Green Citrus (for Orange Lovers)

[boratto]

And here how it sounds:

https://app.box.com/shared/q4fsi2irdi

[johnk]

hmmm. I drew up a vero and built the Orange Citrus without the FAC control (rotary with multi-caps on  the input) and I love it, but this one is a bit different since the orange citrus has the eq circuit before the drive/gain stage and this one has it after it.  the eq cap values are also different on this 'green' version.

[cylens]

It is a "Green" Citrus because it's supposed to emulate a Matamp amp.

I'd love to see a vero for this one (might try to draw it myself)

[rocket88]

i assume it's supposed to emulate a green amp, which still exist, and was connected to MATAMP and orange when they were connected. I don't know how close it will be to sounding like the real amp though. they are monsterous sounding, just check out the band sleep if you haven't before, and you'll get a taste of how insane they can sound. still would love to see this pedal built.

i'm actually working on building an P2P of a green amp, in the process of buying all the parts, the only parts holding me back is actually how to build P2P, which i know should be easier  then i'm making it in my head.

[cylens]

OK, I've tried to draw a layout, I think it is, by fat, the ugliest layout I've ever seen...

I'll try to verify it tomorrow and will post it if it works (there's no need to show it if it doesn't work, it's really fugly)

[johnk]

I drew one up but haven't built it yet. i'm 99% sure that it's correct though.
instead of trimmers, I recommend socketing the four resistors for the drains since this type of circuit is a lot quieter (less noise!) with fixed resistors as opposed to trimpots.

[Alex]

Great layout!
There are a couple of mistakes with Bass 2 and Gain 2.

[johnk]

thanks for catching that. it's been corrected and should be good to go.

[cylens]

hehe, that's much better than what i've done with trimmers (of course, it is!)

one question: did you omit the 1n at Q3 because of the fixed resistor vs timmer?

[johnk]

no, that was an error. I just forgot to add it. I've corrected it now.

[cylens]

ok, great!

one general question about the value of the resistance for setting voltage at Drain: is it circuit dependent? or could i make a small utility with a trimmer to measure the ideal resistance (just a trimmer, transistor socket and 9V/Ground pads) and then put it in the circuit?

[silasmoon]

So I am pretty new to pedal designs, can you explain what a drain is, how one would measure 4.5v on all drains, and how one would wisely step through resistor values to achieve that? I am really interested in designing this circuit as I am a big Matamp fan. Thanks for the help and I'll be sure to pay it forward!

[johnk]

Jfets have a pinout of Drain Source and Gate. to measure the drain voltage, you just power up the pedal with 9 volts and measure the voltage with a volt meter from the Drain pin to Ground to bias it properly.
if you use sockets for the drain resistors (as specified in the layout) you just keep trying values until the drain measures 4.5V (1/2 of the power supply voltage). all Jfets generally measure differently so all of the resistors may or may not be the same value. I usually start with a 10-12K resistor and go from there.
a higher value will lower the voltage and a lower one will raise it. you're looking to get anywhere from 4.5V- 5V on all of the drains.

[silasmoon]

Awesome! Thanks Johnk, really appreciate the walk through. :)

[silasmoon]

Follow up question - any specific color of LED for the desired clipping?

[johnk]

this pedal doesn't use any led's for clipping. that led is the status led (off or on) of the circuit.

[cylens]

has anyone build it? i've used my own layout and the "boost" control is quite subtle, is it the same in the "original" orange citrus?

[johnk]

the boost in the orange citrus is not subtle at all.

[cylens]

Regarding other builders comments, it seems, well, "normal"...

Here's how it sounds, with a bass:

https://soundcloud.com/cylens/green-citrus

I've been stubborn and stuck with the trimmers... well, surprise surprise, it's VERY noisy. I promise I'll listen to you next time, john :D

I find it very difficult to bias Q1, too (J201 everywhere for me)

For the record, here's what I've used (use at your own risk)

[johnk]

that sounds great. I just may have to build it now.