Inductor EQ

[hylaphone]

Hiya, I once had a schematic (which has since grown legs) of an amp from the 70's with an inductor based EQ along the lines of the SVT, but perhaps a few more bands?Does this ring a bell with anyone?

[CrimsonGhost]

Not a valve amp but some old Peavey solid state amps use inductors in the EQ section.

[hylaphone]

Not a valve amp but some old Peavey solid state amps use inductors in the EQ section.

Thanks, but IIRC this was happening between a couple triodes. Pretty sure it was one of the big 70's amps (400PS, SVT, etc.) just can't remember for the life of me

[shooter]

i spent hours look'n through Doug's porn collection, maybe you'll find that special TS 


https://el34world.com/charts/TubeAmpSchematics.htm

[Carlsoti]

It's not the 400PS.

[HotBluePlates]

... Pretty sure it was one of the big 70's amps (400PS, SVT, etc.) just can't remember for the life of me

Ampeg SVT

Careful if you copy:  coils like to pick up hum.

(EDIT: Sorry, this is wrong because it's not multi-frequency as requested.)

[hylaphone]

Ah, I found it.Fender 300PSThanks

[kagliostro]

Which is your interest on the equalizer ?

Years ago at DIYItalia a forumer developed an equalizer borrowed from SVT but without inductors, instead of inductors it used gyrators

If you have interest I can search the resulting schematic

Franco

[hylaphone]

Which is your interest on the equalizer ?

Years ago at DIYItalia a forumer developed an equalizer borrowed from SVT but without inductors, instead of inductors it used gyrators

If you have interest I can search the resulting schematic

Franco

Thanks for the offer, got a fellow who wants inductor mid control for bass guitar. I remembered this Fender design as a simpler approach than the SVT, figured it was worth experimenting with.

[HotBluePlates]

... got a fellow who wants inductor mid control for bass guitar. ...

Gibson had a Varitone that use inductors and caps, but it's worth seeing that like a Wah pedal:  you can get a lot of Treble or a lot of Bass, though a lot of Mids is also sort of a lack of Treble/Bass.  You also don't have control of "How Much."

If you use inductors, you need to fit them in a shielding box of some kind, tied to cable-shields for the internal wiring.  Because that inductor will pick up hum & noise out of the air to add to the signal (which is the basis of hum-cancelling dummy-coils).


Of course, there are also pedals that do this:  WahFul (where you also get to adjust the amount of mid-boost), graphic EQs, parametric EQs.

I'm sure the player believes he needs finger-tip control of the Mid.  However, I bet after 1 gig he will pretty much know what sound he will want to kick on, and the need to have this mid-boost in the Bass itself will vanish.

[hylaphone]

... got a fellow who wants inductor mid control for bass guitar. ...

I'm sure the player believes he needs finger-tip control of the Mid.  However, I bet after 1 gig he will pretty much know what sound he will want to kick on, and the need to have this mid-boost in the Bass itself will vanish.

Sorry, I should have clarified - this is for a bass guitar preamp. I tacked it together today with parts I had on hand, it works really well.