Anyone use an ABY splitter box for guitar?

[Rolsen]

I'm thinking about utilizing both the Normal and Top Boost channels on my AC30 (a newer chinese one). Here is what I've gathered thus far: passive boxes are fine for a/b mode, but for the combo 'Y' mode, some sort of buffer is required before the splitter to prevent tone anemia. Active ones usually have the buffer (I think) but are expensive. Anyone really happy or really sad about their a/b/y box? Also, those who purport to know would say that my buffered pedal that I would use in front of a passive box, a Boss TU-2, sucks your tone up like a milkshake. I hear something when I take this out of my signal chain, but not anything drastic.

[shedshrine]

This little labs unit centurymantra's got in the TapeOp buy/sell/trade looks interesting..

http://messageboard.tapeop.com/viewtopic.php?t=56418

[joel hamilton]

ProCo made one for a while. I use one of those quite a bit. I also just use the whirlwind one a lot as well.
I just set up the amp after getting the ABY box in place, or else it always feels like something is different. Even if you just add any old pedal to the setup after getting the guitar/amp/mic setup, things will change. there isnt a box on earth that doesnt change your tone even if just a little bit.

[ashcat_lt]

Usually, the discusion re: buffer-induced tone suck centers around the use of a number of non-true-bypassed pedals, in bypass mode, in a chain.

The first reason this is considered bad is pretty straightforward. Basically, any unnecessary circuit between the guitar and the amp should be avoided. In these pedals, the signal goes through the buffer at all times, even when the effect is disconnected. This buffer will add some (hopefully)small amount of noise. It might also have some effect on your tone. At the very least, the signal will have to go through one or two AC coupling (aka "DC blocking") caps, which will roll of the sub-harmonics of the guitar signal. This is not necessarily a bad thing. "Hi-pass early and often," I always say! Sometimes these caps are set a little bit high for a bass guitar...

Unless there's something seriously wrong with the design though, the buffer itself should be relatively transparent. This is an extremely simple circuit, and doesn't cost much in the way of parts nor time to build.

The other issue with these pedals is that - in most of them - the whole rest of the effect circuit is always connected at one end, usually the input. This could have the effect of unnecesarily loading the output of the buffer, and might cause some loss of hi-frequencies. Probably will also add some noise.

None of these are generally considered too terribly bad one at a time. That is, one bypassed pedal should be fine. It's when you're one of those freaks who's got to have a different pedal for each section of each song of the set that you run into trouble.

The two inputs in parrallel will present an input impedance lower than either of them on its own. Lowering the input impedance seen by a passive pickup will first decrease the amplitude of the resonant peak at the very highest frequency that your guitar can reproduce, then at even lower Zs, the cutoff frequency itself starts to shift downward (that knee is actually suprisingly low to begin with).

A single Hi-Z buffer will "protect" your pickups from this phenomenon. They will see the 1M presented by the buffer and not give a damn what happens beyond that point. In fact, the circuit involving the pickups essentially ends at the transistor/opamp. From there it's up to the buffer itself to provide the necessary juice to run the load.

The output Z of the buffer is usually inconsequentially small. At this point you can usually get away with splitting the signal a number of times to common audio inputs (whether marked line or instrument) before you run into loading issues, or cable-capacitance filtering...

...IF, of course, all the inputs to which you are splitting have similar input Zs. If they don't, all bets are off. You will get different signal levels at each of the inputs, and things might not divide out optimally, the inputs will interact in unsatisfactory ways, and it will be a big mess.

So usually a Y splitter consists of a total of 3 simple buffers. One to "protect" the pickups from everything else and the other two to "protect" each input from the other.

I regularly use a Boss Stereo Chorus in bypass mode as a Y-splitter without any ill effects that I care about.

On the other hand, I wondered to begin with why you don't just "daisy-chain" the two channels. I've done it on fenders and other such amps numerous times. Many old Fenders, like Supers and stuff, have 2 jacks for each channel. Plug guitar into one, short jumper cable from the second over to one of the inputs on the other channel. Done. Probably does have all the issues of impedance matching and loading which I mentioned above. It sounds so cool, though, who the fuck cares?

Here's a link to some simple buffers for guitar. And here's how to use that to make a splitter.

[TRIFECTA]

I am a huge aby user. I honestly feel it is the only way to utilize amps. I love using an orange for overdrive and my super reverb for clean and reverb, then my traynor is always on for blending purposes. I think it sounds FANTASTIC!
I use certain pedals with certain amps because they just take better to other ones. The biggest thing's when I was searching for an aby system was I needed one that did both channels on. Surprisingly I found most did not have that option. The other thing is the cheap aby pedals have tone loss or uneven between switching. The best one to get is one with transformers in it. Radial makes a GREAT one for good price!! Also keely is making one modeled for frampton and it is INCREDIBLE but pricey!

[ledogboy]

I'm trying to remember- but aren't the normal and brilliant channels on an AC-30 out of phase from one another? I can't recall for sure, but have to assume that is the reason I regularly jumper channels on my Marshalls, and never do on my Vox amps. While jumpering is cool, I presume the reason he wants to AB between the two is for different tones, and only occasionally for mixing the two.
I had decent luck with the standard Whirlwind ABY, but I'd definitely look into the Radial if I was planning on using this type of setup as my de-facto in a live setting. Have fun!

[RefD]

I'm trying to remember- but aren't the normal and brilliant channels on an AC-30 out of phase from one another? I can't recall for sure, but have to assume that is the reason I regularly jumper channels on my Marshalls, and never do on my Vox amps.

they have been on the few i've ever played thru.

[Rolsen]

I believe the older version's channels were out of phase with each other. The new AC30 Custom Classic is different in this regard, at least that's what the vox geeks report on some other forums. ABY'ing with this series of AC30 has been documented.

I've stumbled across a couple contenders:

1) a passive Radial, www.tonebone.com/re-bigshot-aby.htm (has a transformer on one channel plus a phase reverse switch, but has no LED's which kinda sucks, especially when you're the singer and trying to play and tap dance at the same time!)

2) Loop Master, www.loop-master.com (well reviewed, passive with led's, good price but takes 4 weeks for them to build and ship)

I've read lots of poor reviews of the Morleys - apparently lots of signal bleed and loud pops when switching

[Glide]

I run a 1968 Marshall Plexi and a Komet Concorde with a 1968 Marshall 4 x 12 in stereo with a tonebone. EL 34 Nirvana.

[Tears of Rage]

I'm thinking about utilizing both the Normal and Top Boost channels on my AC30 (a newer chinese one). Here is what I've gathered thus far: passive boxes are fine for a/b mode, but for the combo 'Y' mode, some sort of buffer is required before the splitter to prevent tone anemia. Active ones usually have the buffer (I think) but are expensive. Anyone really happy or really sad about their a/b/y box? Also, those who purport to know would say that my buffered pedal that I would use in front of a passive box, a Boss TU-2, sucks your tone up like a milkshake. I hear something when I take this out of my signal chain, but not anything drastic.

If you're using amps that have any gain, stay away from the passive ABY / ABCY boxes (like Rapco, etc.). They fuck with the tone, rob dB, etc.

I have much experience with Kendricks's ABC/Y box, which is buffered. I would not recommend it to anyone. All sorts of grounding issues, which you have to spend lots of time with....lots of trial and error, guessing which amp(s) to lift, etc. Also, it's supposed to be transparent, but it just isn't. Also can hear signal bleedthrough to amps that are switched "off." I've had this box for 10+ years...finally had to stop using it. It plain sucks.

The two that I have been most impressed with are made by Lehle and also the Framptone. Both are buffered and very transparent.