I'm looking for schematics for EQ type pedals like the Earthquaker Devices Tone job or similar ones. I prefer a simpler one over let's say the Boss GE-7 as I want to try designing the pcb myself and going for OSH park for the first time.
Any other suggestions for similar projects are very welcome!
Steve's Tonmeister is a great EQ
http://www.madbeanpedals.com/forum/index.php?topic=6350.msg54354#msg54354
Quote from: marmaliser on November 16, 2014, 07:48:39 PM
Steve's Tonmeister is a great EQ
http://www.madbeanpedals.com/forum/index.php?topic=6350.msg54354#msg54354
I know about the Tonmeister. I wanted to get one long ago, but he's still working on V2 and didn't have V1 in stock. So I thought I give it a go myself and I didn't want to copy his design - I rather redo the design of someone I don't know :D
Barber Barb EQ was a similar one, always wanted to build it, but unfortunately I've never seen schematics or veros.
http://www.barberelectronics.com/barb_eq.html (http://www.barberelectronics.com/barb_eq.html)
Quote from: m-Kresol on November 16, 2014, 07:42:50 PM
I'm looking for schematics for EQ type pedals like the Earthquaker Devices Tone job or similar ones. I prefer a simpler one over let's say the Boss GE-7 as I want to try designing the pcb myself and going for OSH park for the first time.
Any other suggestions for similar projects are very welcome!
Are you looking for a graphical EQ or multi band parametric? If you are looking for graphical, I have the one pedal that's based on the Rohm BA3812 IC on OSHPark that's a disttortion into an EQ section. The EQ itself is pretty small and could be lifted out easily. It uses the 5 GEQ bands plus a high shelf. I have a 7 band GEQ that's an extension of the Rohm IC that I haven't put up yet.
I think Thomas has a 5 band GEQ based on the same IC.
If you don't want to use the Rohm IC, it's easy enough to do a GEQ, but it takes quite a few op-amps or transistors. It's really just copying the same section repeatedly with different caps. The layout isn't really that hard to do, just a bit big.
Quote from: RobA on November 17, 2014, 06:32:32 PM
Quote from: m-Kresol on November 16, 2014, 07:42:50 PM
I'm looking for schematics for EQ type pedals like the Earthquaker Devices Tone job or similar ones. I prefer a simpler one over let's say the Boss GE-7 as I want to try designing the pcb myself and going for OSH park for the first time.
Any other suggestions for similar projects are very welcome!
Are you looking for a graphical EQ or multi band parametric? If you are looking for graphical, I have the one pedal that's based on the Rohm BA3812 IC on OSHPark that's a disttortion into an EQ section. The EQ itself is pretty small and could be lifted out easily. It uses the 5 GEQ bands plus a high shelf. I have a 7 band GEQ that's an extension of the Rohm IC that I haven't put up yet.
I think Thomas has a 5 band GEQ based on the same IC.
If you don't want to use the Rohm IC, it's easy enough to do a GEQ, but it takes quite a few op-amps or transistors. It's really just copying the same section repeatedly with different caps. The layout isn't really that hard to do, just a bit big.
Thanks for your answer. I'm definitely looking for a graphic EQ. Nothing fancy... the idea to do it is actually based on Steves Tonmeister, as thought it would be nice to do something myself. I have no experience in circuit design myself, but I know my way around Eagle thanks to Jacob.
I would prefer to do just do the pcb design, not really the circuitry, as I'm not nearly experienced enough to tell what's what and what might cause problems.
It looks like that one is a Baxandall with a mid band. This site http://headwize.com/?page_id=741 (http://headwize.com/?page_id=741) has a good section on Baxandall EQ's. They are most likely assuming a split rail design and it's for headphones, so the EQ frequencies might be a bit different from what you would want. But, you can use a charge pump to get the -9V rail and they've got all the equations so you can shape the frequencies to just what you want.
It also has the schematic for an active "tilt" EQ that is really nice for tweaking the input to distortion circuits.
Quote from: RobA on November 17, 2014, 09:38:17 PM
It looks like that one is a Baxandall with a mid band. This site http://headwize.com/?page_id=741 (http://headwize.com/?page_id=741) has a good section on Baxandall EQ's. They are most likely assuming a split rail design and it's for headphones, so the EQ frequencies might be a bit different from what you would want. But, you can use a charge pump to get the -9V rail and they've got all the equations so you can shape the frequencies to just what you want.
It also has the schematic for an active "tilt" EQ that is really nice for tweaking the input to distortion circuits.
thanks!
I'll have a look at it the next days.