BLACK FOREST High Gain Preamp - Based on the Bogner Uberschall

[Cap]

@ jim: It sounds killer!  

ok, as promised:
http://dl.dropbox.com/u/3511352/Black%20Forest_1590B%20layout_gate%20version.pdf-------> UNVERIFIED

should be ok   please report errors or tell me if you need explanations. Enjoy  

Ciao

I'm back..finally.. Sorry to report to have a not working black forest Seems that my layout has a mistake.
I'll repost when correct

[J0K3RX]

@ jim: It sounds killer!  

ok, as promised:
http://dl.dropbox.com/u/3511352/Black%20Forest_1590B%20layout_gate%20version.pdf-------> UNVERIFIED

should be ok   please report errors or tell me if you need explanations. Enjoy  

Ciao

I'm back..finally.. Sorry to report to have a not working black forest Seems that my layout has a mistake.
I'll repost when correct

Here ya go, sorry it didn't work... Probe around and check your voltages may give you a clue? Probably a small re-rout of a trace or something easy to fix...So, I wouldn't scrap the one you etched just yet.
http://dl.dropbox.com/u/11178619/New%20Preamps/black_forest_v3.1.PNG

There is probably a few parts you can leave out like C11 and the noise gate etc... It needs an input buffer like the Engl I think? That will be on a small daughter board once I figure it out.

[ggedamed]

Hi guys, i'm here to report having a russian/JokerX Engl on my breadboard. It definitely has the growl. And the noise . Still, my preference goes with the all-JFET-AMT-style circuits. The Engl on my breadboard seems heavy filtered and kinda uni-dimensional. It reminds me a bit about Sansamp GT2 - gorgeous sounds, but not big variation with the position of the knobs, the type of guitar/pickups or the technique (not that I would know anything about guitar technique  ).
Granted, all of these could be errors on my part.
I put some doodling on Souncloud, so if you have any suggestions, I'm all ears. I know that I should tune my guitar and I should practice more, so you can skip that part . I also definitely favor highs, it could be my age. BTW, GZB 7.3.4 (in a Sound JS OD5 box) is an all-JFET-AMT-style distortion, so you can compare between my results.
My native language is not English, so be gentle with the slip-ups.

LATER EDIT: I mistakenly started with a cabsim attached to the end of the Engl mod, not knowing that it sounds better without it. So, if you want to skip the cabsim part, go to 2:15.

[jymaze]

Thanks for the sound sample ggedamed.

What is that GZB thing? I could not find anything... Is there a schematic? It sounds pretty good to me actually.

[Cap]

Thanks in advance Jim. Some voltages...time to double check connections and to audio-probe

Black Forest voltages
Q1
D:4,54
S:0,3
G:0
----------------
Q2
D:4,51
S:0,25
G:0
----------------
Q3
D:4,5
S:0,48
G:0
----------------
Q4
D:4,53
S:0,35
G:0
----------------
Q5
D:4,5
S:0,39
G:0
----------------
Q6
D:8,94
S:4,6
G:4,48
----------------

[ggedamed]

Heh! GZB is an acronym for "Gingi Za Best" which means something like "Chuga-Chuga The Best". Regional joke. I use it to refer to all distortions I ever made.
This one is my interpretation of the AMT L1 series. I intend to say the full story ot its creation (on the both forums, no less  ), only it takes time to gather all the facts and here it is off-topic anyway.
Right now I can tell you that it is the generic tube amp-inspired/Dr. Boogie self-biased common source JFET amplifiers chain, including the AMT BAT85 diodes between gate and source. There are 5 transistors in the distortion part, the first one and the post-TS buffer are 2SK30s, the second stage is 2SK117, the third stage (pre-TS) 2SK117 buffered by another 2SK117. I like 2SK117 because of the higher gain + lower noise compared to pretty much every other JFET.
In case you're interested, the cabsim is also from AMT.
Oh, and having some MAX1044 received as samples from the good guys at Maxim I supplied the distortion part with ~25V and the cabsim with ~17V.
Just pure, clean fun.

Sorry, Jim, I'm stopping the off-topic-ness right now .

[J0K3RX]

Heh! GZB is an acronym for "Gingi Za Best" which means something like "Chuga-Chuga The Best". Regional joke. I use it to refer to all distortions I ever made.
This one is my interpretation of the AMT L1 series. I intend to say the full story ot its creation (on the both forums, no less  ), only it takes time to gather all the facts and here it is off-topic anyway.
Right now I can tell you that it is the generic tube amp-inspired/Dr. Boogie self-biased common source JFET amplifiers chain, including the AMT BAT85 diodes between gate and source. There are 5 transistors in the distortion part, the first one and the post-TS buffer are 2SK30s, the second stage is 2SK117, the third stage (pre-TS) 2SK117 buffered by another 2SK117. I like 2SK117 because of the higher gain + lower noise compared to pretty much every other JFET.
In case you're interested, the cabsim is also from AMT.
Oh, and having some MAX1044 received as samples from the good guys at Maxim I supplied the distortion part with ~25V and the cabsim with ~17V.
Just pure, clean fun.

Sorry, Jim, I'm stopping the off-topic-ness right now .

Dude, don't stop!!! Bring it bro Anything high gain is welcome by me any day!! High gain is the topic as far as I am concerned so it's not off-topic! I am very interested in what you have created!  I spent some time messing with the AMT Legend stuff, all very cool and some of the best around in my opinion...! I also use bat54 SMD diodes between gate and source on the all jfet based preamps, never got around to changing it on the older schematics...

I know people are probably getting discouraged by this never ending thread that is jumping from one pedal to another but the way I look at it is at least it's all in one place...

Don't feel like you gotta post under this thread but you can if you want, I don't care! I just wanna see some schematics, layouts etc.. and the cab sim too! I am very happy with the Hotline 2 and the SCS (both Russian/Ukrainian) cab sims right now but always looking for others...

[jymaze]

I am with Jok3rx: Want to see that GZB!!!

[deadastronaut]

+1 too...

keep em coming..\m/    \m/

[ggedamed]

OK, guys. Thanks for your interest.
I promise I'll make a thread dedicated to the whole process. I found some interesting facts on this journey and it's gotta be presented right. My spare time is quite sparse, that's why it's not yet ready.

[J0K3RX]

OK, guys. Thanks for your interest.
I promise I'll make a thread dedicated to the whole process. I found some interesting facts on this journey and it's gotta be presented right. My spare time is quite sparse, that's why it's not yet ready.

Oh sure, give us all boners with talk of yer cool pedals then make us all wait... nice  

Are you talking about the "original AMT pedals" and biasing jfets using something like a BC547 NPN transistor with a bav21 diode or the like between gate and drain? I know that's kinda vague but I have seen this done...


Edit: ok nevermind what I attempted to say.. here's a pic.

[J0K3RX]

Ok, I think I found the fix for "THE HUM"

Here is what I did and I get ZERO hum! This is what I did just messing around so there is probably a neater way...

1.) Added a 500Ω resistor right on the +9V power on the jack to the +9V input on the board. You may be able to use a lower value.. this is just what I grabbed and it worked so it'sa stayin on there! I thought I would start with 500Ω and work my way down if needed but, 500Ω seems fine...
2.) Added a 100uF cap right on the power jack between the +9V and ground. Maybe 220uF will work better? Make sure polarity is right, of course!  
3.) This is the kicker! All "separate shielded wires" for everything going to and coming from the board and, it matters where the wires are routed preferably not over the top of the board... No noise, for real!!

I also biased the first jfet (J201) and then removed the trim pot, measured it with my meter and replaced it with a fixed resistor of the same value... The trim pot is noisy as hell by the way, and I used a good one!

If you do all this and still get noise then move the jacks away from the board, mine don't like to be any closer than about 2 inches from the board...

Everything else is stock values just like the schematic. I did add 22pF caps between the gate and drain of V2 and V4 but I don't know that this did anything for the noise but it did make it a little less harsh, more tube like sounding, I think.

Note: This circuit is EXTREMELY susceptible to interference form it's own connectors and any external stuff!!!

Ok now, DO IT!   By the way, this doesn't effect the gain or sustain in any way!! And no need for the noise gate!

Somebody that built this Engl please verify! I want others besides me to say it works

[Somicide]

after the SMD thread, I'm thinking I may have to get brave (and a new Rx for glasses) and try it super-tiny.

[stormbringer79]

I'll build one and try it out Joker. Already built the black forest (with gate on perfboard) and liked it, got it set up in an enclosure together with a PT2399 delay and a AMZ booster. It's the only pedal i use nowadays, a bit battery hungry though with all 3 sharing the same battery.

Just gonna wait until i get rid of my fever/headache and try the Engl out, been following the thread for quite a while.

[jymaze]

So I was shielding problems... Glad you found the cure. I am sure filtering the power supply helped too.

Somehow I never had to shield any wires in my builds, the shielding of the enclosure was always enough (I also ground the casings of all my pots). Not sure I ever had something with as much gain tough.

It still does not really explain why a tube screamer in front solves the noise problem... Whatever...

[stormbringer79]

Built a couple of high gain circuits, the DR. Boogey for example, i had some oscillating issues which a buffer resolved aswell. can we just call buffers Magic?

Instrumental song i recorded using the black forest, my delay and my new 7-string (ESP LTD MH-417), alot of the stuff in the song is improvised and quite sloppy, but should give an idea how i made it sound. quite heavily mid scooped and run through guitar rig.
https://soundcloud.com/#stormbringer79/instrumental

[J0K3RX]

Built a couple of high gain circuits, the DR. Boogey for example, i had some oscillating issues which a buffer resolved aswell. can we just call buffers Magic?

Instrumental song i recorded using the black forest, my delay and my new 7-string (ESP LTD MH-417), alot of the stuff in the song is improvised and quite sloppy, but should give an idea how i made it sound. quite heavily mid scooped and run through guitar rig.
https://soundcloud.com/#stormbringer79/instrumental

That sounds FANTASTIC!!! \m/ \m/

Those harmonies sound great man!!! And, those squeal pinch harmonics are wicked! I thought it was a metal version of the Halloween movie theme song at first the way it starts out...  

jymaze - I never really had to shield any wires in my builds either with the AMT clone stuff and Dr.Boogie etc... These are different, obviously! And the tube screamer buffer is puzzling to me also but like stormbringer said, buffer magic...

[stormbringer79]

Thanx

Gonna start building the ENGL 3 with your fixes on perfboard here now. But with off-board pots (out of PCB mount pots, but will keep the leads short) and see what it sounds like. Will try it with both my old guitar (unbuffered passive EMG's), and the new 7-string with active EMG's.

[J0K3RX]

Thanx

Gonna start building the ENGL 3 with your fixes on perfboard here now. But with off-board pots (out of PCB mount pots, but will keep the leads short) and see what it sounds like. Will try it with both my old guitar (unbuffered passive EMG's), and the new 7-string with active EMG's.

Kool! The only pot that gets noise is really just the gain pot so be aware of that...

[jymaze]

Stormbringer,

It sounds awesome! you are quite the player. If you think it is sloppy, I would like to be just half sloppy as your are on these 32nd notes (or whatever they are).