BLACK FOREST High Gain Preamp - Based on the Bogner Uberschall

[J0K3RX]

Jok3rx,

For your BSIABX, change C6 to 100n.

It should tighten the low end enough for your chugga-chugga needs...

You are welcome!

I'll do that! Thanks!!

[pakrat]

Not as gainy and tight as the BF? No thanks! 

[J0K3RX]

Not as gainy and tight as the BF? No thanks!  

That sounds kinda funny doesn't it?   I'm not that way, really! 

[bluesdevil]

Hey Jim - Finally whipped out the ol'  Les Paul with the active EMG pickup. Definitely brought down the hum compared to the passive neck pup, but still need to get it quieter for anything louder than bedroom levels. Man, that guitar was made for this circuit!!
I don't have any commercial pedals with buffered bypass to try out... maybe I'll stick something simple on the breadboard to experiment with.
I'll try to figure out how to splice in that noise gate.... I'm using the first version of the ENGL3 pcb.
This is the best high gainer I've built yet, thanks again! It's hard to believe the Black Forest would be better than this.
   

[J0K3RX]

Hey Jim - Finally whipped out the ol'  Les Paul with the active EMG pickup. Definitely brought down the hum compared to the passive neck pup, but still need to get it quieter for anything louder than bedroom levels. Man, that guitar was made for this circuit!!
I don't have any commercial pedals with buffered bypass to try out... maybe I'll stick something simple on the breadboard to experiment with.
I'll try to figure out how to splice in that noise gate.... I'm using the first version of the ENGL3 pcb.
This is the best high gainer I've built yet, thanks again! It's hard to believe the Black Forest would be better than this.
 

Bill,

I know man! The ENGL flat out MURDERS the competition and that ain't N0 J0K3! \m/ \m/

The noise gate is great but to me it's just a band-aid on the problem, still need to find that hum and kill it! You really should try a trim pot in place of R24 and dial it up or down a bit, it really reduces the noise, for me anyway! The best fix "so far" is the buffered tube screamer or whatever in front of the pedal! It makes it what you would expect or how it "should be" from such a high gain preamp... Doesn't kill the natural noise that you would normally get but doesn't hum like a high voltage transformer gettin ready to blow like it does now!

The Black Forest has a different low end growl to it but I think the Engl is better over all... Anyway, if we find out how to kill this hum then it will open the cellar door to all of these other high gain jfet/mosfet monsters!  

Edit: Gotta give all credit to the Russians for these Beasts!! I never could have (would have) come up with this sh!t myself...

[bluesdevil]

Okay, I'll mess around with a buffer and then a trim in place of r24 before hacking in the noise gate.
I get distracted real easy, but I'll try to get it done in a few days and report back.
Man, hang in there with it!!

[pakrat]

I guess I should build this Engl to join the fight against hum eh?

[kabi]

@ 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

Already etched this board for the BF, will place an order for the missing components late next week. So yes, it will take a while, but I'm digging in gentlemen so wish me luck 

are there any further value changes/modifications worth trying?

thanks

[jymaze]

Ok Jok3rx,

There are choices to be made, to many project... So which one you think is the best between:

1) Engl -like (jfet)

2) Engl from Russia (MOS)

3) BlackForest

I will just make one of them so I want to make the best choice...

[J0K3RX]

Ok Jok3rx,

There are choices to be made, to many project... So which one you think is the best between:

1) Engl -like (jfet)

2) Engl from Russia (MOS)

3) BlackForest

I will just make one of them so I want to make the best choice...

Ha, good question... I think #2 is over all the best but I do really like #3 of course... The jfet Engl-like AMT clone doesn't sound as much like an Engl to me as the Russian jfet/mosfet version and certainly doesn't have as much gain! The Black Forest has a really unique low end growl and very percussive attack but seems not quite as good as the Russian Engl for leads.. So, I choose the Russian Engl for the following reasons

1) It sounds the best overall... It really sounds like an Engl, tons of gain, killer percussive attack, kills for leads, just flat out murders!  
2) It uses the 2N7000 mosfets which are still easy to get and cheap as dirt
3) If we can get this one working 100% then all the other jfet/mosfet based Russian preamps will most likely be fixed as well!

by the way - I have built the Krank also and it has "the hum" of course but screams just like the Engl but in a Kranky kinda way

I have not built the following but are all almost exactly like the Engl and Krank
Buzzefall - Mr.Hector
Modern SLO100
VHT
and I found a Russian jfet/mosfet based Dr.Boogey in the same design as these!

So that's 6 different pedals! YeeHaw!  

jymaze - I know you, you have saved a few pedal from becoming scrap and turned them into gold! I have faith in you!  

[alexzanderepair]

Can ya post a link to the schematic of the #2 engl from Russia (most)

[jymaze]

http://dl.dropbox.com/u/11178619/New%20Preamps/ENGL%20-3-%20J0K3RX.png

[jymaze]

I'll put the russian Engl together then Jok3r and report. I may try to tinker around the first stage to get rid of that annoying noise you experienced.

[J0K3RX]

I'll put the russian Engl together then Jok3r and report. I may try to tinker around the first stage to get rid of that annoying noise you experienced.

Thanks for jumping in the pit! You surly will experience "the hum" and maybe you will have a better idea of what is causing it and how to remedy it? I am hoping...  If you fix it you will receive "Legendary Guru" status, from me anyway!    

[jymaze]

With that type of motivation I cannot fail !

[fretzburner]

This is the one i'm talking about on other thread,perf is ready and will be building it today.I choose this ENGL because of your comment JOK3RX hahaha.

[J0K3RX]

This is the one i'm talking about on other thread,perf is ready and will be building it today.I choose this ENGL because of your comment JOK3RX hahaha.

Yeah, build the Russian version that jymaze posted about 5 posts back in this thread... The AMT E1 clone in the other thread works and has no issues but it doesn't have as much gain and just doesn't have a real true Engl tone. I traced it from pics posted in another forum so I had to guess at some of the parts etc..

The only thing I would change on the schematic is you might want to use a 100k trim pot, I'm not sure what the range is there? And you can mess around with different jfets for V1, V5 and V6 some are less noisy than others. You can also use BS170's instead of the 2N7000's but I like the 2N7000 the best and they are a lot cheaper than the BS170.

[fretzburner]

Thanks! how about supply voltage is it strictly 9V? i will be using this together with my original F1 which is 12v.Should i bias V1 to 4v as per schematic or bias it to around 5.5v?

[J0K3RX]

Thanks! how about supply voltage is it strictly 9V? i will be using this together with my original F1 which is 12v.Should i bias V1 to 4v as per schematic or bias it to around 5.5v?

I don't think there would be any problems running it @ 12v providing your caps are rated as such or higher... You should bias @ half the supply voltage or close. If you are running @ 12v then it will drop by the time it reaches the 1st stage V1 because of R8 and R15, I am guessing it will be around 11v or close to that so half of that would be 5.5v. I would hope that it wouldn't throw off the bias of the mosfets but I don't know? Don't know if this is good to do but you could put a resistor in line with the + power input to drop it from 12v down to 9v and maybe put an internal switch inside the pedal so you can switch back and forth if needed.  

[fretzburner]

Thanks again JOK3RX,now it's soldering time.will give update as i finish this build.