HBE - Power Screamer [goop alarm]

John Lyons · Post by **John Lyons** » 14 Feb 2009, 05:19

Since it's their "flagship pedal" I would have thought there would be something on it here.
Haven't been able to Dig up and posts about it.
I know it's a tube screamer with some tweaks but the one I have here is gooped around the clipping diodes. It gets a very compressed sag sound at one stop on the diode switch.
The other two positions sound like LEDs and then straight back to back diodes.
This one seems to have a good bit of gain on tap. More than I get from a typical landgraff type TS tweak or two. I think it sounds nice.

Just curious if anyone has a clue about the R/C combo off the feedback loop of the clipping stage and the diode configuration. This one belongs to another guy...I'm just fixing it as the whole pedal is pretty sloppily wired and soldered poorly. I don't want to mess with it too much as far as degooping it. Not mine...

john

soulsonic · Post by **soulsonic** » 14 Feb 2009, 06:13

Talk about timing... I just traced one of these last night!

Anyway, the R/C combo of the feedback loop is 3k9+68nf with Boost off, and switches to a 1K+100nf with Boost on.
The diode configuration is a little strange: the left-hand position is a silicon diode one way and LED the other, the right-hand position is only a single silicon diode (this is the super-compressed saggy position), and the center position is no diodes. The silicon diodes appear to be something in the 1N914/1N4148 range... they both measure the same... haven't gotten the exact color on the LED yet, but I'll find out soon enough.

I have it drawn out in my notebook, I'll get it digified soon for sharing.
The input buffer transistor is an MPSA18.

lautmaschine · Post by **lautmaschine** » 14 Feb 2009, 21:57

soulsonic wrote: I have it drawn out in my notebook, I'll get it digified soon for sharing.
The input buffer transistor is an MPSA18.

Looking forward to it!

guiltyspark · Post by **guiltyspark** » 16 Feb 2009, 18:00

soulsonic wrote: Talk about timing... I just traced one of these last night!

Anyway, the R/C combo of the feedback loop is 3k9+68nf with Boost off, and switches to a 1K+100nf with Boost on.
The diode configuration is a little strange: the left-hand position is a silicon diode one way and LED the other, the right-hand position is only a single silicon diode (this is the super-compressed saggy position), and the center position is no diodes. The silicon diodes appear to be something in the 1N914/1N4148 range... they both measure the same... haven't gotten the exact color on the LED yet, but I'll find out soon enough.

I have it drawn out in my notebook, I'll get it digified soon for sharing.
The input buffer transistor is an MPSA18.

The single diode thing is interesting, I've done it by accident and it sounded really "gnarly", that's hardcore assym. clipping for sure.

Guiltyspark

soulsonic · Post by **soulsonic** » 17 Feb 2009, 05:45

Here it is. I was able to check the color of the LED without removing the goop... just ran some current through it and got it to light up - red, no doubt about it.

The single diode selection sounds like total splat.

: HBE Power Screamer

lautmaschine · Post by **lautmaschine** » 17 Feb 2009, 16:03

Even closer to a stock TS than I was expecting

thanks for posting!

John Lyons · Post by **John Lyons** » 18 Feb 2009, 21:04

Thanks Martin!
I need to get this thing buttoned up and sent back.
Was yours as sloppily as the one I have here!

It sounded good though...

john

soulsonic · Post by **soulsonic** » 19 Feb 2009, 23:29

It wasn't super-sloppy... better than some other pedals I've seen... the wires to the controls did break rather easily when I had the board out of the enclosure and all the bits were sort of flopping around. The only thing that really bugged me was how they had all these grounds soldered to backs of the pots; the whole ground scheme in general bothered me, but it's all wired up the way I'd prefer now. I really don't see why they had the parts for the tone control wired off-board either; there would be plenty of room to put that stuff on the board if the layout was arranged a little better. Overall, I'd give it a "C" - gets the job done, but it could definitely be better.

This was a re-boxing job, that's why I had it all dissected; fit into an NSC 1290 no problem - turned the boost footswitch into a toggle switch.

John Lyons · Post by **John Lyons** » 24 Feb 2009, 05:16

I got mine semi taken apart so...
The back of the pot ground scheme and off board tone R/C was what bothered me as well.
The soldering on the board was sloppy though...
At any rate...all re wired, and it does sound nice.
I think the "boost" is pretty subtle to dedicate to a stomp switch.
I'd have gone with a toggle as you did in the rehouse.

The single diode sounds cool with lower gains.
A bit out of control with higher gains.

DougH · Post by **DougH** » 24 Feb 2009, 16:59

Is this the Cusak pedal?

Fuzzer · Post by **Fuzzer** » 24 Feb 2009, 18:34

Here is the Cusack Screamer;

https://www.freestompboxes.org/viewtopic.php?t=1106

bluesbreaker62 · Post by **bluesbreaker62** » 10 Aug 2009, 17:13

Sorry for reviving an old threat, just thought I'd post some pics.

Despite it being YATS, I really like mine:

vai0306 · Post by **vai0306** » 17 Sep 2009, 10:53

someone has the pcb/layout for this project?

thanks

soulsonic · Post by **soulsonic** » 18 Sep 2009, 09:20

vai0306 wrote:someone has the pcb/layout for this project?

thanks

Nearly any Tube Screamer layout could easily be adapted to work for this.

greatwhitemark · Post by **greatwhitemark** » 16 Feb 2010, 12:29

Hi,

Great forum you have here!

Soulsonic thanks for the power screamer schematic.

I want to add the fat boost mod to my older power screamer. I don't need it to be switchable, I just need to know which values to change to fatten up the boost? I don't want to lose any level on the boost though, in fact a touch more would be handy.

Any help would be much appreciated.....

Cheers

mirosol · Post by **mirosol** » 22 Sep 2014, 18:05

I have no idea about the fat boost, but to build a stock version... Currently unverified, but looks ok.
+m