B1 Rev. 2

[peppennino]

R1 and R2 are 3w:
B1 r2 proto or prod?

 

[vdi_nenna]

Dont know if its prod or non-prod.
The schem I'm referring to is in post 1 of this thread.

 

[peppennino]

The link is to Papa's post: only 10 ohm res are 3w

 

[vdi_nenna]

Thank you. First time seeing that schematic.

 

[peppennino]

It has been released by Pass on the link I posted on #221

 

[wg45]

For some reason this took a lot longer than it should.

I've got a new favorite preamp. Thanks Papa!

 

[peppennino]

Great, Will! I love it!

 

[chchyong89]

This pandemic is going to drag for sometimes, and since the B1 R2 is a very low power circuit device, I am interested to make one with +/-12V battery powered version with 6 x 18650 3.7V batteries, no regulators, no input/output caps, as straight forward as possible.

 

[Hikari1]

Any unbalance between pod and neg voltages in the power supply will result in dc on the output. Keep that in mind when using batteries or use a cap on output.

 

[brucew268]

Any unbalance between pod and neg voltages in the power supply will result in dc on the output. Keep that in mind when using batteries or use a cap on output.

I'm trying to understand what you mean since all voltages on the output of the power supply are DC, and the trimpot is meant to remove any DC offset?

 

[R-K Rønningstad]

If the rails (+/-12V for example) decreases by battery end-of-life by the same voltages, to e.g. +/-10V and further down, that’s ok. But if one start to decline before the other so that you have +12V and -10V you will have a DC voltage on the output.

 

[peppennino]

If a single battery discharge s more than others, you will have DC at output. I'd change output 100ohm Res with a cap in case of battery operating ps

 

[peppennino]

Sorry R-K, I wrote before seeing your reply (page change) ^

 

[R-K Rønningstad]

No problem!

 

[Andersonix]

Does this DC offset at output due to differing +/- PS rails imply that DC offset can be dialled out by deliberately varying the + or (-) PS rails? Would that be a way of using 'mismatched' jfets and avoiding output caps?

 

[Zen Mod]

varying rails is not exactly effective way of doing that

 

[Andersonix]

Ja, I'm getting the feeling it's safest to just put a cap on the output...

 

[cucuclock]

Hello, I’ve let design some pcb for the B1 rev 2 and I have some pcb spare. If someone is intersted, please pm me.

 

[ENSen]

I have too much gain in my system so I am thinking about using the B1 rev2 instead of the BA-3 pre I am using today. My PSU is +/-24V. Noticed that in the M2x this buffer is used with +/-24V so it should work, right? Or is there some difference I am not spotting?

 

[peppennino]

B1R2 is 12-0-12, not 24-0-24