Salas DCG3 preamp (line & headphone)

[Russellc]

Well spotted . The third is for the muses volume attenuator and input selector board.

What muse did you get? I just received a box from Academy. It has instructions to mate it to BA 2018, what changes if any did you make using it with DCG3?

Russellc

 

[luckydork]

As usual, you are the Oracle of audio knowledge, thank you. One more question, recently I pick a few BC337-4 for emergency use, are these a drop-in replacement for the BC-550?

 

[Salas]

Yes drop in replacements in this circuit. Same attention must be paid to their beta matching of course.

 

[freebee]

What muse did you get? I just received a box from Academy. It has instructions to mate it to BA 2018, what changes if any did you make using it with DCG3?

Russellc

Unfortunately I have not been able to get it to work. Please let me know if it is worth the bother 😉

 

[voxxonline]

I have dual rail bench power supply. Would like to test each psu in isolation. Can you please advise how to connect it?
Thanks, and sorry for asking such a noob question

 

[Salas]

To create symmetrical voltage from bench PSU you select series mode. The master channel settings are mirrored. The user's manual explains which output posts to connect as +/- and midpoint.

I am not sure on what exactly you want to test though. Please elaborate.

 

[voxxonline]

Thanks. Just power up power supplies first, then connect everything but use the current limiting bench psu instead of transformers.

 

[Salas]

Alright. That's a valid way to test PSUs when without transformers. AC rectification section is being skipped. You should connect the incoming DC at suitable points after the bridge diodes.
When having transformers the simplest current limiting device is a good old dim bulb tester between them and the mains.

 

[voxxonline]

Thanks Salas. I am aware about the dim bulb option. Happened to have a bench psu to safely power up my amp build as well as dcg3. Still need to learn how to use it properly 🤪

 

[Salas]

Which model is it?

 

[voxxonline]

Gw instek gpe 3323

 

[Salas]

You set 25V and what current limit you prefer on CH1, you select Series on the black buttons, you connect Master + to DCSTB F1, Master COM to DCSTB CT, Slave - to DCSTB F2, you press the green button ON

 

[voxxonline]

Thank you

 

[voxxonline]

 

[Salas]

No. You should skip the left and right AC connector points directly to the fuses which are located after the bridge diodes because its DC you feed.

 

[voxxonline]

I did not realise you meant literally to f1
Dc is at 35.25 v now

 

[luckydork]

Hi Salas, sorry to interrupt, so its ok to feed DC to the fuse without first taking out the bridge diode?

 

[Salas]

Yes that is a right way. 35.25V/2=17.6V per rail which is more likely. Check symmetry between + common and - common at the output. It should be near but not dead on symmetrical.

 

[voxxonline]

By symmetry you mean comparison between V output of two psu's? One is 36 dead on, another is 35.2

 

[voxxonline]

Will watch each board until voltage settles. So far I have approx .86 v discrepancy with 4.3 mA across rY. This translates into 200 R ?