Can you use a Quad preamp in the loop

Triaxis, Quad Preamp, Stereo Power series, Recto Preamp

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neuk01642
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Can you use a Quad preamp in the loop

Post by neuk01642 » Sat Jul 07, 2018 4:24 am

Hey
A separate but related post to another I’ve posted.

Can I use the Quad pre into the effects return of my Blackstar Series 1???
I suspect the Quad I’ve bought is faulty but the guy who sold me it is saying I can’t hearing anything because I’m using the loop not a dedicated power amp.

Any advice would be appreciated.

Matt

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Blaklynx
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Re: Can you use a Quad preamp in the loop

Post by Blaklynx » Mon Jul 16, 2018 9:15 am

Of course you can. Any preamp can be used in an amps loop.

Connect Send (or output) of preamp into Return (or In) of amp's loop and plug guitar into the input of the Quad preamp. You'll effectively bypass the amps own preamp section and replace it with the Quad preamp. That's it.


If you had a dual effects loop switcher pedal (or an AB or ABY pedal with in/out loops) you could run both the amps' preamp and the Quad preamp at the same time or switch between the two preamps. This will give you a multi-channel amp. Below is one setup that I used with my Rectoverb. Loop 1 had a Level Control, Loop 2 had a Level Control. I could have this configuration:

Loop 1 only (H&K preamp)
Loop 2 only (Mesa preamp)
Loop1 and Loop 2 (both preamps)
Bypass = no preamps but clean guitar signal straight into power amp
There was also a 'clean guitar blend' switch that allowed the clean signal to be blended into either or both loops.
The Level Controls allowed me to blend the volumes of each loop.

Now consider this... the amp had 2 channels with their modes for each channel. The H&K preamp pedal had 3 channels. You could see how crazy this could get. If I calculate correctly, the total 'amp modes' (effectively 'channels') is:
5 on the amp (2 modes on clean channel and 3 modes on dirty channel)
3 on the pedal
15 when combined (5 x 3) (ie. 1 mode on amp plus one channel on pedal; both running simultaneously)

That's 23 different sounds. Now add the clean guitar signal into those 23 sounds....

The EQ shown sits between the preamps and the power amp. I could adjust the final preamp tone as desired. There's no reason you can't add an EQ into each loop to adjust the individual preamp's tone as required; this way you could better match both preamp's tone-wise prior to sending to the power amp.

Having said all that, when connecting two preamps to run simultaneously, you need to watch for phase. If the phase is out, then you'll get a weak (or let's be correct and say an out-of-phase) output signal. The loop switcher I show has a phase switch on one of the loops. If you run the preamps individually, it's not a problem.

So yeah, use your preamp effectively.


Image
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Image

If you're interested in the chicken head knob replacement on my Roadster amp, go here:
http://forum.grailtone.com/viewtopic.ph ... 98#p476098

neuk01642
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Joined: Sat Jul 07, 2018 2:22 am

Re: Can you use a Quad preamp in the loop

Post by neuk01642 » Thu Jul 26, 2018 11:35 am

Blaklynx wrote:Of course you can. Any preamp can be used in an amps loop.

Connect Send (or output) of preamp into Return (or In) of amp's loop and plug guitar into the input of the Quad preamp. You'll effectively bypass the amps own preamp section and replace it with the Quad preamp. That's it.


If you had a dual effects loop switcher pedal (or an AB or ABY pedal with in/out loops) you could run both the amps' preamp and the Quad preamp at the same time or switch between the two preamps. This will give you a multi-channel amp. Below is one setup that I used with my Rectoverb. Loop 1 had a Level Control, Loop 2 had a Level Control. I could have this configuration:

Loop 1 only (H&K preamp)
Loop 2 only (Mesa preamp)
Loop1 and Loop 2 (both preamps)
Bypass = no preamps but clean guitar signal straight into power amp
There was also a 'clean guitar blend' switch that allowed the clean signal to be blended into either or both loops.
The Level Controls allowed me to blend the volumes of each loop.

Now consider this... the amp had 2 channels with their modes for each channel. The H&K preamp pedal had 3 channels. You could see how crazy this could get. If I calculate correctly, the total 'amp modes' (effectively 'channels') is:
5 on the amp (2 modes on clean channel and 3 modes on dirty channel)
3 on the pedal
15 when combined (5 x 3) (ie. 1 mode on amp plus one channel on pedal; both running simultaneously)

That's 23 different sounds. Now add the clean guitar signal into those 23 sounds....

The EQ shown sits between the preamps and the power amp. I could adjust the final preamp tone as desired. There's no reason you can't add an EQ into each loop to adjust the individual preamp's tone as required; this way you could better match both preamp's tone-wise prior to sending to the power amp.

Having said all that, when connecting two preamps to run simultaneously, you need to watch for phase. If the phase is out, then you'll get a weak (or let's be correct and say an out-of-phase) output signal. The loop switcher I show has a phase switch on one of the loops. If you run the preamps individually, it's not a problem.

So yeah, use your preamp effectively.


Image

Thanks for the input.
Solved the issue. My Blackstar Series 1 has a standby bypass in the input jack (or something like that) meaning even if you're bypassing the preamp and running the Quad in the loop I need to have a jack plugged into the amp input and then turn all the pre amp volumes to zero.
Doesn't mention that anywhere in any literature I could see.
Anyway, problem solved.
I now have my quad pre running through 200 watts of meaty KT88 goodness... Hmmmmmmm juicy tones.

Thanks for putting my mind at rest.

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