BLACK FOREST High Gain Preamp - Based on the Bogner Uberschall

[ggedamed]

LOL, Jim, I took the name and R23 from your layout:



Look in the top-left corner and you'll see a 10k resistor between pin 1 of the GAIN pot and ground. I'm not using a minimum gain limit resistor in my pedals because I want the full clipping range for all guitars, including ones with hotter pickups.

[J0K3RX]

LOL, Jim, I took the name and R23 from your layout:


Look in the top-left corner and you'll see a 10k resistor between pin 1 of the GAIN pot and ground. I'm not using a minimum gain limit resistor in my pedals because I want the full clipping range for all guitars, including ones with hotter pickups.

oops... I forgot bout that lol... Great job anyway!

[JebemMajke]

As far as E3 goes, can i use two 22k ohms instead of 24k ohms?

[J0K3RX]

As far as E3 goes, can i use two 22k ohms instead of 24k ohms?

If you are referring to R23 and R24 you could go up or down a couple of k and should be ok...

[JebemMajke]

Thnx mate. Cheers.

[JebemMajke]

Ok. Build report.
E3 zero noise. First I've tried it with my epiphone sg, active emg81 circuitry with ibanez v8 pickup. Zero noise, balanced highs, balanced mids and starved bass ... no matter what i did there was zero, or almost no bass. And my tuning is drop A#. And i hated it. Than I've plugged my other axe. Yamaha pac 120s, with passive jackson pickups. Love it!!! Fantastic sound, and again zero noise. And let me tell you thins thing is in my test rig, not in the box. And no shielded cables. There were two things that I've changed. Frist is 4n7 cap that is conected to gain pot. I;ve run out of 4.7n caps so i've placed 6.8. And those two 24k resistors became 22k resistors. That's it. Zero noise, hum or anything. Trimmed it to 4.5v and it kicks ass with yamaha made of agathis and other low quality woods and sounds like crap with epiphone made of mahogany:(. Maybe it's because of active pickup. Maybe that emg 81 circuitry would work better with some other pickup. I'll experiment and post the results here.

Oh yeah, ive used it as distortion box. Not as preamp. Direct into clean channel of my amp. PS ether I;ve @#$%ed up or this thing needs a bit more volume. It's not loud enough.

[JebemMajke]

Can this thing be used as preamp for one of those TDA power amps?

[pakrat]

Can this thing be used as preamp for one of those TDA power amps?

I believe Jim's intention is for these to be preamps in front of power amps/return jack of your amps or direct into consoles. But like his sig says, if it sounds good, then it IS good.
Thanks for the build report on the Engl. I haven't recieved my parts for the Engl yet but have built the Black Forest and it rips with emg 81's! And it sounds much better through the return jack rather than the input of my amps. Into a solid state power amp.... even tighter!

[JebemMajke]

4 fets version or the one before? And have you used his layout?

E3 is cool, but lacks bass. It's trebley as @#$%.

[pakrat]

Did you try it in the effects loop return? I know my BF is totally different sounding in front of the amp as opposed to the FX loop. I built the 5 fet version, I believe V4.1 and yes, all of the versions I have built have been JOK3RX's layouts all the way back to V1.
It sounds killer but does have some noise even with the shielded wire. I will build the 4 fet version next followed by the Engl, and based on what Jim said about the new 4 fet version, it sounds just as good as the 5 fet version without the noise.

[JebemMajke]

OMG ... The last cap ... i;ve placed 470p instead of 470n ... That's what's causing that treble. I lll replace little @#$%er and than Ill post a new report.

[JebemMajke]

Much better. And volume is ok, but now i have noise. Not epic, but it's there. It sounds great with SG. I think it will go in the box without noise gate.

[pakrat]

My Black Forest lost a TON of noise when boxed up. I would bet your Engl will be silent when it's finished.

[J0K3RX]

Seems like some different outcomes here...? I don't have a problem with my E3 other than the slight noise when I roll the volume pot back... no problems with the bass at all. Might double check all your values and connections, traces etc... Also, don't forget there is a jumper that goes from the bass pot to the sweep pot, very hard to see in the picture, it's yellow and spans across under the edge of the mid and treble pots about 1 inch long.

Miša - What version of the BF did you build?

[J0K3RX]

Can this thing be used as preamp for one of those TDA power amps?

YES!

[JebemMajke]

Seems like some different outcomes here...? I don't have a problem with my E3 other than the slight noise when I roll the volume pot back... no problems with the bass at all. Might double check all your values and connections, traces etc... Also, don't forget there is a jumper that goes from the bass pot to the sweep pot, very hard to see in the picture, it's yellow and spans across under the edge of the mid and treble pots about 1 inch long.

Miša - What version of the BF did you build?

E3

Yep jumper is there, It's got bass, but not as much as i would like
It's great for black metal though.

This E3 is going my preamp box. 2 Dirt channels and 1 clean. Just to decide which one is going to be second dirt channel

I'm about to build BF 4 fet version. But you haven't verified that layout.

[pakrat]

My parts are on the way so if you don't verify it, I will. Unless someone else beats us to it 

[JebemMajke]

. Tonight i'll etch BF 4 fet version pcb. I think I have most of the parts, if not all of them, on my table. I would love to use it as a second dirt channel on my preamp. That would be cool as @#$%. And to use zendrive as booster for solos. 
I've got a boner just thinking about it 

[pakrat]

Muhahaha! Ask Jim for his cab sim and you can add that in there too!

[JebemMajke]

I've etched hotline 2 allready. But I won't use it in this project. But Sonic maximazer will be included