I just finished getting this kit put together and have an issue with the right channel voltage at T8. All other voltages are correct at T1-T7. All resistors are within spec. I am not sure about the caps since I do not have a tester for those. When I apply 24vdc to the input, both Nutube channels turn green, but the right channel goes dim after 1 second or so. Testing the voltage at T8 shows 3.66 volts regardless of where the Variable resistor pot is set. The left channel can be adjusted and is at 10 VDC and holds that fine. The Right channel adjustable resistor pot is not the issue. It checks out fine.
My suspicion is the JFETs or the 1mU cap just before the Nutube are not working as designed.
Any thought or trouble shooting ideas would be appreciated. If possible, I don’t want to pull the JFETs since I may do more damage than good.
Thanks
Andy
My suspicion is the JFETs or the 1mU cap just before the Nutube are not working as designed.
Any thought or trouble shooting ideas would be appreciated. If possible, I don’t want to pull the JFETs since I may do more damage than good.
Thanks
Andy
Images of the build
A couple of things to note here.
I did a quick wiring when I noticed an issue so please don’t think that I would accept that🙂
Since the AN caps are larger than the ones that were spec’ed, I had to get creative with the power section resistors. One is mounted on the back. All the measurements are in spec there.
Thanks for your inputs.
A couple of things to note here.
I did a quick wiring when I noticed an issue so please don’t think that I would accept that🙂
Since the AN caps are larger than the ones that were spec’ed, I had to get creative with the power section resistors. One is mounted on the back. All the measurements are in spec there.
Thanks for your inputs.
Attachments
@ Andyz
My pleasure🙂
Clean all flux residues on the PCB with Isoprophyl Alcohol are good for preamp long term reliability
How To Clean Printed Circuit Boards - YouTube
My pleasure🙂
Clean all flux residues on the PCB with Isoprophyl Alcohol are good for preamp long term reliability
How To Clean Printed Circuit Boards - YouTube
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