EA Tremolo revisited--rEAgenerated Tremolo

[GGBB]

I had a look at your schematic now and it looks like it will work fine just the way it is. 

Some tips to make it so it "just works" right off:
You can eliminate R11 if you want because it doesn't do anything, but it won't hurt to leave it either.

To get into the values I was suggesting in my previous post just change R12 to 1k, and eliminate R11.

Then you could hardwire R10 as something between 68k to 72k, eliminate the bias pot, and probably come out ok.

If you do use the bias pot, the 100k value you have chosen will do nicely for dialing it into a range where the distortion is minimal.  If you have a meter and you can measure then aim for 6.75V on the drain.  Otherwise just adjust by ear.

Also, bias pot on BS170 isn't needed.  Just replace it with a pair of 47k resistors to get your V/2 reference.

Awesome! Thanks very much.

[duck_arse]

transmog - as you're shunting (are you?) audio to +9V, wouldn't the 330uF be better as a supply bypass, and then the smaller cap back to the bias?

shame, the updated is too late for mine. again, nice tying of R14.

[Transmogrifox]

transmog - as you're shunting (are you?) audio to +9V, wouldn't the 330uF be better as a supply bypass, and then the smaller cap back to the bias?

The currents on 9V won't be any more than what is sourced by the collector resistor.  Actually if it really has any effect against the 9V rail, the collector and emitter currents cancel -- emitter side is pushing current into the 9V while collector is pulling the same amount out of 9V. 

9V bypassing capacitance should be enough to make the audio feedback portion a non-issue.  The bypass cap is still just a noise reduction cap (resistor thermal noise and BJT input noise voltage are shunted to ground instead of being amplified).  This also filters power supply noise.

I still need to breadboard the updated version, but with wav file simulation it is really nice.  With the LFO shifted to where it is always negative or equal to JFET source & drain, the modulation increases to a longer duty cycle with less depth with nice rounded pulsating effect (see sim output for something balanced right at the threshold of reaching perfect cancellation at low level).  Then as you increase depth from what the sim plot shows, it decreases duty cycle and you get more of a rounded square -- like the perfect square wave tremolo effect.  Really pleasant sounding in a wav file simulation output.  I'm getting excited to try it on a breadboard and see what if the real thing is similar.

Maybe you will have to plan another rEAgenerated build when I have firmed this up on the breadboard.

As you can see I finally got some web hosting, so I'm going to start (slowly) rebuilding my FX site, so I'll probably make a rEAgenerated Trem page when I get this more firmed up.

[LightSoundGeometry]

there must be a million layouts ..all modded because of various reasons that are not good ..I just got rick rolled as well .

no one here has the correct and easy trem layout, or an updated link  ?

[midwayfair]

there must be a million layouts ..all modded because of various reasons that are not good ..I just got rick rolled as well .

no one here has the correct and easy trem layout, or an updated link  ?

It's a new design that's been changed multiple times since Transmogrifox's original posting.

You could make your own layout based on his most recent schematic, and then you won't have to figure out if the layout is "easy" or "correct."

[LightSoundGeometry]

there must be a million layouts ..all modded because of various reasons that are not good ..I just got rick rolled as well .

no one here has the correct and easy trem layout, or an updated link  ?

It's a new design that's been changed multiple times since Transmogrifox's original posting.

You could make your own layout based on his most recent schematic, and then you won't have to figure out if the layout is "easy" or "correct."

the link takes you to a rick roll video ..its not a valid link

[GGBB]

Thread with most recent design and layouts:

http://www.diystompboxes.com/smfforum/index.php?topic=111925

[Transmogrifox]

For completeness on GGBB's link, here is where I keep things current on this design:
http://cackleberrypines.net/transmogrifox/rEAgeneratedTremolo/pages/

I remember I first presented this concept almost 10 years ago and it was hosted on geocities.  The link at the start of this thread is dead and that's why you get rick roll.

This year recently refined it and put it on my own web hosting so it won't go away any time soon.  In the thread posted by GGBB are 2 different layouts.  Neither of the 2 layouts have been verified but they have been reviewed for correctness.  It's simple enough I don't think you will have any issues.  If you have issues they will be easily resolved.

If you build the rEAgenerated tremolo let me know if you run into problems and need help.  Fortunately it's a relatively simple build.

Take care

[Kipper4]

Thanks
would 2n5457s work for Q1 and Q3?
58s are getting expensive here.

[Transmogrifox]

Yes. I breadboarded with both, and no significant difference.  I simulated with 2N5485's and tried several other LTSpice JFET models.  Most of the change is in the position at which the depth pot takes it to max depth.  That said I think you can do your most available and cheap general purpose JFET and the result will be acceptable. 

The rEAgenerated design is a little more tolerant of JFET variation due to the bias being set by the BJT's in a feedback configuration and the LFO is DC coupled to the modulating FET gate in the way it is -- allows the slop to be taken up in just changing pot position vs depth...which can be further helped by using a log or audio taper pot for depth.

[Kipper4]

Thank you sir 

[LightSoundGeometry]

hey thanks

[Kipper4]

Your welcome If you do want one pm me your snail mail address buddy.