Could this plan work?

[metropolis_4]

I think this should be straightforward, but wondering if there are any pitfalls?

I want to use a preamp pedal in the effects loop as a “channel 2” for my amp.

Guitar -> A/B box
A -> amp input -> effects loop send
B -> preamp pedal
Both go into some sort of signal mixer on the board
Signal mixer -> effects loop return

Could I just use something as simple as a JHS Summing Amp as the signal mixer?

Would there be any benefit to putting both the amp preamp and pedal preamp into loops on a loop switcher and switching that way?

 

[metropolis_4]

One more question: does a tube amp need to have a load if I’m going out from the preamp (effects send) and never going back in to the power amp (effects return)?

 

[Chocol8]

One more question: does a tube amp need to have a load if I’m going out from the preamp (effects send) and never going back in to the power amp (effects return)?

Thats a sticky question, but I would at least have a resistive load attached. Grounding the return or turning a post return volume to 0 would keep the power amp from trying to push out too much voltage so the load resistor wouldn't need to be very big.

 

[GuitarBilly74]

I think this should be straightforward, but wondering if there are any pitfalls?

I want to use a preamp pedal in the effects loop as a “channel 2” for my amp.

Guitar -> A/B box
A -> amp input -> effects loop send
B -> preamp pedal
Both go into some sort of signal mixer on the board
Signal mixer -> effects loop return

Could I just use something as simple as a JHS Summing Amp as the signal mixer?

Would there be any benefit to putting both the amp preamp and pedal preamp into loops on a loop switcher and switching that way?

Yeah that should work but make sure to get an A/B box with a ground lift and a phase switch. Radial makes a really good one. Lehle too.

With a standard a/b box you will have issues with ground loops and maybe even phasing.

 

[GuitarBilly74]

One more question: does a tube amp need to have a load if I’m going out from the preamp (effects send) and never going back in to the power amp (effects return)?

It depends. What's the amp?

 

[metropolis_4]

Well, I remembered I’ve got a JHS Switchback I could use to test this myself. It works, haha

I laughed at myself because I got really excited about this idea of “what if I could have two different preamps in front of the same power amp” and I realized I just invented 2-channel amps


This might become my new go-to setup! It lets me crank my AC30 to get the drive I want, and then have a completely clean preamp I can switch to when I need pristine clean.

 

[newholland]

honestly, id use the loop normally and put the preamp in front- itll sound more like your amp anyhow.

maybe im missing the point, but why the convoluted signal chain?

maybe just run the amp hot for drive and use an underdrive for cleans if you need to throttle back- but you could also justbuse your guit volume.

 

[metropolis_4]

honestly, id use the loop normally and put the preamp in front- itll sound more like your amp anyhow.

maybe im missing the point, but why the convoluted signal chain?

maybe just run the amp hot for drive and use an underdrive for cleans if you need to throttle back- but you could also justbuse your guit volume.

The idea for me is that about 80% of the time I could live on an AC30 top boost channel pushed to edge of breakup, but that other 20% I need a more pristine clean tone.

So putting a clean Fender-ish preamp as a second channel into the power amp gives me both

 

[newholland]

i wonder if any of em have would let you pull volume under unity gain?

OR ge-7 it down and eq?

AH WAIT- possibly a tech21 blonde! it has SUCH a massive swing on the volume knob and such a wide swinging eq- you might be able to do that by running the volume low and eq it however you need. thats a pedal flexible enough in most ways to pull that off.

 

[newholland]

edit- the tech21 thing works. i just put my leeds in front of a reeves set more or less at a bright EOB and dialed a completely different- bassy thick clean tone by underdriving the amp and eqing!

 

[fetishfrog]

The idea for me is that about 80% of the time I could live on an AC30 top boost channel pushed to edge of breakup, but that other 20% I need a more pristine clean tone.

So putting a clean Fender-ish preamp as a second channel into the power amp gives me both

I use a Homebrew Electronics Detox EQ for exactly this purpose. I don’t think they are made anymore but if think any EQ should work.

Cool idea in the OP though. Hope it works for ya.

 

[laxu]

One more question: does a tube amp need to have a load if I’m going out from the preamp (effects send) and never going back in to the power amp (effects return)?

Yes it does afaik.

But wouldn't you be going back into the AC30 return anyway? So you'd have it connected to the speakers.

You might be a candidate for the Victory V4 preamp pedals, because they have a switching option specifically for your usecase:

Amp Through Mode Explained​

• Amp Through Mode utilises the effects loop of your guitar amp
• When the pedal is ON, you’re bypassing your amp’s front end
• When the pedal is OFF, you’re plugged into your amp as normal

You’re adding two new ‘channels’ to your amp that are independent from your amp’s own front end. Imagine if you could feed the power section of a Fender Twin, for example, with the front end of a Countess, Sheriff or Kraken. That’s exactly what your doing: your single-channel workhorse becomes a three-channel monster.

With this you would avoid the A/B box completely.

They don't seem to make a preamp version of their Duchess (Fender) series, but the Vox-voiced V4 Copper preamp might be of interest to you if you just want to expland your Vox sounds. You could use it as your overdrive channel or use the AC30 for that.

V4 The Copper - Victory Amps

Classic EL84 chime and rock, based on our VC35 Copper and Copper Deluxe amplifiers

www.victoryamps.com