Pot Question for EA Trem

[phxbass]

I want to build the EA Trem from GGG and can't seem to find the 25K log pots.  Where can i find them?  This is only my third build so I'm a little unsure about some things.  Can I substitute a linear pot or a 50k log?  If so what would be the affects of the changes?  I know there have been similar posts on this topic but I can't seem to find one that gives a direct answer.  Any help would be gratefully appreciated.

[captntasty]

You can substitute a linear taper for a log taper and vice versa.  There may be a difference in how it behaves due to the taper issues (this will depend on what function it is fulfilling) but it will work - a 25k pot is a 25k pot.  When you change the resistance from 25K to 50K, you may run into some wierdness - this sort of gets over my head when trying to figure it out mathematically - I usually would go for the 50K and see what happens.  To truly have the circuit working "correctly" certain board components might need to be altered to account for the difference in resistance of the 25K pot.  But again, it will work with a 50K - maybe not "exactly" as it was designed, but it will work and you won't blow anything up .

You can look at the usual suspects mouser.com or digikey.com or a 100 others.  24mm or 16mm (most prefer the 16mm as they are smaller - so you can pack more of 'em in there!).

Give the different value pots a try if those are the ones you have or can get easily - you might end up with "a happy little mistake".

Peace

[Pushtone]

If you do get the "right" pots for the GGG EA Trem you might be surprised when the rate control works backwards.
ie: clockwise is slower.

So as long as your looking you might want to try and find a reverse log pot for that one.

There is also an easy mod in the layouts gallery for a fast/slow footswitch.
I use it a lot on my EA T. Seen it?

[captntasty]

So I'm not crazy - I reversed the lugs around when I built it a couple years ago and also thought a reverse log would work better there.  When you say the layouts gallery do you mean on this site?  Sounds interesting...

[Pushtone]

So I'm not crazy - I reversed the lugs around when I built it a couple years ago and also thought a reverse log would work better there.  When you say the layouts gallery do you mean on this site?  Sounds interesting...

Yes, THE layout Gallery. See the link at the top next to the wiki link.

Andrew has posted a couple:

This is the one I used, 1/2 speed mod:
http://aronnelson.com/gallery/The-Mod-Zone-%21/EA_rate_mod

And this one adds another pot for dual rate control
http://aronnelson.com/gallery/The-Mod-Zone-%21/EA_TREM_DUAL_RATE_MOD

[captntasty]

Thnx, very cool - time to revisit this one...

[phxbass]

Thanks!  These are very helpful suggestions.  I really like the mods...I'm ordering my parts right now.  I can see how this can get so addictive.  I want to build every pedal out there with every mod available!

[smallbearelec]

Try a single-gang 100K reverse log (SKU 1007), or the Univibe dual 100K reverse log (SKU 1004). The EA trem is happier with either of these than with linear taper. If the maximum speed becomes too slow, use smaller timing caps.

SD
smallbearelec.com

[phxbass]

I already went with the 50k...will that work?

[captntasty]

Get it up and running and then you can tell us...  like I said - don't worry about it blowing up or destroying components - it just may behave differently than the "stock" layout.
p.s. not trying to be a wisea*s

[phxbass]

Alright...finally got it going after 2 days of being completely confused.  I thought I checked everything and finally realized I had all my transistors backwords!  What a frustrating stupid mistake.  The 50k pots seem to be working just fine.  I don't really know what the difference would be since I haven't heard it with the 25k pots but it doesn't seem too bad.  It's a pretty quiet pedal but the effect does create a small amount of distortion that doesn't really bother me.  I saw a mod on this forum to make the rate faster so I think I'm going to give that a shot.  Next up: the DOD EF

[phxbass]

Ohhh man...this is great.  I replaced the 1uF caps with .47uF last night and the speed range is perfect!  I can go from nice and slow to stupid fast.  For some reason the slight distortion cleared up as well.  No problems whatsoever with the 50k pots.  Thanks again!