Rangemaster with AC128's - REPORT

[MarshallPlexi]

Today I received 10 AC128's from an eBay auction and I installed one of them in my Rangemaster clone. The sound is WAY better than it was before as I replaced the NTE158 with the AC128. The guitar feels different now and the pedal sounds better. When I say the guitar feels different, I mean the strings feel more rubbery and alive than they did before.

I'm confused about one thing though. The NTE158 was pretty noisy for some reason (hfe - 104), but these new transistors are much more quiet even though the leakage is through the roof on them. I was told that any leakage over 0.300 was unusable, but the unit I tested sounds great with a leakage of 0.460

Any ideas? If it sounds good and is not noisy, what is the problem with having a leaky cap?

Here are the specs on the transistors I received today.

(Transistor used)
hfe - 91
leakage - 0.460

hfe - 86
leakage - 0.630

hfe - 132
leakage - 0.960

hfe - 5
leakage - 0.060

hfe - 138
leakage - 0.800

hfe - 152
leakage - 0.840

hfe - 152
leakage - 0.900

hfe - 126
leakage - 0.800

hfe - 162
leakage - 1.110

hfe - 132
leakage - 0.690

[MartyB]

Cool...it's not what IS, it's what works.  My best Rangemaster build sounds better with a scrounged Japanese germ than with any of more than a dozen bulgarian OC44s  I've tried.  Go with your ear!
MartyB

[bwanasonic]

I don't know much about transistor leakage in practice, as I usually pay other people to pick "good ones" for me, but I am familiar with "The Rangemaster Revelation Moment". For me it was a CV7003 that transformed my RM build from "that's pretty cool" to "OMFG! So this is what a Rangemaster is supposed to sound like!" Granted, the magic only happens with a fairly narrow range of tube amplifiers, and it's picky about what else is before and after it in the signal chain, but man can that thing sing! I can also identify with your observations about "feel". One can only hope that there is some kind of rennaisance in Ge transistor manufacture, or a vast store store of cryogenically preseved *perfect* specimens is unearthed. Maybe some DSP version will get close someday, but it will never match the zen simplicity and beauty of that handful of components, organically interfaced with a wooden crate full of glowing red bottles, iron, magnets and stretched paper .

Kerry M

[amz-fx]

For anyone interested in the AC128 germaniums...  I still have plenty of them left for sale, and the AC188 as well.  (That was not my ebay auction though)

Thanks,  Jack

[Doug_H]

I was told that any leakage over 0.300 was unusable, but the unit I tested sounds great with a leakage of 0.460

IIRC, one of the biggest issues with lots of leakage is that the bias won't remain consistent. Does it still sound good when you leave it on for a while, turn the lights off, put it outside, touch it, when your lucky mood ring changes color, phase of the moon changes, sunspots, etc.? (Only meant semi-facetiously... :wink: )

If so, don't worry about it.

Doug

[MarshallPlexi]

I'll check that out! Thanks for the heads up!

[Doug_H]

Hey, and thanks for the tip on the AC128's.    I just ordered 5 from Jack.

(BTW, I had trouble getting mozilla to process the paypal order properly, had to revert back to explorer. Just a heads-up for anyone who may be interested.)

I have breadboarded the Rangemaster before and thought it was pretty cool. But I'm looking for way cool. :wink:

Doug

[MarshallPlexi]

I think you'll really dig it. To me it takes an amp that is not too loud, and makes it feel like it's RIP-PING LOUD (to quote the guy from the In The Style Of Eddie Van Halen series tapes).

What's really cool with the 0.005uF cap, the bass strings stay's perfectly crisp and tight, like you have no effect on whatsoever, and the high strings sound like the amp is overdriven hard. Crisp tight low end for chord and riff work, and singing sustaining high end for solo's and fills. A tremendous pedal!

Enjoy!

[amz-fx]

There is some more info about AC128s on Jacques' site at:

http://www.geocities.com/stompbox2001/ac128.htm

Enjoy,  Jack

ps:  Got your order Doug, and sent confirmation. Thanks!

[MarshallPlexi]

Thanks Jack!

I have seen that page and from what I understand, I got the newer model. Whatever it is, it sounds great. BTW - I tested the Rangemaster with the CV7003's that I received today and it sounds good. One of the transistors was throwing a "hissy" fit so I replaced it and it now sounds great.

I'm in the process of experimenting with input cap values and am having a blast.  :lol:

[amz-fx]

I have seen that page and from what I understand, I got the newer model. Whatever it is, it sounds great.

I'm in the process of experimenting with input cap values and am having a blast.  

Sounds like fun!

FWIW,  I have a special page of circuits for Ge transistors that I send to everyone who orders either of the transistors from me...

regards, Jack