Splitting a signal to two amps.

[mnordbye]

I may be overthinking this, but does splitting the signal from the guitar (or pedalboard for that matter) to two amps need any buffers etc.? Or is it as easy as hardwiring the input jack to two output jacks?

Magnus

[mnordbye]

I am going to use both amps at once by the way.

Magnus

[mattthegamer463]

I would build a op amp distribution amplifier.  You don't want anything coming out of one amp and into the other...

Basically, take your guitar input, run it into two separate op amp circuits (unity gain would work fine) and then the outputs go to their respective amplifiers.

[wavley]

I've been known to do this several ways...

On old 4 input amps like old marshalls and traynors the inputs are in parallel so you can jump from one amp to the other, this has it's disadvantages; loading, ground loops and stuff.

You can do it by making a passive Y box by putting three jacks in parallel and it has the same problems.

Stereo out from a pedal works, say a stereo chorus or delay, but some of these things are either wet/dry outputs or turn one of the outputs off when the effect is disengaged (the RE-501 space echo is one of these things, everything works fine as long as the chorus is on, but no dry signal in one of the outs)

The best solution I've found is RG's Hum Free ABY, a buffer and isolation transformers breaks up ground loops and the buffer helps with the loading effect.

[mnordbye]

I would build a op amp distribution amplifier.  You don't want anything coming out of one amp and into the other...

Basically, take your guitar input, run it into two separate op amp circuits (unity gain would work fine) and then the outputs go to their respective amplifiers.

I thought as much, thanks for letting me now! Do you have an example of what kind of opamp circuit/schematic you would use?

Would you ground both output jacks to the chassis, or would you mount them isolated from the chassis, and ground them on the board instead? I think i read somewhere that there would be some noise involved when grounding them both to the chassis.

Magnus

[served]

You definitely need some thing with buffers, passive device is not a solution. Because splitted channels Resistances are alsodifferent. So you will not get same result like plugging your guitar straight to the amp. There are splitters out here. Use the search for schematic.

You shouldnot forget that amps input will change the signal. So you need different standalone channels.

[jolly1423]

I've done this two ways myself with great success. A morley amp selector (only like 50 bucks) and then you can choose with stomp switches, amp 'a', 'b', or both. Or I use my boss dd-20. Both outs are always on plus you get the added option of ping ponging delay. It's a little pricier option but a great digital delay pedal.

[MikeH]

I've done the passive split into 2 amps before and had it work fine; but they were both cranked

[wavley]

You definitely need some thing with buffers, passive device is not a solution. Because splitted channels Resistances are alsodifferent. So you will not get same result like plugging your guitar straight to the amp. There are splitters out here. Use the search for schematic.

You shouldnot forget that amps input will change the signal. So you need different standalone channels.

This is where I have to disagree.   Sometimes a passive device is the solution, like Jolly1423 said, he has the Morley amp selector which is just a passive Y with stomp switches.  People have been using them for years and many of them have had absolutely no problems, granted they can introduce ground loop problems and high frequency loss, much like when Jimi Hendrix played with a coil guitar cable into a wall of amps jumped together.  Was it technically the wrong thing to do?  Yes.  Did it sound good?  Yes.  A lot of great 60's and 70's tones were achieved by simple (and sometimes dangerous) means.

Will it change your tone? Yes.  Is that necessarily a bad thing?  This is a whole forum dedicated to changing your tone.

A buffered splitter works for you, just like RG's Hum Free works for me, but these are our opinions.  Which is why I gave options and explanations and didn't flame other people's opinions of what works for them.

[mnordbye]

Anyway, i like the idea of having more control, by splitting the guitar signal into two separate output "channels". I think i'll try to cook up something in that direction. Thanks for the help so far!

Magnus

[R.G.]

Or you could look at the splitter articles at GEOFEX... http://www.geofex.com

[served]

You definitely need some thing with buffers, passive device is not a solution. Because splitted channels Resistances are alsodifferent. So you will not get same result like plugging your guitar straight to the amp. There are splitters out here. Use the search for schematic.

You shouldnot forget that amps input will change the signal. So you need different standalone channels.

This is where I have to disagree.   Sometimes a passive device is the solution, like Jolly1423 said, he has the Morley amp selector which is just a passive Y with stomp switches.  People have been using them for years and many of them have had absolutely no problems, granted they can introduce ground loop problems and high frequency loss, much like when Jimi Hendrix played with a coil guitar cable into a wall of amps jumped together.  Was it technically the wrong thing to do?  Yes.  Did it sound good?  Yes.  A lot of great 60's and 70's tones were achieved by simple (and sometimes dangerous) means.

Will it change your tone? Yes.  Is that necessarily a bad thing?  This is a whole forum dedicated to changing your tone.

A buffered splitter works for you, just like RG's Hum Free works for me, but these are our opinions.  Which is why I gave options and explanations and didn't flame other people's opinions of what works for them.

I hear you. You should know that I didn't mean to push my idea on. I just said what I thought is the solution. I did not say that yours is wrong, or "no don't listen to what wavley said" I was saying what I thought is the solution with out any disrespect to any of you.
That is the bad thing about the internet, you cant read the Tone of your text, I get this really often sadly.
Maybe I should have added a line to my earlyer post " If I were you" which was the aspect I was writing on.

So I am really sorry if you felt offended.

[mnordbye]

Or you could look at the splitter articles at GEOFEX... http://www.geofex.com

Totally missed that one! I'll take a look at it. Thanks!

Magnus

[mnordbye]

I've been looking at the Geofex project mentioned by R.G. here http://www.geofex.com/FX_images/splitter.gif. And it looks like what i want in an Y-box. Though, i have a few questions.

Can someone elaborate on the quite advanced power supply part of the circuit? To me it seems kind of confusing. 

Second, if i don't want the Direct out feature, should i just remove the jack and the 1k resistor?

Magnus

[served]

Yes you can remove the jack and the resistor.

Why such a powersupply? The reason is that this op amp what is used there, needs -9V and +9V. It does not sadisfy with ground and +9V like usual.

If I remember correctly then there is a way to use one battery and some diodes to simulate this type of powersupply.

[mnordbye]

Yes you can remove the jack and the resistor.

Why such a powersupply? The reason is that this op amp what is used there, needs -9V and +9V. It does not sadisfy with ground and +9V like usual.

If I remember correctly then there is a way to use one battery and some diodes to simulate this type of powersupply.

I see. I'm not familiar with the 833 type IC. I'll check out the datasheet. Thanks!

[mnordbye]

Just came across an article over at AMZ. http://www.muzique.com/lab/splitter.htm . I like this idea, but will it suit my needs?

Magnus

EDIT: I guess it will not, since i need to do something about that AC hum problem, and isolate the output jacks.

[metallo]

Can someone elaborate on the quite advanced power supply part of the circuit?

This is already described in the picture. 

The 18V supply increases headroom.

The transistors switch the power, making one physical switch (the stereo input jack) switch two lines (pos and neg).

If you don't have huge signals coming down the input you will probably get along nicely with a single battery and the regular voltage divider/virtual ground supply.

[trixdropd]

Second, if i don't want the Direct out feature, should i just remove the jack and the 1k resistor?

Magnus

You can remove the direct out, but you will add hum by not having 1 solid ground to one of the amps. better to remove one of the transformer based outputs, so you have 1 direct out, and one transformer isolated out.

[wavley]

I hear you. You should know that I didn't mean to push my idea on. I just said what I thought is the solution. I did not say that yours is wrong, or "no don't listen to what wavley said" I was saying what I thought is the solution with out any disrespect to any of you.
That is the bad thing about the internet, you cant read the Tone of your text, I get this really often sadly.
Maybe I should have added a line to my earlyer post " If I were you" which was the aspect I was writing on.

So I am really sorry if you felt offended.

I apologize for going off on you a bit there, because as far as splitting goes I kind of agree with you, but what works for me isn't always the answer.  Personally like to give a lot of options, because sometimes people don't need to go through the trouble that someone with old a$$ stuff like me has to do to keep things quiet.

I think I also felt a bit dismissed...

In reply #3 I suggested R.G.'s Hum Free, then I said it worked for me again in a later post, then R.G. himself directs to his excellent article on splitting, then finally a light bulb went off.

Again, sorry.