B1 r2 proto or prod?

[WBS]

...But sitting in my rack now is Korg B1 which is a different animal but I like it best of all. It's like wearing 3D glasses.

Oh my! And all this time, this is the one I didn't think I needed...

 

[peppennino]

Waiting for R0 to R2 to K B1 comparison on the same setup, in these two days I'll burn-in the R2 and have some serious listening sessions

 

[peppennino]

It sounds FANTASTIC! 🤩
Big THANKS to Nelson for sharing the schematic! 🍻

 

[peppennino]

Happily chez Benny, at home again

 

[audiosteve]

Waiting for R0 to R2 to K B1 comparison on the same setup, in these two days I'll burn-in the R2 and have some serious listening sessions

I would also like to hear that comparison

 

[wg45]

I've built a B1 R2 using the same board as Peppennino. I've used components with the same values as Papa's schematics.

How do I adjust the P101 and P102 for correct performance? I've read through a few threads but haven't found an answer. Jfets are matched Linear Systems, grade B from the Diyaudiostore.

I'm guessing I adjust P101 for V measuring across R101?

P102 is adjusted for 0 DC?

 

[peppennino]

P101 Is the volume pot, p102 (right channel) and p202 (left channel) are the offset trimmers and should be adjusted for 0 VDC at outputs

 

[wg45]

Thanks, Peppennino! It's very clear.

 

[peppennino]

 

[peppennino]

The second one (mine) will be in more "KISS" style in a simple GX287 case

Bere I am
I'm waiting for R1 and R2...

 

[peppennino]

This time I'll try a simple LT1085+LT1033 as PSU

 

[andynor]

Is the value of R102 critical?

Regards,
Andy

 

[Zen Mod]

R102, ref. to ?

 

[andynor]

R102, ref. to ?

B1 R2, 1M

 

[Zen Mod]

anythng from 470K to 3M3
it's there "just" if volpot starts loosing wiper

https://www.diyaudio.com/community/threads/b1-r2-proto-or-prod.363274/post-6435903

 

[andynor]

anythng from 470K to 3M3
it's there "just" if volpot starts loosing wiper

https://www.diyaudio.com/community/threads/b1-r2-proto-or-prod.363274/post-6435903

Approximately what I thought, damn

 

[andynor]

anythng from 470K to 3M3
it's there "just" if volpot starts loosing wiper

https://www.diyaudio.com/community/threads/b1-r2-proto-or-prod.363274/post-6435903

So, if using a resistor attenuator like the Frontpanel from glassware, I get that this part is probably needed anyways. But will I have a bit more headroom wrt choice of values? Parts bin is dry above 68k.

Planning to try Picos way, got some breadboarda today.

This will of course tell me maybe 2% of what the pumpkin is all about, compared to 0% as is. Plus improve my gain structure.

Regards,
Andy

 

[GndSense]

Bere I am
I'm waiting for R1 and R2...

Hi Peppennino,
I was looking at your cool case for your B1 rev2. I notice the switching and volume pot extensions. How did you do that? I'm wanting to do that with my build and not sure where to buy the stuff that allows you to have knobs on the front of a box but move things or switch things toward the back of the box? I'd appreciate your input. What do you even call the added tubes and supports-- in other words if I went to digikey or someplace, how would i even find those extensions, etc. THANKS!!!

 

[Zen Mod]

hardware store, 6mm material

dunno how it's called in your neck of woods, wire, shaft, stud, bar, rod

heck, you can even use M6 threaded rod, usually sold in 1m length, though proper round 6mm will give less wiggle in front hole

and then you can dismantle old broken pot, and use its front as sleeve bearing for front plate

illustration: https://www.amazon.co.uk/PACK-METRIC-THREADED-STUD-ROD/dp/B07DK9CRG9

 

[twocents]

If I went to digikey or someplace, how would i even find those extensions, etc. THANKS!!!

Here is a thread that might help with ideas and terminology
https://www.diyaudio.com/community/threads/where-to-get-pot-shaft-extension.6366/