A/B

[Al Heeley]

I just threw this together;

Its not very complicated or very impressive but its really, really useful.
I can leave 2 guitars plugged in then hit the footswitch to change from one to the other without having to unplug the amp and fiddle about before the start of the next song.
I can have the bass plugged into the common then have either amp or tuner going off from the A/B box. That way i can kill the bass at half time without worrying about feedback or volume controls.
I can use it with my lead guitar to switch between 2 amps. All for about £8 of bits from maplins, and with a stereo jack theres the thrill of retro fitting some LEDs too when life gets a bit too pedestrian.
Really, should have done this years ago.

Edited January 13, 2009 by Al Heeley

[ziggenpuss]

That does sound like a useful piece of kit. I wish I had the talent and brains to be able to knock something up from bits.

It would be a brave person indeed that ever plugged anything into the mains that I'd been tinkering with

[bass_ferret]

You can probably buy a Beringher one for less than you spent on bits but most A/B/Y boxes are a lot more than that. Some are a lot prettier as well.

[silverfoxnik]

I quite like the functional look of it personally and I wish I had the wherewithal to make one myself... Certainly wouldn't want one with Beringher written on it either

[Protium]

What enclosure did you use?

[Finbar]

I have something that does this job which Red Onion made up for me - Has 2 LEDs to show which input is engaged, and I use it as the first thing on my pedalboard to switch between my wireless (for shows) and my normal lead (for practices). Just stops me plugging in and unplugging my wireless all the time.

So yeah, neat bit of kit

[tauzero]

My Behringer AB100 got noisy when mains-powered, so I put together the 2B|!2B box, which is two footswitches, each switching one channel on and off. Allows me to have either instrument switched on, or neither, so I can leave them on stands on a resonant stage with no fear of them feeding back halfway through the bingo. And I put LEDs on too. As I've got one 3-pole 2-way footswitch left over, I'll do a straight A-B box too.

[Al Heeley]

[quote]What enclosure did you use?[/quote]
Not pretty but works, its a simple Maplins die-cast metal enclosure.
[quote]You can probably buy a Beringher one for less than you spent on bits[/quote] sort of misses the point of (a) having all the bits anyway, and ( the enjoyment of figuring one out and putting it together yourself. I built a really great sounding Ibanez Tube Screamer clone from scratch, in the end it cost me a lot of time and components but if I wanted to just go and buy a ready made one I'd go onto ebay and learn nothing about how they work, how to put them together, etc. etc..
I think the 2 LED's is a good next step, one of the jacks is stereo so I can use that as a power-on and fit a couple of LEDs to it to show the switch status.

[Dubs]

how easy is it to make a simple A/B blender?

[Al Heeley]

Ah, interesting Q, I had a big thread on Talkbass and Guitar Nutz going about blend pots last year, trying to find a true blend pot for a passive bass ctrl, and I found all the ones sold in the various guitar parts outlets were not really true blend pots due to differences in the taper of the two pot tracks. This had the effect of reducing the volume significantly at the centre detent position due to bot tracks not being balanced taper. in the end I went back to a standard jazz-bass type with 2 separate vol pots - the change in overall volume throughout the blend pot sweep was a real pain. you ended up having to tweak the volume every time you reset the blend.
I understand with active systems you can get a more accurate track taper so the blend function becomes good enough to be of practical use. I think these tend to be 50k pots.
So it would be pretty easy to make a simple a/b blender, but to make a really good and useful one may be quite tricky.

[Dubs]

[quote name='Al Heeley' post='384789' date='Jan 19 2009, 11:12 AM']Ah, interesting Q, I had a big thread on Talkbass and Guitar Nutz going about blend pots last year, trying to find a true blend pot for a passive bass ctrl, and I found all the ones sold in the various guitar parts outlets were not really true blend pots due to differences in the taper of the two pot tracks. This had the effect of reducing the volume significantly at the centre detent position due to bot tracks not being balanced taper. in the end I went back to a standard jazz-bass type with 2 separate vol pots - the change in overall volume throughout the blend pot sweep was a real pain. you ended up having to tweak the volume every time you reset the blend.
I understand with active systems you can get a more accurate track taper so the blend function becomes good enough to be of practical use. I think these tend to be 50k pots.
So it would be pretty easy to make a simple a/b blender, but to make a really good and useful one may be quite tricky.[/quote]

Cheers for the info. So only an active blender would be worth investigating – I might have to look into that…

[Kev]

i just nabbed a boss ls-2 and its a great blender, no tone suck at all in my setup, and more flexible than alot of the more boutique blenders out there

[Al Heeley]

Here's a little pic from StewMac's site:

This is the basis for a passive blend, but you would need a blend pot with true linear taper. I have not managed to find one yet that blends properly to make it work well enough.

[Al Heeley]

Here's a schematic for an A/B/Y box with pretty LED's

I am ordering some more LEDS and 3PDT footswitches to put one of these together as my next stompbox project.
(Note: Obviously still a passive box, battery is just used to power the LED indicators.)


***If it looks like some of the wires are missing you have to click on the pic to get full size, the lines are only 1 px wide***

Edited January 20, 2009 by Al Heeley

[Dubs]

[quote name='Al Heeley' post='386410' date='Jan 20 2009, 05:04 PM']Here's a schematic for an A/B/Y box with pretty LED's

I am ordering some more LEDS and 3PDT footswitches to put one of these together as my next stompbox project.
(Note: Obviously still a passive box, battery is just used to power the LED indicators.)


***If it looks like some of the wires are missing you have to click on the pic to get full size, the lines are only 1 px wide***[/quote]

I’d be really interested to hear what you think of it if you do make it. If you think it’s good I might have to make my own.

[Al Heeley]

Well this works fine as an a/b in both directions (I/O socket) but I get a scary buzzing when I use it in A+B together to feed into one common output.
What I really need for gigs is an A/B + X/Y box.
The idea is I can leave 2 basses both plugged in for quick change and select either one or the other with the A/B switch, and I need to choose from 2 outputs, one for the amp and one to send the signal to the tuner and mute the amp. That would be ideal for me and I don't need to combine 2 signals together.
Here's a schematic I sketched out:

Its got 4 badly drawn LED's to show which input is selected and which output is selected.
Parts needed: 3 mono jack sockets
1 stereo jack socket
4 LED's
1 x 560ohm resistor for the LEDs
1 9V battery snap
1 x dpdt footswitch
1 x 3pdt footswitch
1 x Maplin die cast metal enclosure

Edited January 24, 2009 by Al Heeley

[Al Heeley]

Here's the A/B-X/Y box all finished and functioning correctly, no interference buxx and silent channel switching. Perfect for what I need on stage

[JakeBrownBass]

[quote name='Al Heeley' post='390446' date='Jan 24 2009, 03:31 PM']Here's the A/B-X/Y box all finished and functioning correctly, no interference buxx and silent channel switching. Perfect for what I need on stage
[/quote]

Hi all,

fancy making me just A/B/Y splitter box with LEDS please
I will happily pay you

It looks great!

Jake

[Al Heeley]

No prob, I'll pm you with the parts list and costs.
Got some more 3PDT switches coming in a week. Need to get another enclosure.
Cheers,
Al

Edited January 24, 2009 by Al Heeley

[Andyalfa]

This is probably a dumb question, but are there any cheap, commercially available A/B switch boxes to speed up my changing instruments half way though a set?

[StanRobinson]

[quote name='Andyalfa' post='391812' date='Jan 26 2009, 02:46 PM']This is probably a dumb question, but are there any cheap, commercially available A/B switch boxes to speed up my changing instruments half way though a set?[/quote]

Try Red Onion
[url="http://www.redonionsolutions.co.uk/Index.htm"]Red Onion[/url]

Cheers
SR

[Al Heeley]

Here's my set of 4 schematics for different splitter boxes:
1) straightforward A/B box with LED's, works 'both ways round'

2) ABY box with LED's - takes guitar input and splits to either A OR B OR both, for 1 guitar, 2 amps

3) ABC box, choose between 1 of 3 inputs to one common output, or 1 input to one of 3 outputs (not yet tested this one...)

4) My own favourite, the A/B + X/Y choose from 1 of 2 inputs and choose from 1 of 2 outputs. I use this for 2 guitars into either amp or tuner

[Al Heeley]

Here's Jake's A/B box: LED indicators, true bypass, can be used in reverse.

Edited January 31, 2009 by Al Heeley