Introducing the "Cream Pie" !

[Dragonfly]

heres a "quickie" with a tele...please forgive the sloppy playing....

gritty tele... http://h1.ripway.com/acarrell/creampietele.mp3

[mac]

I guess that PNP Ge negative grounded could be used without motorboating.

mac

[markm]

Ya know AC,
Since you've moved, I may have to rename my build to "Austin Cream Pie" 

[petemoore]

  Vreadings?
  I'm curious about the bias voltages on this one.
  That Tele sounds a bit compressed, Samples sound great.
  I'm tempted to get 7 pieces together and try this one out...

[jimmy54]

I've just built the cream pie, doing my first vero layout from a circuit in the process.  I used an AC187.  I built this as the sparkleboost is one of my favourite pedals and a circuit from Dragonfly has got to be good.

I've only had a chance to play it at low volume through a fender blues deluxe but it sounds great.  I can see where the cream desciption comes from as the circuit seems to have a nice throaty midrange to it.  I played wind cries mary with it and to me, with the neck pup of a strat it sounded pretty similar to that hendrixy clean/gritty tone.

One thing was when biasing to 4.5v, the 100K trimmer went from about 3v to 9v in a tiny, tiny movement in the trimmer.  Had a hard time getting the 4.5v.

[markm]

I've just built the cream pie, doing my first vero layout from a circuit in the process.  I used an AC187.  I built this as the sparkleboost is one of my favourite pedals and a circuit from Dragonfly has got to be good.

I've only had a chance to play it at low volume through a fender blues deluxe but it sounds great.  I can see where the cream desciption comes from as the circuit seems to have a nice throaty midrange to it.  I played wind cries mary with it and to me, with the neck pup of a strat it sounded pretty similar to that hendrixy clean/gritty tone.

One thing was when biasing to 4.5v, the 100K trimmer went from about 3v to 9v in a tiny, tiny movement in the trimmer.  Had a hard time getting the 4.5v.

Nice.
One thing you could possibly try is using a 50K trimmer instead perhaps.

[Dragonfly]

I've just built the cream pie, doing my first vero layout from a circuit in the process.  I used an AC187.  I built this as the sparkleboost is one of my favourite pedals and a circuit from Dragonfly has got to be good.

I've only had a chance to play it at low volume through a fender blues deluxe but it sounds great.  I can see where the cream desciption comes from as the circuit seems to have a nice throaty midrange to it.  I played wind cries mary with it and to me, with the neck pup of a strat it sounded pretty similar to that hendrixy clean/gritty tone.

One thing was when biasing to 4.5v, the 100K trimmer went from about 3v to 9v in a tiny, tiny movement in the trimmer.  Had a hard time getting the 4.5v.

as suggested, you could use a 50k trimmer....

or, possibly a 22k resistor in series with a 20k trimmer....it seems to bias in that 27k-40k range...

glad you like it so far...keep me posted on your results !

AC

ps...glad you like the SB too !  i think i'm gonna build a Sparkle Boost / Cream Pie combo in a 1590BB box.....save some "real estate" on the pedalboard...

[Dragonfly]

  Vreadings?
  I'm curious about the bias voltages on this one.
  That Tele sounds a bit compressed, Samples sound great.
  I'm tempted to get 7 pieces together and try this one out...

its funny, 'cause i seem to remember reading somewhere that germaniums don't bias with this type of setup, but it seems to work fine....

heres the voltage readings on the CV7112....i set it up a bit "hot", but anywhere from 4.5-5.5v should be fine....

C ---   5.00v
B ---  .19v
E ---  .12v

as for the 3meg resistor...you could probably use anywhere from a 1meg on up...i just chose a 3meg....just a guess though, as i havent tried any other value there...

actually, regarding the sound samples...i dont think they even come close to doing it justice...but for "quickies", theyre ok...they at least give an "idea" about the sound of the Cream Pie....

i hope you put it together Pete...i'd love to hear what you think....

AC

[WGTP]

If you wanted to use an SI, try adding a cap in parallel with the 3 Meg resistor.  My guess would be between 33-47pF.   

[alderbody]

Since i will use a CV7112 too, i'd like to ask if the hfe is somewhat relevant to the sound.

What hfe was yours?

[Dragonfly]

Since i will use a CV7112 too, i'd like to ask if the hfe is somewhat relevant to the sound.

What hfe was yours?

113

[Arn C.]

The lowest npn ge I have right now is 200hfe.   Would this be too high for the circuit?
If not, would I have to use a larger value trimmer?

Thanks!
Arn C.

[Dragonfly]

The lowest npn ge I have right now is 200hfe.   Would this be too high for the circuit?
If not, would I have to use a larger value trimmer?

Thanks!
Arn C.

try it...its probably fine....
i'd go with the 100k trimmer...
id check it on the breadboard first, but everything should be just fine....

[Arn C.]

Thanks Dragonfly!!!!!


Arn C.

[joelap]

Damnit, I was pumped to hear some soundclips but the bandwidth has been exceeded!   

[petemoore]

  HAd a stamp of perf enough for the socket and parts barely...lol
  I used film .022uf>3M3 btw B/C, 1k, .047uf output cap
  50k trimpot biased pretty easily the 158 I stuck in there.
  Circuit is low noise, biased right up.
  EZ-Real good, but I used a 100kl input gain pot, this works fine for me, I did have to use attenuated input so far to prevent what I think is transistor slamming into a rail...first off would be to try different transistors, maybe adding fixed series resistor on the input.
  Cream Pie is a great name to apply to the circuit. Creamy is right, I tested this against...[actually I was about to add a LP cap on my RM, but build the CP] Rangemaster, and would recommend this as a great RM alternative after it's tested more etc.
  It's easily put together and biased, has what sounds like a HF 'ceiling' despite no other LP Filtering than the Ge...This sounds great too !!!
  As Fuzz Booster [Boost>Fuzz] it also stacks up to what competition I have for it, that being compressors, the RM type, Prof Tweed,. Hot sounding circuit for these purposes...I'm preferring what I heard it doing today...real nice.
  So it's got to have a box...and will probably get a very early spot on the PB.
  Then I can try it out bettermore.

[jaydawg]

So I just finished putting the CreamPie on my breadboard. This thing is the balls.

I built it with a 2SB77 PNP. It was the only GE I had in my parts box. I omitted the 500K pot at the input and plugged straight into the input cap. I also used a 47K for the trim pot. This thing sounded great right from the start. I like the sound best with 3.5V at the Collector. It has lots of gain and sound good and gritty.

Next I started tweeking. First I bypassed the emitter resistor with a 4.7u cap. Got more gain and the sound got brighter. Good sound but I like the stock setup better. Then I changed the 1K emitter resistor to 100 ohm. Again, brighter and more gain but not as nice as the stock setup. The last thing I did was add a 100K audio pot to the output. This change I liked. It's just personal taste but I really like gain then attenuate boosters.

So far I like the CreamPie best with its stock values and the volume pot at the output, but I think there is a lot more tweeking to be done with this little baby.  Dragonfly, thank you VERY MUCH for sharing your work. There is huge amount of potential in this simple booster.

jaydawg

[petemoore]

  Ya never know what's up with these Ge boosters.
  @@Rate, I swapped in an SBxxx [lower gain than the 158, around ~79hfe] and twisted the bias, up some from 1/2v, this is very sweet.
  The last thing I did was add a 100K audio pot to the output. This change I liked.
  Agreed, the output pot on this first stage as well as the input gainpot would make it quite a bit more versatile. Guitar knob also works as input gainpot quite well.
  I'm thinking of using a series fixed resistance on the input [maybe a divider], to mimic a chosen setting of the input gain pot [and replacing it], using guitar vol as 'gain', and dedicating that 100kl I have [haven't gotten any pots lately] to the output control...adding an input pulldown resistor
  And maybe just keep it otherwise simple as it is, PNP pos Gnd. and use battery, adding only Reverse Protection diode.
  Mine has very nice voice with only change as .047uf ..[because it'ws there] and 4m7 pulldown.
  I was thinking the transistor didn't like not having it's base to ground resistor, but it seems to like it!! I haven't even taken my base voltage, setting collector at 4.2v of 8.2 supply, it 'popped' on low notes [hb's], raising the C voltage via 50k seemed to help, as well as reducing input gain. But none of that is really mattering...the sweetness zone has been found, it's 'competitive...instant hit here...
  here's the adjectives...but I think they're applicable...
  there's a smooth presence to the high end, like the highs are compressed, this aspect sets it apart from my RM type, which has near danger high end...I was gathering LP capacitors to mod the RM when I decided to persue this build...nice build too, didn't take long, biases GE's easily, sounds great, A1 booster! 
 

[Dragonfly]

man...now i'm blushing !   
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here's a "little" thing or two that i did...and an idea or two....

1)  on the input pot, running a small (i used 100pF) cap from lug3 to lug 2 helps retain a bit more sparkle...this'd be nice on a switch, as its helpful on 'buckers, but probably not necessary on single coils....

2) the output pot would bu useful if you wanted to use it as a gritty booster / light overdrive....anywhere from a 10k-100k should work fine.

3) for those who want a bit more control and temperature stability with the germanium trannies, using a fixed collector resistor (probably about 27k or so) and a 20k external pot would allow for easy bias adjustments when gigging in different temperatures....

4) another "stability" thing to do would be, IIRC, put a a germ diode between base and emitter...i'm going from memory on this mod, so feel free to "pipe up" if i'm not remembering correctly....

5) i think i mentioned earlier in the thread that you may be able to use a lower (or higher) value "collector to base" resistor...probably anywhere from 1meg to 6megs or so...i just used a 3meg becuase it was handy...but it works well....

6) Pete...a thought that may or may not work here...you could try tacking on a diode onto the input similar to what Joe did with the antiquity fuzz...might give a cool little bit of compression....

7) though i "personally" wouldnt need it, the SWTC might be a nice tone control to tack on the end...
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one of the things that i love about this booster is it's "simplicity"...i REALLY think it'd be one heck of a good, and useful, BEGINNER project for working with germanium transistors. it doesnt seem to be "too" picky about the type of germ tranny, and seems to work with a good range of hfe's....it sounds REALLY good with a variety of amps, and, like Pete mentioned, it doesn't get shrill" like a rangemaster. its also easy to build as NPN or PNP, without having to deal with switching around polarized caps, etc....just swap + and - leads from the battery....

like i mentioned...i'm gonna box up a Sparkle Boost and a Cream Pie in one 1590BB box...that should handle all my boosting "needs" 

rock on.

AC


PS....

Pete and Jaydawg...did you happen to write down the hfe of the transistors youve used in the CP ? could be useful data....

[petemoore]

3) for those who want a bit more control and temperature stability with the germanium trannies, using a fixed collector resistor (probably about 27k or so) and a 20k external pot would allow for easy bias adjustments when gigging in different temperatures....
  And that pot works cool 'offbias w/Fuzz...
  4) another "stability" thing to do would be, IIRC, put a a germ diode between base and emitter...i'm going from memory on this mod, so feel free to "pipe up" if i'm not remembering correctly....
  My memory is sketchy too, using a diode with threshold same as transistor, reversed/connected to B/E helps prevent thermal runaway by limiting swing on one half of the waveform/hence reducing current?
  5) i think i mentioned earlier in the thread that you may be able to use a lower (or higher) value "collector to base" resistor...probably anywhere from 1meg to 6megs or so...i just used a 3meg becuase it was handy...but it works well....
  3m3 is 'big', makes bias EZ, sounds good, and were on hand.
6) Pete...a thought that may or may not work here...you could try tacking on a diode onto the input similar to what Joe did with the *antiquity fuzz...might give a cool little bit of compression.
  ...interesting..IIRC the *diode symbol was pointing at the transistor input?
7) though i "personally" wouldnt need it, the SWTC might be a nice tone control to tack on the end...
----------------------------------------------------------------------------------------------------------------

one of the things that i love about this booster is it's "simplicity"...i REALLY think it'd be one heck of a good, and useful, BEGINNER project for working with germanium transistors. it doesnt seem to be "too" picky about the type of germ tranny, and seems to work with a good range of hfe's....it sounds REALLY good with a variety of amps.
  Sounds great, nice RM alternative, fewer[est] parts.