used, some brand new, and the m2x boards untested.

• Two Triad VPT36-4440 (2x18VAC 160VA) Transformers (USED)
• Four diode bridges using MBR20200CT (USED)
• Two Power supply boards with 60,000uf per rail and CL-60 installed for GLB (USED)
• Two M2x boards with 6l6's DC offset modifications (NOT TESTED)
  • Edcors installed with Copper Strips
• Three Daughterboards - Norwood, Ishikawa, and Cedarburg (BLANK)
• Set of Gold Plated Binding Posts (NEVER USED)
• Unmatched set of IRFP240/IRFP9240 Mosfets (NEVER USED)
• Pair of Gold Plated RCAS (NEVER USED)
• XRK's Daughterboard testing PCB (NEVER USED)
• Mu Metal to cover the Edcor Transformers (to shield the Edcors)
• Spade connectors for the M2x boards and the diode bridges

Some of these parts will show wear from storage or use, but I can guarantee the diodes and PSU's work perfectly. I replaced all of these parts with SLB boards which is why I no longer need them.

Every year I use dumpster parts to make a garden system for the summer. I live in a block of 5 apartment with a communal garden & a bunch of neighbours who love to barbecue! The system only has to last the summer. I don't care if it gets broken & abused.
The first 2 years I made 2.1 systems using D3116D2 chip amps using a laptop PSU - they worked well.
Last year I went in a different direction . . .
DVD / Blueray Receivers have one moving part that is guaranteed to fail. When that part fails they are worthless. You can pick them for $5 - $20.
What remains is a remote control USB player (possibly with Bluetooth) & 5 or 6 amplifiers and an active crossover in a single box,
I picked up an LG HT902PB - 1000 watts (yeah, right). The garden sounded great: a 10" sub & four bookshelf speakers.

In helping my small business friends out, I have installed faulty DVD receivers in two local restaurants & two hairdressers.
These units have untold hidden benefits, not least the ability to control the volume and delay of individual speakers is something you are unlikely to get on even high-end commercial systems.

The tolerance is also impressive. The subwoofer channel claims to deliver 255 watts into 3 ohms, so I guess there'd be few problems running two subs off the one channel.

After modding a Marantz CD63 and a CD67OSE I decided to make a list of all the various mod's I found here and elsewhere on the internet.
I'd like to donate my files to this forum, for all to enjoy! 😀

Of course I do not pretend this list to be complete.
This is all I've done to the players so far and more good tips are welcome!

Greetings,

Ray.

Very small PCB based on Yorkville Amps.

Where to buy transformer laminations, magnet wire and bobbins, preferably in Europe?
And . . . whatever happened to delatsch.com ?
Delatsch sells transformer winding spreadsheets and used to sell all the materials needed, like laminations, magnet wire etc.
but now materials are removed from the web shop.
Little use then by buying the spreadsheets if the needed materials are not available for sale.

Attached is a scan of the NAD 3150 Circuit Diagram, which is of good quality.

I have 4 NHT1259 drivers for sale. I purchased these from Madisound back over 25 years ago, for an isobarik subwoofer project. They were (and still are) highly regarded drivers. They have about 100 hours of use, as they have been in storage for the past 20 years. I no longer have the space to store them.

They weigh over 4 Kg each, so shipping costs will be significant, so a local pickup (south-west France) would be ideal.

I will consider any reasonable offer.

note: photos only show 2, however the other two are in identical condition.

Hello,

New to this forum!
I’ve been trying to fix my Poly 61- the transfomer gets hot when switched on (i heard a bang near the power supply side one time when i was fitting a Midi kit) i have descovered this only happens when under load when other boards are connected, and the bridge rectifier gets very hot, so i’m convinced its this that is at fault. After connecting another board to the supply and taking chips off to lower the current load, the transformer cools and the bridge rectifier still gets very hot. I could’nt find any shorts on the other boards.
In the schematic, you can see this part is connected on the secondry side, and is labelled D3. I will attach.

Please can someone advise me which replacement bridge rectifier part to get? I’m unsure what the numbers mean, and the schematic power supply page is unreadable, it just states the part as 4B4B41?
I’m not sure how to test these components also, and if it is at fault, then it might be tricky to buy another seen as this one is at fault? Will a generic bridge rect diode part work as a replacement? I’m cautious of buying another part and using as it could cause more faults (and obviously dangerous), i’ve spent so much time trying to get to the bottom of this and I can see light (maybe) any help here to advise would be appreciated, thank you


Kind regards
Connor

SOLD -thanks for looking

For those interested, here's an opportunity to save a lot of money. I'd like to get rid of some capacitors that I have left over from various projects.

Mundorf MLytic 10.000 uF / 35V 2 pcs.
Mundorf MLytic 15.000 uF / 50V 1 pc.
Nichicon Gold Tune 10.000 uF / 50V 5 pcs.
Nichcon Gold Tune 4.700 uF / 50V 2 pcs.
Panasonic EEUFS1C512L 5.600 uF / 16V 20 pcs.
Panasonic TSHA 4.700 uF / 35V 2 pcs.
Panasonic EEUFR1H221B 220 uF / 50V 20 pcs.
Kemet LH 4.700 uF / 63V 3 pcs.
Panasonic TSHA 5.600 uF / 50V 4 pcs.
Panasonic EEUFR1V222L 2.200 uF / 35 V 6 pcs.
Panasonic EEUFM1V182 1.800 uF /35 V 6 pcs.
Yageo A750KK477M1AAAE016 470 uF / 10V 6 pcs.
Panasonic 16SEPG270W 270 uF / 16V 6 pcs.
Panasonic 16SEPF150M+TSS 150 uF / 16V 6 pcs.
Panasonic PLG0G182MDO1 1.800 uF / 4V 20 pcs.

New completely 254,9 Euro -so now I ask for the half: 125 Euros plus shipping.

The expected shipping costs can be viewed here (select parcel up to 2 kg including tracking): dhl.de

Due to the current customs chaos, I would only sell them outside of Europe subject to checking the effort involved.

The capacitors are new, guaranteed to be genuine, not from Ali or eBay (or similar). They are stored under good conditions, in a well-tempered, smoke- and pet-free environment.

The buyer receives some additional capacitors for free.

I recently bought a Pioneer PL-5. I got it hooked up and found that it didn't play speeds properly. I found a couple YouTube videos that addressed this problem. I took the turntable apart. Cleaned it, oiled the motor bearing, cleaned all the switches and pots with contact cleaner so and so forth.

I put everything back together and tried it out. I was able to adjust the 33rpm with the adjustment pot, but I couldn't get the 45prm to adjust at all and runs too slow. The speeds will would skip fast for a second and the back to normal and there is an audible noise as well when it happens.

I have a feeling that I will need to recap the circuit board, But I wanted to see if anyone else had any other ideas before I start doing that. Is it even worth the trouble recapping it? This isn't my only turntable and fortunately I didn't pay much for it.

Any input would be great!

Thanks

Hello All, I recently was gifted AR 8B bookshelf speakers. Of course the foam surrounds are dry rotted and I have the kit to refoam the woofers.
While I am doing that I got inspired to tweak the crossover thinking that i can improve the sound over the original. The woofer is running free-range with no LP filter. The tweeter uses a 5.0 uF capacitor only. Per what I posted below, it sounds like this was done as a cost-cutting effort and not necessarily to deliver the best sound. I'm thinking a 12 db per octave LP crossover at 2000 Hz is a good idea to prevent distortion. According to AR, the tweeter has an "effective" rolloff of 18 db at 2000 Hz using the single 5.0 uF cap. Should a more sophisticated HP filter be used incorporating an induction coil and a cap, and should the HP filter use a 12 db/octave slope as the tweeter was designed to have a natural rolloff giving an effective 18 db/octave slope? Or should the HP filter use a 3rd order filter? Please advise, the more I look into this the more I am getting confused! Thanks!

"The two-way AR8B is the smallest and least expensive speaker system in the current Acoustic Research line. Like all AR speakers, it is an acoustic-suspension model, and it has a newly designed 6-inch woofer that crosses over at 2,000 Hz to a 1-1/4-inch “liquid cooled” cone tweeter. (The tweeter presumably uses ferrofluid or a similar material to damp and cool its voice coil.) The crossover network has been simplified and its cost reduced by designing each driver to have a natural rolloff outside its operating frequency range. As a result, only a capacitor is needed to protect the tweeter against damage from powerful low-frequency signals. The effective crossover slopes are 12 dB per octave for the woofer and 18 dB per octave for the tweeter."

Click to expand...

I thought that I should share my recent amplifier build:





Single-ended 6S41S cathode follower amplifiers that deliver 7 W each. Here is the schematic:



Running the output tube as cathode follower gives a very low output impedance for a single-ended amplifier. These amplifiers can drive difficult loads, but the concept has its cons. The output tubes need over 500 V peak to peak to deliver full output. The driver tube 6E5P-I is a small power tube with high amplification when connected in triode mode. It has a gain around 50 and can deliver quite a bit of current. By using an interstage transformer, I can get the required voltage swing without a very high supply voltage. Also, I step up the signal 1:2 with the interstage transformer and I also step up the signal with 1:2 with the input transformer.

The sound quality is great. It is most certainly the best-sounding amplifier that I have tried with my current speakers.

A couple of years back I scored a decent pair of the old RadioShack Optimus 8B speakers for $50- with some other stuff tossed in for free
Somebody over at AudioKarma was desperate for a set of the mid range and tweeters so I took them out and flipped them [ at a reasonable profit] and the boxes with that great woofer have been sitting in the shed for a long time and I have no idea what to do with them now.
The boxes are in excellent condition although missing the original grill, which I suppose is why they were only $50-
I'm at a loss as to how to proceed so I'd appreciate some thoughts and inspiration from the collective minds of the forum members. I haven't actually finished anything since I made that huge 18" part sub and I am feeling frustrated
Edit
Nova 8B

TI high power amp chip from tpa3251 family

They are in a plastic tube and have been since I bought them about 10 years ago from Digikey. Shipping would be from Germany.

I would like 100 euro for the lot with shipping on top.

I will post photos later.

Thanks

I'm into Audio of all sorts, and have to do most of the repairs myself as it's almost impossible to get any repairs done specially to vintage stuff. This site has valuable information.. Thank you

I'm wondering if there is someone out there that has a working amp circuit board for a realistic sta 2700.

I'm looking to build an Aleph Mini, currently trying to gather parts to order, for now I have found:

https://www.ebay.co.uk/itm/266392011176?mkevt=1&mkcid=1&mkrid=710-53481-19255-0 - the pcb
https://www.ebay.com/itm/156560013829 - mosfets
alternatively, but I'm not sure if it'd be quite right - https://www.ebay.com/itm/115126018088?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=wGG0QMocRHa

https://a.aliexpress.com/_EIU0SPC - enclosure

I'm just not quite sure about the PSU, what board / transformer should I use, and how to wire the potentiometer, switch.

In my search for a monster open baffle woofer I stumbled the W21 21" open baffle woofer. It looks interesting but the more I research Lii Audio the more something seems off. I cannot find much objective information on them. Most of the people talking about them seem to have conflicts of interest. Then I found there are more than one version of this driver....some may even be copies or made by another company?

The driver on Alliexpress looks very different from the one for sale on lii-audio.com website.

The first one seems to have a single voice coil, the latter double. The first one has a lowish QTS of 0.39 and MMS 201g while the other one sports QTS 0.82 and MMS 644g.

Normally I would assume the Alliexpress is fake but then I read this by caisson rj:

I am happy to see some people talking about Lii Audio Xizi founded in 2006 and Lii Song founded in 2016 which is a copy of the original Lii Audio. I visited both headquarter in Hangzhou and it was clear to know which one fake it. If you hold both speakers in hands it's is really obvious. The short story is that Xizi Lii Audio hired one guy to expand the business outside china and that guys screwed him and founded Lii Song and took the foreign market. There is currently quite a lot of new drivers made by Lii Audio that are coaxial drivers that are simply harder to copy for Lii Song so in the future you will see more and more drivers that Lii Audio will only sell. I am talking 21 inches coaxial stuff, premium range etc.

CAN SOMEONE SET THE RECORD STREIGHT? SHOULD I BOTHER WITH ANY OF THESE DRIVERS?

ALSO...IS A 21" DRIVER WITH A 201g MMS even realistic?

https://www.aliexpress.com/i/1005003529835421.html

https://www.lii-audio.com/product/w21/

Does anyone have experience with any of the Lii audio/Lii Song 15/18/21" woofers?

Some sound clips of this speaker recorded with my phone and powered by my SuSyLu 100w Class A amp:

Test of SuSyLu 100W Class A Amp - YouTube

Example of speaker in dark “espresso brown” stain and satin lacquer with Duratex coated baffle.


Example of beautiful build by as8912:


Another Example of a floor standing FAST TL by Plott:

This is a great shot of the internals as provided by Plott:


Example of a floor standing TL version of this speaker by Moutik:


Example of a smaller sealed version with PS95-8 full range drivers by Jimk04, here.

I wanted a speaker design worthy of the exceptionally high performing ScanSpeak 10F/8424 Discovery 3.5in full range driver. I decided that a short sealed Dagger TL coupled with a sealed bass unit would give me the best overall transient response and clarity. I decided to mate the 10F/8424 with the superb Dayton RS225-8 aluminum cone woofer for bass duties. The design ended up as a 24 liter volume for the woofer and a 1.1 liter 3-sided pyramid Dagger for the 10F/8424. The important external dimensions are: 10.0in wide baffle, 7.5in CTC distance from woofer to fullrange, and 24 liter internal volume (sealed). You can make the height and depth to suit your individual case, but it will need to be deep enough to house the Dagger. The internal dimensions I settled on were 8in wide x 12in deep x 16in tall.

However, if you make it out of 18mm plywood like the ones I had my cabinet maker build - make the box using these dimensions.

Dimensions of sealed box version: most important is to make the width 10.0in (external) and CTC spacing between drivers 7.5in and adjust the depth and height so that you have about 24 liters volume. If you make it out of 18mm plywood it ends up about 18in H x 13.5in D. The 10F is located 4.5in top to center. You will need a rear chamber for tweeter (fullrange) so use a sports cone or wooded “Dagger” tall 4 to 5 sided pyramid. Stuff Dagger and main box with polyfill or fiberglass to taste.

New SketchUp Plans by @jrKC for sealed version here.



The short sealed TL is made of three 6in wide x 12.5in long triangles. Construction will use 1in thick pink XPS foam and regular foam core for the short TL. The front baffle will also use a thin sub-floor plywood in order to provide adequate support for the heavy 8in driver. The design will have the option of a bass reflex vent that can be sealed for use with a Linkwitz transform, or opened up for some additional bass when group delay is not an issue. The system will use miniDSP for XO and EQ duties and bi-amped. Here are predicted results in 4pi space with baffle step and diffraction effects accounted for. XO will be at 500Hz with 4th order LR. The RS225-8 is an exceptionally flat response driver and choosing a slightly higher XO frequency will keep the distortion on the 10F very low while giving more weight to the mid bass as it comes from an 8in woofer. Calculations show that with Linkwitz transform, bass extension should be about 42Hz (f3) with max SPL around 101dB.

SPL vs freq for sealed case at 24v (no Linkwitz transform) - the hump at 2.5kHz is the baffle diffraction:



Impulse response for sealed case:



Group delay for sealed case is 2.5ms at 100Hz and 5ms at 50Hz:



For bass reflex option, here is SPL vs freq at 24v:



Here is group delay for bass reflex (2.5in dia x 11in long vent - rear firing) case, not too bad actually (about 10ms at 50Hz)



Here is the Sureply thin baffle with driver holes and drivers to show basic look:



Here is construction on XPS enclosure beginning:



Here is the enclosure with Dagger TL internally mounted and bracing, wiring, and terminal cups installed:



Currently waiting for liquid nails glue to dry...

Edit April 27, 2015: New LR2 XO @350Hz and new sound clips of many different genres. Have a listen, this speaker sounds fantastic!

10F/8424 & RS225-8 FAST Ref Monitor - Page 2 - diyAudio

Here is the new LR2 XO @350Hz:


Update April 30, 2015: New Butterworth 1st order linear phase XO (BW1 XO):


Phase for BW1 XO:


Step Response for BW1 XO:


200Hz Square Wave with BW1 XO:



1.6kHz Square Wave with BW1 XO:



New sound clip with 1st order BW1 XO: http://www.diyaudio.com/forums/atta...or-10f-8424-rs225-8-fast-bw1-350hz-clip-b.asc

Edit May 14, 2015: Stereo Pair completed!



Edit Dec 16, 2015: forgot to post final lock-down configuration with Harsch XO:


IR:


Step response:

More info on final setup here: 10F/8424 & RS225-8 FAST Ref Monitor

Distortion:


Group delay about 5ms at 50Hz:


Edit Jan 5, 2018: using passive 1st order transient perfect XO for past 2 years.


Recent implementation with film caps and air core:


frequency response and phase using passive XO:


Impulse and step response:


Latest tweaks to the passive 1st order XO with simulation files:
10F/8424 & RS225-8 FAST Ref Monitor - Page 95 - diyAudio





Edit Dec 3, 2018: BOM for XO is here.

Edit: Dec 27, 2018 - Wxn just built a pair using SB23NRXS45-8 and TG9FD-4 with DSP from a DCX2496 here. The results look great and he did a great job on the cabinet:


Nice waterfall:


Edit: Dec. 27, 2018 - I should have mentioned that Aatto built a nice set using the SB23NRXS45-8 with 10F/8424 as well but using a bass reflex box and miniDSP and also with passive XO, but can't remember what he is currently using here:


Also, forgot to mention the nice set with RS225/10F that I built in espresso brown stain - these are working out real well as the WAF is excellent as evidenced by the fact that they are upstairs next to the TV 🙂 :


And of course, here is my current setup. These have been my main speakers for over 2 years now and, I keep coming back them because they sound so nice and balanced. The sharp percussion and wonderful stereo imaging also bring me back. Here they are in my speakerlab, now re-done post basement flooding (back in July 2018) with a new engineered wood flooring, so the echos are a mess and sound treatment is definitely needed now that carpet is missing. Looks nice and clean though - the clutter is building up again (mostly foam core speakers in storage around the corners).


Edit Dec 16, 2019: Thanks to JPS64 for making a super layout for the XO PCB. This will make building this speaker that much simpler.


Edit Dec 21, 2019: new TL floor stander for RS225:
10F/8424 & RS225-8 FAST / WAW Ref Monitor

Measurements of TL here.



Edit Dec 22, 2019: Just wanted to remind folks that there was a design made for this speaker XO with an RS100-8 and RS225-4 here:
10F/8424 & RS225-8 FAST / WAW Ref Monitor



Edit Mar. 20, 2020: Revised plans for the TL in all 3/4in BB plywood.


Photo of the TLs in action next to the sealed version:


Edit March 30, 2020: Vistaton B80 Variant with modified XO



Edit May 19, 2020: this is the XO for the 4ohm RS225-4. You can use your favorite 8ohm 3.5in full range on top. Just make sure it’s 8ohms and adjust R1 to taste.



Edit July 24, 2023: Keantoken developed a crossover specific to the TC9FD-8 to be used in this speaker with the RS225-8. The response looks very smooth and has a wonderful step response. More info here:

https://www.diyaudio.com/community/threads/10f-8424-rs225-8-fast-waw-ref-monitor.273524/page-196

Schematic:


Measured frequency response appears to have 1st order XO near 1500Hz.



Nice stuffing/padding plan collected by GUJoe:

In a joined effort, Bill, Dagfinn and I went into much detail by developing replacement diagrams for MM cartridges, divided into two parts, first the output section with coil, that we called the Generator, and second for the complete Cantilever assembly.
An achievement never realized before to the best of our knowledge.
Having developed the transfer functions for both both parts, we were able to prove that these two parts don't "see" each other, in other words, the external load on the Generator does not influence the Cantilever's movement in any way.
Another benefit by having the replacement diagrams, was that it was now possible to find the optimal load in LTSpice for a specific cartridge as regards to it's FR.
Because being too long to put it in a posting, we have added the results in the attachment as a PDF.

Happy reading,

P.S. A few typos haven been corrected and further explanation has been given to indentation.

I have been playing with WinISD and have decided to attempt to design a speaker with a slot port. This is what I have made in SolidWorks pretty quickly. The slot is 1in x 8in with a total length of 32in measured from the centerline of the port. I included rounded corners to hopefully lower air speed.. I am asking here if this is realistic and if this works. I found a woofer that I could use to tune the enclosure to 25 Hz.
These are supposed to be decent-sized speakers. The total dimensions of the enclosure is 27x13x9.5, this is a section view to show the port path.

Hello Community,

i want to build my own audio setup for my desktop PC.
My idea is to have 1 tweeter and 1 midrange woofer on the left and right side,
completing the setup with 1 subwoofer in the center under my PC monitor.
What I am mainly listening to is obviously music, occasional podcasts and movies.
The audiosignal is coming only from the aux output (single ended?) of the PC.

The speakers:
2x Tweeter => https://www.parts-express.com/Dayton-Audio-DC25T-8-1-Titanium-Dome-Tweeter-275-045?quantity=1
2x Mid-range => https://www.parts-express.com/Dayton-Audio-DC160-4-6-1-2-Classic-Woofer-Speaker-295-309?quantity=1
1x Sub => https://www.parts-express.com/Dayton-Audio-SD215A-88-8-DVC-Subwoofer-295-484?quantity=1

The IC's I want to use are the TPA3116 for the tweeter and midrange speakers, the TPA3156 is for the subwoofer.
Configuration of the tweeters 2x15W, midrange 2x50W, subwoofer 1x70W.

Now, my first question is...is this even possible, meaning if this is a reasonable setup, does it make any sense what I am trying to create,
leaving out the fact that there are finished solutions for it?

If this all makes any sense, here is what I managed to do in Kicad 6 until now:
Tweeter schematic:


- I am planning to have a couple of external switches to control the state of the amplifiers,
meaning that I have one switch to mute them all and one switch for the shutdown functionality.

- From what I understand in the datasheet the three IC's need to be synchronized.
I decided to leave it to the 400Khz, for the simple reason because the recommended schematic in the datasheet, already does it this way.
How am I supposed to connect those three IC's together, the datasheet makes the example only with two same IC's. I didn't find any citings stating that there is the possibility of connecting more than two IC's togther, so I guess I won't be able to use a subwoofer in this configuration?
Regarding the master IC, which one should it be? I currently picked the tweeter IC as a master.

- My biggest confusion remains on the plimit voltage divider, which sets the output power limit for the speakers.

This is the formula I found in the datasheet.
For Pout, do I need to take 15W or 30W in the calculation?
Rs is the total series resistance, is this the resistance of the speakers on the output + Rds(on) (120mOhm) + the output filter resistance. What do I do if don't have a filter yet, do I need one?
In theory I have all the values required, except for Vp, so I altered the formula to solve for Vp. I got some results and tried to calculate the voltage divider values with the appropriate formula and came to 13,5KOhm and 10KOhm...obviously I do not feel very confident of the result because of the explained reasons above.

- For the supplyvoltage, can I power it all with 24V?

- When the power output of the amplifier changes, do I need to change any output components too? Like the inductors? Do they remain the same if I want to drive a 15W speaker or 50W speaker?

- The endgoal is to have all the components in THT format, except for the amplifier IC, because I would like to solder it myself. Is this a good idea or should I switch to SMD? Does it change anything on the functionality/quality of the endproduct?

These are the questions for now, I also made the schematic for the midrange and subwoofer, but the questions are the same, just for another usecase. So I am going to leave it out for now.

I am also waiting with the pcb design, since I am not so sure what I started here in the schematic...

With the hope that I have chosen the right section of the forum, I would like to thank in advance those who are willing to go through this project with me.

I was following Ian Hegglun's thread "Towards a wideband non switching Auto Bias power amp",
and I was inspired by one of his ideas - Alexander-type input stage and VAS based on op-amp LT1223.

I wasn't familiar with this op-amp, as it seems too fast for typical power amplifier.
There is no point to use expensive ($10.00), high slew-rate op-amp, just to throttle it
later on in order to make the amp stable.

But, if it's driving VAS not from the output, but via rails (like Alexander amp),
the whole amp is more stable and less temperamental.
This amp here shows slew rate of well over 200 V/us, and it's a very simple schematic.

My past attempts show that it's very difficult to actually build stable amp that
can achieve slew rates over 150 V/us. This is first amp I see, that shows phase margin over 75, and
also decent gain margin. In the sim, it seems to be solid, well behaved amp.
So I think I'll give it a try.
First, I came up with LatFet version (dual-die Exicons ECW20N20 & ECW20P20) - that's the one I'm
going to build, and later on with HexFet version.
Both versions show similar results in LtSPice.
Noise floor (1kHz FFT) is at -280dB, and all harmonics are below -120db (inaudible).

Update 29 March 2025: Based on the actual build, C4 should be removed. With it, amp had tendencies to oscillate (when using LT1223).
I keep it in the schematic, purely for the simulation purposes. Apparently LTSpice sim is slightly disconnected from reality.
Also, gate resistors have been changed to R2: 220 Ohm and R3: 100 Ohm.

Update 30 March 2025: If using different op-amp, C4 should be present (2pF).
The following op-amps have been confirmed to work correctly (besides LT1223):
LT1357, TLE2071, TLE2081, AD711, OPA134, LF356. These op-amps were not simulated in LTSpice, just confirmed that they seem to work OK
in the real amp. The schematic and sim may not be optimal for these op-amps, so there might be some space for improvement
if using non-LT1223 op-amp.

Update April 2025: Actual amp has been built and finished. See Post #47.

Update April 2025: HexFet version has been built and tested. See Post #55.

Hi,

I'm trying to offload several DIY audio parts and even a pair of full speakers. I will charge actual shipping/insurance costs to your destination based on your preferred shipping arrangement (coming from Aurora CO 80016). Here are the items I have for sale:
$1000 - DIY Aleph J in 5U Chassis
$1000 - DIY Bookshelf Speakers with 15W/8530k-00 ($220/ea retail) + Seas Millennium ($482/ea retail) + Jantzen Crossover
Free - Pair of planar magnetic tweeters of unknown manufacturer - will ship with first person to buy > $100 worth of gear from me
$110 - Pair SB Acoustics SB17NAC35-4 (1 impedance measurements never mounted + 1 BNIB)
$180 for 4 or $100 for 2 New Peerless HDS 830875 Midwoofers (1 taken out of cardboard to look at but never mounted or measured)
$180 for 4 or $100 for 2 used Seas ER19RN-TRD mid woofers (These were in surround sound speakers for about 2 years)
$80 for pair of GRS PT6825-8 8" planar mid/tweeter (new)
$70 for pair of GRS PT6816-8 8" narrow planar mid/tweeter
$80 for pair of Dayton RS52AN-8 2" Dome Midrange (new)

$2300 for all OR
$1500 for all except either the Aleph J or DIY bookshelf speakers

While there is a bit of ambiguity purchasing a DIY loudspeaker designed by me. All I can say is that these sound excellent. Except for overall output level, everyone who has listened to the bookshelf speakers prefers their sound over the pair of Kairos (Jeff Bagby design) I built previously. They image very well and don't require any EQ to my ears unless I use them in my office as desktop speakers. I've built lots of speakers from LX521, Troels "The Loudspeaker" and really find their sound signature second only to the LX521. "The Loudspeaker" was fun because it had no practical output limit in a domestic setting. Of course they are 5.5" drivers so best crossed over to subs if you want to play loud but without or for near field they sound fantastic. There is just something special about this pairing of great drivers. I've attached the final simulated response captured as a screenshot. I can provide design files in SoundEasy but can't launch the app anymore due to lack of support on modern computers. If I remember correctly I did end up padding the tweeter down a little more by ear but you can always manipulate L-pad to your liking.

Likewise the Aleph-J amp is in the DIY Audio Store deluxe 5U chassis and is a beast. I really like the sound of the amp but have been using Hypex plate amps for my recent builds so it's been sitting around. I've used it a bit in my home studio but it's really just too big (and runs too hot) for that space. I had a 300b amp running "The Loudspeaker" but changed to the Aleph-j in that application (I sold those speakers a while ago).

For references check out my eBay/Reverb rating (user jf4828 on both). I'm happy to do transactions through those platforms if you prefer but would have to charge a bit more to cover selling fees....

I'm happy to snap some more photos if needed; just let me know what you'd like to see 🙂

Joel

$145 shipped CONUS. These drivers have been mounted briefly, but not seen any use beyond testing.

Hello everyone. My name is Andrés and I'm from Argentina.
I use Google Translate to write and be understood.
Vine a este sitio buscando información, ayuda, consejos y curiosidad.

Hola a todos. Me llamo Andrés y soy de Argentina.
Hago uso del traductor de google para redactar y que me entiendan.
Llegué a este sitio en busca de información, ayuda, consejos y curiosidad.

I'm looking for a schematic of a transistor amplifier. This isn't a push-pull amplifier. It's a different setup.
I've attached a simplified diagram to clarify the order.

Unused. $75 shipped CONUS

Brand new. $60 shipped CONUS or $45 local pickup in Dayton Ohio

Found

Looking for 1 complete crossover & mounting plate for the Realistic / Radio Shack Nova 8B or Optimus 5B speaker system. Prefer a complete one with uncut wires. Will take a pair if necessary.
Thanks!

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Crimping is king these days.

I am considering two DACs one (ZEN Air DAC) uses the Burr-Brown Native DSD1793 DAC chip; the other one (Topping DX3 Pro+) uses the ESS ES9038Q2M chip. Which one is better?

Hello all and thank you in advance for any advice you can give!

I'm a long-time music lover but relatively new to tube audio equipment. I built both the TU-8200 stereo amp (currently running KT88's and with upgraded caps) and the TU-8500 preamp. This stereo is used 99% for phono input (Project Carbon Debut EVO with upgraded sub, platter, and cartridge). Currently running through Fostex BK-16 Folded Horn spearkers I also built.

I've been generally very happy with the sound. The volume is ample for my moderately sized open living room/kitchen. I rarely use this stereo with headphones.

However, lately I've been reading a lot about 300B tubes and other options and the TU-8900 looks really intriguing. I am wondering, how much of a difference am I going to notice trying out the 8900 with my setup. Open to trying different speaker and/or preamp options in the future, but the first step would be the new amp.

For reference, my musical taste is varied but a large amount of what I listen to is both old and new soul and funk with a healthy amount of fusion and jazz thrown in. Lettuce, Tower of Power, Stevie Wonder, Bill Withers, Weather Report, Earth, Wind & Fire, Amy Winehouse, Khruangbin, Donny Hathaway, The Meters, Otis, JB, Aretha, Herbie, well, you get the picture. However, I listen to a fair amount of other stuff, occasional hip hop and electronic music, jazz, psychedelic, etc. I grew up on classic and 90's rock. I don't listen to rock as much anymore but occasionally throw on things like Led Zeppelin, Pink Floyd, Soundgarden, Alice in Chains, Radiohead, Flaming Lips, etc. Rarely play classical and occasionally some folksy stuff (Dylan, Joanna Newsom, Joni Mitchell, Cat Stevens, etc.).

So I guess I'm asking if, for my musical tastes, will the 8900 offer something above and beyond what I already have? If so, for the music I frequent, would 300B or 2A3 be a better choice? At the price of these tubes, it would get a bit costly to do much tube flipping.

Thanks again!

Best,

Josh

If anyone’s got some spare BF862s (not the sketchy ones from eBay - tried those, definitely not legit), I’d be happy to buy at least 10 pieces.

Hi people 😀

I have necessity to build a kit similar to this
http://www.siliconchip.com.au/cms/A_101145/article.html
For the dog of my neighbor. (I cannot sleep anymore 😡 )

what type of piezo tweeter can I use?
which is it the maximum power that I can use? 😕

I have to look for datasheet of the manufacturer..

Folks:

Does anyone know of a source for Aikido Noval pcbs aside from Glassware? Glassware has been out of those boards for months, and my many emails to Mr. Broskie (all with some variation of “Tube” in the subject line) have all gone unanswered. I have the Gerbers for the Octal variant but would prefer to build a Noval Aikido. If the Gerbers are available, I would happily have boards made.

Thanks in advance!

Regards,
Scott

Dear friends,
there are many enthusiasts of loudspeakers building here so I thought this link would be very useful for someone.

http://hificompass.com/en/speakers/measurements

It is needed to register at the website to have an access to the speaker drivers compare feature.
With no registration one can click on driver model name in the table and get to the speaker driver measurements page.
There is the mesurements description above the table. Just click on it.

To moderator - sorry if I place this thread in a wrong place, you can transfer it in the correct place.

Best regards,
HiFiCompass

Hi All,

I'm Brendon from Perth Australia.
Thank you for welcoming me into this community...

I'm a newbie in the audio world and look forward to learning more a d enjoying the journey.

The most important thing in an EMI filter are the coils, these must have a particularly high permeability and a very low internal resistance, smaller coil values and very large X2 capacitors are best in order to achieve a lower cutoff frequency of the filter, be careful with Y capacitors, too high values can trigger the FI!

The last picture shows a Chinese DC filter and EMI filter board, which sits directly in front of the transformer in a ChipAmp amplifier.

I had a few of these laying around.

6 sets are allocated to Poland.

The rest are up for grabs.

$10/each .+ shipping at cost.

R

Rod's instructions say "a 0.5°C/W heatsink for normal hi-fi use if the quiescent current is maintained at the minimum recommended of 20mA."
I don't know what to do with that.
This is the heatsink I was considering and I found this calculator, but I'm not sure what value to use for Ts (max).

Hi there !

After an attempt to design a bluetooth DAC, with questionable technical choices, I decided to be reasonable and make an S/PDIF version.
The DAC is still based on the PCM5102A chip, without additional preamplification stage, and the 100x50mm 4-layer PCB receives one ground plane per layer, connected together by vias.

I will use this module for S/PDIF to I2S conversion: https://www.audiophonics.fr/en/inte...spdif-to-i2s-dir9001-24bit-96khz-p-17274.html
For volume control, I'll use this: https://www.audiophonics.fr/en/preamplifier-modules/motorized-volume-control-board-50k-p-15006.html

From what I understand, the DIR9001 module will synchronize to the S/PDIF clock, and the PCM5102A will also synchronize via the I2S bus. I still connected the MCK pin of the DIR9001 module to an oscillator, so the DAC should keep running correctly without an S/PDIF signal, because my Tripath amp does not like to operate without a source.

I placed an LC filter at the 12V input because the DAC will be powered by an external SMPS power supply. Please tell me if the values of this filter are correct.
As advised for my previous design, the low noise 3.3V LDO is cascaded to a much larger 5V LDO to lighten its workload.

As this design was quite conventional, I couldn't resist adding a quirk, a high pass RC filter, for optional use.
Indeed, I chose the PCM5102A because it is the only decent DAC chip that I felt capable of implementing, being a beginner. But I know that it tends to be a little too generous in low frequencies.
So I added this high pass RC filter which cuts at 48Hz in the hope of being able to obtain more controlled and clean bass, if the need arises. I can use capacitors with significantly different values to fine-tune the filter. Let me know if this is a bad idea 🙂

EDIT : I just saw a big error on my high pass filter which in reality is a low pass 🤣. I am going to correct this and I am thinking of using a relay in order to be able to bypass this filter easily.

And here are the pictures :

Looking in another thread whith an unusual current limiter an idea struck me.
Here is a simple current limiter working on the base current of the output transistors.
Of course there is some potential problems. We must have output transistors with a known current gain jus as well as the drivers and the limiters.
And when the base current is limited the fast switching will also be limited. But it is simple and nearly fits a SOA with max current at low voltage for the output tranistor and 0 current with max voltage. If the current gain is 100 for all transistors max current is about 15 ohm from full voltage. Max current 5,3 A in this case and the half with the output short to ground.
The IS 1 and 2 is just for DC simulation.

I'm planning to build the above crossover and have a 25ohm rheostat I'm hoping that there is some way to use for P1.
Is it possible to sand a portion of the metal rheostat body and solder the 15ohm resistor to it as a 3rd lug, or do I just
need to purchase a wire wound 25ohm potentiometer with 3 lugs? Rheostat in question is pictured below.
Thank for your help.

Hi, my name is George, living in Germany.

I am looking for interesting discussions about audio/hifi equipment and sound improvements that I can use in my home.

Hello,

I'm searching for the latest firmware for my Marantz NR1504.

The reason?

Certain internet radio stations don't play anymore on my Marantz NR1604 and NR1504.

For the NR1604, I found, asked and received the firmware on this forum. Thanks again. And this solved the problem.

So I'm looking for the firmware now for the NR1504.

Many thanks in advance!

Stijn

I'm finally restoring my inherited Quad 303!

I'm following this guide:

https://www.rs-online.com/designspark/refurbishing-a-classic-quad-303-amplifier

I've replaced all the capacitors and everything went good 😉

Now to the problem:

Adjust RV100 for 33.5 volts between tags 5 and 9

One of the channels gives me an irregular reading of 38-41v with the pot all the way up. With the old pot setup it was reading 60v.
I only had to make minute adjustments to the power supply pot and the other channel.

What do you guys think is the culprit?

I'm a noob with a soldering iron.

Hi!

Back with a Sony TA-F770ES. The pour thing has blown its output mosfets.
These 2SJ200/2SK1529 seem pretty close to the 2SJ115/2SK405 in the Luxman LV series that I successfully replaced with IRFP340/9240 with only very minimal modifications. I know from experience that these Sony amps can be pretty unstable, is there anyone that has tried this replacement before and/or can simulate what results this would give and if there are any mods that have to be done to the bias circuit for example ?

Thanks !!

I have been using the excellent and free software package called REW and a sound interface card (or DAC/ADC) to measure my amps for years now. It’s fast, easy and really costs nothing if you have a sound interface already. REW is normally used for measurement of speakers with microphones, however, it’s interface, GUI, and math engine are top-notch and lend themselves to an excellent amp measurement tool. I have been asked numerous times via PM’s to assist DIYA members make their own measurement setup using REW. Recently, I was asked again in the M2X thread when I chimed in that one doesn’t need expensive dedicated distortion analyzers from HP/Agilent/etc. all you need is a decent sound interface and REW. Plus a dummy load resistor and some wiring.

First of all, I want to thank member John Mulcahy, the author of REW - what a wonderful gift he has given to the DIY community. He is also always there to answer as technical question on REW.

So what can a sound card and REW do for you in terms of audio distortion measurement? Here is a typical FFT spectrum that I took using a $99 Focusrite Solo USB sound interface and REW with the Alpha 20 amp. This is 2.83vrms into 8ohms:


The plot above tells us several things about this amp: it has a dominant second harmonic distortion signature (sweet sounding), it has a little third order (gives it some bite), it’s devoid of higher orders, or higher odd orders specifically, which can sound fatiguing; it has an overall low level of total harmonic distortion (as seen in onset window); the mains noise at 60Hz and 120Hz is essentially zero - that is, it is very quiet and hum free; finally, the noise floor is about -110dB below the signal so it has very black blacks.

How hard is it to take this data? Well that’s the purpose of this thread. To show you how easy it is to do.

Another example of how REW can tell you how to tune your amp to achieve a harmonic distortion profile of interest. Some amps have this variable knob that lets you tune the type and level of distortion to your liking:

DLH Amplifier: The trilogy with PLH and JLH amps

Here is an example of measuring a preamp driving a 7k ohm load, this is the Aksa Lender putting out 20Vpp into 7kohms:


So where to begin? Let’s start with getting a copy of REW on your computer. Works on PC or Mac but I am only familiar with the PC version. Go here to download REW, and while you are at it, please donate some funds to John Mulcahy to continue his excellent work.

REW - Room EQ Wizard Room Acoustics Software

Once you install it, install software or drivers for your sound interface. I have used even the built in sound card in a PC to do this and it can work. However, those are generally very noisy and you won’t get the nice -130dB noise floor that some standalone interfaces can achieve. I personally use a Focusrite Solo (2nd gen) and 2i4 (2nd gen). They both have the same ADC’s but the 2i4 has a front end that is more flexible. I also think it has slightly better low noise characteristics. But you can use any sound card as long as it is supported by REW - and that includes any Java supported card. I haven’t found one that is not supported yet.

Next step is to connnect your interface by plugging in the USB cable, for example. Some of you might have other interfaces. The go into the setup menu and configure the sound interface. I typically the non-ASIO interface as I find that more finicky to work. Then choose your input device as your sound card and your output device as your sound card. Choose input and output amplitude to be “Master” and set to amplitude of 1.0 - this lets the full signal be generated by the sine wave generator and the full signal be captured by the ADC.

On the input settings choose the channel where you will connect your amp’s load resistor. Channel 1 is typically the “Left” channel and channel 2 is “Right”.

At this point you can see what the inherent self noise of your sound interface is without anything connected. Click on the “RTA” button along the top. In this dialog, click on the gear to adjust the settings. I use something like this:


You can try other settings. Making the averages smaller like 0.88 exponential and choosing 32k points will give you almost real-time updates to the FFT. You need to click on the span button to set your range of measurement from say 20Hz to 20kHz. On the vertical scale button on upper left click on dBFS. Then click on the red button to acquire your FFT spectrum.

You will see a relatively flat spectrum (hopefully) but this will tell you what the noise floor of your setup is. A cheap built in sound card on my pc only gets -110dB. The Focusrite get -130dB. There are ways to achieve better noise floor and much is discussed in threads elsewhere. For many of our SS amps around here the typical noisefloor of the Focusrite is fine as distortion is typically no lower than -100dB abd typically -80dB or so.

This is all fine and good but how do we measure distortion in our amps? Well we first need to make a dummy load resistor to simulate your speaker load. You need a power resistor with the same impedance as your amp that you are testing. Typically 8ohms or 4ohms. It also needs to handle the amp’s power output. A good one is a metal shelled 25w resistor mounted to a heat sink.

Here is an example of one with the wires you will need to make to connect it to a sound interface:


Here is a sketch of how to connect your load resistor to the sound interface and the PC:


For measurements of amp power up to 1w (8Vpp) it’s ok to connect the dummy load to your sound card directly. However, if your amp ever had a burp and hits the interface input preamp with too much voltage it can fry the input stage. I would recommend adding a ~10:1 voltage divider using a 20k and 2k resistor and taking the middle node attenuated output as the signal to your sound interface.

Edit May 10, 2024: circuit for floating balanced input needed for bridged class D amps here https://www.diyaudio.com/community/...ion-measurements-with-rew.338511/post-5925805

Also, if you are using Class D amp, you need a steep filter to keep the high frequency noise out while not distorting the low frequency to prevent aliasing the data. I used the filter suggested by Voltwide/Bucksbunny here: https://www.diyaudio.com/community/...ion-measurements-with-rew.338511/post-6714709



Depending on your sound interface, they may be good for 20v max input so that would give you pretty good protection. Never put full 25wrms (40Vpp) into your sound interface unless you want to fry it.

Now you need a way to generate your 1kHz (or whatever frequency you like) excitation sinewave. You can use the audio output of your sound card and the built in generator in REW. Then connect the audio out of the sound interface to your amp’s input. Adjust the level using the amp’s volume knob if you have one or the knob built into the Focusrite or the level in the generator interface.

Another way is to use an independent reference frequency source. A dedicated low noise high precision generator from HP is expensive. You can use a digital audio player with a good DAC as your source. I use a Cayin N3 which has the excellent AKM4490 DAC. Create a 1kHz sound file in lossless flac format using a program like audacity. Then play that into your amp as the excitation source. Those has the benefit of decoupling your source from your measurement to avoid ground loops. Especially if the source is a battery powered DAP. It’s also typically quieter.

So now connect your audio source to your amp, connect your amp to your dummy load, connect your audio interface to the dummy load, and connect a DVM to the dummy load and set to AC volts. Increase or decrease the amplitude of the 1kHz sine wave until the DVM reads 2.83vac. That’s same as 1w into 8ohms. A typical standard at which distortion measurements are taken.

That’s all for now. I will update later as I did this post with my phone and will get back with more details. But this should get many of you started.

Update June 3, 2019: Here is a loopback using Focusrite Solo gen2 and Akitika 2ppm 1kHz oscillator at 1.0Vpp into 10k:


Update Sept 24, 2020: member Wtnh made a very nice and useful schematic and connection diagram for us to use. Although he used an EMU sound interface, a lot of it applies to other sound interfaces as well (like Focusrite, or any other with combo XLR/TRS balanced inputs):