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DIY Stompboxes => Building your own stompbox => Topic started by: Pierre on October 21, 2005, 10:34:08 AM

Title: Pez 90 question
Post by: Pierre on October 21, 2005, 10:34:08 AM
Hi !!!
im just about to build the Pez 90 (mxr90 clone) from Tonepad...
here's my question: there's a 15 µf cap and i cant find it anywhere, what can i use instead?...(if i can use something to replace it :icon_rolleyes:)...
THANK YOU !!!!
Title: Re: Pez 90 question
Post by: Herr Masel on October 21, 2005, 10:50:21 AM
You can probably use something close (10µf) or you also put a 10 and a 5 together to make 15, at least so I believe.
Title: Re: Pez 90 question
Post by: Mark Hammer on October 21, 2005, 10:57:20 AM
The 15uf cap is part of the LFO and likely involved in determining the range of sweep speeds or the shape of the LFO waveform (I just don't get those one op-amp oscillators :icon_redface: ).  As such, you want something that is VERY close to the stated value.  HM is correct in suggesting a "composite" cap made up of whatever values add up to 15uf or close enough.  Alternatively, you can TRY a 10uf and see if the sound is acceptable.  The circuit WILL function - it just may not sound exactly like the stock unit.  That's not wrong, just maybe not exactly what you were hoping to get.  If the sweep sounds weird or is too fast (or rather, you can't get it slow enough for your tastes) then start looking into getting closer to 15uf.
Title: Re: Pez 90 question
Post by: Pierre on October 21, 2005, 11:18:25 AM
ok...but, since 15µf is not a standar value, at least here in Europe, i wonder what value did European DIYers in this proyect...
thanks for answering !!!! :icon_biggrin:
Title: Re: Pez 90 question
Post by: Arn C. on October 21, 2005, 11:29:38 AM
FYI:

I just put a 10uf and a 4.7uf together in my capacitor tester and came up with 14.92uf.
Another pair gave me 14.84uf.

Arn C.