About Preamp And Poweramp Parts In An Amp

[zanshin777]

Preamp : It's the primal tone factor of an amp. It shapes tone by EQ. Not as well as the poweramp does, it adds some volume and gain to the tone.

Poweramp : Primal feature of this part is to boost the signal transmitted from the preamp. It determines the volume and gain capacity. (Except gain knob)

1) Most single channeled amps have two distinct parts which are preamp and poweramp. In these amps when we crank the gain knob do we get gain by means of preamp part? (Boosting the coming signal from the guitar directly)

2) For Multi channeled amps -For example DSL-401 is a two channeled amp which has clean and od channel- do it have a distinct preamp and poweramp for each channel? (So it has 2 preamp and 2 poweramp, one is for each channel.)

 

[Metalblaze]

Re: About Preamp And Poweramp Parts In An Amp

1) Yes, by cranking the gain knob on preamp, you raise the amplification of the first valve if I remember right. edit: actually the second or third one.

2) The multichannel amps have 1 preamp stage and 1 power amp stage. The different channels just get into play later in the circuit according to how gainy they are. Low gain channels get the signal after the first one or two valves. High gain ones use the whole circuit.

But maybe some amps have separate circuits for different channels (I think the JSX of Peavy has separate circuit for clean channel? - but not sure) but the power amp section is always one and the same.

edit 2: The JCM 800 on the other hand for example has the first two triodes dedicated to the high and low channels respectively set to different gain factors and the rest of the circuit is the same for both channels.

 

[Dr. Vegetable]

Re: About Preamp And Poweramp Parts In An Amp

edit 2: The JCM 800 on the other hand for example has the first two triodes dedicated to the high and low channels respectively set to different gain factors and the rest of the circuit is the same for both channels.

I think this is the more common arrangement for multi-channel amps. Each channel has its own (independent) pre-amp, but all share a common power stage. But it really depends on the amp - any number of designs are feasible.

 

[Metalblaze]

Re: About Preamp And Poweramp Parts In An Amp

I think this is the more common arrangement for multi-channel amps. Each channel has its own (independent) pre-amp, but all share a common power stage. But it really depends on the amp - any number of designs are feasible.

Yep.