Running Two Amps Together

[Tal_175]

Do you ever run multiple amps together? It's an easy way of getting an awesome sound. It's also useful when you occasionally need more power.

[marcwhy]

Yep, lots of fun (and cool potential sounds)! I use an AB-Y pedal (since none of my effects are stereo) so I can do a "wet-dry" thing, or just have two different amps/speakers. A lot of guys on TGP get pretty crazy with this (i.e., "wet-dry-wet," with various effects, etc), but that's far too much work for a jazz gig! I rarely have a "need" for two amps at a gig (vs. one amp with two cabs), but it's still fun!

[rpjazzguitar]

I used to do it all the time. Now I do it occasionally.

I always go through a Boss ME70, which has L and R outputs. On the ME80 they are always identical. On the ME50 there was a stereo chorus setting which sounded great right in between the speakers but which made the guitar sound out of tune elsewhere in the room. My guess is that's why that feature was discontinued. I don't know if the ME70's outputs are always identical, but they are for the patches I use. Sorry for this digression.

There are other ways of using 2 amps to thicken the sound, probably involving subtle delays, but I haven't done that.

So, I can go to two amps easily with almost no additional hardware. The only problem is ground loop hum. The proper way to deal with that is, I'm told, a isolation transformer. I use a fix which I'm told is dangerous, so I won't explain it.

Another approach, which I've tried a few times recently, is to go into a JC55 from one side of the ME70 and then run the other side into a PA with speakers on either side of the stage. (I've complicated that a bit by going first into a Little Jazz with the speaker off -- gets me EQ where I can reach it and I like the sound). Most of the sound has been the JC55, but having the PA reinforce it has sounded great.

I haven't yet tried playing with only the PA, but I'm headed in that direction.

Another way I've done it is to use my LJ as a monitor and then put the JC55 at the front of the stage facing the audience. I've then told whoever we're trusting to balance the sound (a musician, sometimes also the customer) to feel free to adjust the volume on the JC55. That way, I don't get any complaints about the guitar volume being wrong.

I just posted some tracks in the Showcase section using the amp plus PA approach. A Yamaha Stagepas 300 on poles. Handheld recorder in a cavernous room but you can get an idea.

[Tal_175]

Yep, lots of fun (and cool potential sounds)! I use an AB-Y pedal (since none of my effects are stereo) so I can do a "wet-dry" thing, or just have two different amps/speakers. A lot of guys on TGP get pretty crazy with this (i.e., "wet-dry-wet," with various effects, etc), but that's far too much work for a jazz gig! I rarely have a "need" for two amps at a gig (vs. one amp with two cabs), but it's still fun!

Do your amps or AB-Y pedal have a polarity switch? My Polytone has a polarity switch, but when I ran it with my Princeton, it sounded a bit out of phase regardless of the switch setting. I suspected that maybe the polarity switch didn't work, I opened the back and switched the ends of the speaker wire and voila, I got that fat, full sound I had expected. I do have some pedals and modellers with dual output but in this case I was using the second input plug of Princeton to connect to Polytone.

[Tal_175]

So, I can go to two amps easily with almost no additional hardware. The only problem is ground loop hum. The proper way to deal with that is, I'm told, a isolation transformer. I use a fix which I'm told is dangerous, so I won't explain it.

I suspect that involved disabling the ground in one of the amps. Yeah, that removes a protection mechanism from getting electrocuted.
Radial Twin City is one solution. It's not cheap but it's a quality product:
Twin-City - Radial Engineering

[DawgBone]

I tried a twin-twin reverb stereo arrangement once but wasn't all that impressed especially since I wasn't using any effects that worked panning the stereo field. That would've def changed things. I would otherwise consider running two complementary amps rather than doubles, but if they become a critical part of your sound now you need four amps instead of two since you really should have gig rig redundancy if you are serious.

[Cavalier]

1 dry, 1 wet is really effective.

[Stringswinger]

I have a vintage TC Stereo Chorus plus pedal and I have used it to run two amps in stereo (and you can leave the Chorus off). It is a very full sound, but it requires bringing more gear to the gig than I want to carry.

[Cunamara]

Jonathan Kreisberg uses a Fender tube amp paired with a Polytone. When I saw him in Minneapolis he was using borrowed amps, an MBIV I think and a Fender DR in a small room. Great gig, great rhythm section (trio).

[Tal_175]

This video has some useful information for those who want to experiment with running two amps together:

[Herbie]

I had a leslie emulator Mini Vent and it sounded orgastic with two amps! But nowadays I play on so small venues that two amp is not an option.

For those rare occasions I still have a Lehle P-Split to avoid hum. Lehles are pricey but hi-quality.



LEHLE P-SPLIT III: Passive splitter, DI box & reamplification tool

[marcwhy]

Do your amps or AB-Y pedal have a polarity switch? My Polytone has a polarity switch, but when I ran it with my Princeton, it sounded a bit out of phase regardless of the switch setting. I suspected that maybe the polarity switch didn't work, I opened the back and switched the ends of the speaker wire and voila, I got that fat, full sound I had expected. I do have some pedals and modellers with dual output but in this case I was using the second input plug of Princeton to connect to Polytone.

I've (fortunately) never had any polarity issues; I use the AB-Y box from Rattlesnake Cables (looks like they're out of stock right now, but I'd email him and check on availability). [Great pedal, too, BTW, if you want to use two guitars into one amp!]

[pauln]

Keep in mind that every* gain stage reverses polarity; the Fender black face Normal channel has one less gain stage than the Vibrato channel (because of the reverb return recovery) so the channels are opposed polarity.

* - this may include pedals and multi effects units (and they may include a polarity reversal courtesy switch as well because you probably don't know the number of gain stages)

[Tal_175]

Keep in mind that every* gain stage reverses polarity; the Fender black face Normal channel has one less gain stage than the Vibrato channel (because of the reverb return recovery) so the channels are opposed polarity.

* - this may include pedals and multi effects units (and they may include a polarity reversal courtesy switch as well because you probably don't know the number of gain stages)

Luckily there are only two polarities. It doesn't matter how many times the polarity is switched within the design of the amp or from the pedals going into the amp, in the end the speaker cones are going to move based on one of the two polarities. So if the polarities of the speakers don't match, they'll create opposite air pressures. The polarity of one of the systems needs to be reversed at one of the points along the chain, from the guitar all the way to the speaker wires.

[jim777]

Not exactly the same thing, but lately I have been playing my EBMM JP6 solidbody (which has separate magnetic pickup and piezo outputs) into two amps and it has been fun. Piezo into the TM Twin reverb and pickups into the Mark IV. Not terribly useful unless you are covering something like Pink Floyd in a rock band situation, but still very cool and dramatic. Just flip the 3 way switch and literally everything changes with no footwork required