DIrect coupled(DCB1) buffer build

[sachu888]

Hi,
just completed our version of DCB1 buffer. I was using Pass B1 buffer with LDR volume control since last 2 years.I have heard many expensive preamp,but none could come close to B1. I only heard only good things about DCB1.My friend and FM Omishra designed these PCBs.I ordered few PCbs for group of friends. It really takes B1 to another level,highs are clean and clear with good bass ad mids.Its very simple to build with very less components. It can be run with 2 X 9V batteries. I am running it with my OPS power supply @ +/-10 V. see few pics before.Enclosure is just for checking it quick and dirty.
Few pics :





Regards,
Sachin

 

[Binkman]

Interesting; Another creation.

Am I wrong but do I see two traces for potentiometers L and R CCW. CCW meaning the direction to turn the pots 'off'?

The "CCW" printed on the pcb left and right.

 

[sachu888]

Yes Counter clock wise(CCW) printing is correct. Please see back side of PCB


Regards
Sachin

 

[omishra]

Nice one Sachin, what are output offsets with no source connected? Should be <5mV.

 

[omishra]

Interesting; Another creation.

Am I wrong but do I see two traces for potentiometers L and R CCW. CCW meaning the direction to turn the pots 'off'?

The "CCW" printed on the pcb left and right.

That should not be confused with 'CCW' direction, its ground for L & R, which would be pins at which both channel wiper connects at minimum volume position.

In the end it does not need PCB, I built double buffer on vero board or general PCB whatever you call it. It just works fine until you have quite and decoupled PS. DIYA member Salas has build shunt regulator for this. I felt its good to get benefited from OPS, my own leaner PS.

 

[Grainger49]

Hmmm, I may need to do one of these for my buddy who owns a record store here. He already has a CNC. I think he will benefit from a buffer between it and his tube amp.

I'll empty another meat container. (That is what the CNC is in.)

 

[sachu888]

Hi Grainger
You will love it.

Regards
Sachin

 

[earthsounds]

Can I get one?
........Please.

 

[earthsounds]

Hi.
I have two matched jfet pairs , how to fit them?
Matched in q1 and q2 or
matched q1 and q3 ?

 

[omishra]

Matched pairs are (Q1,Q2) and (Q3,Q4). If parts in each pair has slight mismatch then lower current jeft at inner position of PCB (within matched pair). In any case do not break matched pair.


Sent from my iPad using Tapatalk

 

[sachu888]

Jfets should be matched tightly and also your voltage(+/-) should be equal,else you may have higher DC offset. Kindly measure DC offset without connecting any input.It should be below 5 mv.

Regards
Sachin

 

[earthsounds]

Jfets should be matched tightly and also your voltage(+/-) should be equal,else you may have higher DC offset. Kindly measure DC offset without connecting any input.It should be below 5 mv.

Regards
Sachin

I have 2 pairs that are nicely matched but the pairs differ from each other about 20%.
Is that bad?

Regards
Rafal

 

[omishra]

I have 2 pairs that are nicely matched but the pairs differ from each other about 20%.
Is that bad?

Regards
Rafal

That is not a problem. In each pair, JEFTs should match. Two pairs must not be matched quad.

 

[sachu888]

DCB1 gets a new Teak faceplate





Regards
Sachin

 

[earthsounds]

Good looking !!!!!

 

[earthsounds]

What's inside ?

 

[sachu888]

What's inside ?

DCB1, Power supply, R core transformer,5:1 input selector, and LDR attenuator.

Regards
Sachin

 

[earthsounds]

Sorry botrytis.
I thought that since Sachin likes to upgrade his builds, there may be some new things inside as well.

 

[djnagle]

Can't you read the thread? Look before your post - that is what is inside.

That is a little harsh to call someone out in public like that

 

[sachu888]

I am Sorry my mistake. I should have been more clear.

Regards
Sachin