Pass B1 clone. Configure for some gain?

[Colin151]

Was wondering if anyone had any ideas about this.

I have a Pass B1 buffer clone (the version with the green 2008 R0 circuit board) and was wondering if there is any way to wire it so it gives some gain?

If anyone has any ideas I'd love to hear from you.

Cheers
Colin

 

[Zen Mod]

no way , José

😉

for gain , include JFet BOZ in front of it

 

[Colin151]

Sorry for the dealy in replying and thanks for the info.

The JFet Boz looks good. Plenty of gain. Might as well use it without the B1 afterwards. Do you know if the boards on Ebay alright to use?

Cheers,
Colin

no way , José

😉

for gain , include JFet BOZ in front of it

 

[Zen Mod]

sorry , I never looked

make it on Veroboard

 

[dazed2]

Following up on ZM's suggestion, I have a question.
Is there a reason to have the JFet BOZ with the B1 behind it?
Since the JFet BOZ already is pretty much a pre-amplifier circuit, is there any reason to have a buffer in the way?

 

[Fenris]

JFET BOZ has a high output impedance. The buffer improves it by giving it a low impedance.

 

[Hikari1]

You don't need veroboard or a pcb. It's a pretty simple circuit.

 

[lorienblack]

Looks like an ideal solution for getting some extra gain for my b1 and phono stage, in need of some gain.

What is the gain from this? And would you recommend a good value for the caps?

Appreciate your feed back on the performance of the BOZ 🙂

Cheers

 

[BigE]

no way , José

😉

for gain , include JFet BOZ in front of it

What do you do with the pots of the BOZ/B1?

 

[Zen Mod]

pot is always in front

so , selector - pot - BOZ - buffer

 

[BigE]

So buffer always running flat out. Thanks!

 

[woody]

Now Tubecad did talk about how a unity gain buffer might be rewired for 6db
of gain. Might be interesting to try this with the B1. Just return the output directly to ground and make the center of the power suply now become the output.

 

[Hikari1]

Looks like an ideal solution for getting some extra gain for my b1 and phono stage, in need of some gain.

What is the gain from this? And would you recommend a good value for the caps?

Appreciate your feed back on the performance of the BOZ 🙂

Cheers

If I remember correctly i think its about 25 gain. Cap value is 10uf. Jfets need to be matched and source and drain resistor values may need to change based on jfet idss. Runs at about 16v rails...you may be able to use your psu from the b1 although the jboz will be more critical of the supply quality. I used 12 aa batteries. With only 2 active devices the draw is pretty low.

Sound is good but its a simple design that is not the ultimate preamp. I liked it in front of an f5 betterr than a passive pre. I have since moved on to a pass ba3 front end pre. Its better. I adssume zenmods pre or jumas pre would be better too. But the jfet boz is good. Just lacks a little refinement and detail.