How To Use Two Guitar Amps Together [Connections, Phase, Polarity & Why Analog Dry-Through Matters]

Using two amps together sounds great, but how do you actually do it?

Welcome to the show. Dan and I pretty much always use two amps on the show, and very often when playing live too. It’s something that countless artists have done down the years… but how do you actually connect them?
In this video we run through the most common and easiest ways to connect two amps together. There are other ways – for example using effects loops, slave/direct outputs and so on – but that’s getting ahead of the scope of this video.
A big part of this video is to do with polarity and phase, which is the most important topic related to using multiple amps. So start by getting your head around that, and move on from there!

Finally, it really doesn't matter what two amps you use! (Erm, just make sure they're both analogue to avoid phase problems, or indeed two of the same or very similar digital amps. Mixing one analogue and one digital will give you phase problems.)

Enjoy the episode!

If you want a specialist device to connect two amps, it MUST have these two features…
-One of the outputs is ground isolated
-One of the outputs has a polarity flip option

Examples of devices we would recommend:
• TheGigRig Humdinger (and AB Baby, G3, G3S)

• Radial Engineering BigShot ABY

• Bright Onion Active Splitter

There are others, just make sure it has an isolated second out AND a polarity flip switch. Good luck!

Pedals & Stuff in this show
• J Rockett Audio Hot Rubber Monkey V2

• TheGigRig Humdinger

• Jam Pedals Waterfall

• Catalinbread Belle Epoch Deluxe

• Walus Audio Mako D1 [original version, links to latest version]

• Source Audio Nemesis ADT

• TheGigRig QMX4

Interesting bits and go-to sections
0:00 Intro playing 
1:57 Why use two amps?
2:50 Four ways to use two amps
5:00 Way 2: Link The Inputs
6:15 Hum & polarity problems
8:30 Splitting the signal before the amps
9:00 One amp must be earthed/grounded
10:45 A specialist splitter device
11:35 Phase & polarity explained
15:23 Where does the polarity change happen?
15:40 Way 3: Use A Stereo Pedal To Split
17:50 A splitter on the pedalboard 
20:00 Where to split on the board?
21:20 Vibrato in one amp only: chorus!
22:15 Problems with splitting the signal path
22:50 Why Analogue Dry Through Is Crucial
28:00 Polarity & analogue dry through sound examples
30:00 And with the delay sounds
31:35 Why use two amps, again?

Guitars in today’s show

Amps in today’s show
• Fender ’65 Deluxe Reverb with stock speaker

• Two Rock TS1 50-watt 1x12 combo with TR1265 speaker

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[stuartbowlerwell]

"Why?"
"Because it's Awesome!"
Roll credits...

[robertwillett]

Once you figure out the polarity and the ground lift to have no hum. There's nothing better than ( I call it ping ponging) a good chorus, delay, or an ambient type of effects. But it can be difficult. You must educate yourself. It's incredible. You guys did a great job.

[michaelwebb]

This is kind of a full circle video for me. The only reason I found you guys was because I searched YouTube for a video on how to use two amps about 5 years ago. I had absolutely no idea about effects pedals, other than something like a zoom 505 or a digitech rp100. I had a pod xt live at the time and when I found you guys, it completely changed my life. Here it is 5 years later and I’m such a gear nerd, I have over 40 pedals, 9 guitars, 7 amplifiers, and I am so much more educated on everything guitar and gear related. You guys are and have always been the best guitar and gear related channel out there, bar none. Love you guys, and keep on doing what you’re doing!

[simoneh]

I've always avoided the ground/earth loop by having both amps plugged into the same power strip/bar so that they are on the same ground potential. My understanding is that the hum actually comes from two amps being connected to different grounds which usually have slightly different ground potentials, and then when the loop is made, current will flow from one ground to the other through the amps, and that gets amplified as hum. Having them on the same ground greatly reduces this so that I haven't had hum problems by just using a pedal to split the signal. I happen to be lucky that what comes out of both amps is in polarity too.

[ajb]

I only play in the house, and have always used two amps. When people ask "why"?, I answer "Why not? I've got 'em!". And yes...such a big sound with minimal volume! Someone went through all that trouble to make the amps...we should use them!

[nickm.]

Struggled with an old nemesis doing wet dry setup at one point. No one could explain what was going on. Was dealing with the latency because it wasn’t dry through. Glad they fixed that.

[buffalofeathers]

As someone who IS into this, it WAS gold! Thanks, gentlemen!

[johnpierson]

Yes, this video is absolute gold! I'm an EE and and an old guy and have been playing guitar for 50+ years. What I really think is great is your clarification of polarity versus phase. The terminology is mixed up in many peoples understanding and how products don't always use the terms consistantly. And in this world of awesome digital effects pedals, the analog dry through issue is now becoming a common issue. I recently bought an Eventide H90, which I think is quite incredible. But in a recent episode, I heard Mick say the lack of analog dry through made it a non-starter. I now understand why this does not work in a "TPS Dual Amp config". The H90 is still awesome, but not in all configurations. Eventide claims that they had more phase problems with with analog dry through and therefore did not implant this in the H90... Super great episode!

[jbels]

This was so over my head, but there is nothing better than two people being passionate, educational and funny!

[evanmiller]

Learned everything I know about two amps from this show. Biggest mistake I made was flipping polarity on the gig rig to get the amps in sync and then going into a stereo reverb pedal (Boss RV500). Since the two signals going into the pedal were out of phase, the reverb volume was almost non existent. I thought something was wrong with the pedal. Once I figured it out, my best results came from doing everything on the board including going into stereo pedals and then putting a humdinger on one of the stereo outputs only. That way I could kill hum and flip polarity if necessary. Have a great weekend.

[jlukmo]

I just purchased a VOX AC15 C2 and a Roland JC 40 to do this. you are bad for my personal finances.

[Frozenguy]

You finally convinced me to play with my polarity even though I thought I was in phase all the time. Well.. Turns out I was wrong! I used the inverter module on my zoia to flip the polarity, but once I found out I had to flip it I just swapped the two ends of the cable to my speaker.

[gyugug]

Excellent episode once again chaps. For anyone hasn't tried this, it's a game changer. Another thing - the more diverse sounding amps you use, the wider the sonic spectrum - for example I use a Roland JC120 with a Kustom 100. Another thing - as Mick rightly mentioned - it doesn't have to be TPS wet/dry e.g. I use separate fuzzes on each signal path - wet/dry fuzz is a new dawn! Cheers :)

[damirkaleb]

Congratulations from me. This very detailed video is very useful for young people. Unfortunately I have to say, many of them don't want to KNOW. KNOW or ask someone who knows. Our generation, experimented, exchanged opinions. It's not shameful NOT TO KNOW, BUT it's sad and stupid not to ask someone who has thighs. Well, I'm not going to write "User's is just A great appreciation on my part, as with care and simplicity you try to spread your knowledge related to the equipment necessary for a musician-guitarist. In this way "electric" music (rock, R/Roll, haeavy, blues, country, pop, etc.Continues and remains ALIVE still.(old, first, generation's guitarist. Ian Judas)

[eingeschränktesLichtraumprofil]

cool episode!
another big difference between phase and polarity is:
polarity is not frequency depending. everything is just mirrored on the time-axis.
out of phase is frequency depending. if the latency is i.e. 10ms which eaquals 100Hz, everything that is n*100Hz is amplified and everything that is 2n/(n+1/2)*100Hz is eliminated.

[MatthewFarrell-sw]

A great, succinct video on how to get joy from running two amps, I wish someone had explained it so thirty years ago.

[jamiebarr]

I am still very much an Absolute Beginner on this, after watching the really in-depth vids, I really needed this! Next trick - find a suitable amp for home playing to match with a Blues Jr and add a Humdinger to my board!!! Much love, guys.

[Cheguebuddha]

I will just say what I use at my home studio and absolutely enjoy it tremendously! Wet-dry Egnater Tweaker 15 into a Jensen P12R and Quilter Superblock US into a Jensen Blackbird 100watt. Both 12". Oh my gawd what a lovely huge home friendly tone and volume!

[allisonholmesmusic]

A well timed video. I just bought a Vox AC15C2 and I already owned a Fender GTX50. I was wondering how to use them together. A lot of this went over my head but at least I know what pitfalls to look for. I’ll check out your other videos to see if a deeper dive makes it click for me.

[tarkett]

I went from a tps wet dry 2 amp setup to a 3 amp tps wdw, and now I’m tinkering with a 6 amp monster wet wet dry dry wet wet setup with different effects going to different wet amp combinations and different drives to the dry amps, what a rabbit hole I stepped into