bias cuestion on a JCM900?

O

Ostia Man

New member
If the bias of a JCM900 is set to high does it makes ground noise?
I leave mine in a tech's shop and he told me it may be the bias.
 
Ostia Man said:
If the bias of a JCM900 is set to high does it makes ground noise?
I leave mine in a tech's shop and he told me it may be the bias.
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Are you just making sure you are getting good info or is that what he said after looking at it? He should know, otherwise I would take it to another shop.
 
Ostia Man said:
really?
so it dos'nt.
shit!
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I ain't saying that. I edited my post to make my point more clear, since it wasn't after proof reading.

Grounding issues is like a hum or buzz sound. I haven't messed with the bias on an amp, but for guitar effects, if the bias is too high they will squeel.
 
well, when i turn on my amp even on standby you can hear the hum.(Its like a B or Bb I can remember) and I think is in power section because when i use the fx loop send it dos'nt make noise. the tec said it may be bias.
I just wanted to know if that makes any sence...
 
jeeeezis julius.... aint no way in hell that that's a bias problem.... hums on stand by??? dont see how... stand by removes the B+ voltage from the outputs.... and bias for a pedal??? bias is ONLY any issue for tube output stages... not preamp/linelevel devices.... you guy's NEED to find better techs... seriously...
 
dementedchord said:
and bias for a pedal??? bias is ONLY any issue for tube output stages... not preamp/linelevel devices.... you guy's NEED to find better techs... seriously...
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Right......because you can't adjust the voltage to a pedals circuit. :rolleyes: And by the way, a pedal isn't a preamp/linelevel device.....
 
Outlaws said:
Right......because you can't adjust the voltage to a pedals circuit. :rolleyes: And by the way, a pedal isn't a preamp/linelevel device.....
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are you trying to agree or is it sarcasm....really?? i was kinda giving the pedals the benifit of the doubt by including them in with line levels.... and there is no bias adjust on a pedal.... not sure what kind of voltage adjustment your alluding to... guess it's just my bad for trying to help... i was just a pro tech for @18 yrs... warranty certified for boogie/marshall/fender/crown/qsc/soundcraft/allen and heath/roland/korg/kurz/yamama/hammond/and others.... so what could i know right???
 
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