Vintage 2N3055 Neve

[mjrippe]

The ones you posted a photo of are from the last week of 1975.  7552 = 75 year, 52 week

Here's a photo of three Motorola 3055 from my drawer.  Date coded 7739, 353, and 8352.  Anyone know what the three digit code means?

 

[Aaronrash]

I'm not sure but almost every vintage unit I see has 421 or 423. Maybe these were the gold pin versions

 

[mjrippe]

Interesting, the 353 date code one *does* have gold pins, the other two don't.

 

[CJ]

lots of threads on the leaky ol 3055,

even one fro the old place 

http://recording.org/index.php?threads/2n3055-neve.41843/

amount of DC thru the xfmr pri might have an influence on the sound,

 

[Aaronrash]

After reading that apparently allot of 2N3055 "ring" and are all over the place.

I'm not sure how to test for this though. Also not sure how to screen them for bandwidth.

 

[gridcurrent]

2N3055 comparison

 

[betty]

Probably a bit late coming in on this but here is some history.
Yes, Neve originally used Motorola 2N3055 transistors. But during a supply problem, our buyer bought some Westinghouse ones. What do Westinghouse make? Power supplies. What was the bandwidth of these transistors? Dreadful!
Root of the problem was that the Motorola ones far exceeded the necessary spec and should have been given a different number. So thereafter transistors from different sources had to be carefully checked.
Those who can remember how to read transistor spec sheets can look them up. I can't!!
I was a system design engineer with Neve at the time.

 

[JohnRoberts]

Probably a bit late coming in on this but here is some history.
Yes, Neve originally used Motorola 2N3055 transistors. But during a supply problem, our buyer bought some Westinghouse ones. What do Westinghouse make? Power supplies. What was the bandwidth of these transistors? Dreadful!
Root of the problem was that the Motorola ones far exceeded the necessary spec and should have been given a different number. So thereafter transistors from different sources had to be carefully checked.
Those who can remember how to read transistor spec sheets can look them up. I can't!!
I was a system design engineer with Neve at the time.

The original 3055 (RCA?) was slower than dirt (maybe 200kHz GBW) but was very rugged so very popular for use in power supplies and general purpose circuits. When the parts got better they (motorola) were afraid to change the part number because that would likely lose sales with engineers preferring to buy the known good original PN. Early "faster" transistors were generally more fragile too.

JR