UBE Screamer v2

Here is an updated post for the UBE Screamer v2. The UBE Screamer was invented by the smart guys over at RunOffGroove.com, tireless purveyors of all things stomp box from the early days of the hobby.

The UBE Screamer was their entry in the FX-X contest of August 2006 over at DIYStomboxes.com. Check out that site there is so much good information there, it’s where I go for help!

This is my spin the RunOffGroove UBE Screamer. In a nutshell the UBE Screamer reenvisions the Ibanez TS-808 Tube Screamer with inverters from 4049UBE replacing the op amp stages in the original. It’s an interesting idea.

Here is the schematic from RunOffGroove.com

There is an issue here where the signal from U1A is inverted but the at U1D is not inverted. These signals are mixed at the 100k and Rx resistors into U1E. Rx is a resistor adjusted to tasted, choose values from 100k to 500k. Since the signals are out of phase, the lower the value of Rx the more the sound gets that out of phase sound that comes from picks that are out of phase.

In an attempt to solve this I used the remaining inverter stage between U1A and Rx to get the signal in phase. I also added a trim pot in place of Rx to make adjustment easier. Here is my schematic with the changes.

Here the names have changed. The single enters IC1C which acts as a buffer with a gain of roughly x1. It splits from here into the IC1D and IC1P signal paths.

IC1D is the distortion overdrive path. IC1P is a x1 buffer that inverts the signal before it is mixed with the output of the overdrive/distortion section at IC1A which is the output buffer.

Here is a list of parts:

C1 10n
C2 2n2
C3 470n
C4 100n
C5 1n5
C6 150p
C7 100n
C9 100n
C10 100u
C11 100n
D1 1n4148
D2 1n4148
D3 1n5817
GAIN B500k
TONE B500k
VOL B100k
POT1 1M (2262 type)
IC1 CD4049UBE (Must be UBE Type)
SocketDIP 16 (Use a socket for IC1)
R10 100k
R11 100k
R12 220k
R14 330r
R15 RLED (Any value 470r to 5k)
R16 100k
R17 100k

Here found a box, measured and drilled. This was left over from some experiments.

I fit the pots and LED into the PCB without soldering! Then put everything into the box and fit the nuts and washers to hold it all in place. I maneuvered the LED into its hole. Last I flipped it over, holding the PCB in place, and soldered everything.

At this stage you should be able to remove the PCB with the pots and LED as a unit, and this should fit back in the box easily. Here I drilled the DC jack, the foot switch, and the input and output jack.

Last I put fit everything back in the box to wire it all up!





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