Schematics of an A/B box?

[Surgeon]

Anyone? I've looked a couple places (Artie's page for example, which is FILLED with tons of great schematics) but I can't just find any... Maybe I didn't look hard enough or in the right spot... Anyone can post a link to one... Oh yeah, I'm not good enough with electronics to just come up with something...

thanks

 

[Artie]

Re: Schematics of an A/B box?

Hey Surg; The term A/B box can refer to any of several different functions:

1. Guitar signal to two different inputs.
2. Preamp signal to two different amps.
3. Power amp to two different cabs.

If its "1", I can post a link to a simple one later today.
2 is a bit more complicated, but still doable relatively easy.
3 is a major undertaking. I'm working on one, but its still got bugs, and it wouldn't be any cheaper right now, than a commercially available one.

Let me know.

Artie

 

[rhmcfarland]

Re: Schematics of an A/B box?

Fulltone has one... check his website

 

[Surgeon]

Re: Schematics of an A/B box?

Artie: Oh sorry... see how dumb I am about this stuff... Ok, well lucky for me it's number one... I wanna send my guitar signal to two amps...
I'd appreciate if you could post the link when you find 2 minutes...
Thanks a lot man, you're such a helpful fellah!

Rhm: thanks man!

 

[Artie]

Re: Schematics of an A/B box?

Artie: Oh sorry... see how dumb I am about this stuff... Ok, well lucky for me it's number one... I wanna send my guitar signal to two amps...
I'd appreciate if you could post the link when you find 2 minutes...
Thanks a lot man, you're such a helpful fellah!

Rhm: thanks man!

Cool . . . #1 is easy. Trouble is, I can't post it til I get home from work!

So, in about six hours! :yell:

(Although, If you want to do a search, I posted a pic of this for someone else - just can't remember who. You'ld have to search for "A/B box", or perhaps all posts by me.)

 

[Surgeon]

Re: Schematics of an A/B box?

Cool . . . #1 is easy. Trouble is, I can't post it til I get home from work!

So, in about six hours! :yell:

(Although, If you want to do a search, I posted a pic of this for someone else - just can't remember who. You'ld have to search for "A/B box", or perhaps all posts by me.)

Thanks, I'll try a search but if you don't mind and if it's not too much trouble, please post it tonight too... I'm at work also and can't spend much time here...

Gracias again,

Phil

 

[Artie]

Re: Schematics of an A/B box?

Thanks, I'll try a search but if you don't mind and if it's not too much trouble, please post it tonight too... I'm at work also and can't spend much time here...

Gracias again,

Phil

No prob. Besides, I just did the search, and it didn't show up. It may have been from the "old" forum.

Film at eleven!

 

[Surgeon]

Re: Schematics of an A/B box?

No prob. Besides, I just did the search, and it didn't show up. It may have been from the "old" forum.

Film at eleven!

 

[Bludave]

Re: Schematics of an A/B box?

Why not just go buy a Morley A/B box. I just saw one at GC for $39.00.

 

[Surgeon]

Re: Schematics of an A/B box?

Why not just go buy a Morley A/B box. I just saw one at GC for $39.00.

Because I want to have the fun of building it myself...

 

[Artie]

Re: Schematics of an A/B box?

Ok, in these diagrams, I use this switch form, to make it easier:

In this, A=A, B=B, etc.

So, here's the simplest form of A/B switch, (shown both ways):

That one is easy, because it only requires 1 SPDT switch, and three guitar jacks. The problem with that is, the input of the non-selected amp is left floating, and there may be ground loop problems since all grounds are connected together.

This is the next best way:

In this one, we've completely isolated the two amps, and their grounds from each other, by using a DPDT switch. We still have the problem of an amp input left "open" when not selected.

This one solves those problems:

This uses a 4PDT switch to simultaneously, isolate the grounds, and short the input of the non-selected amp. The downside, of course, being that a 4PDT footswitch will be a little harder to find. And a bit more costly.

See if this covers your question Surg. If not . . . I LOVE to draw.

Artie

 

[Artie]

Re: Schematics of an A/B box?

btw - all of those designs still share the common problem of possibly, (likely), inducing a "pop" into either/or amp when switched. That problem can be overcome, but it requires a little electronics in the circuit, and thus, power.

I can draw it up if you'ld like.

Artie

 

[Surgeon]

Re: Schematics of an A/B box?

Thanks a lot again Artie, that's really nice of you!

About the extra drawing... I'm no good: So everything you can add is most welcome!

A big thanks again!

 

[Artie]

Re: Schematics of an A/B box?

No prob Surgeon. Glad to help. That "last" schematic will take me a bit to get together. I've had it done on paper for quite some time, but I still have a couple small "bugs" to work out.

I'll try to get it done by this weekend.

 

[Surgeon]

Re: Schematics of an A/B box?

No prob Surgeon. Glad to help. That "last" schematic will take me a bit to get together. I've had it done on paper for quite some time, but I still have a couple small "bugs" to work out.

I'll try to get it done by this weekend.

I cannot thank you enough Artie, this is really nice of you... If you don't want to have to dig that thread back since it'll probably slip on a second if not third page you can just PM me... You can also dig up the thread, so everyone can benefit from your knowledge...

Thanks again,

Phil

 

[Artie]

Re: Schematics of an A/B box?

I cannot thank you enough Artie, this is really nice of you... If you don't want to have to dig that thread back since it'll probably slip on a second if not third page you can just PM me... You can also dig up the thread, so everyone can benefit from your knowledge...

Thanks again,

Phil

I'm right in the middle of finally getting off my butt, and getting my "Guitar Electronics" webpage together. Its just a link right now, but I hope to have the crux of the content done by mid-November.

All this info, and drawings will be on it. That way, folks will be able to link to pages there when the same questions come up, like 50's mod, pup splitting, etc.

 

[proxy]

Re: Schematics of an A/B box?

To get rid of that pop that those switches induce, sometimes sticking a 1 megaohm resistor will do the trick.

An A/B is pretty simple, but if you go with an A/B/Y make sure it has isolated grounds.

 

[Surgeon]

Re: Schematics of an A/B box?

I'm right in the middle of finally getting off my butt, and getting my "Guitar Electronics" webpage together. Its just a link right now, but I hope to have the crux of the content done by mid-November.

All this info, and drawings will be on it. That way, folks will be able to link to pages there when the same questions come up, like 50's mod, pup splitting, etc.

That's a great idea Artie! I'm sure folks will just love it... I know I will!