Salas DCG3 preamp (line & headphone)

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Tea when are you planning on closing the GB. I notice you have around 70 names already.
nash

Pretty Soon. I was hoping for a little more momentum for some other boards. They may need to wait for getting a GB for all boards. Small runs means lost $ generally. So it may start this weekend, and Salas and I will have to decide about the other boards. People who really need or want the BIB for instance will really need to raise their hand.

I'm planning to run my DCG3 with 150 mA bias because I will be feeding my Audeze LCD 2 (fazor) headphones with it. Are the stock sinks included in the DCSTB full kit sufficient for this? Should I purchase taller ones? I will be using dual trafos and dual boards.

Yeah, and I'm also curious when Tea-bag is closing the group buy... :D

No, they should be fine, but I could alter a few heatsinks if insisted, since I carry 2" ones for the Reflektor-D. But only recommended for people who want to use one half a DCSTB board, say for a smaller headphone amp. (My son's goal)

Using dual trafo, your 1/2 the current through the bipolar TO-220's that I was doing. And, I am probably running it hotter than recommended according to Salas. The resistor's one may get in the GB might be more conservative.

So let's try to keep GB stuff off this thread and onto the GB Thread.

http://www.diyaudio.com/forums/group-buys/297899-gb-salas-dcg-3-dcstb-power-supplies-new-post.html

As other people start building this board, I will actually try to modify my blog on the board to note differences in parts, order of assembly that may arise not covered under the general build guide.
 
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*By the way DCG3 was designed against no other design. Not even looked to one other design for ideas. Its completely original. Its also not designed with technical perfection in mind. Its just designed for acceptable spec vs few silicon junctions in the signal path.
 
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I tried to record from the DCG3 with a Zoom H2n recorder (line input mode at 24/96) when I still had the board in the open test frame so to post it and give you guys an idea but after I replayed the recorded file through the same DAC, DCG3, HD-600 chain it was evidently below comparison vs the original audition so I ditched the idea.
 
I have some of the Hammond 229D34 transformers for this. I used the Quasimodo, for the first time, and got the following values for the snubber, C2 10nF, C3 150nF and 413 for the resistor. Please note this is the first time I used the Quasimodo and may not have this just right, but hopefully this helps someone.

Jim
 
Goodmorning here.

As a followup on my relay adventure, i just wanna tell that i recieved the last of my parts yesterday, along with some 150mW omron relay's.

So after plugging such one in, the voltage stays on 12vdc on the coil (11.46vdc excatly)

Lesson learned :)

Jesper.
btw. : Thoose relays also claims to be gold clad contactors!
 

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Good late evening here :)

This is the most thrilling part of diy; nearly finish the "raw" build, ready(allmost) for testing dc-offset, and to see if anything blows up !

I did my own amateur layout, copycatted most of Salas pcb, and keept in mind that i had to do it myself, so pcb traces and layout could not be so tight.

I checked and checked and tripple checked that the schematic i had drawn in diptrace was correct, and after the pcb layout, i also checked x 4 or more for errors... But i never can know for sure if it will work... just need a little more work before going into test-mode.

It's nice to do the pcb part i think, but then again i am old fashion :)

All parts are matched up, bias decided to around 100mA - DN2540 two perfect match at 1.010 (~101mA)

BC560 matched, PF5102 matched etc... phyywww...

please :xfingers: for me...

Now its time for chocolate and coffe for the nerves...

Good evening to all here.

Jesper.
 

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diyAudio Chief Moderator
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Hi Salas

What is the function of Rb1 Rb2 3k3 resistors ?

Does the stabilizer need a minimum current draw to work ?

What current does the DCG3 use by itself ?

R-bleeders. Just to have something draining it out when not connected to anything else during tests or when something stops pulling further down the line in an installation.

To work, no. To work very good, pull no less than 50mA from it. You may supplement any low consumption circuit with more aggressive bleeder values. Locally or further away.

5mA per rail for the Leds.