GGG EA Tremolo

[Ultrakd]

I was wondering if anyone has built this pedal here and what they think of it. I am looking to get a tremolo pedal and I liked the sound of this one. Does anybody have any view opinions on this pedal or anything? Anyone have an clips of ones they have built or any pics?

[aleister]

I built one of these a few years ago and I still use it.
Nice old school type chop going on, not really over the top or EHX type crazy.
The best aspect of this pedal imo is that I can also use it as a boost pedal if I just use the level and turn the other 2 knobs all the way down.
It is a very nice clean type boost too, very underrated pedal.

[Cardboard Tube Samurai]

^^Yeah, what he said

[Main.Ace.FX]

I haven't built this one specifically, but I have built a super choppy sounding square wave tremolo that has its own OD/boost capabilities, both with and without the tremolo effect...awesome sound, and really easy to build and modify

[Ultrakd]

Ok cool, yeah Im wanting one to make one so I can play some of Green Days songs that have it lol. Like Boulevard of Broken Dreams

[sixstringphil]

That was the build that got me started.  I needed something to replace the tremolo on my Princeton, and nothing I tried in the stores worked for me. So I took a chance and tried building one myself based on the reviews of the EA I had read. Got it built and LOVED it! It doesn't chop as deep and fast as some other trems, but it sounds super! The boost is really nice. There's a layout of the isolated boost section in MarkM's gallery that I used for a long time.

[Main.Ace.FX]

you can replace capacitors that control the rate....better yet, out multiple caps on a switch and change between speed ranges

[Ultrakd]

Does anyone have any ideas as to how to add a wave pot into the circuit?

[boogietone]

What do you mean by a "wave" pot?

[KBG]

Wave shape.
http://www.diystompboxes.com/smfforum/index.php?topic=91444.msg780155#msg780155

[Ultrakd]

Wave shape.
http://www.diystompboxes.com/smfforum/index.php?topic=91444.msg780155#msg780155

Thanks KGB I found that post like a little bit ago.

[GGBB]

Another way to increase max rate is to reduce R11 or better yet substitute a trimpot.  But there's not a lot of room there value wise so don't expect something like 100R to work - the capacitors won't cycle if that value is too low.  However even just a bit lower gives it a nice little boost.  I built the ROG version this way along with some depth mods to allow it to have more of a chop sound when necessary and it turned out pretty well.  The EA is a very nice sounding tremolo.

As far as that wave pot mod goes, is it really a wave pot as in square/sine wave shapes?  I'd love to have that.

What I did for more chop at higher rates was to replace R7 with a pot so I can dial in some extra depth when using higher rates.  My "Chop" pot wiper is tapped by a second foot switch which when off leaves the entire pot as the R7 value.  When engaged, turning up the chop pot lowers the R7 value giving it more depth.  I also have separate high and low speed pots that are toggled on the same second foot switch and an extra trimpot to control the overlap between the two speed pot ranges.  The chop pot is only effective on the high speed setting, so when I switch to "Turbo" mode, the chop pot kicks in boosting the depth at the same time as the speed.  In addition to providing switchable modes, splitting the ranges up allows linear pots to be used effectively so I didn't have to hunt for a reverse taper pot.  I use a 20K for the high speed setting and a 100K for the low range, and I adjusted the 10K trimmer which is in series with the low range pot for about 15K overlap which is not much speed-wise.  Having a bit of overlap just makes the pedal more usable/flexible.

[Ultrakd]

Another way to increase max rate is to reduce R11 or better yet substitute a trimpot.  But there's not a lot of room there value wise so don't expect something like 100R to work - the capacitors won't cycle if that value is too low.  However even just a bit lower gives it a nice little boost.  I built the ROG version this way along with some depth mods to allow it to have more of a chop sound when necessary and it turned out pretty well.  The EA is a very nice sounding tremolo.

As far as that wave pot mod goes, is it really a wave pot as in square/sine wave shapes?  I'd love to have that.

What I did for more chop at higher rates was to replace R7 with a pot so I can dial in some extra depth when using higher rates.  My "Chop" pot wiper is tapped by a second foot switch which when off leaves the entire pot as the R7 value.  When engaged, turning up the chop pot lowers the R7 value giving it more depth.  I also have separate high and low speed pots that are toggled on the same second foot switch and an extra trimpot to control the overlap between the two speed pot ranges.  The chop pot is only effective on the high speed setting, so when I switch to "Turbo" mode, the chop pot kicks in boosting the depth at the same time as the speed.  In addition to providing switchable modes, splitting the ranges up allows linear pots to be used effectively so I didn't have to hunt for a reverse taper pot.  I use a 20K for the high speed setting and a 100K for the low range, and I adjusted the 10K trimmer which is in series with the low range pot for about 15K overlap which is not much speed-wise.  Having a bit of overlap just makes the pedal more usable/flexible.

Could you give me some more info to what you did. This sounds interesting but I got a lil confused lol

[GGBB]

Basically, I added two more pots and a second 3PDT footswitch.  The two extra pots are for "chop" - which is really just depth boost - and a second speed control.  The footswitch switches between the two speed control pots which are different values so that I have two ranges of speeds to choose between (high or low with some overlap).  The footswitch also engages the depth-boost "Chop" pot when using the high speed range setting.  I also tweaked the top speed higher by lowering the 1K resistor (GGG's R11) that is connected to the speed controls - this was done with a trimpot and experimentation and I forget what value I ended up at.

The "Chop" pot replaces the 120K resistor attached to terminal 3 of the depth pot (GGG's R7).  Experiment with values, but a linear 500K should work well.  I actually used a 1M and bumped the depth pot to 500K.  I also substituted 100K for the 68K on the other side of the depth pot (GGG's R19) but that shouldn't make much difference.  One part of the footswitch is used to connect the 0.47uF cap (GGG's C4) to either terminal 1 or terminal 2 of the chop pot.  Terminal 2 is the chop engaged, so turning up the chop pot lowers the resistance and therefore increases depth.  Switching to terminal 1 puts the whole pot in series functioning as if it were a plain resistor.  If these values surprise you, they did me too.  I originally started with some very different ideas for values but through experimentation ended up with these - shows how much I understand what's actually going on electronically.  The other parts of the switch are used to toggle between the two speed pots and between two indicator LEDs (to tell me which mode the pedal is in).

The speed pots are 20K for high range and 100K for low range.  Linear will work fine.  The original single speed control really needed to be reverse log to dial in faster rates more accurately, but by splitting it into two pieces I have an entire pot dedicated to the fast rates (top 20K) so it is less sensitive at the fast rates.  If you want even more precision try a 10K but be aware that you'll lose a little of the slower portion of the high speed range.  With 20K I can still use it for moderate rates.  Keeping in mind the logarithmic nature of the control - 10K versus 20K isn't much different.  With a separate high speed range, I didn't need the low range to go to the max rate, so I added some resistance in series with the low range pot.  This eliminates the touchiness of a linear rate pot at higher speed settings.  I used about 5K (with a 10K trimmer) giving me about 15K overlap with the high speed pot.  Again this is logarithmic so it's not as much actual speed as it may seem mathematically.

I had a lot of fun coming up with this and putting it together.  It's almost like having two separate tremolo pedals in one.

[Ultrakd]

Do you have any pics of it? Im curious to see it, what bout sound clips Im intrigued lol 

[GGBB]

Do you have any pics of it? Im curious to see it, what bout sound clips Im intrigued lol 

Heh-heh, I figured that would come up.  No pics and no clips.  I actually haven't fully completed the pedal yet .  The board was done several months ago but I haven't built the enclosure.  I am going to put this into a Hammond 1590N1 which is a really tight fit for 5 pots and two footswitches plus everything else.  I've laid it out in software and it will fit but I'll have to be extra precise so I have been procrastinating.  But it spent a lot of time on the breadboard so I have played with it quite a lot.  I'll see what I can do about sound clips this weekend (the wife is away so I can play!).  Sonically it sounds just like the EA Tremolo because that's what it is, but my mods give it a little faster max rate (and actually a fractionally slower min rate too) and a bit more of a chop sound when the chop and depth controls are maxed.  Early on I found that after I tweaked the max rate of the EA circuit higher, the depth seemed shallower, but at moderate or slow rates the depth was just fine.  To get the pedal to sound the way I liked it at fast rates, I had to turn up the depth as well.  So that ultimately led me to the two range setup with the chop boost added to the fast range.  I can toggle between a fast choppy sound and a slower or more subtle sound.

[Mark Hammer]

I've built a couple of EA tremolos, using assorted layouts, and was quite pleased with how they came out.  The bonus is that you can use it as a clean boost if you set it right.

Last weekend, while Steve Daniels was visiting, he brought along one of his Tremulous Bear pedals, and the gang (including myself) were quite impressed with it.  A lot of different "feels" available, some of which seemed to come close to tube-bias tremolo at times.

So, not to take anything away from the EA, but there are other designs that may encompass a little more of what people hope a tremolo to do for them.

[Ultrakd]

Yeah I was checking out the tremulus lune and Im really liking that pedal.

[Mark Hammer]

The Tremulous Bear and the Tremulous Lune are two different pedals.

Bear: http://www.smallbearelec.com/Projects/TremBear/TremBear.html
Lune: http://fuzzcentral.ssguitar.com/tremulus.php

[Ultrakd]

The Tremulous Bear and the Tremulous Lune are two different pedals.

Bear: http://www.smallbearelec.com/Projects/TremBear/TremBear.html
Lune: http://fuzzcentral.ssguitar.com/tremulus.php

Yeah I know, I think Im liking the Lune though. I might wanna try making that. I like pedals with lots of knobs lol.