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DIY Stompboxes => Building your own stompbox => Topic started by: Apokas on May 22, 2004, 04:03:43 PM

Title: Piezo preamp
Post by: Apokas on May 22, 2004, 04:03:43 PM
I want to make a preamp for piezo elements for my guitar.
I have the PCB`s and schematics for Alembic Stratoblaster, for all I know it is a clean booster so it should do my job. Anyone else suggest a better preamp?
Title: well
Post by: petemoore on May 22, 2004, 04:41:20 PM
I like Jfets, and the Stratoblaster is a good booster, nice sound.
 Fetzer Valve is another, info at Runoff Groove.
 The Mosfet Boost is probably the cleanest boost of all, whopping boost, check at AMZ for that one.
 I would stick with FET's...but that's me.
Title: Piezo preamp
Post by: Apokas on May 23, 2004, 03:37:43 AM
I think I will do the Fetzer Valve  as well. The moosfet says doesnt color the sound but I dont think that will be a good quality for piezo elements.
The FET says it emulates the valve sound so it will be a good idea for a piezo setup.
Any other comends?
Title: Piezo preamp
Post by: Apokas on May 23, 2004, 08:26:28 AM
Here it is a design I made.

http://www.guest.animebliss.net/BIOU/Piezo%20Pre-amp%20PCB%20and%20schematic.GIF

If the sound it too bright should I put a capacitor at the positive lead of the piezo? (marked on diagram with a green X)
Title: k
Post by: petemoore on May 23, 2004, 09:41:16 AM
You could cut highs anywhere in the signal path, a capacitor to ground will allow a path for the highs to be shunted/rolled off.
 Somewhere after the boost stage will also get any high end content in created in the boost stage also...[where I'd start with the rolloff caps].
 Many schematics use a rolloff cap near the output...take a look and check them out. A Pf cap [starting at around .0022uf or .0047uf] should control high end N/P.
 I'm just thinking I'm beginning to understand...look at the rolloff caps/resistors at the end of the Thunderchief.