Salas DCG3 preamp (line & headphone)

[vgeorge]

Nice build. What value volume pot are you using?

A 20k with smd resistors. Not the best but it does it' s job.
Need to say that I am really happy so far with it.
As a preamp it has to drive double runs of 6 meter cables to the amps, a combine load of about 8k. Bass was much improved, as well as resolution and impact of presentation, at the same time not being harsh at all.
Also could drive my cans, AKG712 pro with ease. Will listen more and come back.
Also it is set for 2X gain, as I do not need more.

 

[mlackey]

DSTB question

Salas, do you think the DCSTB could be used (in another application) at 0.5A to, oh, maybe 1.0A per rail?

 

[Hikari1]

What gain would you guys recommend for 89db speakers and a pass f5 (15db gain)? Iam thinking 3x or 4x but I'd like to use it for headphones too...4x might be a little much with grados, 3x might be a little low with the f5. What do you guys think?

 

[Salas]

Salas, do you think the DCSTB could be used (in another application) at 0.5A to, oh, maybe 1.0A per rail?

Yes if the sinks will be handling it the MJEs can have enough Hfe up to 2-3A

 

[Salas]

What gain would you guys recommend for 89db speakers and a pass f5 (15db gain)? Iam thinking 3x or 4x but I'd like to use it for headphones too...4x might be a little much with grados, 3x might be a little low with the f5. What do you guys think?

Nothing stops you to choose 3.5x for instance (1.25k/499)

 

[Salas]

P.S. 4x was practically fine for control on 82dB panels and 19.5dB Cubie2 at a friend's system btw. So 3x might still work alright for F5 on 89dB speakers?

 

[Hikari1]

Good to know. Thanks Salas.

 

[Salas]

The presentation was effortless, even for the most demanding program material and did not cause fatigue even at the moderate SPLs that we were enjoying.

We were listening to 98dB peak at four meters distance on many tracks as I measured today for the same pot position. That's 104dB at 2M or 110dB at 1M from point source loudspeakers.

 

[Dimdim]

OK, scratch that "moderate", replace it with "serious".

It did not feel like 98dBs. That's one more hallmark of a very good system.

 

[Salas]

Average was 87-91dB at four meters but the peaks were sneaky high. Not difficult to peak there with moderate power and 94dB/W/M speakers. But there are worse... Vgeorge's horns in that picture are 100dB+ sens for instance.

 

[ammel68]

Another question...do the electrolytic caps have to be 100uF or will 220uF work?

I already have quite a few quality 220uF caps with 5mm LS, but I can purchase the 100uF Panasonic FCs if need be.

Thanks.

 

[Salas]

Possibly but untested.

Happy new year to all!

 

[zman01]

Happy New Year!

 

[ammel68]

Possibly but untested.

That doesn't tell me much. Why would more PS capacitance not work?

Happy New Year.

 

[massimo]

Retsina is the trademark folk wine of old Athens. Was everywhere in taverns and associated with music. Some are holding the opinion it is a wrongly underestimated unique wine, some can't stand it. Your mileage may vary.

-OT mode on-
I'm not a Retsina fan, but I recently read that the Restina 2013 made by Costas Kostantakis in Milos island is simply marvelous, totally different from the cheap wine often seen in taverns.
-OT mode off-
Happy New Year and happy listening!

 

[Salas]

That doesn't tell me much. Why would more PS capacitance not work?

It will basically work but it will also start the phase turn lower in frequency for DCSTB's output Zo characteristic curve and I haven't tested for possible influences in sonics beyond the parts values I recommend.

 

[Salas]

-OT mode on-
I'm not a Retsina fan, but I recently read that the Restina 2013 made by Costas Kostantakis in Milos island is simply marvelous, totally different from the cheap wine often seen in taverns.
-OT mode off-
Happy New Year and happy listening!

Because Jesper and the following posts influenced me I asked for a better than mainstream one in a local wine store and I had most of it yesterday. More refined taste. Very light in the head it also proved. Happy new year again

 

[massimo]

Kexribàri, looks good, where is from?
Is that a Vasilopita? Who find the coin?

 

[Salas]

Its from Thessaloniki. Yes that is Vasilopita. Isn't cut yet because the others have a hangover and will eat later

BTW kehribari is "electron" the fossil resin in ancient Greek speak where the word electricity comes from due to its high static build up when rubbed

 

[lykkedk]

Because Jesper and the following posts influenced me I asked for a better than mainstream one in a local wine store and I had most of it yesterday. More refined taste. Very light in the head it also proved. Happy new year again

Upss i am sorry Salas ... Myself had way to many weissbeer's yesterday, along with this Restina; no more than looking at newyears skijump it will be today i think!

Garmisch-Partenkirchen - New Years Skijump - Enjoy the flight into the New Year!

Jesper.