EAtremolo problem.

[jpm83]

My problem is that tremolo effect is very weak. I have to crank depth pot all the way up to get that kind of effect that I can use. And volume also is kind of on/off switch there is not much of range.
I have check´d the circuit and every component is in their own place right way. I have replaced J201 with 2N5457 and 2N5088 with 2N3904, because I couldn't find either. I made this tremolo from Torchy's vero layout. It is the ROG EAtremolo.

[gez]

There are hundreds of posts on this in the archives.  The original article (I would have linked to it but the site seems to be down) explains how to combat this problem.  You should be able to figure out what to adjust from this post:

http://www.diystompboxes.com/smfforum/index.php?topic=16459.0

This one has a novel approach, though I agree with Paul's comments...too many variables.

http://www.diystompboxes.com/smfforum/index.php?topic=32083.0

Search function is your friend.

[jpm83]

Thanks for answering.

[jpm83]

Is there still something I can do to increase Depth on this trem. I changed the 120k resistor to 68k and 68k to 149k and I made a jump in the place of 180 ohm resistor but is still a bit weak.

[gez]

Is there still something I can do to increase Depth on this trem. I changed the 120k resistor to 68k and 68k to 149k and I made a jump in the place of 180 ohm resistor but is still a bit weak.

Can you link to the schematic please.  Not being funny, just a bit pushed for time.

If I recall, there's just a divider coming off the LFO output.  Making resistors smaller in value requires a corresponding increase in the output cap value.  Anyway, a link would help. 

[jpm83]

[Can you link to the schematic please.  Not being funny, just a bit pushed for time.

If I recall, there's just a divider coming off the LFO output.  Making resistors smaller in value requires a corresponding increase in the output cap value.  Anyway, a link would help. 
[/quote]

Here is schematic and info about those mods I have made.
http://www.elixant.com/~stompbox/smfforum/index.php?topic=35217.0

[Paul Marossy]

It's certainly not going to work with a 2N5088 and a 2N3904 - those are regular NPN transistors, not FETs...  

[jpm83]

It's certainly not going to work with a 2N5088 and a 2N3904 - those are regular NPN transistors, not FETs...  

Q3 is NPN tranny.

[gez]

In the above schematic there's a resistor chain from the output of the LFO to ground.  You need to develop more of the LFO's output across everything lower than the wiper, whatever its setting may be.  There are a number of options, but my prefered one would be to increase the value of the 68k rather than making the 120k smaller, that way you don't need to increase the .47u output cap (which is a bit close for comfort with the values given IMO).

Don't have time to check data sheets for trannies etc, make sure you use a FET for Q2.

[Paul Marossy]

Q3 is NPN tranny.

Oops, sorry, I misread that.  

The 2N3904 doesn't have quite as much gain as the 2N5088, but I think it should still work OK in spite of that.

make sure you use a FET for Q2

Yeah, and watch the pinout! 

[jpm83]

Thanks for infos. I think I first solder the 120k resistor back and then do other changes if necessary.

[jpm83]

Well I did that and it has now a bit more Depth. Would that be too much if I increased the value of that 68k resistor to 220k, I have now in that place 220k and 470k resistors in parallel.

[gez]

Well I did that and it has now a bit more Depth. Would that be too much if I increased the value of that 68k resistor to 220k, I have now in that place 220k and 470k resistors in parallel.

You can up the 68k to whatever you like.  If you make it something like 1M though you'll probably need to use a larger value pot.  There'll come a point where increasing it further doesn't make much of a difference and you might find you get problems with popping noises (or similar) if the FET is turned hard off/on.  Suck it and see.