Darlington RangePig

[petemoore]

http://img.photobucket.com/albums/v207/petemoore/RangePIG.jpg
  Something to try for excellent application of lower than desirable Ge Rangemaster PNP Transistors.
  I used an OC44 [hfe of 55 IIRC] and an NTE169 for Q2...chimey...increased gain...beautiful !!!
  Best RM for me to date...try it and let me know what you think !!
  I would think the same technique would work in a FF.
  Use a small bypass cap across the 100k between Q1e and Q2b for even sparklier high end !!

[Dragonfly]

http://img.photobucket.com/albums/v207/petemoore/RangePIG.jpg
  Something to try for excellent application of lower than desirable Ge Rangemaster PNP Transistors.
  I used an OC44 [hfe of 55 IIRC] and an NTE169 for Q2...chimey...increased gain...beautiful !!!
  Best RM for me to date...try it and let me know what you think !!
  I would think the same technique would work in a FF.
  Use a small bypass cap across the 100k between Q1e and Q2b for even sparklier high end !!

very cool pete...i'll have to try this with some of those "unusables" i've got lying around ...  [/color]

[brad]

Wait a second...it's a darlingto pair with both a Ge and Si transistor?  That is an amazing idea!

I have a bunch of NPN germs with gains of 40, so I might have to make a piggybacked Bazz Fuss with a 2n5088 or somethin'!

[petemoore]

  I used a NPN to build a comparison RM with.
  Hafta say I boxed the PigRanger...then used it to record with...
  Everytime I do a Rangemaster I wonder if I got it, this time I care less about how Rangemasterey it 'really' is because it's just too sweet.
  Works great for me, definitely worth a try.
  Stable
  TONE is chiming beautifully, high notes ring, Chords sing, where I pick changes the tone, Markedly...it's a beautiful thing !!!
  It 'Tutors' me though, on picking strength...and rolling the volume of the guitar for the sweet chord strums.
  Perfect.

[Steben]

Well, ain't this PigRanger higher input impedance with the darlington solution?

[petemoore]

  Not sure to not worried, but isn't input impedance determined by the 68k/470k string between V+ and V- ? [base bias resistors]

[puretube]

soon I`ve gotta go tryin`to piggyback a Tube & FET,
and darlington the both, too  ;

then I`ll go CMOS inv. & Tube... 

and CMOSinv. & FET;

and all those combos with BJTs, too...

[petemoore]

  I was *sitting with this transistor and RM Circuit going 'dakhkh...no need to worry about a box for this one...
  *Thinking....typing....reading RG's response about noise...thinkin' yupp...gonna go ahead and try that.
  tried it/liked it
  Built it into 1 board
  Boxed it...I've been enamoured with it, 'that's what I'll be using, it sounds really  great.

[Steben]

  Not sure to not worried, but isn't input impedance determined by the 68k/470k string between V+ and V- ? [base bias resistors]

Well I thought to have read in RG's article (Austin treble...) that the input impedance is also based on the Transistor impedance (around 12k) and that the biasing is basically there for the desired voltage. Emitter-followers on the contrary have input impedance based on the biasing resistors...?
Darlington have higher current gain and I thought higher gain gives higher input impedance in BJT circuits.
RG ?

[petemoore]

  Sounds like your figures on impedance could be correct...I hope so...er I'd tell ya if I knew, sounds perfectly reasonable.
  That's ok too, maybe this brings it away from yer RM Circuit... ...and most certainly doesn't take transistor variances out of the equation.
  It is really just another variant of a gain circuit, I got a little lucid and lucky figureing out...the main + I have with it is that the tone of the unit I have here is really cool...RM"s are always different that LPB's, Microamps, Jfets, of course, to my ears it sounds about purely GE, has excellent low noise floor, is stable, has good to better output for RM.
  Should be tried with transistors low leakage, lower gain that other circuits 'like'...I know we have some of these, as I do, therefore I suggest this as as good a thing to try as any.
  Maybe there IS some magic thing in mine or in the circuit as shown, whatever the case, I've now got a booster with Lots of character to the tones, working great !!
  As shown it may be an excellent option for certain Ge candidates.

[EdJ]

Hey,thank you for your work Pete!
I am gonna try it this weekend.
Will let you know.
Greetings,Ed

[MartyMart]

Pete, this is a "SWEET CIRCUIT"  !!
I just built one in an hour !! that's my record so far for a "quickie"
I had one lonely OC44 sitting around, from a Keeley RM clone that
never worked right, popped it in with a 3906 in Q2..... dreamy !
I used .047's in and out, so its a "tad" more full range.
Your dead right with the "chiming/singing" reference, that's
exactly what it does ... beautifully !!
There's a tiny bit of crunch with the 100k maxed/mined, depends
how I wired it ! and my 10k is a trim pot, set at 3/4 gain ....

Its a "keeper" 
Thanks,

Marty.

[bioroids]

Well I thought to have read in RG's article (Austin treble...) that the input impedance is also based on the Transistor impedance (around 12k) and that the biasing is basically there for the desired voltage. Emitter-followers on the contrary have input impedance based on the biasing resistors...?
Darlington have higher current gain and I thought higher gain gives higher input impedance in BJT circuits.
RG ?

Any resistor you put in front of the stage will affect impedance in some way.

Miguel

[Paul Marossy]

Reminds me a little of Joe Gagan's favorite trick for a Fuzz Face type circuit - using a Si transistor for Q1 and a Ge for Q2, or was it the other way around? Anyhow, the Darlington transistor is a different animal. Interesting idea that I'll have to try sometime...

[vanhansen]

That looks cool, Pete.  I gotta get me some Ge tranny's.

[bioroids]

This is cool Pete! I never buila a RM that I liked, maybe this would be the one!

Miguel

[Paul Perry (Frostwave)]

If you have a steady tone source, you can check the imput impedance like this:
run the signal generator into the rangepig through a variable series resistor (maybe a 500K pot).
Set pot to zero, & measure output voltage.
Then adjust pot till output is 1/2 what it was.
Now the input pot is set to the input impedance!! and you can disconnect the pot & check the
pot resistance, that is it.
(this assumes 1. your rangepig isn't clipping, and 2. the signal source has a low impedance).