simple 2 knob hi gain distortion..collaboration?

[arma61]

if you use an 8 pins (or more) IC socket then you can parallel caps to "uncommon values" and mix type (ceramic, poly, electro..)

[deadastronaut]

if you use an 8 pins (or more) IC socket then you can parallel caps to "uncommon values" and mix type (ceramic, poly, electro..)

i think i know what you mean..!
what like another socket full of caps.to choose from by way of switching on the input?..sorry its early..im still half asleep. ...?

ahhhhh the inevitable mods are already coming...

while i m at it , ive got a tonestack on a small breadboard , i'll try it with that today and see how it behaves...just out of curiosity..


edit: wow! this thing is loud as it is an amp i suppose......i matched my bypassed level to this and the volume on the effect goes
to about 10 oclock on the pot...to be unity....

[phector2004]

Have you tried it as an amp?

Haven't read up on the chip, but its the 'heart' of the noisy cricket, ruby etc, maybe it can drive headphones at 4am when the neighbors would otherwise be sharpening their knives 

[culturejam]

In reference to the vero build: where's the other FET? I only see one.

[deadastronaut]

Have you tried it as an amp?

Haven't read up on the chip, but its the 'heart' of the noisy cricket, ruby etc, maybe it can drive headphones at 4am when the neighbors would otherwise be sharpening their knives  

no i havent but i bet it would drive a speaker though!.......so you know my neighbours then?...

i'll have to find a speaker and try it...(yep noisy cricket, ruby)...amps.

would it have to be an 8ohm speaker...or any?..

[deadastronaut]

In reference to the vero build: where's the other FET? I only see one.

yep 1 only (for now)..this was where i was trying  out the big daddy and smash drive.. trying to see if they fizzed...

going to try the original schematic again...with the 100uf cap 9v to ground..again!!!..got a lot on at the moment

busy busy busy...will do it asap........

[caspercody]

I built the Purple Plexi, and Krank pedals and these do not fizzle out on a sustained note. But it sounds like something is getting louder as the note fades off. I can not describe it any better than that. I looked at the schematics for these pedals and both of them have capacitors on the power supply side to ground. The Purple Plexi has additional diodes on the power supply.

[deadastronaut]

I built the Purple Plexi, and Krank pedals and these do not fizzle out on a sustained note. But it sounds like something is getting louder as the note fades off. I can not describe it any better than that. I looked at the schematics for these pedals and both of them have capacitors on the power supply side to ground. The Purple Plexi has additional diodes on the power supply.

hi caspercody...no fizzle?...but sounds like its getting louder?...i take it the purple plexi is a 386 too!..(havent looked yet)..

as ive said' i built 4 versions of the 'krank' and they all fizzled on the decay, even when changing the ic's....it seems like a very 'sensitive' ic..

ive even asked youtubers demoing the 'krank' and they have confirmed the fizzle too....

ive looked at the schematics over again..yep they do have caps to ground too..but still have noise issues...

it seems like an inherent problem with 386 circuits...the vero on this thread is verified and seems to work  ok.


i am working on a simple tone control for it at the moment...mainly because i have an old enclosure with 3 holes drilled already..
and to see how it sounds...cheers rob.

[caspercody]

The Purple Plexi is a 386 based pedal. There is also a 10 ohm resistor in series with the positive battery to pin 6 and a 100n to ground.

[deadastronaut]

The Purple Plexi is a 386 based pedal. There is also a 10 ohm resistor in series with the positive battery to pin 6 and a 100n to ground.

cheers i'll take a look at that...but it still  has problems though!!!!....im not sure what the cure could be on that!..

its a shame that these problematic circuits get circulated before they are completely tested..thoroughly eh!...

[Slade]

What 386 are you using? JRC386? LM386? N1? N3?

[deadastronaut]

What 386 are you using? JRC386? LM386? N1? N3?

hi slade...lm 386n-1

[caspercody]

The other thing I read is that the manufacturer does recommend a 10u from pin 7 to ground. This is to help stabilize the circuit.

[deadastronaut]

The other thing I read is that the manufacturer does recommend a 10u from pin 7 to ground. This is to help stabilize the circuit.

yep...done that on the vero page 3...

[Slade]

What 386 are you using? JRC386? LM386? N1? N3?

hi slade...lm 386n-1

Daniel Schwartz recommends using LM386 N-3 for this 386 based pedals.. Maybe you should try that.

[deadastronaut]

What 386 are you using? JRC386? LM386? N1? N3?

hi slade...lm 386n-1

Daniel Schwartz recommends using LM386 N-3 for this 386 based pedals.. Maybe you should try that.

ok...i think i have one..and a 4....is there any noticable difference between a jrc..and a lm..then?

edit: i stuck a simple tone control on the end...volume unity is now at 2oclock on the volume pot...
it goes from bassy to very bright..but a good range.. needs tweaking a bit...i would prefer more of a scoop .but its sounds great with my morley wah too...


just made this for the hell of it..and  to fit an old box i have with 3 holes ready drilled...shame to waste a hole etc......

[deadastronaut]

anyone messed with this yet then?.......

[tubelectron]

Hi deadastronaut,

It seems that you get rid of the "bad decay" by filtering the +9VDC with a 100µF... It is so simple that we  often forgot it ! So your circuit was surely suffering High Frequency (RF) or ultrasonic oscillation - I wonder how I forgot to suggest it to you, as I do it on nearly all my stompboxes : a RC filter which stops the hum coming from a non-filtered PSU wallwart and AC grounds the + to mass (-) to avoid RF oscillation.

ButButBut : saying that, I am not sure, but I think I forgot it when I have done my 386 trials... The job will have to be redone then... What a nut.

About the hum when unplugged : maybe your circuit is badly shielded, or the input jack is not grounded when unplugged, or a mass connection is lacking somewhere... It is so simple that we again often forgot it !

Anyway, congratulations - your dual fet + 386 will be a killer machine, then.

A=!

[deadastronaut]

Hi deadastronaut,

It seems that you get rid of the "bad decay" by filtering the +9VDC with a 100µF... It is so simple that we  often forgot it ! So your circuit was surely suffering High Frequency (RF) or ultrasonic oscillation - I wonder how I forgot to suggest it to you, as I do it on nearly all my stompboxes : a RC filter which stops the hum coming from a non-filtered PSU wallwart and AC grounds the + to mass (-) to avoid RF oscillation.

ButButBut : saying that, I am not sure, but I think I forgot it when I have done my 386 trials... The job will have to be redone then... What a nut.

About the hum when unplugged : maybe your circuit is badly shielded, or the input jack is not grounded when unplugged, or a mass connection is lacking somewhere... It is so simple that we again often forgot it !

Anyway, congratulations - your dual fet + 386 will be a killer machine, then.

A=!

hi tubelectron. i take it mass=ground?....im guessing.!..

yep the 100uf has definately helped. am back on the 2 fet j201's project now...

just trying to get the right gain out of the fets going into the 386!...

any thoughts on what the 2 fets setup should be...as i am just experimenting with many values on the breadboard...??

cheers rob.

[Gus]

There is a "design" flaw in the first schematic.  The lack of a gate to ground input resistor and output cap.  You are relying on a path to ground for the gate to ground resistor at the input that a guitar or effect before this MIGHT supply(interesting thing with JFETs is you can use high value resistors for the gate to ground or ref, 3gig etc so a leakage path can work as a resistor sometimes).  Also you are relying on a input cap on the following effect amp etc device after the first circuit.  DC on the output might "upset" the following circuit.  If this is feeding a tube preamp check the operating points of the first tube in the amp with the first circuit plugged in the amp.

Two caps in series are just the same as one cap of a lower than the smallest value cap,  easy to find math on the web to figure it out.