transformer hum
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transformer hum
I've recently built a Blackvibe 6v6 from using a schematic from Rob Robinette's website. The amp sounds great but I notice that my overdrive pedal adds noise which is coming from the amp, not the speaker. I'm aware that transformers create an unavoidable hum, but should this get louder when using an overdrive pedal? Any help is greatly appreciated.
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Stevem
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Re: transformer hum
Where is your OD pedal sitting, on top of the amp?
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Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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romberg
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Re: transformer hum
How is the overdrive pedal being powered? It could be that the power supply of the pedal and the amp are causing a ground loop and picking up 60hz hum.
Mike
Mike
Re: transformer hum
Thanks for the replies. I'm powering the pedal with a one spot cs6. Quite far from the amp. The weird thing is it's only when I switch on the boss od3.
Re: transformer hum
Tried it again today both with batteries and the one-spot power supply. Everything is behaving normally. You could be right Mike, some sort of ground loop causing random problems, or I'm in an electromagnetically noisy environment? I'll keep an eye on it. This is my first amp build so I don't know if I made a mistake, but I grounded the bias pot to the preamp ground as it was nearer than the power amp ground. Was this a bad idea? I would imagine if it created extra noise it would be apparent through the speaker, not the transformer.
Re: transformer hum
I have an old boss hm2 that is suppose to be powered by either a 9v battery or a 12v wall wart. But... It works just fine with a 9v power supply as long as:
My guess is that your boss pedal is also doing something funky with the grounds and this is causing your ground loop. The amp is probably just fine. It might help to have the amp and pedal power supply not spread apart but using the same wall outlet. Or... If your pedal is old school like mine, see if the hum goes away if you power the pedal with a battery.
Mike
- The power supply is not really isolated. And many of them are really not even though they are marketed that way.
- The power supply has some other dodgy boss type pedal plugged into it along with the hm2.
My guess is that your boss pedal is also doing something funky with the grounds and this is causing your ground loop. The amp is probably just fine. It might help to have the amp and pedal power supply not spread apart but using the same wall outlet. Or... If your pedal is old school like mine, see if the hum goes away if you power the pedal with a battery.
Mike