Splitting Audio Signal

[Brandon]

I am thinking about starting a project where I will need to split an
input audio signal (from a guitar) into two matching output signals.
To put it simply, I need to "Y" an audio signal. Sounds pretty
simple, right? I'm wondering what the best approach is though. First
of all, are there any IC's out there that would make this easy? If
not, how might I go about doing this without an IC? I was talking to
a friend at work and one suggestion was to amplify the input and send
it through two audio transformers. Does that sound like an acceptable
solution? Any help would be appreciated.

-Brandon

 

[Phil Allison]

"Brandon"

I am thinking about starting a project where I will need to split an
input audio signal (from a guitar) into two matching output signals.
To put it simply, I need to "Y" an audio signal. Sounds pretty
simple, right? I'm wondering what the best approach is though.

** Make or buy a Y lead.

Many guitar amps have dual inputs (1 & 2), so you can run a lead from jack 2
of one amp to jack 1 of the other - the plug into jack 1 of the first amp.



....... Phil

 

[Brandon]

I am thinking about starting a project where I will need to split an
input audio signal (from a guitar) into two matching output signals.
To put it simply, I need to "Y" an audio signal. Sounds pretty
simple, right? I'm wondering what the best approach is though.

** Make or buy a Y lead.

Many guitar amps have dual inputs (1 & 2), so you can run a lead from jack 2
of one amp to jack 1 of the other - the plug into jack 1 of the first amp.

Hi Phil. Thanks for the quick response. Guitar equipment is kind of
what this is for but think more along the line of building an effects
pedal than running one guitar into two amps. Leaving the application
out of this, what I need to do is split one input signal into two
"isolated" output signals that will have a 1 dB gain. Using a plain
"Y," the gain on each output would be less than 1 dB and would depend
on each output's load.

Surely there is an IC that would do something like this.

-Brandon

 

[Eeyore]

Brandon wrote:

Surely there is an IC that would do something like this.

What you need is a 'circuit' not 'an IC', an IC on its own is not enough. The kind
of IC normally used within audio preamp circuits is an op-amp and there are
several dozen or so very acceptable types suitable for audio ranging from tens of
cents each to tens of dollars for esoteric ones.

I suggest that you buffer the guitar output with an op-amp stage, this will
prevent the 2 loads affecting the sound of the guitar. Transformer isoaltion of
the 2 outputs may not be necessary depending on what you plan to conenct them too.
More info please.

Do you want this to be battery powered btw ?

Graham

 

[Jon Slaughter]

"Brandon" <bcr07548@creighton.edu> wrote in message
news:5efa2054-53ac-4c06-8e24-0b8617642b93@p69g2000hsa.googlegroups.com...

I am thinking about starting a project where I will need to split an
input audio signal (from a guitar) into two matching output signals.
To put it simply, I need to "Y" an audio signal. Sounds pretty
simple, right? I'm wondering what the best approach is though. First
of all, are there any IC's out there that would make this easy? If
not, how might I go about doing this without an IC? I was talking to
a friend at work and one suggestion was to amplify the input and send
it through two audio transformers. Does that sound like an acceptable
solution? Any help would be appreciated.

You use buffers or op amps.

Basically if you don't use some type of buffer then the two devices, unless
very high impedence, will interact with each other.

If you don't have any op amps/buffers handy then you could try just making a
y cable. If the inputs to the two devices your trying to connect to are high
impedence then it will probably work. If not then a buffer should work.

Basically what happens is that one or both of the device load the guitar so
that you are not sampling the true signal. Adding buffer's isolates the
guitar from the devices. Any op amp should work but there are many
specifically for audio that will do a better job(probably any will do if
your not trying to make hi fi).

There may or may not be specific IC's that do this but probably quicker just
to use some op amps if you got them. The transformers would work but
probably not the easiest way unless you happen to have two audio
transformers handy. With the op amps you will need a power source and that
is probably its biggest drawback.

What kinda devices are you trying to run the guitar signal into? Most
should have high impedence inputs in the first place so you probably should
need to do this.

You can configure the op amps as buffers or amplifiers as they will
accomplish the same goal but the amplifier will obviously amplify the
signal(Which you could add a pot to make it variable).

 

[Brandon]

Surely there is an IC that would do something like this.

What you need is a 'circuit' not 'an IC', an IC on its own is not enough. The kind
of IC normally used within audio preamp circuits is an op-amp and there are
several dozen or so very acceptable types suitable for audio ranging from tens of
cents each to tens of dollars for esoteric ones.

I suggest that you buffer the guitar output with an op-amp stage, this will
prevent the 2 loads affecting the sound of the guitar. Transformer isoaltion of
the 2 outputs may not be necessary depending on what you plan to conenct them too.
More info please.

Do you want this to be battery powered btw ?

Graham

Thanks for the reply Graham. This will be battery powered and what
each output will be connected to could vary, which is why it is
important that the load of one output not have much effect on the
other. Maybe an output will be connected to an amp, maybe another
effects pedal, who knows. Standard musical electronics though.

I have a few op-amps laying around actually but I'm still not sure how
I would get two output from a conventional 8-pin op-amp. Adding an op-
amp would buffer the input and give me a single amplified output but
how would I split that output is the question. If I used an
instrument as an input to an op-amp and used the output as one of the
two outputs I am after, could that output be used as the input to
another op-amp without affecting the "quality" of the signal?
Essentially, what I am getting at is "chaining" op-amps so each output
is being used as the input for another op-amp AND being sent off
somewhere for someone's eventual listening pleasure.

 

[Eeyore]

Brandon wrote:

Surely there is an IC that would do something like this.

What you need is a 'circuit' not 'an IC', an IC on its own is not enough. The kind
of IC normally used within audio preamp circuits is an op-amp and there are
several dozen or so very acceptable types suitable for audio ranging from tens of
cents each to tens of dollars for esoteric ones.

I suggest that you buffer the guitar output with an op-amp stage, this will
prevent the 2 loads affecting the sound of the guitar. Transformer isoaltion of
the 2 outputs may not be necessary depending on what you plan to conenct them too.
More info please.

Do you want this to be battery powered btw ?


Thanks for the reply Graham. This will be battery powered

There are implications here regarding battery life versus some aspect of performance,
notably the ultimate signal to noise ratio but I reckon you'll be OK with TI's TLC27x
op-amps (that's a low power type). The current draw of various audio op-amps varies
significantly.

and what each output will be connected to could vary, which is why it is
important that the load of one output not have much effect on the
other.

Exactly. The guitar on its own likes to see a very high impedance load or the 'tone'
will be affected.

Maybe an output will be connected to an amp, maybe another
effects pedal, who knows. Standard musical electronics though.

Ok. As long as there are no potential 'earth loop' issues, you won't need the outputs to
be transformer isolated from each other.

I have a few op-amps laying around actually but I'm still not sure how
I would get two output from a conventional 8-pin op-amp.

Conceptually, you just need 2 'isolating resistors' driving the 2 output jacks connected
to a common output from the buffer stage.

Adding an op- amp would buffer the input and give me a single amplified output but
how would I split that output is the question.

With those 2 resistors. That's all you need to avoid any unwanted loading effects on one
output influencing the other output. You could of course add more buffers but that'll
decrease battery life.

If I used an instrument as an input to an op-amp and used the output as one of the
two outputs I am after, could that output be used as the input to
another op-amp without affecting the "quality" of the signal?

Absolutely yes.

Essentially, what I am getting at is "chaining" op-amps so each output
is being used as the input for another op-amp AND being sent off
somewhere for someone's eventual listening pleasure.

The multiple buffering is the kind of thing you'll find in high-end pro kit but is not
strictly necessary in your application IMHO.

Graham

 

[Phil Allison]

"Brandon

I am thinking about starting a project where I will need to split an
input audio signal (from a guitar) into two matching output signals.
To put it simply, I need to "Y" an audio signal. Sounds pretty
simple, right? I'm wondering what the best approach is though.

** Make or buy a Y lead.

Many guitar amps have dual inputs (1 & 2), so you can run a lead from
jack 2
of one amp to jack 1 of the other - the plug into jack 1 of the first
amp.

Hi Phil. Thanks for the quick response. Guitar equipment is kind of
what this is for but think more along the line of building an effects
pedal than running one guitar into two amps. Leaving the application
out of this, what I need to do is split one input signal into two
"isolated" output signals that will have a 1 dB gain.

** I simply do not believe you have any need for " isolation " or 1 dB gain.

You cannot leave the aplication out and expect anyone with a brain to
still take you seriously.

Prove it, or fuck off.




....... Phil

 

[Brandon]

On Nov 21, 2:57 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:

Brandon wrote:
Surely there is an IC that would do something like this.

What you need is a 'circuit' not 'an IC', an IC on its own is not enough. The kind
of IC normally used within audio preamp circuits is an op-amp and there are
several dozen or so very acceptable types suitable for audio ranging from tens of
cents each to tens of dollars for esoteric ones.

I suggest that you buffer the guitar output with an op-amp stage, this will
prevent the 2 loads affecting the sound of the guitar. Transformer isoaltion of
the 2 outputs may not be necessary depending on what you plan to conenct them too.
More info please.

Do you want this to be battery powered btw ?

Thanks for the reply Graham. This will be battery powered

There are implications here regarding battery life versus some aspect of performance,
notably the ultimate signal to noise ratio but I reckon you'll be OK with TI's TLC27x
op-amps (that's a low power type). The current draw of various audio op-amps varies
significantly.

and what each output will be connected to could vary, which is why it is
important that the load of one output not have much effect on the
other.

Exactly. The guitar on its own likes to see a very high impedance load or the 'tone'
will be affected.

Maybe an output will be connected to an amp, maybe another
effects pedal, who knows. Standard musical electronics though.

Ok. As long as there are no potential 'earth loop' issues, you won't need the outputs to
be transformer isolated from each other.

I have a few op-amps laying around actually but I'm still not sure how
I would get two output from a conventional 8-pin op-amp.

Conceptually, you just need 2 'isolating resistors' driving the 2 output jacks connected
to a common output from the buffer stage.

Adding an op- amp would buffer the input and give me a single amplified output but
how would I split that output is the question.

With those 2 resistors. That's all you need to avoid any unwanted loading effects on one
output influencing the other output. You could of course add more buffers but that'll
decrease battery life.

If I used an instrument as an input to an op-amp and used the output as one of the
two outputs I am after, could that output be used as the input to
another op-amp without affecting the "quality" of the signal?

Absolutely yes.

Essentially, what I am getting at is "chaining" op-amps so each output
is being used as the input for another op-amp AND being sent off
somewhere for someone's eventual listening pleasure.

The multiple buffering is the kind of thing you'll find in high-end pro kit but is not
strictly necessary in your application IMHO.

Graham

Thanks again for the reply Graham. That helped a lot and I think I
have a good starting point (along with the help of an electrical
engineer friend of mine.) Actually, I figure I will be running this
off of a power adapter so battery life shouldn't be much of an issue.
Using multiple op-amps might be overkill but I might do it just to try
to preserve the all-important "tone." Some guitar people are so picky
about things that might have the slightest effect on a signal's sound.

 

[Brandon]

** I simply do not believe you have any need for " isolation " or 1 dB gain.

You cannot leave the aplication out and expect anyone with a brain to
still take you seriously.

Prove it, or fuck off.

...... Phil

Man, so much hostility. I'm a computer programmer and I see a
lot of responses like yours where people are trying to weed out who is
genuine and who is asking for answers to homework. If it makes you
feel any better, I'm asking for myself, even if I'm far from an expert
about all this.

Maybe my application doesn't required buffered outputs and unity
gain. But here is what I was getting at. I am fairly new at most of
this but I'm trying to accomplish something that I think would be
fairly straight forward - take an audio signal and get two high
quality "copies" with similar gain and where the load on one won't
affect the other. What I was asking was how that is generally
accomplished.

And actually, now that I think about it, maybe an exact 1dB gain isn't
necessary but something pretty close would be. Many guitar effects
that might be used in conjunction with what I am working on will
depend on the signal's gain. Overdrive/distortion is probably the
best example of an effect that depends on gain. An input signal is
amplified to the point that it passes a threshold in a component
(diode, transistors, vacuum tube) where clipping occurs. If your
input has less gain, less clipping will occur, which is why it would
be important to keep the outputs' gain close to that of the input.

 

[Jamie]

Brandon wrote:

I am thinking about starting a project where I will need to split an
input audio signal (from a guitar) into two matching output signals.
To put it simply, I need to "Y" an audio signal. Sounds pretty
simple, right? I'm wondering what the best approach is though. First
of all, are there any IC's out there that would make this easy? If
not, how might I go about doing this without an IC? I was talking to
a friend at work and one suggestion was to amplify the input and send
it through two audio transformers. Does that sound like an acceptable
solution? Any help would be appreciated.

-Brandon
i've take to the TL08x line for simple audio..

the TL084 has 4 op's in it.

http://focus.ti.com/lit/ds/symlink/tl084.pdf
--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

 

[Phil Allison]

"Brandon the Bullshit Artist "

Phil Allison

** I simply do not believe you have any need for " isolation " or 1 dB
gain.

You cannot leave the aplication out and expect anyone with a brain to
still take you seriously.

Prove it, or fuck off.


Man, so much hostility. I'm a computer programmer

** Explains a whole lot - but justifies nothing.

Maybe my application doesn't required buffered outputs and unity
gain.

** Then fuck off.

But here is what I was getting at. I am fairly new at most of
this but I'm trying to accomplish something that I think would be
fairly straight forward - take an audio signal and get two high
quality "copies" with similar gain and where the load on one won't
affect the other. What I was asking was how that is generally
accomplished.

** Been answered.

And actually, now that I think about it, maybe an exact 1dB gain isn't
necessary but something pretty close would be. Many guitar effects
that might be used in conjunction with what I am working on will
depend on the signal's gain. Overdrive/distortion is probably the
best example of an effect that depends on gain. An input signal is
amplified to the point that it passes a threshold in a component
(diode, transistors, vacuum tube) where clipping occurs. If your
input has less gain, less clipping will occur, which is why it would
be important to keep the outputs' gain close to that of the input.

** You are nothing but a wanker and fool.

Fuck off.



........ Phil

 

[Eeyore]

Jamie wrote:

i've take to the TL08x line for simple audio..

That's a particularly stupid choice given that it was the sister TL07x line that
TI intended for audio.

Graham

 

[Jamie]

Eeyore wrote:

Jamie wrote:


i've take to the TL08x line for simple audio..


That's a particularly stupid choice given that it was the sister TL07x line that
TI intended for audio.

Graham

Talking about stupid, I noticed you stepped right up.

I picked that due to it's P-Channel fet input and the
device the poster wanted to use on it.

Go fly a kite..

--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

 

[Eeyore]

Jamie wrote:

Eeyore wrote:
Jamie wrote:

i've take to the TL08x line for simple audio..


That's a particularly stupid choice given that it was the sister TL07x line that
TI intended for audio.


Talking about stupid, I noticed you stepped right up.

I picked that due to it's P-Channel fet input and the
device the poster wanted to use on it.

Bollocks. The TL07x and 08x have the same internal design. The 07x is simply quieter.

Go fly a kite..

Go learn something and stop talking shit.

Graham

 

[Jamie]

Eeyore wrote:

Jamie wrote:


Eeyore wrote:

Jamie wrote:


i've take to the TL08x line for simple audio..


That's a particularly stupid choice given that it was the sister TL07x line that
TI intended for audio.


Talking about stupid, I noticed you stepped right up.

I picked that due to it's P-Channel fet input and the
device the poster wanted to use on it.


Bollocks. The TL07x and 08x have the same internal design. The 07x is simply quieter.



Go fly a kite..


Go learn something and stop talking shit.

Graham

Talking shit? You're one to talk.

Your nothing but full of shit, wanker!

The little difference in noise isn't going to
matter in this app and the 8x series are cheaper.

What a wanker..

You're a waste
of Band Space.

Btw, I just added "Wanker" to my spell check, it obviously
never heard of it how ever, i've have and seen the ramblings
of a wanker!.
Just thought you might want to know that little tidbit..


--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

 

[Brandon]

But here is what I was getting at. I am fairly new at most of
this but I'm trying to accomplish something that I think would be
fairly straight forward - take an audio signal and get two high
quality "copies" with similar gain and where the load on one won't
affect the other. What I was asking was how that is generally
accomplished.

** Been answered.

Yeah, by someone other than you. Worthless.

 

[Phil Allison]

"Brandon"


** Go drop dead

- you ASININE pile of autistic dog shit.





........ Phil

 

[The Captain]

Stop squabbling, children.

Phil Allison wrote:

"Brandon"


** Go drop dead

- you ASININE pile of autistic dog shit.





....... Phil