I like it.
where do you actually live? Are we neighbours? Is the neighbours broken AC the reason we have the same issue?
PS: no AC here. More in need of bonfires.
Even further away, Serbia 🙂 I'm still a newbie when it comes to this, so i'm expecting feedback for the pcb. Visually traces are on point with NP one, but more heads are better than one 🙂
I've made few modifications and it's ~1cm wider, more notably thicker/more even traces, increased lead spacing for 270r for 5W resistors instead of 3W since those heat a bit too much for my taste without a heatsink. Spaced caps more, and more evenly.
Sent out an order to print 5 pieces in black color since i think it will look great with red PRP resistors.
Sent out an order to print 5 pieces in black color since i think it will look great with red PRP resistors.
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hello all,
i have a korg B1 i bought from another hobbyist. after months of good service it has now developed a loud screech/squeal noise. i turn it off and it goes away but then comes back. i searched for this issue via google and didn't find any results. is this a known issue?
i'd love any troubleshooting ideas.
thanks!
i have a korg B1 i bought from another hobbyist. after months of good service it has now developed a loud screech/squeal noise. i turn it off and it goes away but then comes back. i searched for this issue via google and didn't find any results. is this a known issue?
i'd love any troubleshooting ideas.
thanks!
How about some well pit pics of the circuit, along with test point voltages references to gnd?
if the PSU checks out that is 🙂
I was just thinking that if the operating points were set to the extreme, that might be a possible culprit. I measured/saw instability in such circumstances with my old build. Checking the TP’s will rule that out if not the case.
Serbian tubes rule
Edit: I knew where you were going with your question. But the Nutubes deserve the benefit of the doubt. Or?
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thanks for the responses!
alas, i don't have another power supply to try
i used the test points in this: https://www.firstwatt.com/pdf/art_diy_nutube_preamp.pdf
the DC values (T5-T8) were spot on. i am not getting stable results for the AC values (T1, T3, T4).
alas, i don't have another power supply to try
i used the test points in this: https://www.firstwatt.com/pdf/art_diy_nutube_preamp.pdf
the DC values (T5-T8) were spot on. i am not getting stable results for the AC values (T1, T3, T4).
i'll see if i have one with the same connector...
if i have the dreaded microphonics, what does that sound like?
connector - improvise
are you a DIY-er , or what?
for test even wires to plug are ok
make this test first, then you'll know more what to blame
i'm a semi-DIYer; not the most expert, but i've built simple things
OK, will start with the power supply...
OK, i cut the cord and stripped the wires and then used my MTM (set to AC) on the bare wires. just as with the test points, i am not getting a stable value. so this points to the power supply. what is the best place to order a new one?
many thanks!
many thanks!
when i test the power supply wires the value on the multimeter keeps bouncing around; doesn't stop at one value. i have one probe on one of the wires, the other probe on the other.
just confirm DC voltage and polarity so you can feed KB1 with it
then connect PSU to KB1 , power up and hear do you have previous problems
no need to measure anything else, and you can't measure anything meaningful with DMM, of importance to your exact problem
aha, i assumed there was a rectifier somewhere in the pre, not that the power supply changed to DC. measured DC and it is right about 24 volts.
will reconnect and try again but, as nothing has changed, i assume the problem will still be there.
per above, T5-T8 were spot on. also, i bet T1, T3, and T4 will be OK if i measure for DC.