Preamps?

[marcg71]

Hey folks,

Was wondering if someone could help me with understanding the role a preamp (e.g. bogner fish) plays when used in with a normal amp (marshall) head? I am very old school, have only used heads with pedals, etc. But I've been wanting to add to my sound ( a little more gain and bottom end) and I'v seen rigs online that have rack preamps with heads and I don't understand the setup. Any help would be greatly appreciated!

Marc

 

[Gearjoneser]

Re: Preamps?

In a head, you've got the preamp section (gain and EQ), being separated sometimes by an FX loop, which places FX after the pre but before the power section.

By using an external preamp unit, you're bypassing the head's preamp section by patching it into the FX return. Then, instead of plugging into the head, you plug into the preamp, and use a short guitar cable from the preamp out into the head's FX return. If your head has no FX loop, you're outta luck because there's no way to get in between the pre and power section.

You never want to plug a preamp into the front of an amp, because then you're stacking 2 sets of gain and EQ on top of each other in series.

The main benefit to using a stereo power amp rather than a mono head is that most modern preamps have A & B outs for stereo. By using a head, you'll only be using A into a mono power section. It'll still sound fine, and you won't need 2 cabs either, but it won't sound as wide as a stereo power amp into 2 cabs.

If you use pedals, they go before the external preamp. If you use rack FX, you plug into the preamp, 1 ft guitar cable into FX unit, 3 foot guitar cable to head's FX return - cab.

 

[marcg71]

Re: Preamps?

I really appreciate your response, this makes total sense. I guess I still wonder why anyone would use a head if they went this route? I play in a cover band and I need all kinds of different gain and voicings, but I can tell you I am tired of tap dancing during and between songs and really would love to just minimize down to some modulation pedals and call it a day. I 've been very reluctant to use anything digital up to this point being afraid it won't sound organic. You sound like you know exactly what you're doing any suggestions? I've been out of the game for 10 years and just getting back into it. I do have an fx loop.

 

[Sirion]

Re: Preamps?

The reason why someone would use a head may be that they are still using the power amp section of it. Rack power amps are in general a little different from their head brothers. The normal rack preamp have loads of gain in it, and the power amps are made mainly to be able to reproduce the signal loud, not to distort like regular power amps do. Even the tube ones mainly use the tubes to get the tube sound, but don't really distort much. I think that is the reason why many put their preamps into power amps in a head.

 

[Rich_S]

Re: Preamps?

One reason they might use a head is they happen to like the sound of it's power stage. Remember, guitar amps (unlike hi-fi or PA amps) are not simple what-goes-in-must-come-out-only-a-lot-louder black boxes. Guitar amps (tube guitar amps, really) have power stages that distort, compress, and otherwise color the signal. Overdriving the power stage of a tube amp sounds different than generating overdrive in the preamp stages.

Edit: Sirion said basically the same thing at the same time.

 

[marcg71]

Re: Preamps?

Thanks a bunch! Do you happen to know anything about the mesa triaxis preamp? Any good?

 

[April]

Re: Preamps?

triaxis is much better than many others such recto recordig, v-twin,
but not as good as
engls 530
soldano sp77, 88(mega rare!!!!)
CAE 3+
Bogner

but it had wyde range of sounds a nd midi swiching....in consert work it very useable feature

 

[Gearjoneser]

Re: Preamps?

Yeah, the Triaxis is a great unit. It's not cheap, but it's a killer unit.
The Marshall JMP-1 is pretty nice. I used to have one and liked it.
The ENGL pre's are nice too.
The only really good Soldano is the Caswell motorized preamp, co designed by Tim Caswell.......he modded amps for Lynch, Slash etc.

The Bogner Fish is amazing, but discontinued, and the collector prices are obscene. Hafler/Bogner made some under the Hafler name....those are pretty nice.