EA Tremolo question

[Barcode80]

actually, 2 questions. first, i want to use 1uF electros in place of the 1uF polys in the layout (i'm using markm's layout. not the version in his gallery, but the old one it replaced. same question applies though). which direction to they need to go?

also, can i sub in a j201 for the mpf102?

[jayp5150]

You could just get some non-polarized electros.

ROG's site states that a J201 OR an MPF102 can be used.

BTW, if you haven't built this before, it's a killer pedal. I made one for my cousin, and he loved it.

Have fun.

[squidsquad]

Another note:  many complained that the EA didn't go fast enough.  This is solved by using .68uf caps instead of 1uf....in the LFO section where 3 of em are wired together.

[jlullo]

yeah, patrick, you're going to love it!

[markm]

Another note:  many complained that the EA didn't go fast enough.  This is solved by using .68uf caps instead of 1uf....in the LFO section where 3 of em are wired together.

Very true.
If memory serves me, the BYOC EA Trem uses .68uF caps for this reason.

[MartyMart]

Yup, I have 680n ( 0.68uf ) poly's in mine too - works a treat
MM.

[Alex C]

I used polarized 1uF electros for those with no problems.  I used Mark's most recent one I think, the one that's here now: http://aronnelson.com/gallery/album76/ROG_EA_Tremelo_LAYOUT

I've marked on this schematic (from ROG) portion the orientation of the caps in my build:


And here I've marked with a + the positive lead of each on Mark's current layout:


I just applied what I've seen with electros in the signal path before.  The negative lead is usually oriented towards ground or on the far side of the input signal.

It would probably be easier/better to go with 0.68uF if you have them.
Hope it works for you, I'm really pleased with mine too.
-Alex

[Barcode80]

okay cool, i will try the .68 polys when i get home...

[markm]

I used polarized 1uF electros for those with no problems.  I used Mark's most recent one I think, the one that's here now: http://aronnelson.com/gallery/album76/ROG_EA_Tremelo_LAYOUT

Yes Sir,
That's the current one.
Thanks Alex!

[Alex C]

Thanks Alex!

Thank you for your layouts and your generosity with them, they're appreciated very much around here.

[markm]

awww shucks!

[Barcode80]

yeah mark, now that i've mastered printing yout layouts, it is like a whole new world has opened to me. combined with your etch tutorial, you've singelhandedly sprung me leaps and bounds forward in my learning!

[Barcode80]

okay, put in electros, fired it up, and no pulsing LED. it just stays on. also, i'm getting negative voltage () at the D of Q1. any ideas?

[markm]

okay, put in electros, fired it up, and no pulsing LED. it just stays on. also, i'm getting negative voltage () at the D of Q1. any ideas?

Try a different JFET perhaps......also, make sure the orientation of the LED is correct as I beleive the wiring for the LED was backwards in that build. The EA is notoriously "picky" about JFETS as I understand it although, I've never had any issues with mine.

[Barcode80]

you are probably right about the LED. i think now that i put it in according to the red and black wires as opposed to looking at the flat side of the LED  i'll swap and post results.

[Barcode80]

okay, swapped the LED and replaced the J201. nothing. switched the LED back to the way i had it, it stays lit again.

[Barcode80]

okay, i just switched to the newer layout in markm's gallery. i built it all, with all new parts except for the 500k pot (but it is tested and working) and i am getting the same issue. it is basically acting as a clean boost. a very good one, but i need a trem! the LED is also not blinking, just like the last build. i've checked all wiring. i've searched the forum. any ideas?