Mixer for preamps

[PRR]

> *Now* we're talkin'!

Still too extravagant. Each TL07x can drive many stage-loads without strain. We just make a direct and an inverted, switch each output jack to one or the other.

[swisher]

Thank you so much! 

[swisher]

Still too extravagant. Each TL07x can drive many stage-loads without strain. We just make a direct and an inverted, switch each output jack to one or the other.

Is it good solution to connect preamps like that? I mean - if I will turn volume down on one preamp isn't the volume up on three others?

[PRR]

> Is it good solution

There's no volume controls in the plan I posted.

If you "turn volume down on one preamp" that's probably what you want; one less than others?

Maybe I am not understanding the question.

[swisher]

Maybe I asked a question in a wrong way - sorry for my english, I'm still learning.
If you put two guitars to one preamp using Y cable, there will be a problem with the volume (because of volume pots in the guitar). If you turn down one guitar then the other one will be a little bit louder. And that's why I asked about this. I'm not sure but I think if I will turn down first preamp (pre-gain or volume) the other preamps will be a little bit louder because of this. Or am I wrong?

[PRR]

> two guitars to one preamp using Y cable, there will be a problem with the volume

Two (multiple) sources to one output, yes, they will fight.

One source to multiple good loads, no fight.

Think how house lights are wired. You have one power company. You can plug in 1, 2, 10 lights, they all work fine.

There is a problem if you have "bad" loads. If a "light" is really a short-circuit, when you plug it in "infinite" current will flow and pull the power company voltage down to zero. And the wires burn-up. In *power* systems we have fuses (breakers) to detect this and disconnect shorted loads before the wires burn down the house.

In small audio, usually we don't get "burn-up". But if one buffer is simply split to four loads, and one of those loads is shorted, the other 3 outputs also go to zero volts, no signal. But we can usually design a resistor to put in each output, which will not reduce the voltage to a good load (enough to matter), but limits the current into a shorted load so that the buffer is not over-loaded.

[swisher]

I finished PCB for splitter, I hope it will works Now I'm working on mixer part. Three questions:
- what do you think about J175s for muting instead of relays?
- can I use common supply for two mixers or should I separate it?
- can I use common supply for splitter and mixers?

[ElectricDruid]

I finished PCB for splitter, I hope it will works Now I'm working on mixer part.

Good work! good luck with it!

Two questions:

Well, technically, I think I count three, but I'm being pedantic

- what do you think about J175s for mutting instead of relays?

I don't like either option so I'm not the right person to ask. I'd probably use FETs over relays if pushed.

- can I use common supply for two mixers or should I separate it?
- can I use common supply for splitter and mixers?

Yes, you can use the same supply for everything, as long as it can supply enough current. For simple low power stuff like mixers and splitters, that shouldn't be a problem.

HTH,
Tom