Comments on: Stereo Vacuum Tube Studio EQ based on 1955 Circuit

By: Peter Engel

Peter Engel — Thu, 22 Aug 2024 20:03:12 +0000

Great work. Just one (dumb?) question: I don’t see a separate level control for the bass and treble. What am I missing?

By: Daryl Byron West

Daryl Byron West — Mon, 22 Apr 2024 02:50:25 +0000

In reply to Pief.

The dual-gang pots are easy to customise. Simply get two double-gang pots; one 250k and the other 500k. Dismantle both pots and remove the four carbon track substrates. Reinstall in the right configuration – e.g; lower 250k upper 500k (?)

I build custom pots all the time, for custom guitar wiring. Just be mindful how the pot comes apart and ensure you replicate the procedure for rebuilding; all you’re doing is swapping the carbon tracks around. Eeeezy Peeezy.

By: Paul Morison

Paul Morison — Fri, 31 Mar 2023 13:17:42 +0000

In reply to Pief.

Hi all
Thanks for building and testing this, fascinating
I have a Neutrik bode plotter, I will build this, and post the plots. Then we can see the various frequencies and the action of the Q controls!

When you say you used 2 tubes in parallel, is that just as it sounds, connect them pin for pin in parallel to lower the noise!

I’ll post plots as soon as it’s finished

Paul

By: Pablo

Pablo — Fri, 08 Jul 2022 11:12:01 +0000

In reply to Nicolás.

Hola Nicolas : Soy Pablo de Argentina . Podrías enviarme esos escaneos de revistas ? .. Me interesa !…Mi correo es pablitosax@yahoo.com

Saludos !

By: Markku

Markku — Mon, 27 Apr 2020 04:07:53 +0000

Correct me if I’m wrong but to me it seems that if you turn treble Q fully to ground side then gate is grounded and there is no signal at all in output. Should there be a resistor from wiper to gate like in bass side.

By: Lapiaga

Lapiaga — Sat, 25 Apr 2020 15:11:58 +0000

Fantastic and inspiring! Can we hear it?

By: Nate Nate

Nate Nate — Thu, 19 Mar 2020 21:29:43 +0000

Great build! Curious… Are there no input and output transformers?

By: admin

admin — Wed, 19 Sep 2018 19:44:10 +0000

In reply to Nicolás. hi Nicolás, sure, please send them... CR

By: admin

admin — Wed, 19 Sep 2018 19:43:28 +0000

In reply to Pief.

Hi Pief. Dual pots are made, but i couldn’t find one this body size with these values AND the long shaft.

I wish I had more time to post but life has gotten hectic and I waste too much time on instagram! I’m posting there most days, check it out if you haven’t already… same name…

By: Nicolás

Nicolás — Wed, 19 Sep 2018 18:41:31 +0000

In reply to admin.

That´s good. I have done it a few times also.
Another less useful tip: 16mm Alpha pots with pull switch only come in “guitar” values. You can also exchange those resistive elements with almost any other brand.

BTW, if I search the “schematics” tag, the latest post is about those Argentinian magazines I sent you… 3 years ago.
I have some more stuff. Do you want some scans?