EA Trem from Tonepad debug help

[Barcode80]

build reports on the Tonepad website from users (incidentally, a lot of good help in these build reports when people take time to read them):

Name:   Max Mejia
E-mail:   ettnician@hotmail.com
Date:   9/30/2010
Build Report:   Hi, I just finished the EA tremolo. It gives a nice amp type tremolo effect. a Few tips. Q1:low Gain npn Q2:j201 Q3:High Gain npn. replace the 12k with a 4.7k and add an LED in series for a tricked look. I auditioned a few FETS MPF102, 2N5457, and J201... 102 and 2n5457 are Low-Mid Gain FETS. The results are a subtle effect boring... The J201 High gain Makes this pedal awesome Tremolo effect is more Pronounced. My first tremolo was a pulsar clone. This one is way easier to build... I how ever prefer the Pulsar but This EA Trem is definetly a keeper. Cheers.

Name:   Rbert Reynisson
E-mail:   private
Date:   3/28/2010
Build Report:   I had some problems with distortion in this circuit. Since I see others have had similar problems this might benefit some: Replaced the 15k resistor (the one connecting Q1's collector to 9v+) with a 4k7 resistor. That fixed it. Robert

Name:   John Hostetter
E-mail:   private
Date:   11/2/2009
Build Report:   I have this breadboarded now and it sounds effin amazing. This is my first circuit from scratch and I wasn't sure if it would work out. The distortion and decay sound unbelievable and the tremolo is just like the one I used to have on my Music Man.

Name:   Blake
E-mail:   private
Date:   9/14/2009
Build Report:   Succesful build. Had to sub a few parts with what I had on hand. 2n5484 for the FET and a 2n4401 in place of the 2n3904. Also I had no 12k so used a 10k in place of and raised the 3k to a 3.87k. I only had 200 ohm and used that in place of the 180, and I used a 550k in place of the 560k I was very worried this would make or break the circuit but it worked out just fine. Unity gain is perfectly at the 12-o'clock position of the level knob. Nice rich tremolo from such a simple circuit.

Name:   Xe-Kyu
E-mail:   private
Date:   8/2/2009
Build Report:   Thanks, guys. I read your report that order me to change the parts. I made it in korea and it works! Because of my stupid guitar, there are some little distortion or something ......... how can I say uHm anyway, it is a good pedal to the beginer, althoug it is "intermedite". (Please forgive my little spelling mistakes)

Name:   Goran
E-mail:   narog60@gmail.com
Date:   7/22/2009
Build Report:   Hi there
This was easy build. As Leonardo discovered there is error with Q1 and Q3. Q1 should be 2N3904 and Q3 2N5088 or 2N5089 what I used. Q3 has to be high Hfe transistor in order make oscillator work.
here are the mods I did:
replaced 12k resistor with 4.7k and added led between it and collector of Q3- this gives you visual rate indicator and can serve as off on indicator combined with the stomp switch
replaced 120k resistor with jumper,22uF capacitor with 100uF, and 0.47uF with 1uF to get more pronounced tremolo effect
also used 50K pot for volume control
All in all very simple but great sounding effect, thanks Tonepad!!!!

Name:   Leonardo
E-mail:   lcontarino@gmail.com
Date:   5/29/2009
Build Report:   Hello. I'm from Argentina. This afternoon we finish up the tremolo, but I found a bug in the layout, which is between the transistors Q1 and Q3, the layout shows that the Q1 is a 5088 and Q2 a 3904 so this is wrong and Conversely, Q1 3904 and Q2 5088. There is also an error in the listing of parties that indicated only 1uF capacitors 2 and 3 in the layout and we can also see the list of material indicated electrolytic capacitors 3 Uf 1 and 2 has only been in the layout and assembly. I hope it helps someone because of the tremolo sounds great.

[jkokura]

Lots of people have it working right man. As you can see, from the build reports, and there are 7 or 8 reports in there of people who have it working. Some have made modifications to make the circuit work better for them. I'd guess some have similar problems we do, and it's an interesting phenomenon actually. I don't think there's anything wrong with my circuit, it's just part of the way it's working! Next time I'll use sockets for the transistors and try a whole bunch out, because I think it has something to do with it. I wonder if because of the age of the actual circuit there will need to be modifications because of slight adjustments to the way parts are made now! I imagine there has been updates to the types of parts that were made and used 30-40 years ago, and that those adjustments might be making things harder for us now!

In a similar note, I have a pedal in for repair from a guy, it's a boutique trem out there, and it's got the same thing going on. This is a commercially available pedal, at least it's an older version of the pedal, with the same thing going on.

There problem isn't with the design or with Tonepad. This circuit long predates the tonepad layout, and Francisco simply created a PCB for it and sells it. There are probably tens of thousands of trems either built from or based on Craig Andertons EA Tremolo.

Jacob

[Govmnt_Lacky]

yeah right...but many people had problems with tonepad and the govmnt lacky in this topic...find me another person who did that working wright!

Let me correct you right here.... I NEVER stated that I had a problem with THIS build (Tremolo), I merely stated that when I had a problem with a SansAmp GT2 board that I purchased from Tonepad, I could never get a hold of Fp to help resolve the problem. Call me crazy but, when I purchase something from someone, I expect them to stand behind their product. Otherwise, they need to put on their website that I assume ALL RISK when I purchase.
Now, I have etched many boards from Tonepad since this incident without problems however, I will probably not order another board directly from Tonepad again.

Tonepad is an invaluable resource for DIYers and I give it it's due credit. I hope Fp keeps it going. I am merely one person posting about my experiences. You and the rest of the people on here may have different experiences.

[Barcode80]

Absolutely right. Selling a product, he should stand behind it. Posting free layouts for all to use on the other hand, one can't complain. And his layouts always either work without fail, or someone will submit a build report with minor corrections. His projects are verified.