0C44 Rangemaster

[duffrey]

Hey guys, after searching long and hard I have found the legendary mullard OC44 chip for my rangemaster clone, but they are dang expensive.  Its going to doulbe the price of my pedal.  So my question is this.  In reality is there any advantage sound wise in going with the original OC44 vs. a tested PNP from someone like Smallbear?  Or any other advantages?

Jeff

[R.G.]

Have you read the GEO article, and also the article on selecting germaniums for Fuzz Faces?

There is no magic in the transistor being labelled "OC44". What matters is what the device inside does, and having the "OC44" label is NOT a guarantee that you'll like what it does, only that it met certain electrical tests - which I can guarantee were completely unrelated to how well it would do a Rangemaster - when its maker made it.

A selected PNP of another type is a far better bet than getting an "OC44" label. Otherwise you're taking pot luck that the one OC44 that you can get and pay for is going to be even acceptable, let alone GREAT. Testing for the application is the only way to get one that will have any guarantee of sounding good.

[Jason Stout]

duffrey, I have a feeling you will get a wide range of replies from your question. Some will say that an OC44 makes all the difference, some will say don't bother.
I have a question for anyone who has sorted through a batch of OC44 transistors. What is a good amount to buy to ensure a "good one"? Is it worth buying 4, or 2, or 1, or 25? I know you could get a good one right off the bat, but from experience, what is the minimum lot size?

[Jason Stout]

R.G. I didn't see your post, but you have sorted germanium transistors, could you recommend from experience, to anyone who wants an OC44, a "safe" number to buy?

[duffrey]

I have read the article at geo.  
So is it safe to say then that any pnp transistor falling within those critical values would sound very similar.  
I have ordered a pnp from Smallbear, it was only $4, so I thought why not, but the guy I'm looking at purchasing the OC44 from says I have to buy two.  Both of which are tested as well, but he says that of the lot he has that 1/3 of them die after a 24hr burn in, which is why he wants me to buy two.  
Any additional thoughts?

[Gstring]

I thought that I had to have OC81D's , had to go on a witch hunt to find  in England. Granted my effect sounds great, but I imagine there would have been a  newer version which would have been a fraction of the cost

[brian wenz]

Hello Hello--
    You could have the "best"  sounding OC44 in the world according to "experts" and it still may not do it for you.   All the OC44's I've used in Rangemasters had to be "fine tuned"  with the bias in order to sound "good" ................but each one of 'em still sounded different!  
I've built all kinds of treble boosters with different trannys, and they all sound real good but real different.   It depends alot on the  guitar and amp you're using. [It also depends on your EARS!]
Check out all the different treble booster circuits and the many trannys used in them for ideas.  Maybe the Vox  [silicon] would work better for you......  ?    [Look into the Range Pig, too!]
Brian.

[petemoore]

I got the Rangemaster working very well.
 The tranny I got from SB Ge Hfe 69 [I just tested it again] sounds different than the NTE158's.
 Also the piggybacking can have a direct influence and there are many experiments that are taking place with that.
 My limited Exp Piggybacking includes Miss Piggy, a YAFF, An Si Rangepig [bout to try Ge Rangepig], and a Ge FF.
 The added ability to tune the ckt and related tone definition make this a shoe in [though Ive yet to try] for the Rangemaster seeders with limited OC44's etc.
 I simply trimpos the first two resistors RB1 and Re, with 100k and 10k board mount pots, and atart with a [long leg] large resistor from base to power^ so that I can tack parallel ones on it but I think the 470k there allows wide bias with the two pots...the 10k of course goes on the box.
 I just start with a 8pin IC socket for a Piggyback arrangement...then I straddle across the little [1k-10k] resistors from the bottom of one IC side column [four holes in a row] to the other, under and connected to  the emitters socket holes...then try different tranny's > tune bias > play with the Pigresistor/ [take notes?] ...repeat... works great !!!

[1wahfreak]

I bought about 100 of them a while back and got about 50 real good ones from the bunch. If that's any indication of the success rate, I'm not sure. I kept the good ones and luckily was able to return the remainder (how cool is that) for other types.   The ones I kept were all between 80 and 110 hfe and leakage well under 100uA.
One question I have is: if selecting by hfe and leakage alone is not a guarantee for tonal success what is? I've heard that some vintage pedal dealers sort for frequency response but what the hell does that mean for those of us who don't have O-scopes? Do we just need to train our dead ears for minute differences in frequency?

[Bluesgeetar]

Gstring, I found and bought 18 OC81D from a place in England.  They don't have any more though.  They had 80 quantity but they dried up fast.  There is a night and day difference on sound.  Be advised.  Take everything that involves opinions on trannys/sound with a grain of salt.  You have two camps some that say any tranny and some that say you have to have the magic numbers and brand.  I am in the specific numbers and brand camp.  Not everyone here hears the same although some of us think we all have the same ears.  Trust your ears first.  Go for the numbers; OC44. OC81D  all the way man!!!!!!!!!!!!!!!!!!