Are class "A" circuits quieter than "AB" circuits?

Mike7

Member
Messages
566
I had a very interesting experence concerning amp noise at
a club we've been playing at. This place had to be the worst wired
place I've ever experenced. There was so much hiss/noise coming from the guitar amp I was going to give up and just not play there anymore.
We had tryed everything we could think of but nothing worked, last night I
brought a class "A" amp and had dead silence when not playing even with the guitar on 10. So is the class "A" amp just such a different circuit that
the noise no longer exists?
 

CharlyG

Play It Forward
Silver Supporting Member
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7,761
Class shouldn't affect it near as much(if at all) as single ended vs push pull..and a good power supply in the amp.
 

pdf64

Member
Messages
7,283
So is the class "A" amp just such a different circuit that the noise no longer exists
No, (generally) the circuits look pretty much the same, just lower voltages etc put the OUTPUT tube/s into different operating conditions.
This place had to be the worst wired place I've ever experenced. There was so much hiss/noise coming from the guitar amp
If environmental interference, it would be getting into the amp INPUT, nothing to do with the output class.
My guess is that the source of the interference just stopped, someone got rid of a bad cable etc, a different guitar was used (with humbucking pickups) or the amp in question has been designed to cope with high levels of electromagnetic interference; but the amp is the least likely of those.
Pete
 

teemuk

Member
Messages
3,159
So is the class "A" amp just such a different circuit that
the noise no longer exists?
No.

You compared apples to oranges. The particular apple happened to be designed for lower noise. Another apple might be noisier than the orange.
 

GT100

Member
Messages
3,783
Actually single ended Class A and parallel Class A amps tend to hum more.
Push pull Class A amps don't hum any more or less than others...

Lloyd
 

zenas

Member
Messages
8,698
One of those outlet cheakers is a handy thing when gigging in bars. Lots of bars were wired by some drunk with a large tab back in the day.

Funny my Tele has single coils and my Les Paul is the one that picks up all the hum.
I know that's ass back wards. Some day I need to look into that 30 year old Gibson and see what's going on.
 

mark norwine

Member
Messages
17,157
not to stir the $hit, but here's something else: since the overwhelming majority of amps sold as "Class A" are actually running in AB1, one wonders if the OP's amp was even really a class A to begin with...
 

phsyconoodler

Member
Messages
4,315
Stages are weird things.Sometimes one extra thing plugged into a power bar can wreak havoc....

We need a whole lots more info than 'I bought a class A amp and it was quiet'.

What amp did you have that made all the noise? What guitars,what cables,what outlet did you use?
Was anything added or taken away from the other night's session? Etc,etc...

Were you standing in a different spot or put the amp in a different location,tilted back....

More info needed!
 

DT7

Member
Messages
2,796
...since the overwhelming majority of amps sold as "Class A" are actually running in AB1, one wonders if the OP's amp was even really a class A to begin with...






To the OP, Class A amps, watt-for-watt, are generally noisier. That is all.
 




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