My last Api'ish preamps

Hi folk,
want to show you two devices that I've built two weeks ago.
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The basic idea is to get microphone preamps with direct outputs and silent mutes with onboard mixer and reamp output with per-channel sends for feeding guitars effects/amps. And yes, it's all in the stompbox form factor for live performance on the stage!)
Circuitry preamp section inspired by 312 with a couple minor changes. Input transformers - EA2622 (Thanks Jeff Steiger for supplies!). 2520 opamp based on gar2520. As it rather difficult to fit output transformer in to the size of enclosure, I used that1646 as output bal buffers. Gain is changed by rotary switch. Slow start phantom power supply. In order to avoid clicks mute function is made on the relay with led indicator. Effects sends with pre/post mute. For visual control of the output volume - 5 segment signal led indicator on LM3915.
Circuitry summation based on 325 amp. Summing section has balanced line out or unbal guitar level out that inspired by NYD reamp schematic and use matching transformer.
The power supply is external for each devices.




here is block dia:

Hello,
congratulations for your build it looks really good.

Could you please elaborate more on it's uses and goals?

thanks

Whoops said:

Hello,
congratulations for your build it looks really good.

Could you please elaborate more on it's uses and goals?

thanks

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Hi, thanks!

Mainly that's a three api'sh preamp in one box with aux bus for creating parallel effects. That's it)

Do you use it live?

Whoops said:

Do you use it live?

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I built them for guys who use it live)

Well it looks great,
well done!

Whoops said:

Well it looks great,
well done!

Click to expand...

Thank you!

I've got a lot of information here, that's why I post preamps here. Who knows, may be information about my preamps would help to anyone else.

Looks really good.

How close are the foot switches to the knobs? Just wondering if any issues stepping on the knobs by accident.

john12ax7 said:

Looks really good.

How close are the foot switches to the knobs? Just wondering if any issues stepping on the knobs by accident.

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65.5mm between two footswitches and 40mm between footswitch and send knob.

That's some seriously nice kit you've created there 

Fab utility captured in  a compact yet quad-awesome format.

Rounded off with some really nice-to-haves, like the metering and adapability to preamp/sum etc at the pcbs - lends  some definite product-placement  appeal too!

I am mostly done with my 'api-ish preamp/sum'  builds, BUT I have to ask "do you have some  pcbs you could sell"

I'm doing something by way of a guitar DI with distribution amps and return-summing in a floor standing box.

Kind of a "one ring to rule them all' thing   For myself.

Some of your boards would be a real pro touch!

Well done

And  also, where can one get an enclosure like that - like a cast aly pedal box,  but BIG 

alexc said:

And  also, where can one get an enclosure like that - like a cast aly pedal box,  but BIG 

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That's standard GAINTA enclosures (well known as best choice for guitar pedals), model B019, with matte black spray paint.
You can find more here: http://www.gainta.com/en/al_die-cast-housing/al_b_case/

Regards pcb - as it was a custom project I've ordered just five boards, so no spares. Boards was created in pretty specific way, to keep in mind small sizes, connecting all spare wires and so on.