Question about using two heads together

[BillyBass]

If you need to use two 4 ohm cabs, could you pair two (minimum 4 ohm load) heads together through the FX loop, i.e. use a patch cable between the send of one amp to the return of the other?  By doing this I assume the first amps' EQ would work for both but the volume controls would be independent and both would have to be adjusted?

 Or do you have to either use both amps separately in 'stereo' or buy a 2 ohm minimum load head?

 

[BassmanPaul]

My speaker cabinets are all 4Ω chosen because all my amplifiers are happy working into a 2Ω load.

You could use two 4Ω amps one into each of your two cabinets. Linked together Effects Send to second amp Effects Return. It will work and the first amps controls will operate for both amps.

Edited November 13, 2020 by BassmanPaul

[Bill Fitzmaurice]

Not all amp send/receives are configured the same. Some have the master volume before the return, some have it after. Only by trying it can you know for sure, assuming you don't have block diagrams for both amps.

[warwickhunt]

I experimented with this 20+ years ago and as Bill says,  different amps are configured in different ways.  You can easily split the signal from your bass via a pedal and send to two diff amps/cabs.  Added advantage that you can treat the two signals with effects etc and keep one signal pure.  

[BillyBass]

My main head is a MarkBass.  Following @Bill Fitzmaurice's post I connected my pedal pre-amp to the return jack on the MarkBass; the master volume worked but the gain didn't.  So the gain is in the pre amp, which makes sense, but the master volume control is after the fx loop.  This means that should I purchase a 2nd MarkBass head, I would have to adjust the volume on both heads.

[warwickhunt]

If your preamp is in a pedal the simplest/cheapest route is to buy a stereo power amp that can drive a pair of 4 ohm cabs... or am I missing something?  You could also use your Markbass head as a preamp/slave and drive the external power amp.  

 

[BillyBass]

After having two heads die on me in rehearsal studios since the first lockdown ended, I am acutely aware of how having a back up head can be a life saver.  The more bits I use for a rig, the more bits I'll need in case they die.  Power amps and a separate pre can all go wrong.  I thought pairing 2 identical amps would be ok as the back up could be a 3rd of the same head.  Even better would be a single head and an Elf as back up!

Another thing.  PA power amps generally come in one size.  I want something that will fit on top of cab with no overhang.

I'm in no hurry to decide what to get yet, its not as if I'll be gigging anytime soon!

[warwickhunt]

9 minutes ago, BillyBass said:

After having two heads die on me in rehearsal studios since the first lockdown ended, I am acutely aware of how having a back up head can be a life saver.  The more bits I use for a rig, the more bits I'll need in case they die.  Power amps and a separate pre can all go wrong.  I thought pairing 2 identical amps would be ok as the back up could be a 3rd of the same head.  Even better would be a single head and an Elf as back up!

Another thing.  PA power amps generally come in one size.  I want something that will fit on top of cab with no overhang.

I'm in no hurry to decide what to get yet, its not as if I'll be gigging anytime soon!

I'd use a different rehearsal room!    I've been playing bass 40 years and I've had 1 amp die that was out of the blue (you often get clues that things aren't right).  I started carrying a 'spare' DI or preamp pedal just in case and on that occasion I quickly went pre pedal into PA (bass into foldback).  

ANY bit of kit can go wrong btbh a power amp is less susceptible than a bass amp.  Why not just buy a 2nd bass amp that can handle stereo 4 ohm or 2 ohm?  You can then go pre pedal into 'new' amp and no need for your Markbass.  As for overhang... stand the amp on its edge /side beside your cab (or even flat on the floor behind).

[Dan Dare]

On the rare occasions I need to use an additional head to drive additional cabs, I run it from the tuner out of the main one into its instrument input (setting the input gain to accept a line level signal) and adjust the eq to suit.

Edited November 15, 2020 by Dan Dare