SOLVED Nobelium Preamp/DI Issues

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danwojaz

Member
Hey,

I built a nobelium a few weeks ago and It appeared to work, but while playing through it, the low E string Distorts/ farts out when played hard. When I heard this, I unplugged the jack from the input and a loud squeal came from the speakers. I am using a one spot for power supply with 9v 1700ma.

The Bass, Treble and Volume can adjust the frequency of the squeal.

I have replaced the tubes with new tubes and still have the same issue. The sound comes out of the 1/4" output and the DI output.
 
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It only happens, when everything is unplugged. I have gone through making sure nothing is going to ground that shouldnt, I am wondering if I have a bad filter capacitor like C6 since the tone controls impact the squeal frequency.. If I cant figure it out, Ill probably just order another board and order all of the parts from Tayda instead of mouser.

When plugged in, the noise goes away, but when the volume is turned up on a passive bass guitar, it almost sounds like a slight fuzz when you hit it will too much volume. Its not quite a fuzz, but thats the best way I can describe it.
 
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If one LED is lighting up and the other isn't, it's a pretty good sign you have continuity issues on your tube daughter board connections, and that's one of the most common issues I see with C2C builds in general. Check all the solder joints on both sides of all the pins, make sure you have enough solder but not too much on each one, make sure there are no cold solder joints and also no joints that were heated so much the solder pad lifted off the board (I've seen it a couple times now).

If you're comfortable CAREFULLY checking voltages, probe the cathode of the UF4007 and let me know what voltage you're getting. If everything is working but the sound is off, that can also point to a low plate voltage
 
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That high pitched noise is probably heterodyning. What are you using to power it?
Since the noise only happens with nothing plugged into the input, I'd probably just replace the input jack with a shorting jack (switchcraft 12a, or 112a) with the switch lug tied to ground.
On my board, I haven't experienced that noise, because there's always something plugged into the input. The first pedal in my chain has a shorting input, so it's dead quiet, til I plug in and start flailing about.
 
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danwojaz said:
@hooper could you try unplugging the input and see if you get noise? I tried using a one spot 9v and it has enough current, I tried my strymon power supply, mono power supply, and a dc power generator.
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hooper said:
That high pitched noise is probably heterodyning. What are you using to power it?
Since the noise only happens with nothing plugged into the input, I'd probably just replace the input jack with a shorting jack (switchcraft 12a, or 112a) with the switch lug tied to ground.
On my board, I haven't experienced that noise, because there's always something plugged into the input. The first pedal in my chain has a shorting input, so it's dead quiet, til I plug in and start flailing about.Could you try in plugging the input and see if you get noise?
Click to expand...
 
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vigilante398 said:
If one LED is lighting up and the other isn't, it's a pretty good sign you have continuity issues on your tube daughter board connections, and that's one of the most common issues I see with C2C builds in general. Check all the solder joints on both sides of all the pins, make sure you have enough solder but not too much on each one, make sure there are no cold solder joints and also no joints that were heated so much the solder pad lifted off the board (I've seen it a couple times now).

If you're comfortable CAREFULLY checking voltages, probe the cathode of the UF4007 and let me know what voltage you're getting. If everything is working but the sound is off, that can also point to a low plate voltage
Click to expand...
Not really sure how to ask questions hear but my nobelium won’t light up and I’ve tried everything, mosfet heats up and one led works tubes won’t glow either
 
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STEVE said:
Not really sure how to ask questions hear but my nobelium won’t light up and I’ve tried everything, mosfet heats up and one led works tubes won’t glow either
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Does it sound right but just no backlight led on the tube?
Also, I'd recommend posting your own thread in the sushibox fx sub forum with detailed pics of both sides of your board and wiring. Accompany with detailed description of the problem and maybe what you e tried this far plus rating of your power source.
 
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