Salas DCG3 preamp (line & headphone)

Seanwu did use a MUSES. Look back in posts #1650 #1808 #1924 #1929.

That LDR can change impedance via software so Manniraj can test several values to his own liking.

Thanks for pointing out. I'm really happy with LDR (which eventually be inside this pre of the friend of mine) and as I've written comparing it with a relay based one with standard Dale resistors, it seemed like the LDR cleared up some kind of distortion. So I guess the quality of resistors is very important as nashbap states.
Muse and LDR seem the best choices if remote is needed. A Kozmo-alike with remote and quality resistors is in the 500 $ region.

There are two Muses chip pot kit models I think?

I'm only aware of the MUSE 72320 that is discussed in the analog line section.
 
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Savvas, even with the op-amp installed, offset on my example still varied by 4 or 5mV despite getting matched devices from Tea Bugs(Bag...LOL).
Even after trying different op-amps, which made no difference, I just had to live with the varying offset on both channels.
Q1 Q2 are free or bound together with heat shrink / zip tie? You changed between different Jfet input op-amp types, or between different samples of the same type? Tried with another DMM? Some are jumpy in their mV range.
 
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Yes, I use the MUSES pot and have no problem with it.

I like MUSES although I did not compared it with other pot. The sound is clean and no balance issue.

I am using SONY MDR-CD900ST headphone. Really love the sound quality of DGC3.

Never seen that model in Europe. Is it a Japan only studio headphone? Better than the usual SONY professional models?
 
Savvas, even with the op-amp installed, offset on my example still varied by 4 or 5mV despite getting matched devices from Tea Bugs(Bag...LOL).
Even after trying different op-amps, which made no difference, I just had to live with the varying offset on both channels.

Don't know, I thought it's normal, even when playing, in both preamps dc offset stays below 1mV most of the times.

Come to think of it, Tea Bug is so, so .... exotic. :D Rather be a bug than a bag.

So far, I'm very pleased with BIB powered DCG3. More depth, background organs are more well-defined, dynamics are missing though but it's only 50 hours till now and some parts need replacing like the 10mf I'm waiting instead of the 4.7mf I'm currently using

I've got to go back reading about MUSE chip from the other thread, still haven't figure out what I should go for
 
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Have had up to 2mV on one channel only with an AD823 sample that its next one sample put below 1mV and with all my OPA2134 samples it was always low, same low with the humble TL072s and their better TLE082s. The OPA2604 was behaving too. Maybe the initial sans op-amp offset procedure needs revisiting in some cases.
 
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MDR-CD900ST

Yes, it is a Japanese only studio headphone. It seems not available at ordinary retailer. However, not too hard to find here in Taiwan.
I've heard that it is quite popular in Asia recording studio.

Stated as very efficient too and not folding like other SONY I see. 106dB/mW at 63Ω translates to 118dB/1V. Will be at 120dB SPL with only 25mW. Can you hear any hiss at max volume? I couldn't hear any with the very efficient Sennheiser HD8 DJ at least. But those are HF drooping. SONY are usually peaking somewhere in HF. Is it more expensive than the ubiquitous MDR-7506? Using a Japanese Muses kit with Nichicon Fine Gold caps on it and Japanese market exclusive meant headphones, you are surely treated into a dose of Japanese audio culture tone :)
 
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Could there be some bugs in the Excel BOM?

  • CMF551M0000FKR6 are for R12 and R13 -> thats 4 instead of 2 peaces?
  • BF256B are for J3 -> I do not find J3. Is it Q5, perhaps?
  • MKS2C041001F00JSSD is for C4 -> Is it for C3, too?

I have updated the spreadsheet.
Correct on 1M resistor, 4 pcs should be in kit.
Correct J3=Q5 on board
Correct 1UF63V wima if C3,C4

:)