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A/B/Y Box for 4 hole input Marshall
Posted: Sat Feb 08, 2014 11:08 am
by sickman82
Just a quick query. I'm looking to add a bit of versatility to my Super Lead with a diy A/B/Y box. Am I going to need a powered or passive switcher? I see some people saying they lose a bit of clarity/volume when the signal is split passively. All I want it for is to switch between inputs I and II, and have the option to bridge them.
Does anybody have a recommendation for a schematic? Many thanks.

Re: A/B/Y Box for 4 hole input Marshall
Posted: Tue Feb 11, 2014 11:41 pm
by Froumy
No reccomendations for a schematic, sry, just figure I'd give you a bump.
I use a Whirpool a/b/y for that purpose(common ground). It's covered in goop, so I can't tell you what the schematic is, but I've noticed no issues. If you wire it right, I don't see any reason that it'd be different than channel jumping.
I use a Tone Bone for multi - amp switching(amp1/amp2/both) in conjunction with the 4 holer a/b/y. Ground isolation a must.
If you ever see a multi amp setup in your future, be sure to include that feature. My local music shop seems to sell a bunch of home brew versions for $40(non-isolated grounds), so you can definitely put one together cheap. I'd definitely add a 9volt, and LED's to your switching circuit.
Re: A/B/Y Box for 4 hole input Marshall
Posted: Wed Feb 12, 2014 2:26 pm
by rgorke
I used a simple A/B box to go between inputs. the issue was the volume jump but it was doable.
Re: A/B/Y Box for 4 hole input Marshall
Posted: Thu Feb 13, 2014 6:19 am
by sickman82
Thanks for the input guys.
Just making sure before I go ahead and built it up. I guess it would make sense to make one that can cover everything anyway, just in case I do go for a two amp rig in future. Two Leads would certainly be nice, but a tad overkill for pubs and clubs!
On the other hand, it would be awesome!

Re: A/B/Y Box for 4 hole input Marshall
Posted: Mon Feb 17, 2014 1:08 am
by Am_I_Evil
You could simply make pedal with one switch that connect/disconnect two cables that comes from an amp, but probably in this case you would get some noise from outside... So I would add another small box with relay inside, so the cables from amp will be short as possible. This is just thinking,....
Re: A/B/Y Box for 4 hole input Marshall
Posted: Wed Mar 12, 2014 12:27 am
by sickman82
Well, I bought a Radial Big Shot ABY and received it yesterday. It totally sucks the tone from the amp. They claim on their site that it can do what I'm wanting to do, yet it's like putting a mattress in front of my cab.
It's passive, so perhaps a buffer would help? But that means spending more on something that isn't guaranteed to work. I tried a Zvex Super Hard on (closest thing I have to a buffer), but there was zero difference with that in front of the Big Shot.
What a bummer.. any of you guys know what I'm doing wrong?
Re: A/B/Y Box for 4 hole input Marshall
Posted: Sun May 25, 2014 6:55 pm
by neikeel
sickman82 wrote:Well, I bought a Radial Big Shot ABY and received it yesterday. It totally sucks the tone from the amp. They claim on their site that it can do what I'm wanting to do, yet it's like putting a mattress in front of my cab.
It's passive, so perhaps a buffer would help? But that means spending more on something that isn't guaranteed to work. I tried a Zvex Super Hard on (closest thing I have to a buffer), but there was zero difference with that in front of the Big Shot.
What a bummer.. any of you guys know what I'm doing wrong?
That is disappointing, but reassuring in a way....I was debating on whether to get a Lehle dual or a Radial JX-2 Switchbone as it has had pretty good reviews and seems pretty clean, it also has ability to tweak the pick up loading too
http://www.tonebone.com/switchbone.php. Confess I did not look at the Big Shot, given your experience glad I did not. Of course the JX-2 is three times the price and not passive!
My other ABY is a Star Touch passive (battery for lamps only) which is simple and quiet but there is a volume drop with split signal, ok with NMV switching if you boost the signal a little but less good with dual amp set up.
If anybody is thinking about the Lehle I bought the 'little' version (no tuner out but you can adjust it to make sure you do not get volume drops, it was cheaper. I have tried to use one of the amps out for my tuner but the buffer does screw with my signal = not good. I would consider the newer Lehle Dual which has three outputs (two amp and one tuner) but it is twice the price of the little one (around £220 in the UK

Re: A/B/Y Box for 4 hole input Marshall
Posted: Mon May 26, 2014 2:48 am
by emmjaydubya
I have used the Little Lehle (the white one) for years as a switcher between the channels on my Matchless DC-30. I like how it doesn't make a 'pop' when switching like some passive A/Bs. I'll eventually get one of the more elaborate ones that has a tuner out...