splitter/blend for Amp feed

[Ubertech_s]

HI All

can any one point me in the right direction for a circuit that will feed two amps safely and cleanly

ideally it would:

A/B two amps (switch)
A+B two amps with blend to mix between the outputs
have LEDs to display the selection
be low noise and transparent

Anybody got any ideas?

Thanks Shaun

[Neil mcNasty]

Have you tried to do a search for ABY Amp Switch?
Like THIS SEARCH?
There's loads of information on that on the web. Both Passive and active...

When you say "Blend to mix between the outputs"...
Do you mean like a volume adjust for each channel so that you can set the balance between them, or do you want it to blend ch1 into ch2 and the other way around?

[Ubertech_s]

Hi

Thanks for the answer - I feel a little stupid now as I hadnt done a basic search!

I have a couple of questions/clarifications

passive box -  involve simple connections and a battery for LED?
Active - more complex circuit involving transformers?

which is the best for use with a pair of amps?

When using a pair of valve amp is there any electrical risk to the guitarist, or pedals when using a passive box?

I was hoping to use the 'blend' to mix between the two outputs when using the Y - so fully left would be A, centre would be A+B, fully right would be B. I was after one balance knob for this, rather than one knob for each channel.

thanks in advance

[Neil mcNasty]

Don't feel stupid, feel lazy!

Ok. I'm not quite sure how to implement the Blend function that you specify, and I do have some problem seeing the need for this, since the switching already does that to your signal (decides where the signal will go)
You either have two switches that turns on/off each amp (A & B), or you have one switch that toggles between the two (A/B), and one that activates both (Y)
In my mind that eliminates the need for a blend.

Electrical Risk?
No! There is no electrical risk of any kind involved by using a passive switch.
It is no different than plugging your jack into the amp.

Re: the passive/active bit...
Yes. A passive switch would be just a couple of switches, jacks and some wiring + power/battery for the LED indicators. And is the easiest way to go.
An active circuit is much more complicated and is "supposed" to better, but then again you'll have issues like headroom to consider, specially if you like to push your amps hard with your pedals (like using a booster to push it into overdrive)
You can also add transformers to a passive circuit, not just the active ones...

Personally I use a passive switch because I set some of my pedals LOUD!
But I've also added a 42TU018 transformer with ground lift feature, for each channel in order to avoid ground hum between the amps.
This will lower your volume a little bit (transformer has a resistance equal to a 10K resistor in the audio path), but it reduces ground hum issues which is always present when running two amps at the same time.
But, these kind of ground hum issues are only noticeable if you play very quiet and in-between playing. When playing normal you'll probably never hear it.
And for the record: I've never used the ground lift feature so far...

So go the easy way first and build yourself a passive switcher and see how you like that.
Most of the time the simpler stuff works best!

Cheers!
Neil