3rd EA...lol

[petemoore]

How critical is that 100k [and exactly what is an RA..reverse audio] to getting the Modified EA's [with the LED] LED to go on and off?
 This one otherwise looks exactly like the schematic as the other one did and also the LED is not flashing also.
 WOW this thing is turning into my recurring nightmare...

[B Tremblay]

The 100k-RA Rate pot can be reduced in size to 25k (the original value) and different tapers can be used as well, with no difference electronically.

I specified reverse audio taper for the smoothest transistion across the pot rotation.  You can use a linear or audio taper, but the transistion from slow to fast may be more abrupt.  I increased the size of the pot for slower minimum Rate.

You could try increasing the 1k resistor that is in series with the Rate pot.  For staterters,  use the stock value of 2k2.  You'll sacrifice a bit of the faster speeds, but it may get the LFO working.  What are transistor are you using for the LFO?

[petemoore]

I'm getting tremolo like sounds !!!
 The LED doesn't appear to change...stays lit.
 Basically it seemed to be working about right with the .1uf's  [3], but quite fast to very fast using the 100kA rate pot, depth pot varied depth, at that speed it's hard to tell any approximate % of attenuation at the bottom of the sweep, nice tremolo sound but fast.
 Trying .047uf's [3] created a real cool, slightly phasey tremtone on the open A string, playing notes lower [G F and E on the low E string] caused other higher and higher pitch sounds as lower and lower notes were at input.     [reminded me of a spinning fan in a strobe light...ya know when the wheel spins so fast it looks like it's slowly turning backward?]...]which if could be isolated would be cool but 'side' oscillations were present.

[B Tremblay]

The three caps in the LFO section are supposed to be 1uF - if you're using 0.1uF, then it is possible that the LED will not appear to pulse due to the 10x faster rate.

[petemoore]

James Bond's guitar player had it so good...
  Trems like crazy and sounds great but seems to be dependant so far on having over 9v on  [I use batteries] power supply...any neat tricks to fix that?   lol...I've got an alarm battery that charges to like 13+v but it is rather bulky.

[gez]

James Bond's guitar player had it so good...
  Trems like crazy and sounds great but seems to be dependant so far on having over 9v on  [I use batteries] power supply...any neat tricks to fix that?   lol...I've got an alarm battery that charges to like 13+v but it is rather bulky.

At a guess, I'd say this is happening - higher supply = higher collector current = higher gain for LFO transistor.  

Solution?  Use a higher gain trannie or re-jig the LFO trannie to run at a higher collector current?

[petemoore]

I'll have to root around like dog on the floor and find that dang MPSA18 I dropped...dohh ahd try that...
 It works with the Darlington -MPSA13- I was using my never dies alarm battery for testing [charged full is like 13+volts] and realized later that 'normal' batteries [I tried three of my rechargables] arent firing it up...havent got an actual voltage where it cuts off but Im content that it is too high...phasers and fuzzes work fine with the little batteries
 By the way what exactly is the 100k trim for...it seems to tune in the tone or 'bias?' out the signal?

[gez]

By the way what exactly is the 100k trim for...it seems to tune in the tone or 'bias?' out the signal?

The 100k trim is there to bias the MOSFET.  Gate thresholds vary from device to device so if a divider with fixed values is used for bias, the results will vary from device to device- not too good!  With a trimpot, the wiper can be adjusted to get exactly the right amount of drain current flowing, thereby biasing the amp exactly where you want it.

You should adjust the wiper up from earth till you measure about half the supply on the drain.

[smoguzbenjamin]

It worked for me to just turn it up until the sound got through.

[petemoore]

could be set by ear...but I have that set so the Mosfets Drain is at 4.86v out of 9.21...plenty close for offbeatnik Tremolo type stuff.
 What a machine.  Gafta build another one of these and put the rate on a treadle pedal...!
  I'm deciding it is worth a DIY'ers while to figure out some knob turning device that doesn't require a hand.
  Seems like one could [in many cases] use only a small portion of a oversized pots travel to get the amount of variable resistance needed to change the parameters of a smaller pots full travel...setting that up with pot sidelug resistors to get the change you want with only a small amount of pot travel and 'direct drive' that [connect the potshaft to a pedal] to a see saw.
  The more I think about it the more I find that I like the idea of have a buncha treadles werkin for ya like on phazers, boosters, tremolos, vibes...
  I did a treadle in a large RACO involving a clock spring for reel takeup of the 'string around the putknob' driven by the coutersprung treadle...on a Splitter Blend...someday or another would be direct wired into a multi analog Ckt effects chain panner

[idlefaction]

heh, i now what you mean, wouldn't it be great to have pedals on everything!  but i did this once and found that i had so much choice that i stopped using any of it!!!

try and make your effects rig easy to use so you can concentrate on playing good rather than stomping switches  

[gez]

I'm deciding it is worth a DIY'ers while to figure out some knob turning device that doesn't require a hand.

There used to be just such a pedal on the market (perhaps still is?).  It looked like a wah but had a cable coming off it, a bit like a flexible drive shaft for a drill.  The end would slip on to the shaft of a pot and the treadle would control its rotation.  They didn’t cost much.

Perhaps you could somehow use a drill’s flexi-shaft to do the same thing?

[gez]

Alternatively use a cheap/dead wah pedal.

[smoguzbenjamin]

Yeah an expression pedal would take care of that. Or you could have the rate changed by an envelope circuit, trems like mad at first but as the note decays it goes slower.