B1 with Korg Triode

[ffarges]

Yes same / trim pots have no effect right now

 

[wapo54001]

Yep I am checking. - the bottom looks clean though ;-)

Go back to the original picture -- you got the IN ground and signal reversed? Or are you using red for ground?

 

[wapo54001]

Go back to the original picture -- you got the IN ground and signal reversed? Or are you using red for ground?

Hmm, sorry, I looked again, looks like you are using red for ground.

 

[ffarges]

Yes I used some left over cable therefore color is not normalized.

 

[jamayfie]

You’ve probably ruled it out, but just for those playing at home: you are using Fairchild jfets, correct?

 

[ffarges]

Yes fairchild from the kit and I put some reference voltage.
Still checking

 

[Zen Mod]

if you don't have 9V1 where it must be, start with that

pull one pin of 9V1 zener out and test it with diode test of your DMM

 

[ffarges]

Yes same results. I removed it and replace by another one (1N4739A 9.1V / 1W) and it doesn’t change - still 0.2mV at T4.
As mentioned I used to have 9.1V when all parts where removed (steps 41, 42 and 43 in the guide. All voltages where correct).

 

[Zen Mod]

resistor in front of 9V1 zener is measuring in ballpark?

approx 270R?

 

[ChrisM91]

Today I upgraded the B1K PSU.

The external 24V PSU is LM317 based, built on perf board with lots of pre-filtering. I also added a half wave rectifier/regulator PSU PCB left over from another project for 12V/-12V for a Muse volume control (when I get around to ordering/installing!).

Still have T7/T8 at 9.5V. Haven’t got around to experimenting yet. Listening to the new RHCP album now and it sounds VERY good!

 

[ffarges]

@Zen Mod - ARG! That was it. 270kOhm instead of 270 Ohm

I manage to find 3x 100Ohm (3W) and tested a frankestein interim. It is alive now at 9.5V on T7. This one will be finish for Easter as a present ;-)

 

[Zen Mod]

 

[ffarges]

@Zen Mod always the same mistakes. My eyes are no longer sharp . Thanks for the pointer!

 

[Zen Mod]

well, talk to me about that

wearing spectacles from my tender age of 15

now, one for general driving and looking at bright side of life, second ones for PC work and looking at bright side of life, third ones for work and reading and looking at bright side of life, and in most cases when working having 2x lens head thingie

good thing is that I'm not much blinder than I was Kiddo, bad thing is that eyeballs are getting elasticity of pool balls



moral of the story - use DMM instead of:

- memory,
-brain,
-eyesight,
-Guru advice,
-etc.

 

[Pilk]

BNIB Korg B1 Silver kit on Swap Meet.

Korg B1 Silver

 

[Nelson Pass]

well, talk to me about that

wearing spectacles from my tender age of 15

now, one for general driving and looking at bright side of life, second ones for PC work and looking at bright side of life, third ones for work and reading and looking at bright side of life, and in most cases when working having 2x lens head thingie

I have 4 also. Pretty much the same thing.

 

[PaulInWA]

I'm curious if anybody knows the brand of the resistors that are used in the B1K? I bought my kit in November 2021. Picture of the resistors in question is attached.

 

[Ben Mah]

I think they are Vishay:

https://www.vishay.com/docs/28722/sfr16s25.pdf

 

[ChrisM91]

Just wanted to say I have now read all 375 pages of this thread


Still loving my B1K with upgraded coupling caps, increased capacitance in the onboard PS caps, a few "nicer" signal path resistors, shielded wire, and linear PS (though I may "upgrade" the perfboard LM317 setup to PCB based shunt regulator down the road).

If I had to do the build again after knowing what I know and reading this entire thread I'd:

• float the 270R resistor (maybe even make it 5W)
• make the 10K trimmers multi turn. The stock single turn trim pots are rather sensitive

Still plan to upgrade the stock pot to an Academy Audio Muse volume control, really curious how that changes the sound. Also need to play around with bias, still sitting pretty at 9.5V

 

[rmpfyf]

Upgrade time. Silly question for the Salas UltraBiB users - what current draw are you designing for? ~200mA counting the extra margin Salas recommends?