Introducing the "Cream Pie" !

[cab42]

Carsten, I remember that thread, I've had great results using the OC140's with red dot as "emitter"
only to find that the dot means "collector" !!
Just shows you that the "symetrical" idea is true, mil spec and all

MM

First time I used one, I didn't know the pinout and just plugged it in. I thought I was lucky, but that was a kind of win-win situation.

I have a colleague, an elderly gentleman who was originally trained as an electronic tech in the airforce in the sixties. He told me that if you scrape of the paint of the OC140 you can use it as a phototransistor!

Regards

Carsten

[mac]

what about putting the SWTC in between stages ?

Right away!

hmmm..cream pie driving a mosfet stage anyone?

I don't have a mosfet but some fets. Can try CP > fet or fet > CP.

mac

[Barcode80]

i posted in another thread about the tube sound OD soindg a bit brittle to me. what do you guys think the results of combining it in a box with the cream pie would be? i'm thinking it might fatten it up a bit, but i'm not sure...

[jaydawg]

I glad to see the gain pot idea took off. I thought it worked well. I was also playing around with using a 4.7u on a switch off the emitter to ground as a mid boost.

jaydawg

[mydementia]

Here's a PCB layout for the "Cream Pie V2" !

CREAM PIE V2

have fun !

AC

Andy - looks like the diode is floating in space... should be connected to the trimmed side of the +9V rail - right?  I built a pair of these circuits together (liked the idea of driving one into the other - or using one at a time) and get VERY low output...but I also don't have any NPN Ge trannies... the 2N2222's aren't quite the same... anyone have a good Si recommendation?  I'll get to the surplus store this week and pick up some reasonable trannies. 

The soundclips are great - and the circuit is simple.  Great job...as usual!
Mike

[MartyMart]

Mike , these may be helpful :

2N2369 ( Si NPN low gain metal can )
2N3903 ( Si NPN low/med gain plastic top )
2N3114 ( Si NPN low gain large metal can )
2N2270 ( Si NPN low/med large metal can )
2N4401 ( Si NPN med gain plastic top )

The "warmest/Ge" sounding are the 2369 and 3114 but still not up with an
OC140 (CV7112) - aron and smallbear have them, HIGHLY recommended !

Marty.

[mydementia]

Thanks Marty.  I tried 2N4401's this morning and still get almost zero output...

What about the 2.7k resistor from the E to Ground?  Missing from the PCB but present on the vero...

[mac]

For those who want to use Si... forget it. Even leaky Ge will sound better. I have tried with silicons, 2369, 3440, 1613 all low gain but they all luck the typical Ge signature.

BTW, I am posting the Cream Pies Ge > FET preview version with tone control soon.

mac

[Dragonfly]

Here's a PCB layout for the "Cream Pie V2" !

CREAM PIE V2

have fun !

AC

Andy - looks like the diode is floating in space... should be connected to the trimmed side of the +9V rail - right?

yep...the layouts are fixed now...thanks !

I built a pair of these circuits together (liked the idea of driving one into the other - or using one at a time) and get VERY low output...but I also don't have any NPN Ge trannies... the 2N2222's aren't quite the same... anyone have a good Si recommendation?  I'll get to the surplus store this week and pick up some reasonable trannies. 

The soundclips are great - and the circuit is simple.  Great job...as usual!
Mike

i havent tried a silicon in it, so you'll probably just have to "experiment" a bit...sorry i',m not more help on this...

AC

[Dragonfly]

What about the 2.7k resistor from the E to Ground?  Missing from the PCB but present on the vero...

i forgot to remove it when i decided to add the gain pot...the 2k7 is the value for the LED resistor...

here....

[mac]

i havent tried a silicon in it, so you'll probably just have to "experiment" a bit...sorry i',m not more help on this...

Si sound good, but after hearing the Ge version you feel something is missing.
Si will bias around Rc: 33 - 47K if Vbe: 0.6V and hfe: 100.

mac

[mac]

Cream Pie and Fet stage with tone control:

http://geocities.com/guitarfxs/images/creampie_fet1.gif


mac

[Dragonfly]

Cream Pie and Fet stage with tone control:

http://geocities.com/guitarfxs/images/creampie_fet1.gif


mac

looks cool...hows it sound ?

i hope you dont mind...i "appropriated" your drawing and "butchered" it up so i could post an idea that just came to me...this was the quickest way to draw it out...if you'd like me to take the picture down, just let me know !


i'm pretty sure some value adjustments will be necessary...but it could be interesting...


AC

[mydementia]

Hey Andy - looks like the pop cap and protection diode need to come off the other side of the trimmer on the PCB... I got NO output until I cut these two out of my circuits.  Makes sense...  

I got some NPN Ge trannies today - pretty sweet sounds, I must agree!  I'm going to futz with the circuits some more...might add a switchable Ge Diode pair at the end of the circuit to soften it up a bit...maybe a BMP Tone control...  Fun stuff.
Mike

[dosmun]

I built the Ver2 tonight after trying ver1 last ngiht.  This thing kills into my already driven Rivera.  Big fat and RRRRRRRRRR!!!!!!

[markm]

This thing just keeps on evolving!
Very Cool Andy.....(and guys!).
I can't wait to start building this thing but I gotta finish up some stuff first.
Great Job fellas! 

[bean]

I have an OC44 waiting to do something so this is definitely my next build. Thanks, Andy!

[manson]

What about the 2.7k resistor from the E to Ground?  Missing from the PCB but present on the vero...

i forgot to remove it when i decided to add the gain pot...the 2k7 is the value for the LED resistor...

here....

Does anyone already have a pcb layout for this one?

[markm]

There are 2 that I know of....
One in Dragonfly's Gallery and one in my Gallery.
Thanks again Andy, I can't wait to build the darn thing!!

[R.G.]

Andrew, could you give a read to "Avatar specifications:" in the "READ THIS BEFORE YOU POST" sticky?