signal splitting, buffers at the end of a chain

[liddokun]

I've done some searching, and I found some useful threads, but not something that really answers my question. I'm sure someone could give me a simple yes or no, or a few suggestions.

I need to split my signal from one guitar to go to two different amps at the same time.
I found this over at Jack's site:http://www.muzique.com/lab/splitter.htm

He suggests using it at the start of the chain, guitar going directly into the input. But will this work fine at the end of a chain? Say, guitar>pedals>signal splitter >amp a and amp b?
I don't need to adjust the circuit any way except perhaps what's suggested there by Jack?

[R.G.]

I need to split my signal from one guitar to go to two different amps at the same time.

He suggests using it at the start of the chain, guitar going directly into the input. But will this work fine at the end of a chain? Say, guitar>pedals>signal splitter >amp a and amp b?
I don't need to adjust the circuit any way except perhaps what's suggested there by Jack?

I believe that the article in question is primarily concerned with the use of an input buffer, not an output buffer. They're different. Here's why.

- a guitar is a variable impedance source; it has a low frequency impedance of a few k ohms to maybe 20K ohms. This rises with increasing frequency because the pickup is a huge inductor. It peaks out somewhere around 4KHz to 10KHz when the 1H (Yes, one HENRY) to 6H inductance is shunted by the coil's self capactance and the impedance starts down again. But the impedance of the coil up near the peak is maybe 100K to 200K. This is where the treble is.
- loading of less than 500k on up will noticeably diminish the treble you hear; this is the "tone sucking" you hear about.
- every foot of cable driven by the pickup also eats treble because cable is a capacitor.
- an input buffer removes essentially all of the input loading by appearing to be a very big resistor. The guitar's treble is not compromised by the effect, no matter what it is, because the buffer "protects" the guitar's pickup from the effect loading and cable loading.
- a splitter (a) buffers the guitar from loading and (b) provides enough output to drive more than one effect or amp without loading the guitar.
- an amp splitter in particular is a different animal, for a different reason. Amps are AC power driven, and they have different AC potentials. They are very prone to causing hum. An amp splitter needs to do something about that AC hum problem.

So an effects chain buffer is not equal to an amp splitter in most cases.

What you want is a (a) buffered input, (b) isolating output amp splitter. A good isolating A/B/Y box which is set to "Y" is what you want. Actually, an A/B/Y with no "A" or "B", only Y and with isolated outputs.

[liddokun]

Thanks for the reply, R.G.

This seems to be more troublesom than I suspected. So, would the JFET splitter work to split the guitar at the beginning of the signal going into two different effects chains, but would not work at the end of a single effects  chain feeding two amps simultaneously?

So your improved hum free A/B/Y would be what I'm after, correct? Does it have the option to run one signal to two amps at the same time as well as selecting between just one or the other amp?


EDIT: After inspecting your circuit further R.G., seems like it's exactly what I need. I was going to omit the switching and just have the signal run to A and B all the time, but might be useful to have the amp select switch too.  

FURTHER EDIT: I noticed this your humfree a/b/y requires bipolar power. Can I use this project here at tonepad :http://tonepad.com/getFile.asp?id=118
to eliminate the need for 2 batteries?