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DIY Stompboxes => Building your own stompbox => Topic started by: Tombaxter97 on September 12, 2017, 07:20:02 AM

Title: elec caps instead of ceramic
Post by: Tombaxter97 on September 12, 2017, 07:20:02 AM
http://pedalparts.co.uk/docs/EATrem-MkII.pdf

I only have 1u elec caps and not un polarised. Would it be okay to use 1u elec caps in the circuit as c6,7,8
Title: Re: elec caps instead of ceramic
Post by: GibsonGM on September 12, 2017, 07:24:04 AM
I'd do it, Tom.  Orient the "+" L, L and "up" for C6, 7, 8.  I've never had a problem doing this; I'm sure there is a 'best practice' that I'm avoiding, though, LOL.

Title: Re: elec caps instead of ceramic
Post by: Tombaxter97 on September 12, 2017, 07:53:20 AM
Ah thanks.

I'm putting them into the pcb so from that picture on the pdf which way should the negative leg go (up being top of page and down being toward bottom) as I can't work it out and can't see it being the same orientation for all three
Title: Re: elec caps instead of ceramic
Post by: duck_arse on September 12, 2017, 11:32:53 AM
we love the phase shift osc here Tom. and those caps provide hours of fun for everyone.

you'll have to noodle this for yourself, as I didn't see a pcb trace pattern, but here's the good oil - the collector of the osc trannie will be more positive, and the base of the trannie will be more positive, because the other end of those two caps will be attached to ground via a resistor/resistance. so, the one in the middle is connected to "less positive" at both ends. what to do?

doesn't really matter, put it in either way. you can take the fixed resistor leg to positive instead of ground, making one end very positive, and the other end less positive. or use poly caps and forget all about it.
Title: Re: elec caps instead of ceramic
Post by: antonis on September 12, 2017, 11:43:08 AM
C6 & C8 negative legs to R11..
C7 negative leg to R10..

P.S.
You don't have to worry a lot about polarity 'cause J201 will beat them in a malfunction-time race..  :icon_wink:
Title: Re: elec caps instead of ceramic
Post by: Tombaxter97 on September 12, 2017, 01:57:18 PM
Thanks a lot for the help, going to give it a try tomorrow!