Okay, I've been discussing this over the GG&A forum, but I thought I'd throw it in here and see what you guys think of it as well.

Right, so my ultimate intention with my rig is to be running a full-rack setup. But, as you all know, rack gear is very expensive. I'm currently running a VK 112, through a 2x12 speaker cab I made. As I was lurking over at GG&A, I spotted this thread, discussing the practice of running a preamp (a Pod, in this case) through the FX loop of an amp, thus bypassing the amps built in preamp.

This is the point where the light in my head came on.

I can afford an ENGL e530 preamp in the very near future, and if I could run it through my VK's FX loop, I'd definitly get it. My first thought was:

"Hang on, this amp [EDIT - the VK] has no master volume. I would not be able to control the volume level of the power amp!"

Having posed this in the VK thread, someone suggested that a simple volume control after the preamp would act as a master volume for the power amp. So I'll be making one of those, it's a pretty easy build.

My second though was:

"Holy crap, can I A/B this thing and play through the VK preamp and the ENGL preamp at choice!?"

Why, you may ask? The main reason I'd want to do this is so I can run an effects loop into the VK, using the clean channel only, and a seperate effects loop into the ENGL, and be able to switch between the two all at the press of a single button. And I quickly conjured up the following diagram of how cool it would be:

This is where the grey area starts to rear its fat, ugly head... because I don't know how to set it up, in terms of what to plug into the FX loop, etc. Anybody fill me in?

Also, if something is wrong in this post, please do not hesitate to burst my bubble, as I don't want to spend all the money on the ENGL and not be able to use it!

EDIT: By my estimates, if I hooked the ENGL up to the return loop (contrary to what the diagram says) then the VK's preamp is bypassed, and I'm coming straight into the power amp.
Last edited by Mathamology at Dec 4, 2008,
How do you intend to install the master volume? Are you modding the amp?
How will you run both the Engl pre and the clean FX chain into the same FX loop in the VK?

Sounds awsome if it will work, just don't see how to get the FX and the preamp into the same loop without somthing more elaborate than and A/B.
The master volume will simply be an external unit. Just a simple volume control in a hard casing. This apparantly works in the same way as a master volume, though I was sceptical when I first heard this.

The idea is that the ENGL is patched into the return send on the FX loop. So when the signal is routed to the ENGL, the VK's preamp is bypassed completely. When the signal is routed to the input on the VK, because the FX loop is not completely patched, it will be bypassed. I hope.
I'm not sure if the FX return will bypass like you want it to, might want to test it out with just a pedal.

How do you intend to hook up this master volume?
Oh, I see what you mean about the volume control. Is it passive? You might also want to test that out with a cheap stompbox first.

Edit: Maybe use a cheap ART mic preamp (30USD) to make sure that no ill effects will come to the Engl if used in this manner.
Is what passive? Why ill effects might I encounter with the Preamp? I'd much rather iron out any flaws than go ahead, do it, and regret it, but I'm a bit confused as to what would be at risk with the setup.
1: Is the volume passive?

2: I may be totally off base on this, but I think there could be some issuses with loading or not haveing a place for all the juice in the preamp to go. Just verifying that your setup will work using a cheap mic preamp that you don't care about frying seems like a sensible precaution to me.
Last edited by SVStee at Dec 5, 2008,
By passive, do you mean it does not require any power source? If so, I believe the schem's I've been looking at are passive.

Okay, I'll definitly be giving it a try out first, but I don't think there are any adverse effects of a preamp not having a load. Definitly not in the same way as a power amp. Still, always better to be safe than sorry!

EDIT: By the way, this is my 800th post
Last edited by Mathamology at Dec 5, 2008,
Alright, cool.
Can you hit me up with a link to this volume control?
that's pretty clever, I don't know if it would work though. I'd be very interested if it did, it seems like it could be a good way to get a different sound out of my mini colossal
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Links to the volume controls I've been looking at:

UG made (forgot which user now)
Simple one pot design

Quote by jacobs
that's pretty clever, I don't know if it would work though. I'd be very interested if it did, it seems like it could be a good way to get a different sound out of my mini colossal

I'll be trying it out next week with a distortion pedal & EQ into the FX return, and a line into the main amp input. Once I've built the EQ, that is

I'll let you know how it goes.
You wont need the volume control, each channel on the preamp has a volume control. I run mine through my DSL100 and that has no master volume.
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