Green Citrus (for Orange Lovers)

[glasspak73]

On the vero layout here there is a cut between the 47Uf cap and the 2.2k resistor on the Source of Q1.Should i not put this cut in when i make mine and follow the schematic exactly or should i keep the cut and remove the 47Uf cap.

[Frank_NH]

OK.  I see.  John must have thought it good to remove the cap, but left it in the vero.  I would leave out the cut and the 47 uF cap for now.  Try the effect.  If you think it needs more gain, install a cap where the 47 uF is now.  Honestly I'd go for something like 100 nF, which would boost the upper mids and trebles, or you can socket and experiment.

[El-even]

Hi folks,

do i need to match the fets for this build, and if yes, what is the best method/advices to achieve that?

make this http://tagboardeffects.blogspot.fr/2012/07/greatly-improved-jfet-matcher.html, buy a pack of fets an go on ?...

[johnk]

guile31 wrote

Hi folks,

do i need to match the fets for this build?

no, that's what the resistors marked with a '?' is for. they bias the Jfets.

[johnk]

glasspak73 wrote

On the vero layout here there is a cut between the 47Uf cap and the 2.2k resistor on the Source of Q1.Should i not put this cut in when i make mine and follow the schematic exactly or should i keep the cut and remove the 47Uf cap.

actually, that cut is NOT supposed to be there. the 47u does connect to the source.

[El-even]

thanks John

[El-even]

i've breadboard it (johnk-v2) and it's noisy at hell  (i know it's because of the breadboard and all electronic stuff i have around) but, the real issue i have is the boost is very subtle, i mean his effect is essentialy audible in the low drive zone; passing 12/13h on gain pot the boost is very very just detectable... are you sure of the pot value (1k)?

other thing, i need at least >47k resistors to bias correctly the jfets (4.5v on 2n4547 & j201), i think it's not a "problem" but i'm far from the "common" 10-12k .
my psu give ~9.3v, maybe it's the cause

btw, this preamp should sound very nice once boxed with shielded wires etc, very promising

[glasspak73]

Thank you John

[johnk]

guile31 wrote

i've breadboard it (johnk-v2) and it's noisy at hell  (i know it's because of the breadboard and all electronic stuff i have around) but, the real issue i have is the boost is very subtle, i mean his effect is essentialy audible in the low drive zone; passing 12/13h on gain pot the boost is very very just detectable... are you sure of the pot value (1k)?

other thing, i need at least >47k resistors to bias correctly the jfets (4.5v on 2n4547 & j201), i think it's not a "problem" but i'm far from the "common" 10-12k .
my psu give ~9.3v, maybe it's the cause

btw, this preamp should sound very nice once boxed with shielded wires etc, very promising

it shouldn't be noisy at all. the boost is not a huge boost but it I find it useful. and yes, it is a B1K pot.

[El-even]

I have a huge amount of radio/electrical interferences in my neighborhood (mobile antenna, workshops, electrical tower...) and this is the noise i give when i build circuits
sometime is tolerable, sometime is desperate...like with jfets i think because i already have the same issue with a sabbra cadabra; unusable at home but "best pedal ever" for the guy i sold it (no interference at all in his basement)

so, i went to a random circuit found on the web (100r in serie with the 9v and a filter 100r rez/100p cap on input) and...
alleluya, a major part of the noise is gone

the boost is discret but perfect to shape the disto/fuzz

i'm quite happy to riff this sludge beast but i still have a little "maybe" issue; i notice an interaction between the treble and the gain pots
i mean if i turn fully clockwise the gain AND the treble, the tonal background change, it is like the tone crossing a step in the "global" form and it is not really linear but almost like another stage

the result crossing this stage is addition of trebly crisppy gated harmonics wich disappear if i turn back a little the treble pot OR the gain
and the pedal is still usable but souding a little fuzzy different in this fully setting

did you notice the same in this circuit or another and in this case, probably resulting of bad component (jfets or cap maybe)

v+= 9.31v                                    @9v (in theory)
q1 (2n5457)= 5.16v                          4.98v  
q2 (2n5457)= 4.73v                          4.57v
q3 (j201)= 5.16v                              4.98v
q4 (j201) = 4.91v                             4.74v

once socketed, my biasing resistors are all measured in the 10-20k range but in fact, they are all from my 50-60k range stock

[traktop]

Any of you guys have tried this one on a semi/cranked amp? Or this is like one of those amp in a box that works better on a totally clean amp.
The acapulco gold for example, always seemed to work better on cooked amps than into clean platforms.
Cheers, Gilberto.

[StephanCOH]

Finally built one yesterday. Tested it in all it's unboxed glory.  A little noisy (which will hopefully be fixed after it is boxed). The boost is massive. Sound was fine already, though I have not properly biased the transitors yet. Got them to about 4v each but had no more resistors of the correct value to get them into the 4,5v-5v range. Hope I'll be able to box it this week and give it a proper testdrive at band-rehearsal next week.

[StephanCOH]

Played it at rehearsal volume yesterday. Cranked it and played it into a clean set JetCity 50 with neutral EQ. Thick and creamy sound, not really high gain, but plenty enough for doom and stoner-rock. Heavy sound, no additional fuzz need (for now, I know I am going to want one sometime).

Going to be on my live board on sunday.

[traktop]

I really wanted to like this circuit as an "amp in a box", but it never really did.
I even boxed it with some shockets to try different caps before every fet stage...
To me it sounds mushy with no focus at all.
It worked great stacking it before the model T build though...

[rocket88]

One of the reasons is it's not based off the Green Amp or even the Matamp preamp, seems to be an attempt to get something to sound similar, I don't think it hits the mark at all which I think I've said before. I've actually got the schematic for both the Green MV120 and Matamp GT120 & GT100, and it's on my list to make a preamp pedal for, like the model t.