Salas DCG3 preamp (line & headphone)

[jimk04]

Great! Not sure whether to go for the 601 or the 2511. Which one did you get?

 

[Crazoff]

Hello. The design of the printed circuit board. My implementation of the possibility of using 2SA970 or BC560 transistors.

 

[Marra]

I was fortunate enough to pick up a 2511 from another forum member. Such a smooth operating pot and good sound to boot.

 

[wolkegeist]

Hi Salas, are there any alternative to DN2540? It's quite expensive to buy a bunch of them and match

 

[Salas]

No, its characteristics are integrated into the design for predictable results. You can alternatively buy only two M3s and tweak R10s for about same bias current in the channels instead of matching Vgs (off) out of many M3s.

 

[Salas]

3 way speakers Nick.

Result is usually drier with BC560s if that's suiting better a system.

 

[hpasternack]

FWIW, twice now I've ordered pairs of DN2540s (from Mouser) and although Idss differed 30% between the pairs, the pairs themselves were very closely matched. I suggest you just order two and you may get lucky. Otherwise, there's no harm in using different R10 values between channels to get equal currents.

Also, a bit of bad news: I see that BF256 is now obsolete and unavailable from the usual sources.

 

[Salas]

BTW prepared yet another high spec U1 chip alternative on an adapter to try later on as DC Servo

 

[Salas]

Also, a bit of bad news: I see that BF256 is now obsolete and unavailable from the usual sources.

ON Semi still lists it as active nonetheless

Products - ON Semiconductor

 

[Tea-Bag]

Also, a bit of bad news: I see that BF256 is now obsolete and unavailable from the usual sources.

I still have several hundred.

 

[hpasternack]

Neither Digikey nor Mouser show a date for a new shipment, but if you want to spend $240, Digikey shows Rochester will sell you a minimum of 3005.

 

[Crazoff]

BF256B ON SEMICONDUCTOR, ????, ?????? ? ??? ???????????

 

[vgeorge]

BTW prepared yet another high spec U1 chip alternative on an adapter to try later on as DC Servo

For me 4625 is a keeper.
This chip is closer to no chip on the dc servo, but let wait for Salas final opinion.

 

[donhughes111]

3 way speakers Nick.

Nick,
can you give us a quick rundown on your speakers. And, the subjective sound quality got better with the DCG3 - correct?

Thanks,
Don

 

[Salas]

BF256B ON SEMICONDUCTOR, ????, ?????? ? ??? ???????????

Since you are making a board you have the freedom to put a Toshiba 2SK209-GR(TE85L,F) surface mount for J3. Watch the pinout and use 1R R3. You can use this SMD as J1 J2 to substitute any suspect uPA68H as well. The 2SK209s usually come close for IDSS right out of their packaging. Keep R1 & R6 physically close enough to their gate pins. For through hole uPA68H or BF256B genuine & sorted out for IDSS, as well as for Vgs matched DN2540 M3s ask Tea Bag for help. He has a stash of proper active parts.

 

[Salas]

Disclaimer:

I can't guarantee that altered DCG3 builds for parts or boards will measure and sound exactly like the approved original, but hopefully they could work satisfactorily enough.

 

[Salas]

For me 4625 is a keeper.
This chip is closer to no chip on the dc servo, but let wait for Salas final opinion.

I listened carefully and I prefer it over the smoother OPA1656 for impact and clarity while both offer a palpable degree of better "analysis" over the older school BOM op-amp. But the AD823 remains closer to the genuine tonality and image size of the preamp when without DC-Servo chip at all which is ultimately the most natural state (precarious mode of use, not recommended).

 

[Salas]

YMMV of course, those are very good op-amps. Used various music genres but on this track comparisons were easier (pun intended)

Happiness Is Easy (1997 Remaster) - YouTube

 

[thimios]

Who can recognise this k117?
I think that is fake.
The seller is Reichelt elektronik....

 

[Nikos]

For me Thimios looks original..