Build and Review: DIY Dual Mic Preamp (ESP P-66)

With my new audio interface I want to take advantage of all 6 analog inputs to record nice multitrack drum stems, so I'm adding 2 mic inputs with this preamp project. It's powered by 12V AC and should add two low-noise clean channels for dynamic microphones. I struggled mightily with this build so hopefully I can provide some insight to anyone else building this project!

Here's the song I recorded for the demo at the end:

[richardrgoodwin]

Best live 'magic smoke' capture I've seen in a while!

[Rob]

Excellent! As a woodworker, I always measure at least twice and as a circuit builder I check many more times. Also I like Linear Technologies LT1086 positive regulator over the lm317. However I love Li-ion batteries on a split rail. ESP is excellent. I have made his power amp and hope to do his preamp with tone controls next. Now if we can get more electricians to sing on YouTube, I'd give that a thumbs up to that too:).
Cheers, Rob

[ToysForTheGods]

I really appreciate the video. I have only two things to add from my perspective. Motherboard stand offs are super cheap and you can usually just drill an appropriate hole and they will almost always cut their own threads. And I do plan on building this almost identical to what you have done here but with combo XLR output jacks instead of 1/4" just for versatility.

[searchiemusic]

when you said 'you only need 4 mics for drums' i started sweating, i can barely manage 16 tracks on my reel to reel lmfao

[TheMusicRig]

Thanks for sharing the process of this build. Really cool mic pre.

[benridgway]

I had to watch the magical smoke release three times. Normally I only get to see the results but not the process.

[iblesbosuok]

Twist cables which connect pin#2 and pin#3 from XLR sockets to PCB. Pots cables also. Would increase interference immunity.
It is better to choose insulated sleeve output sockets to avoid ground loops. Use single ground connection between chassis and circuit's ground.
Use deserve quality 1:1 signal transformer to get floating balanced output.
Sorry for my terrible language.

[Wizardofgosz]

I didn't realize he had designed a microphone preamp. I just finished building his phono stage for fun even though my preamp has a phono stage it seem like a fun project. Now I need to go and look this project up and see if it's worth building.

[mikeykarisma]

I didn't expect the amazing ending!
Thank you for that!

[CarlosYounes]

Nice!
Gosto muito dos projetos ESP.
Muito honestos e sérios.
Parabéns pelos trabalhos eletrônicos e músicas.
The best regards
Cheers from São Paulo - Brasil

[uriel-heavensguardian]

Thank you for sharing this! This was an awesome watch!

[GeoffBosco]

“Four preamps should be all you need to record live drums.”

[bpn]

Great build but most importantly GREAT cover at the end. Any chance that you upload the whole song? To my ears, your voice suits it better than the original.

[MegaCadr]

I like how you specify “not successful”:)

[dez]

incredible video, love it. Great song as well,

[FernandoGonzalez-cnuu]

Cool video, but I really don't trust those boards from Elliot Sound. You really shouldn't have that many (or any) reversed footprints and switched power inputs. But you dealt with it like a champ! Good job, and nice music.

[Mtaalas]

I hope you completely cleaned the board after that capacitor blew up?
Electrolytic is corrosive. IPA and scrubbing gets rid of it...

[thedavesofourlives]

cool but... that effort and the power supply goes in the same box? Wouldn't an external supply be way quieter?

[ivanmaskov]

I was planing to build this preamp for years :) great stuff diy perks also made it but portable version for field recording.. Also i have steinberg, it has great preamps color wise but lot of noise, it has 2068d jrc opamp i am planing to upgrade it with lm4562 bi texas instrument.. Can you make video of you upgrading yours? I have low knowlage of eletronics

[ivolol]

Would have been nice if they put a simple Widlar transistor current sink in the design underneath the differential transistor pair, instead of just 2.2k resistors, usually really ups the CMRR