BLACK FOREST High Gain Preamp - Based on the Bogner Uberschall

[jymaze]

Jok3rx, you are right, I forgot there was no trimpots... I am just used to these being always there... You can try to just do the mod for the first of the mosfets since it dominates the noise figure then 10k at source and about 15k at drain, you have to change the cap too, as stated) and see if it is useful to you at least. You will loose a little gain, but it is ok.

My bad... The other tweaks still stand nonetheless

[nordine]

Hey good people, there seems to be happening cool stuff here 

i wanted to know the main differences in tone in both circuits Black Forest and Engl3.. or maybe, what are they suited better for... for example, which one does a better djent tone? that kind of stuff... cheers!

[J0K3RX]

Hey good people, there seems to be happening cool stuff here 

i wanted to know the main differences in tone in both circuits Black Forest and Engl3.. or maybe, what are they suited better for... for example, which one does a better djent tone? that kind of stuff... cheers!

djent - engl... Although, the Black Forest is not to be laughed at either! Truth is both would be very good but a lot of times they (guitar players) roll back the gain on the preamp to get that djent tone...

[J0K3RX]

Jok3rx, you are right, I forgot there was no trimpots... I am just used to these being always there... You can try to just do the mod for the first of the mosfets since it dominates the noise figure then 10k at source and about 15k at drain, you have to change the cap too, as stated) and see if it is useful to you at least. You will loose a little gain, but it is ok.

My bad... The other tweaks still stand nonetheless

Wow... Diggin a deep hole here! Gettin worse and worse. sounds very thin and mostly just mids not to mention, for some weird reason this made the tone stack almost totally non-functional and my mid knob has now become some sort of volume knob

Doing this is like chasing a greasy olive around your plate with a fork trying to stab it but it escapes every time and shoots off to another side of your plate... Where's my hammer! 

[J0K3RX]

Ok, I installed the noise gate add-on and whoa! No adjustment pot for the gate, just a 1M resistor... Sounds perfect to me, completely silent and no lack of anything except that damn hum! I may just wire this permanently in there and always on... Sounds perfect to me and I gotta say that sweep knob is a friggin GREAT idea!!! Makes the tone stack able to get endless ranges of tones from huge scoop to skull popping mids! Bout ready to call it a wrap with the gate! You build this with the gate and you won't be sorry!!! No Hum, just blistering High Gain! 

I did make a couple changes and I will list those later.. tired

pics and sound samples to come...soon

[scuzzphut]

Chin up mate 
It's not working 100% and the clearcoat needs a polish, but.....

[J0K3RX]

Chin up mate 
It's not working 100% and the clearcoat needs a polish, but.....

Nice!! Not working 100%? What's wrong with it?

Looks great! 

[deadastronaut]

+1 looks 

[jymaze]

Jok3rx, you are right, I forgot there was no trimpots... I am just used to these being always there... You can try to just do the mod for the first of the mosfets since it dominates the noise figure then 10k at source and about 15k at drain, you have to change the cap too, as stated) and see if it is useful to you at least. You will loose a little gain, but it is ok.

My bad... The other tweaks still stand nonetheless

Wow... Diggin a deep hole here! Gettin worse and worse. sounds very thin and mostly just mids not to mention, for some weird reason this made the tone stack almost totally non-functional and my mid knob has now become some sort of volume knob

Doing this is like chasing a greasy olive around your plate with a fork trying to stab it but it escapes every time and shoots off to another side of your plate... Where's my hammer! 

Sorry man I sent you on a wrong path, I just forgot you did not use trimmers... MOSfets are actually pretty variable too (less than fets though) so I used trimmers too in the rare cases I used MOSfets, then swapped with a resistor when the ideal value was found. I don't believe in pre-canned values for anything with "fet" in the name!

I really have to breadboard that thing and try real life tweaking myself since it seems to react weirdly... There is something that does not match calculations, or even Spice simulations, just can't get my finger on it. But high non-linear behavior is not the easiest to simulate for sure.

[J0K3RX]

Jok3rx, you are right, I forgot there was no trimpots... I am just used to these being always there... You can try to just do the mod for the first of the mosfets since it dominates the noise figure then 10k at source and about 15k at drain, you have to change the cap too, as stated) and see if it is useful to you at least. You will loose a little gain, but it is ok.

My bad... The other tweaks still stand nonetheless

Wow... Diggin a deep hole here! Gettin worse and worse. sounds very thin and mostly just mids not to mention, for some weird reason this made the tone stack almost totally non-functional and my mid knob has now become some sort of volume knob

Doing this is like chasing a greasy olive around your plate with a fork trying to stab it but it escapes every time and shoots off to another side of your plate... Where's my hammer! 

Sorry man I sent you on a wrong path, I just forgot you did not use trimmers... MOSfets are actually pretty variable too (less than fets though) so I used trimmers too in the rare cases I used MOSfets, then swapped with a resistor when the ideal value was found. I don't believe in pre-canned values for anything with "fet" in the name!

I really have to breadboard that thing and try real life tweaking myself since it seems to react weirdly... There is something that does not match calculations, or even Spice simulations, just can't get my finger on it. But high non-linear behavior is not the easiest to simulate for sure.

That's ok man... same path I have been on. Obviously I am walking down the wrong trails into the black forest of high gain madness.... Need your help! 

[fretzburner]

Don't want to change any component because really liked the sound as per schematic but the noise is killing me.Some compromises should be made with this.

[J0K3RX]

Don't want to change any component because really liked the sound as per schematic but the noise is killing me.Some compromises should be made with this.

Have you tried that noise gate add-on yet? I have done a few changes and some other stuff... Will post this weekend

[fretzburner]

External noise gate yes(mxr v2 clone) but on slow passages i can hear the hum with the notes.

[fretzburner]

Tested today hooked to F1 channel send/return without gate,the noise seems natural to me this time.Almost same noise as my stock GT2 and DT-2.F1 channel send/return colors the sound a bit(don't know if it is buffered...maybe).And as what Jok3rx advised to put a buffered pedal in front to lessen the hum.I think i'm done with this,hopefully the noise will not increase upon housing this to 1590B enclosure.

[J0K3RX]

Tested today hooked to F1 channel send/return without gate,the noise seems natural to me this time.Almost same noise as my stock GT2 and DT-2.F1 channel send/return colors the sound a bit(don't know if it is buffered...maybe).And as what Jok3rx advised to put a buffered pedal in front to lessen the hum.I think i'm done with this,hopefully the noise will not increase upon housing this to 1590B enclosure.

The F1 send / return is buffered...

[fretzburner]

Thanks Jok3rx for the clarification,it's done and noise level is very tolerable without gate.

[J0K3RX]

Ok, try this... Stick a 15k resistor across the input (from input to ground) and tell me what you think Depending on how hot your pickups are you might try between 10k and 20k, mine seems good at 15k... no noise and the vol rolls back nice and clean. Probably the same deal for the Black Forest as well...?

[jymaze]

I think 15k is too low for an input impedance Jok3rx!

It loads the guitar a lot!!! For sure there must be less noise than across a 1meg resistor, but it is too low for a passive pickup. There is a high-frequency roll-off that occurs then.

It may sound fine at high gain, but probably too round and muted at low gain.

I would not go under 250 - 500k.

Of course, if there is a buffer before the pedal, then this low impedance is not an issue at all.

I think that it has the merit to confirm that the noise experienced here is picked up at the first stage (picks up a lot of noise because of high impedance, but it is always a problem with passive instrument input) and amplified until becoming unbearable. Is till have to bread board that thing...

[J0K3RX]

I think 15k is too low for an input impedance Jok3rx!

It loads the guitar a lot!!! For sure there must be less noise than across a 1meg resistor, but it is too low for a passive pickup. There is a high-frequency roll-off that occurs then.

It may sound fine at high gain, but probably too round and muted at low gain.

I would not go under 250 - 500k.

Of course, if there is a buffer before the pedal, then this low impedance is not an issue at all.

I think that it has the merit to confirm that the noise experienced here is picked up at the first stage (picks up a lot of noise because of high impedance, but it is always a problem with passive instrument input) and amplified until becoming unbearable. Is till have to bread board that thing...

Nope... Not round and muted at all! Are you sure about 500k? That doesn't work...

fretz... Can you verify?

[jymaze]

I guess it is fine for high gain stuff since the missing high end will not be missed anyway because so much high frequency is generated in the distortion process.

If it works for you... It is just not real good to load the pickups usually, although some designs do it (a lot of fuzz pedals...). Whatever works for you at that point