Salas DCG3 preamp (line & headphone)

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#5,021
Nice stuff. Lots of work and a good looking outcome. The sadly defunct Selectronic R-Cores are a joy to see.
What mono op-amps? You host dcstb rectification on vertical daughter boards, possibly with de-ring snubber components?
Or is it an electronic bridge? No rail fuses? Let us know how you will like it in the sound system for line and cans. Congratulations.
 
#5,022
I have a few of those R-cores from good old times and I must say that they serve me well.

The vertical boards in DCSTB are the rectifiers based on LT4320 a pair of dual mosfets. I started using them a while ago and I am happy with them. Not cheap though.

I haven't tested the trasformer's snubber network yet, but this is possible in this build. All I need is a quick and dirty Cheapmodo build.

Re fusing - I forgot to place them in the design of DCSTB. In fairness, initially I planned to use a different regulators, but realised that DCSTB is so simple to build, so I started with that one. Anyway, when this amp gets its proper enclosure it will get the proper fusing too.

As for the sound, I only managed to listen to it yesterday for an hour or so. The sound does not disappoint! It is really smooth. However it is a different presentation when I compare it with my current headamp. I will need to spend some more time with both 🙂

Thanks again!

F
 
#5,024
This is very FET, with minimal components signal path, very Class A thing, so it owes to sound distinct enough. Take your time.

What type of op-amp you used for DC servo since it has to be single channel chip in your case?
 
#5,025
It's AD823 in SOIC-8 package, but I use only single channel in each chip. I do not think I will be rolling opamps in this build 😉.

BTW: do you know any single opamp that would be good for this amp? I am thinking about the next build that I may do.
 
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#5,029
I have a friend with old K701 made in Austria that he likes them only when driven by the DCG3. Finding them too dry on other gear he says. He had brought them over since my prototype DCG3 was in an open case.
 

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#5,031
frd__ said:
Nice! Same here. I've had my pair for about 12 years. So far I replaced the earpads and changed the regular jack to 4 pin XLR.

I could not agree more about their sound signature. They need a serious amp to produce the full sound.
Click to expand...

There is a mellower wider trend still happening on various headphones when on DCG3 but on the 701s its most noticeable was my experience when he tried to demonstrate what he means.
 
#5,037
Im going to install my pre to a new case, becouse Im switching my psu from DCBTS to 2xubib 1.3 pairs (not enough room on my current case).
This might be stupid question, but here it goes: Can the heatsinks be too effective for the Ubibs to work as they should? And same question for Dcg-3 board.
My bias is 150mA.
 
#5,039
Dual mono SSLV1.3 vs dual mono DCSTB can give something like 10% better subjective result in a well resolving system. Mainly for better bass and midbass phrasing, also for a bit cleaner and sweeter overall result. Needs of box area occupation and PSUs sinking are substantially more. The law of diminishing returns obviously kicks in. You have to decide if worthwhile.

By the way, a shared between channels mono SSLV1.3 PSU scenario would be a poor idea since DCSTB is dual mono already.
 
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