BLACK FOREST High Gain Preamp - Based on the Bogner Uberschall

[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

Report:

Built this one and tested working! Not as BIG sounding as the Black Forest and not as much gain as I was hoping for but with a little kick in the @ss with a tube screamer it does the trick... Good thing is no noise/hum and has good tone! I still have to check voltages, just biased by ear so maybe I can squeeze a bit more gain out of it or I could add a boost like the BF? 

[pakrat]

Jim, whatever you do..... don't stop posting these!!! Like others have said, there are people interested in these and heavy tone "technicians" are hard to find. Please keep up the good work 

@Rob Soooo sorry to hear about your mom! We lost my dad last year to melanoma after a hard fought 3 year battle. I know what you are going through and as terrible as it is, stay strong for her. If there is anything I can do for you, just ask.

[J0K3RX]

Jim, whatever you do..... don't stop posting these!!! Like others have said, there are people interested in these and heavy tone "technicians" are hard to find. Please keep up the good work 

@Rob Soooo sorry to hear about your mom! We lost my dad last year to melanoma after a hard fought 3 year battle. I know what you are going through and as terrible as it is, stay strong for her. If there is anything I can do for you, just ask.

Where the hell you been?

[J0K3RX]

Kinda disappointed with the all jfet/J201 Russian preamps.. Not even close to the preamps with the 2N7000's mosfets! Maybe because they used those Russian KPC104A freaky fets had something to do with it? I may try to retro fit the Uberschall with the 2N7000 tonight... will have to change the source and drain resistors as well.. no big deal. I'm thinking 56k drain and 43k source like all the rest of the jfet/mosfet preamps?

[bluesdevil]

Jim - Did you build the ENGL yet? Just wondering if you are getting a loud hum like I am.

[pakrat]

@JOK3RX   I was "out sick" for a few months with an infection in my front teeth. It was causing me to get the flu over and over. Now that I'm better I've been rewiring my studio and upgraded to a pro tools 9 rig. Calibrated a Tascam MS-16 today with a 30 year old MRL tape. It shredded pretty bad but it got the job done 
I need to do some catching up to see what changes you have made, but it seems you are still on the quest for "the sound". Don't feel bad, I have an AXEFX II and I'm probably the only one in the world not satisfied with the heavy tones..... I always go back to my Randall RG100. And so, the quest continues......
It's good to see you're still working on this though. If there's anything I can do to pitch in, let me know.

[J0K3RX]

Jim - Did you build the ENGL yet? Just wondering if you are getting a loud hum like I am.

Yeah man, I built it and yes I get the loud hum... The only thing I can attribute it to is some sort of problem in the power filtering? It's not really caused by the high gain from what I can tell but more like a power hum. You can turn the gain way back on the pedal and the hum is still there full force... This is what you are getting, right? Anyway, I am working on this because if I unlock this secret then all of these Russian preamps will be bad @ss! I have asked about this in the Russian forum but I am still trying to figure out wtf they are saying? Something about lowering the supply voltage on the drains of the mosfets and some other stuff that I can't figure out, yet??

Have you tried a tube screamer in front of it? Or, another pedal with non-true bypass buffers in front of it? It stops the hum almost 100% on mine with a retail $30.00 tube screamer (TS-7) in front of mine!? WTF, right!? Anyway, I don't even have to switch the TS on, it just being in front of the ENGL is good enough... no hum and the volume roll back is fixed also Confused? But, I would like to know if that fixes it for others so, if you have a pedal (any pedal) without true bypass can you give it a try?  

I really wish there were more hours in a day! I hardly have time to work on these lately... This late night stuff is bull sh!t!  

Edit: BTW - The noise gate add-on almost completely removes this hum as well but takes a bit off the high end and gain.. not much though and you can compensate by raising the treble a bit and kicking a tube screamer on if you want that all out face melting gain! The way I look at these pedals is they are "preamps" (which they are) and almost every "Real Tube" preamp I have ever played I have always used a TS in front for that extra tightness and slight gain boost! Even if the preamp already has mega gain I still use the TS and roll the gain back on the preamp a bit... Most metal players I know do this even with their $5k ENGL Invader heads or Diesel VH4's... The tube screamer is one of the most valuable non-valuable devices ever created for high gain guitar! I usually always build them into my pedals anyway..

Just FYI - I have etched and drilled all of the boards for ALL of these preamps so slowly I am populating and testing them So far the Krank is the best but it has a bit of a hum also

[J0K3RX]

@JOK3RX   I was "out sick" for a few months with an infection in my front teeth. It was causing me to get the flu over and over. Now that I'm better I've been rewiring my studio and upgraded to a pro tools 9 rig. Calibrated a Tascam MS-16 today with a 30 year old MRL tape. It shredded pretty bad but it got the job done 
I need to do some catching up to see what changes you have made, but it seems you are still on the quest for "the sound". Don't feel bad, I have an AXEFX II and I'm probably the only one in the world not satisfied with the heavy tones..... I always go back to my Randall RG100. And so, the quest continues......
It's good to see you're still working on this though. If there's anything I can do to pitch in, let me know.

Axe-FX II B!tch... lol

I have a friend that has one and it's sick! Already been down the F@%$#D up teeth road so I know what that's like... Fortunately I am now missing half of my teeth.. or maybe that is unfortunate? I guess it's just how you choose to look at it. My mouth is half full of teeth or my mouth is half empty of teeth   

[bluesdevil]

Hey Jim - Still have not tried with a buffered pedal.... will report back when I do. The hum is so bad, you can hear it even when playing. Damn, it's great if not for that hum!!
The circuit is definitely tight enough for me without anything going into it, but then again I'm used to fat and sloppy fuzzes.
Holy hell, I read back a few posts and am depressed about the cancer reports.... my mother is going through stage 4 breast cancer right now and can feel for you all.
My own health is not too good, I'm allergic to everything it seems!! I'll post on a separate thread about my current bout with Krylon painted enclosures.

[J0K3RX]

Hey Jim - Still have not tried with a buffered pedal.... will report back when I do. The hum is so bad, you can hear it even when playing. Damn, it's great if not for that hum!!
The circuit is definitely tight enough for me without anything going into it, but then again I'm used to fat and sloppy fuzzes.
Holy hell, I read back a few posts and am depressed about the cancer reports.... my mother is going through stage 4 breast cancer right now and can feel for you all.
My own health is not too good, I'm allergic to everything it seems!! I'll post on a separate thread about my current bout with Krylon painted enclosures.

You can try a trim pot on R24. Just remove R24 and tweak the pot until you get a lower level of noise... You will have to do it by ear and find a happy medium between noise and gain. If you go too high or too low with the trimmer it will completely cut out all the sound and you will get no signal passing at all but if you find the right spot it reduces the noise greatly...  Also, you can replace R8 with a 2k resistor and R15 with a 3k resistor... These don't have to be exactly 2k and 3k, you can use like 2.2k and 2.7k or some combination. You will have to re-bias the 1st stage again after this... Did you hear my sound sample of the noise gate? It's only 2 1N4148 diodes and a 1M resistor placed between stages 3 and 4... This makes the pedal almost completely silent and it doesn't clip notes or anything like that...

Sorry to hear about your Mom!!! 

[J0K3RX]

Here is the noise gate schematic.. It goes between stages 3 and 4
You can use a switch on the 1M resistor to turn it on or off or you can use a 1M/B pot to adjust the gate level.
If you use the pot, all the way off is no gate at all and basically bypassed. Or, you can hardwire it in there with a fixed resistor and have it on all the time...
It's not at all like a regular gate... There is no attack and all that, it's just instant and never clips notes or kill sustain, even at clean or low volumes..

This is based on the Peavey JSX Joe Satriani signature series preamps.
http://dl.dropbox.com/u/11178619/New%20Preamps/JSX%20Full%20Schematic.pdf

[deadastronaut]

nice one jim, i'm going to try that gate on the spitty which i have on breadboard with tonestack at the mo just to see if it'll work with it....

then i'll be trying out some of these killer looking schemo's that ive been dying to try out...cool stuff man,  did you sort out your gallery yet?..

@all: thanks for the kind words guys. all the best to you & yours too.

[J0K3RX]

nice one jim, i'm going to try that gate on the spitty which i have on breadboard with tonestack at the mo just to see if it'll work with it....

then i'll be trying out some of these killer looking schemo's that ive been dying to try out...cool stuff man,  did you sort out your gallery yet?..

@all: thanks for the kind words guys. all the best to you & yours too.

Nope, haven't got a login for the gallary yet... Still trying to organize

I was thinking about your spitfire.. I need to build it again, kinda forgot how it sounds? Actually, I still have one of the first boards I made, version 3 I think? I know it didn't have all the noise of these from what I remember.

I built a bsiab x2 also and I kinda borrowed from yours and some random schematics I have collected... Wasn't real happy with it but it didn't sound too bad and had loads of gain.. The thing I didn't like about it was that it just didn't tighten up on the lows like these others do.. Sounds fantastic for 6 string stuff and great for leads but doesn't like the sub frequencies of the 7 or 8 string for sure! Maybe you know how to tighten up the @ss end? 

Here's mine.. no schematic just kinda free styled it


Went sort of by this and your version 3 and added the tone stack

[deadastronaut]

hi jim, yeah the spitfire isn't noisey anyway...i was just curious.

ive stuck a BMT stack on the end and am crudely endlessly swapping values on it...but it does tighten it up a bit too..

might give ^ that stack a go too...cheers man.

thats mad with the extra fet before the stack...hmmmm....

[J0K3RX]

I have ADD (attention deficit disorder) and some odd OCD (obsessive compulsive disorder) as well... Can you tell? I just go from one thing to the next and have a million ideas running through my brain all the time! I was just thinking of programmable tone stack and volume/gain from another post where some dude made a programmable tube screamer using Arduino so, you could save presets, clean, dirty etc...   then I just had to slap myself and say NO!  Jeesh, WTF is wrong with me???

[deadastronaut]

lol...yeah that sounds familiar, i have a million different ideas going on at once too...small solar projects, magnet motor ideas, joule thiefs, beer brewing, along with pedal idea stuff too...

thats why i have 7 breadboards..

i have difficulty sleeping sometimes...not enough hours in the day man.....

[J0K3RX]

thats why i have 7 breadboards..

i have difficulty sleeping sometimes...not enough hours in the day man.....

7 bread boards? You got me beat on that one by far... I only have 2. If I build something like one of these preamps I get totally lost if I walk away from it for a day... I come back and spend an hour trying to figure out wtf is going on here?? I really need to bread board one of these so I can swap parts on the fly rather than etch a board and remove parts, add parts, cut traces, re-attach traces... by the time I get something workable my board looks like a battle field mess of sh!t with stuff hangin all over it lol! I would never post a pic of my test work I would be shunned from the scene and banned from all forums

[deadastronaut]

yeah ya gotta bread these hi gain buggers...only problem is the squeeeeeeeling when you do..

but as long as you keep in mind that it will be fine once shielded, its well worth doing for ease of modding etc....

[J0K3RX]

ok, what do you all think of this?? This is the Russian Uberschall, not quite as gainy and tight as the BF or the engl but has some good heavy tone, I think? The sweep knob is super useful, can get all kinds of ranges of tone with it! Also, there is no hum on this one which is a HUGE plus!!

Pretty sure if I change C4 to 470n or 220n it will tighten up the low end...

http://dl.dropbox.com/u/11178619/New%20Preamps/UBER-JFET1.mp3

[jymaze]

Jok3rx,

For your BSIABX, change C6 to 100n.

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

You are welcome!