DIY EQ anybody?

[Mark Hammer]

These two heat-n-serve boards were drawn to our attention over at the Music Electronics Forum.  Quite the bargain, if only for the pots.

http://www.goldmine-elec-products.com/prodinfo.asp?number=G18062
http://www.goldmine-elec-products.com/prodinfo.asp?number=G18065

[Earthscum]

I've had my eye on those for about a week now... just don't have $ atm. I plan on doing one 15 x 15 just to have around, and getting a couple of each just for the pots.

[MetalGuy]

This looks like e very good bargain. I wonder if those pots are W-taper (S-curve) but even if they aren't it's still a bargain.

[MarcoMike]

yes, that's cool! but I guess the whole tone thing is missing... only pots on that board... I am already going crazy, thinking of soldering 60 almost identical opamp circuits!

[twabelljr]

I've been looking at this cicuit for a while: http://sound.westhost.com/project64.htm. Pre and post distortion EQ or just one EQ. Would take alot of opamps to make the filters, but like Mark said,

Quite the bargain, if only for the pots.

[Earthscum]

Jeez... make it easier on yourself...

http://www.geofex.com/article_folders/eqs/paramet.htm

or, just get an EQ chip. Has OpAmp and transistor array set up just for making multiple gyrators in a feedback loop. Car EQ's use these... Kraco. If you're gonna complain, remember the PT2399 was made for Karaoke machines, lol.

Steve sells these:

http://www.smallbearelec.com/Detail.bok?no=570

[Mike Burgundy]

...and they don't ship to the Netherlands. Grmbl.

[Mark Hammer]

Jeez... make it easier on yourself...

http://www.geofex.com/article_folders/eqs/paramet.htm

or, just get an EQ chip. Has OpAmp and transistor array set up just for making multiple gyrators in a feedback loop. Car EQ's use these... Kraco. If you're gonna complain, remember the PT2399 was made for Karaoke machines, lol.

Steve sells these:

http://www.smallbearelec.com/Detail.bok?no=570

For a guitar or bass-oriented pedal, I agree wholeheartedly.  Graphic EQs with 15+ bands, however, are oriented towards room adjustments, rather than instrument revoicing.  That may not apply to EVERYBODY here, but there are enough members here who have a personal investment in sound reinforcement, that I thought they'd want to know about this.

[Mike Burgundy]

very cool chip - wasn't aware of that one yet - thanks!

[Processaurus]

The stereo 31 band board in that same section might be pretty neat for a 32 step analog step sequencer, if you could kludge on one extra pot!

[mjkirk12]

From electro-music.com forum, by way of Synth DIY:

<quote>

The end product these EQ boards go to is here:  http://www.ashly.com/product/gqx-series.htm

The sliders are Alpha (probably a customized version) have a center detent, and a center tap connection to the resistance element, which is connected to ground on the pcb.
The min and max ends of the pots are on common busses, presumably part of the feedback loop of the on-board summing amplifiers.
I don't know yet what the resistance value is.
The wipers each have a pad on the back-side of the board that I assume goes out to the individual filter for that pot.
The wiper connections have the aforementioned solder blobs/bridges on them - I'm talking big, up to 0.25 inch buck-shot-sized blobs here.
Somebody was heavy-handed with the solder for sure.
The op-amps on the boards are JRC2043D standard DIP8 duals.

In a nutshell - bunch of sliders, with a grounded center tap, all parallel connected in the feedback loop of an
on-board summing amp with a master boost/cut gain control and a power "on" indicator LED.

</quote>

[Mark Hammer]

The stereo 31 band board in that same section might be pretty neat for a 32 step analog step sequencer, if you could kludge on one extra pot!

What, you got something against unusual middle-eastern time signatures?