BLACK FOREST High Gain Preamp - Based on the Bogner Uberschall

[J0K3RX]

Okay, just finished the ENGL3 and have it hooked up to my breadboard jig (power and I/O jacks). It fired right up..... yippee, no debugging!!!!!!!
With Chromesphere's corrections, it works. I am getting a hum, probably due to such a high gain circuit exposed without any shielding.
The only difference is I changed out the J201 in Q1 for a 2n5457. Also the pots are laid out correctly... no worries there.
Only question I have is what are those two empty pad holes on power rails near bottom right corner supposed to be for.... a missing component?
    Compared to Dr. Boogey, I say this is a tighter, higher quality high gain sound. Just need to box up and put shielded wires for in/out to see if that kills that hum.
       Thanks to Jim for the great project and to Paul for the BOM and finding mistakes on the layout.

 

Well that is really good news man!!!   Very happy it worked!!! Looks like it's etchy time at the J0K3RX ranch! Those empty holes/pads are just extra.. don't know why but I always add a few extra? It's got some blistering high gain doesn't it!!? By the way, how does the sweep pot work?

Stick a tube screamer in front of it and see how you like it!!

[J0K3RX]

Ok, here's the noise gate option.. I could have built it on-board but I opted to go this route instead. It mounts right on the bottom of the gate on/off switch. The 2 diodes are 1N4148..

[bluesdevil]

Damn, I should have waited for the layout with noise gate!! Well, I can still splice and dice my board to get it in there.
I don't know if the "sweep" control is working as it should, after giving it a longer play...... mostly just effects volume and midrange?
Ah, I don't have a tubescreamer, but I have a Les Paul with an active EMG bridge pickup I will try soon..... gotta dig it out of the closet.

[J0K3RX]

Damn, I should have waited for the layout with noise gate!! Well, I can still splice and dice my board to get it in there.
I don't know if the "sweep" control is working as it should, after giving it a longer play...... mostly just effects volume and midrange?
Ah, I don't have a tubescreamer, but I have a Les Paul with an active EMG bridge pickup I will try soon..... gotta dig it out of the closet.

You can still add the gate without too much trouble on the other layout... That's what I did on mine.

I didn't expect the sweep would do a whole lot but I thought it may make the tone stack react differently, bump the mids and or give it a scoop maybe? Probably doesn't justify a pot...? I don't like presence when it really doesn't need that either. Maybe I should move the volume over and put the gate at the end?

Trying to keep all the board layouts relatively similar for each different preamp.. A couple of them could almost use the same board all together..

[bluesdevil]

Hey Jim - Yeah, it helps dial in just the right tone..... more useful than a presence control, so I would keep it on.
Gotta get this in an enclosure soon, thanks again!

[chromesphere]

Sound demo please
Sound demo please
Sound demo please
etc

[hangingmonkey]

Hey JOKERX, whats the deal with the BF, i had held off because of all the updates and changes. Is the last one you uploaded the finished one?
Cheers

[J0K3RX]

Okay, I will do a shootout with what I have here...

Black Forest
AMT B2
Dr Boogie
5150 amp (i'll just use the preamp and the same cab sim stuff as the others)

I will do them in a mix so that we get the best idea of how they all blend in.
I will try to get time to do this tonight...

I have been considering trying to make a jfet ampeg svt preamp version too...

Maybe when Mark gets a chance he would be so kind to do this? I would love to hear that!!!   Time permitting... I know people get busy.

Hey JOKERX, whats the deal with the BF, i had held off because of all the updates and changes. Is the last one you uploaded the finished one?
Cheers

Hangingmonkey - I would see what version Mark used, he seems to have the best sounding build to date! Or you can keep "Hanging" until I get finished with the new version of the BF... up to you?  

[J0K3RX]

Sound demo please
Sound demo please
Sound demo please
etc

+1

[markmcconachie]

Sorry guys, I have been really busy
I 100% still plan to do the comparison though!

It's worth noting that the sound of mine can't really be compared from my sound clip, in a mix (evan a rough, crappy mix like that) guitars appear to sound really different than on their own...

[hangingmonkey]

Okay, I will do a shootout with what I have here...

Black Forest
AMT B2
Dr Boogie
5150 amp (i'll just use the preamp and the same cab sim stuff as the others)

I will do them in a mix so that we get the best idea of how they all blend in.
I will try to get time to do this tonight...

I have been considering trying to make a jfet ampeg svt preamp version too...

Maybe when Mark gets a chance he would be so kind to do this? I would love to hear that!!!   Time permitting... I know people get busy.

Hey JOKERX, whats the deal with the BF, i had held off because of all the updates and changes. Is the last one you uploaded the finished one?
Cheers

Hangingmonkey - I would see what version Mark used, he seems to have the best sounding build to date! Or you can keep "Hanging" until I get finished with the new version of the BF... up to you? 

Thats cool im not in a rush. Ill hang for the new one

[markmcconachie]

Okay, I will do a shootout with what I have here...

Black Forest
AMT B2
Dr Boogie
5150 amp (i'll just use the preamp and the same cab sim stuff as the others)

I will do them in a mix so that we get the best idea of how they all blend in.
I will try to get time to do this tonight...

I have been considering trying to make a jfet ampeg svt preamp version too...

Maybe when Mark gets a chance he would be so kind to do this? I would love to hear that!!!   Time permitting... I know people get busy.

Hey JOKERX, whats the deal with the BF, i had held off because of all the updates and changes. Is the last one you uploaded the finished one?
Cheers

Hangingmonkey - I would see what version Mark used, he seems to have the best sounding build to date! Or you can keep "Hanging" until I get finished with the new version of the BF... up to you?  

I used the layout that has no presence, the only change I made I think was a 270pF cap in place of a 250pF. Also I get very very little noise from the pedel (I am not using the noise gate).

[hangingmonkey]

Cool, look forward to the demo!

[J0K3RX]

Ok, not the Black Forrest but it's an Uberschall... Russian version, and from working with the others this one I believe is a ball buster!!!

Anybody care to do a QA on this one?







~ Jim

[deadastronaut]

@jim: cool, just curious, does this design with the gain pot to ground, rather than the other design gain going to 4.5v have that vol pot issue?...

hmmm....cheers man.

[J0K3RX]

@jim: cool, just curious, does this design with the gain pot to ground, rather than the other design gain going to 4.5v have that vol pot issue?...

hmmm....cheers man.

Rob,

Great question! But, I have not built this one so I don't know if this one has "that vol pot issue" at all...? Although, I see what you are saying and I can tell you that I saw that myself a while ago. So, I ran the gain on the Engl 3 to ground hoping that it would have something to do with it... Nope, still did it.  

I do know that others (in the Russian forum) have built this using j201 and 2N5457 combinations with really good results so, we will see? I believe it will work first build just like the Engl but I hope I didn't make any small mistakes on the layout, tired and eyes play trix after a while... I do have it about half way built already so I will try to finish it soon... Waiting on a Tayda order for exact resistor/cap values etc.. If anybody else feel like being a Guinea pig, feel free to help out and build this one   I will upload the board transfer if anybody wants it!  Still need another set of fresh eyes to check it over first..?

~ Jim

[jymaze]

Actually the gain pot bottom leg should go to the polarization point of the jfet and not the ground to avoid creating DC across the lugs of the gain pot. or maybe it is a deliberate choice from the designer to have the jfet polarization changing with the gain put being turned? I doubt so though...

[J0K3RX]

Actually the gain pot bottom leg should go to the polarization point of the jfet and not the ground to avoid creating DC across the lugs of the gain pot. or maybe it is a deliberate choice from the designer to have the jfet polarization changing with the gain put being turned? I doubt so though...

So, you think I should make it like the engl then? Or, at least make the board so you can jumper it either way?

Edit: I updated the layout a few posts up... see what you think?

[jymaze]

Yep, I guess it is good to keep both solutions and see if it makes any difference. I am not sure it would make any type of difference you could hear though, but it just makes more sense from a design point of view.

[J0K3RX]

This one was a lot like the Uberschall so I pounded it out real quick... Thank you sir, may I have another!  

One good thing is I kinda got to double check my work on the Uber and the SLO while doing these... Pretty confident they will work! Let me know if anybody wants the transfers??

I give to you SLO-RECTO