BLACK FOREST High Gain Preamp - Based on the Bogner Uberschall

[markmcconachie]

Well, here is a rough demo I recorded of the pedel before I decided to do the comparison.

https://soundcloud.com/mark-cameron-mcconachie/black-forest-preamp-test-1/s-WW8Ta

[deadastronaut]

@jim: you little teaser...

@mark: sounds great man..

[meffcio]

Here's a teaser...

Great layout. Looks really compact for such a circuit. 

[J0K3RX]

Well, here is a rough demo I recorded of the pedel before I decided to do the comparison.

https://soundcloud.com/mark-cameron-mcconachie/black-forest-preamp-test-1/s-WW8Ta

Mark -

Kick @ss!  \m/    \m/

[jogina111]

gutted out some of my get the j201's. The problem now are the nF and pF caps. By the way, how do this compares to the dr. Boogey?

[J0K3RX]

This is the schematic used for the ENGL 3 - It is verified working but I verified it with another layout without the on-board pots... same values as the one posted I just have not had time to build the new layout! Should work good... basically the same layout that I have already built except that the pots are on-board... If somebody has some free time can you look over it for mistakes I may have made?

You can use J201's or 2n5458's for V5 and V6

[J0K3RX]

gutted out some of my get the j201's. The problem now are the nF and pF caps. By the way, how do this compares to the dr. Boogey?

That is a matter of opinion but in my opinion there is no comparison - The engl whoops the Dr.Boogie's @ss...!

BTW - the Engl uses three 2N7000 mosfets! <-- 2N7000 still super cheap! You can also use BS170's

Notice: There is a voltage divider that comes from R23 and R24 going to the gain pot, R6, C9, R13 and R18 at around +4.5v
The 4.5v rail is the 3rd trace up from the bottom if you were wondering why it is labeled +4.5v

[markmcconachie]

gutted out some of my get the j201's. The problem now are the nF and pF caps. By the way, how do this compares to the dr. Boogey?

That is a matter of opinion but in my opinion there is no comparison - The engl whoops the Dr.Boogie's @ss...!

BTW - the Engl uses three 2N7000 mosfets!

Notice: There is a voltage divider that comes from R23 and R24 going to the gain pot, R6, C9, R13 and R18 at around +4.5v

I am looking forward to building this

[markmcconachie]

gutted out some of my get the j201's. The problem now are the nF and pF caps. By the way, how do this compares to the dr. Boogey?

I have not built the Engl, but the Black Forest (Ubershall) compairs well to the Dr Boogie. It's a totally different sound and imo sounds more amp like. It also responds much more to pick dynamics and rolling the guitar volume back.

[J0K3RX]

I will upload the layout board transfer as soon as a few of you look it over and check it for errors... Krank is next  

Notice: only one trimmer on the Engl!  Nice!

[deadastronaut]

^ yay 1 trimmer nice, and a good mix of fets.

where is the 'sweep' on the schemo?

[J0K3RX]

^ yay 1 trimmer nice, and a good mix of fets.

where is the 'sweep' on the schemo?

Rob,

Sweep is on the Krank schematic but I like it so I left it on the Engl... They both use roughly the same board design and I didn't want to have a empty space for a pot on the engl layout... I guess I could have made it a presence pot but the thing already has plenty of presence!

Sweep just makes R25 variable... Changes the characteristics of the tone stack.

[deadastronaut]

ahhh gotcha, cool.

i breaded the boogie recently, and i got pissed off with the trims, too variable for my liking, i also tried various tone stacks on it, but still wasn't really satisfied,

once i get my current projects done i'll defo dive into this big time, i'm still after a great hi gain tight as f... sound as well as my other distortion....thanks for sharing man. !!! \m/     \m/

[J0K3RX]

ahhh gotcha, cool.

i breaded the boogie recently, and i got pissed off with the trims, too variable for my liking, i also tried various tone stacks on it, but still wasn't really satisfied,

once i get my current projects done i'll defo dive into this big time, i'm still after a great hi gain tight as f... sound as well as my other distortion....thanks for sharing man. !!! \m/     \m/

Rob,

Might try the Framus Cobra tone stack or the Blackstar ts... I am going to be trying them soon!

About your projects... when you get done = never... kinda like when I ask my wife about something and she says "oh, maybe someday" which translates to don't hold your breath..    Just kiddin of course. Keep making cool sh!t, you have my permission

[J0K3RX]

Here is the board transfer for the Engl 3 if anybody wants it... Just print the pdf, it prints to size. Will fit in a 1590BB or a 1590B... I would stick it in a 1590BB so you have room for a tube screamer, cab simulator etc... Plus I am making a clean channel, so... up to you.

BTW: J1 and J2 are to be jumpered/connected with a wire.. can't really see it in the diagram (yellow line) because it's hidden under the pots so, I labeled it on the board

PDF
http://dl.dropbox.com/u/11178619/New%20Preamps/E3%20Transfer.pdf

Image


This thing has sh!t loads of gain and tone... NOT your sisters fuzzy wuzzy fuzzbox!  

[deadastronaut]

NOT your sisters fuzzy wuzzy fuzzbox!  

, yeah ''when i get my projects done= never''

correct, they are never done, finished , complete, are they...always room to tinker.

[meffcio]

J0K3RX , you're like Santa, but a lot after the Christmas ;p
Anyway, I'd like to suggest two things:
1. Consider creating a new topic. We're no longer talking about Black Forest, but about a whole collection of your stuff, so..
2. The design in your PDF file is in a really low resolution.. While it shouldn't f*ck up things, it's still always better to have the pcb design as best as it can be. Consider using PDF creator and printing the design to a file with that software. This way the design will be in much, much better quality, and then you can use Inkscape, or other kind of software to add the rest of the stuff, like title, etc.

[hangingmonkey]

Thanks for the layouts, more stuff to add to the list of things to build.

So, are the engl3 and black forest preamps, ie should i plug the output into the effects return of my amp?

Thanks!

[euronymous0001]

hey jok3rx,

just remembered this thread
http://www.diystompboxes.com/smfforum/index.php?topic=89399.80 

looks like i need to revisit my failed board of the krankenstein. who knows, I might make it work after 20 months of clearing my head from debugging the sucker 

[J0K3RX]

hey jok3rx,

just remembered this thread
http://www.diystompboxes.com/smfforum/index.php?topic=89399.80  

looks like i need to revisit my failed board of the krankenstein. who knows, I might make it work after 20 months of clearing my head from debugging the sucker  

What jfets/mosfets were you using, J201 and 2n7000? If so, then why no trimmer on the drain of the first jfet?  

I am looking over your layout...

Edit: found a couple minor things but it looks ok? Except for no trimmer on the drain of Q1 and R2 has no value listed on your schematic? There is a very tight window on the bias of Q1 and if you don't get it just right then it's game over... Do away with the PRES pot, which is actually the "Sweep" pot and should be around 50k to 100k in series with an 18k resistor so it doesn't bottom out to nothing. Actually for trouble shooting sake I would just get rid of the pres pot and use a 33k resistor... I also see you used BS170's in place of the 2n7000's which should be fine but not sure if there are minor differences, I will have to compare data sheets...

From what I can see it looks ok?