Korg Nutube B1 transistors

[Rogols]

Hi! This evening, I assembled a full kit that I bought three or four months ago. But now I see the transistors in position Q2 are marked differently. They are all marked with J113, two of them also marked with WH44, one KH33 and one KH34. The transistors in the other position JQ1 are all the marked KH35. Have I got the wrong transistors? Regards, Roger Olsson

 

[andynor]

Hi! This evening, I assembled a full kit that I bought three or four months ago. But now I see the transistors in position Q2 are marked differently. They are all marked with J113, two of them also marked with WH44, one KH33 and one KH34. The transistors in the other position JQ1 are all the marked KH35. Have I got the wrong transistors? Regards, Roger Olsson

Naaah, those are probably just batch numbers. Those transistors and resistors are matched by Papa himself, I believe, so just use them and think nothing of it 🙂

 

[Rogols]

Thank you! Then I'll go ahead with the rest of the assembling.

 

[JMFahey]

"J113" is the main identifier; and presumably it´s present on all.

As said above, the others are probably batch numbers or date codes, won´t change sound at all.

 

[Dennis Hui]

Also please make sure you don't mix up Q1/Q2/R1 since R1/Q2 are matched to give a specific current.

 

[Nelson Pass]

And that current is the Idss of Q1. The reason for this is we want the Gate and Source voltage to be equal. This way you can read the high impedance Plate voltage without the voltmeter dragging it down.

 

[Rogols]

Thank you all for your input! Now it’s all done, and it sings beautifully. Happy New Year! Roger