Tube preamp before amp

[TatankaWilly]

Hey guys,
I did a search for this but didn't find anything specific so I will go ahead and ask.

I like to keep things pretty simple; I have a Cort Curbiw 4 with active pickups going into a TU2 tuner, then a Presonus TubePre, which I generally split the signal there using the DI function of the Presonus into the house and the line out going to a Fender 60b. I am planning on in the next couple of weeks of purchasing a Zoom B9 and replacing both the tuner and Presonus.

All that to ask this: when running out of a "pre amp" do you plug into the regular inputs on a combo amp or the power amp input?

Thanks!

 

[caeman]

You do either! But not at the same time. And only if the preamp is sending a hot enough signal. Some power amps need a hotter signal, others not so much.

 

[bongomania]

If you plug the external preamp into the main instrument input on your amp, then you are running both preamps in series, so you get all the EQ, tone-shaping, noise, clipping, etc. of both of them at the same time. Whether that sounds good or bad is up to personal taste. If you want to avoid that situation, plug the external preamp into the power amp input on the amp.

 

[Biggbass]

You can also go from the preamp into the effects return, bypassing the amp's preamp
so you're not double pre amping the signal.

 

[SirMjac28]

You can also go from the preamp into the effects return, bypassing the amp's preamp
so you're not double pre amping the signal.

Question when you do this are you also bypassing the tone and master volume? I have a Mesa M3 Carbine it seems when I do this I loose the ability to change the tone or master volume on the amp?

 

[bongomania]

Yep. Well, wait a minute, it should disable the amp's tone controls and the INPUT gain/level knob, but not the Master (output) volume knob.

Incidentally the effects loop return jack is the same as a power amp input jack.

 

[caeman]

The Crate PowerBlock 150 works like mjac's Mesa. If you bypass the front port and go FX return, the volume knob no longer functions.

 

[TatankaWilly]

Yes, when I plug into the power amp in plug I bypass all EQ and gain and master volume knobs. I assume I get 100% amplification of just the signal I am putting in. Thanks for the quick replies. Awesome. I generally have been plugging into the Power amp in because the Presonus puts out a pretty hot signal. I will try to turn the gain down on it and see if I can use the standard input and still maintain use of the EQ and master volume.

 

[SirMjac28]

I thought mine was the only one it's never been a big deal but I thought it was strange that none of the front panel controls work I assume if I ran an effect and used both the send and return the functions would return? I would try it but I finally have my amp settings right where I want them and I know if I screw with something it's gonna ruin everything

 

[bassbrad]

It all depends on the amplifiers architecture, some amps have the efx loop before the master and others after, check the block diagram to see.
I have always used PV and GK amps that place the efx loop before the master volume, the GK also has a gain (boost) stage before the master so it is very easy to use a 400 or 800 for just the power section.