Double Bass Best Two-Channel Preamp for Doubling?

[Wasnex]

That’s what I do...as I stated in my post No. 81. Markbass Little Mark 3 works like this...

That's interesting. The LMIII manual does not specify whether the effects loop is parallel or series, but plenty of threads say Markbass effects loops come from the factors setup as parallel. Usually with parallel loops there is a blend or level control, but I don't see any sort of control like that on the LMIII

Pretty sure acoustic image works like this also

Yes the Acoustic Image manuals clearly identify the Effects Loops as parallel. Some of the amps also have front panel, level controls for the Effects Loops. I believe these control the level of the Effects Return, so you would be able to turn the Upright Off when you are not playing it.

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You may also have similar functionality with some series loops. It depends on how the circuit is broken. Most amps break the circuit when you insert a plug into the Return. The idea is the Send can be used to slave a second amp, so you don't want to break the connection on the Send. But I believe a few rare amps do actually break the connection on the Send, and some also break the connection on both the Send and Return.

If your amp has a series Effects Loop and the connection is broken only the Effects Send, you can still use the Effects Return like an Aux input, and the amps internal signal path will not be interrupted.

 

[Zbysek]

That's interesting. The LMIII manual does not specify whether the effects loop is parallel or series, but plenty of threads say Markbass effects loops come from the factors setup as parallel. Usually with parallel loops there is a blend or level control, but I don't see any sort of control like that on the LMIII

Yeah, there is no blend or level control on LM3...

 

[Zbysek]

One final issue to resolve is how to mute the upright bass. Probably not much of a problem to roll of the volume on the bass guitar since most people run them wide open when they are playing.

But most upright basses don't have a volume or mute. In order to maintain consistent volume levels, I prefer to avoid fiddling with gain and output controls on my amps and preamps. Using one side of an ABY pedal to switch the signal would work, but if the signal is line level I am not sure how long a regular AB pedal would work. Of course you are not switching when you are sending a hot signal, so it would probably be fine.

That’s why I prefer pedal preamps with mute switches. I (together with others probably) even talked Josh Broughton into upgrading his Messenger preamp with mute switch and other upright-friendly features...

 

[Zbysek]

If your amp has a parallel effects loop then you can just plug your upright preamp into that and call it a day. The bass guitar goes in to the regular input and has eq etc. the upright preamp will want a mute, your bass guitar can be muted with its volume knob.

After spending hundreds experimenting with double channel preamps and full blown pedal boards I discovered the perfect solution was hidden in my amp the whole time.... but it does depend on the signal path of your amp.

What’s your amp?