help me make a mid control

[thetragichero]

okay so instead of your standard tmb stack I'd like to throw a more effective mid control along with maybe a James (love me some James tone stack!). i was thinking of something low Q, couple of octaves centered around 600hz or so. I've got a number of inductors around, so i searched for a calculator for a simple lcr filter and ended up with this:



I've got at least two triodes available (half a 12ax7 and half a 12au7), but coming to difficulties on designing for tubes (pretty sure i could make a mid boost/cut with a single op amp)
i have looked at a number of schematics, most helpful were ampeg (most of them use four triodes, one version of the v4 uses three. all seem to use more switching and options than I'd like)

I'm open to suggestions!

[Stevem]

Is this for guitar or bass?
600 HZ even for guitar is getting pretty high up out of the mid range , as a high D on the E string is less then 1200 HZ if I recall right

[thetragichero]

guitar. i might play with frequency, that was just the first number that popped into my mind with values that would work in the real world. to me the exact frequency is like the seasoning added to make it tasty. I'm just looking for the recipe to experiment with. i suppose i could investigate "tube differential amplifier" (just thought of it now)
I'm a pretty good googler so part of the reason for the thread is so that the next hack like me who's looking to do this will have an easier time. wu's for the kids, as the man said

[thetragichero]

I'm thinking if i run a phase splitter (concertina would be great), inverting out to one of the outer lugs of our mid pot (what value do ya think?), non-inverting out to the other outer lug. center lug to our lcr filter
all of that in parallel to our regular tone control, combined at a cathode follower?

[wpaulvogel]

A bridged T makes a wonderful midrange control. Drive it with a cathode follower for a flat response at full cw setting. Makes a great mid scoop, easy. 2 caps, a resistor and a pot. 600 hz is probably perfect for guitar because every string is producing strong harmonics. Low E 81hz is mixed with 162 & more.

[Kagliostro]

Someting to be tried



K

[roberto]

I posted a very simple and effective solution here, more than 10 years ago:
https://ampgarage.com/forum/viewtopic.p ... ids#p97649

[Kagliostro]

Ciao Robi

K

[Colossal]

I posted a very simple and effective solution here, more than 10 years ago:
https://ampgarage.com/forum/viewtopic.p ... ids#p97649

Thanks Roberto, that is helpful. I'm going to implement Bob I's Baxandall in my friend's bass amp.

[roberto]

OT

Ciao Franco!
So we "meet" on "foreign" sites where ideas stream faster.
I hope to see you more often!

/OT

[roberto]

Thanks Roberto, that is helpful. I'm going to implement Bob I's Baxandall in my friend's bass amp.

Glad you find it helpful.
It's something that is often needed in Baxandall-like eqs, but very rarely implemented.

[thetragichero]

I posted a very simple and effective solution here, more than 10 years ago:
https://ampgarage.com/forum/viewtopic.p ... ids#p97649

i have to plug everything into tsc myself but this looks to be the ticket! i prefer bax for treble and bass anyway so this is simple, elegant, and doesn't require extra tubes
thank you thank you!

[Kagliostro]

Excuse me, just a moment for a short OT

So we "meet" on "foreign" sites where ideas stream faster.

and fortunately , in our area things are now extremely slow

I hope to see you more often!

I too

Thanks, OT closed

--

Just put a 1MA pot instead of the switch: you'll have a midboost by pot.

connected as rheostat I suppose

Franco

[roberto]

Yes Franco, correct.

[Kagliostro]

OK

Franco