ABY switching pedal problem

[Tunathedog]

Hi All

I hope it's OK to post about repair/customization rather than building from scratch. I have a secondhand Morley ABY pedal. Problem is, I can't get an even signal out. Something input to just A or B sounds fine, but if I do A+B, then one of them will get much quieter with attenuated high frequencies. I tried a looper pedal in A and guitar in B; the guitar lost that fight until I added a buffer pedal to the chain. If I switched looper to B and guitar to A it was still the guitar that got weaker.

I replaced a couple of 100k resistors that seemed to have gone open (one on each channel), but the LEDs and the two other resistors seem to be working fine, and that's about it for components.

Any ideas how I can fix it or what might be going wrong? Is this normal for an ABY pedal?

Thanks!

Caspar

[GGBB]

That could be completely normal depending on what you plug in. I don't think the Morley uses any buffers between inputs, so when you have both on they are connected directly to each other - not unlike using a y-splitter in reverse - and therefore bring down the impedance seen by each, which - again depending on what it is - can cause tone loss. Basically you have to use buffers if you want both on at the same time. The Morley is not faulty - it's just doing what it does.

[ElectricDruid]

From your description, it sounds like it's this thing:



I'm not surprised you're finding problems. It's a very basic mix, just tying the outputs of the two pedals together directly. There's no real mixing going on - just the two outputs fighting. So, yeah, for *that* ABY pedal, I'd say it's quite normal.

[iainpunk]

yes, that morely pedal is designed to SPLIT one signal in to two paths, its not a mixer, which is what you seem to want.

there are plenty mixer designs on the web, from a simple passive mixer to somewhat complex active mixers.
there are also buffered splitters and mixers in one pedal.

cheers

[Tunathedog]

Thanks all. So it sounds like it's just the Morley design. Time to build another buffer pedal so I can do one per input. (Incidentally, it does advertise itself as a splitter and mixer - just evidently doesn't do the mixing so well.)

[GibsonGM]

Is there room inside it to use couple of opamps to do the job? Or JFETs...

[GGBB]

Is there room inside it to use couple of opamps to do the job? Or JFETs...

I had the same thought. Should be plenty of room. But it will make the box only usable in one direction unless switching was added.

[bluebunny]

That's a terrible design.  Indeed, using the word "design" is a bit generous!  A device whose function is to short the outputs of your pedals is never going to end well.  And for the cost of two resistors, you would avoid the fighting that Tom rightly points out will otherwise ensue.  Shame on you, Morley.

[GibsonGM]

But, they saved 3 cents per unit....  

[GGBB]

That's a terrible design.  Indeed, using the word "design" is a bit generous!  A device whose function is to short the outputs of your pedals is never going to end well.  And for the cost of two resistors, you would avoid the fighting that Tom rightly points out will otherwise ensue.  Shame on you, Morley.

Ahh, but some perspective helps. I think the original intent was to solve a very common problem - switching between two guitars into one amp or one guitar into two amps - or your Fender's two amp channels. For that, it's perfect, and you certainly can't complain about Morley build quality. After all it is apparently "one of the most popular utility pedals of all time." And they do recommend other products tailored for splitting and mixing. https://www.morleyproducts.com/tag/switching-pedals/

(Not affiliated, just a fan.)

[bluebunny]

That's a fair point, Gord.

[ElectricDruid]

I think the original intent was to solve a very common problem - switching between two guitars into one amp or one guitar into two amps - or your Fender's two amp channels. For that, it's perfect, and you certainly can't complain about Morley build quality.

Ok, I can see how that works for the A/B switching (in either direction) but what's the "A&B" for? Why would I want to connect my two guitars together at once, or connect my two amp channels together at once? Just curious.

[GGBB]

Ok, I can see how that works for the A/B switching (in either direction) but what's the "A&B" for? Why would I want to connect my two guitars together at once, or connect my two amp channels together at once? Just curious.

Not sure about playing both channels of the same amp at the same time but I suppose that's possible.

Two amp setup?

Dry / wet?

Kids do the darndest things?

[Gargaman]

"Please note that for splitting your signal we recommend using the ABY MIX or ABY Pro as those are better suited for splitting"



There are so many 'A's on the enclosure..I bet you can get lost

[ElectricDruid]

Kids do the darndest things?

Lol! Gord, that might just be it.

[iainpunk]

I think the original intent was to solve a very common problem - switching between two guitars into one amp or one guitar into two amps - or your Fender's two amp channels. For that, it's perfect, and you certainly can't complain about Morley build quality.

Ok, I can see how that works for the A/B switching (in either direction) but what's the "A&B" for? Why would I want to connect my two guitars together at once, or connect my two amp channels together at once? Just curious.

so you never jumped the channels on a fender amp? that's how you unlock the magic!
both channels get added together for more signal tp hit the power section for more natural breakup

cheers

[ElectricDruid]

so you never jumped the channels on a fender amp? that's how you unlock the magic!
both channels get added together for more signal tp hit the power section for more natural breakup

I can't tell if this is serious or not.

Either way, I never had a fender amp *at all*, so it's a moot point!

[GibsonGM]

so you never jumped the channels on a fender amp? that's how you unlock the magic!
both channels get added together for more signal tp hit the power section for more natural breakup

I can't tell if this is serious or not.

Either way, I never had a fender amp *at all*, so it's a moot point!

Oh, it's serious!  I wired my 18W Marshall with a pull pot for the master vol to do just this.  They used to do it to Fenders too.   You can use both channels to color your tone, too. Not that it's what you'd want to do *all* the time, but sometimes, it IS magic