Vintage 2N3055 Neve

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Aaronrash

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Jan 5, 2012
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As much as I've learned about classic Neve designs, I have never really fully grasp the role of the 2N3055. To my understanding it drives the output transformer. It must be extremely influential to the sound and it's kind of surprising that people spend all their time talking about Marinairs and never speak much of the old 2N3055s

From what I have heard Geoff say, they screened them for performance. To what standards?

Also, everyone says they are extremely slow... What do you mean slow? Like a tube rectified supply where it chokes on transients?

If the modern 2N3055 are fast then this entire sound character would be overlooked and failed to be reproduced.

I have a few vintage 1970's Moto 2N3055 that I am thinking of putting in my AMS Neve 1073.

There is also a rumor that only the "Gold Pins" ones are genuine. Mine don't have gold pins. Can someone confirm this?

 
"Slow" in the context of power transistors related to their ft or gain bandwidth. Transistors are current amplifiers and the current gain drops off with higher frequency.

I do not understand any possible benefit from using sub standard parts in modern design. Perhaps  in a legacy design some desire to recapture an old sound that was influenced by the parts available at the time.

JR
 
JohnRoberts said:
"Slow" in the context of power transistors related to their ft or gain bandwidth. Transistors are current amplifiers and the current gain drops off with higher frequency.

I do not understand any possible benefit from using sub standard parts in modern design. Perhaps  in a legacy design some desire to recapture an old sound that was influenced by the parts available at the time.

JR

So in the higher frequencies you might get a little "sag" maybe kind of like a tube slew rate?
 
Aaronrash said:
people spend all their time talking about Marinairs and never speak much of the old 2N3055s
It is a hot topic in some circles.
[quote author=Aaronrash]
Also, everyone says they are extremely slow... What do you mean slow? [/quote]
Neve amplifiers fitted with Newmarket 2N3055's are actually Motorola hometaxial parts.  They are slow relative to newer, epitaxial 2N3055's.  There is plenty of info about 2N3055's though not necessarily pertaining to Neve.
[quote author=Aaronrash]
If the modern 2N3055 are fast then this entire sound character would be overlooked and failed to be reproduced.
[/quote]
There are Neve lovers that would agree.  I've sold vintage RCA hometaxial 3055's to Neve owners that were happy with the results.
[quote author=Aaronrash]
There is also a rumor that only the "Gold Pins" ones are genuine. Mine don't have gold pins. Can someone confirm this?
[/quote]
I've seen Newmarkets minus gold pins.

Geoff Tanner would surely have insight into the subject.
 
what is the old and new bandwidth??? if it is very high out in the audio spectrum I would say that you are hearing something different or you are not hearing a difference.

I can belive that an old motorola can sound better but I preffer to believe that they were better trancistors.
 
These are my thoughts exactly.

There hasn't been enough talk about them for me to really understand what the differences are with a new one vs a vintage.

I have heard allot of people talk about "how important a vintage 2N3055 is to the classic Neve sound" but nobody explains the technical reason why.

Keep in mind vintage Neve sound is not HiFi in my opinion. It has a lofi thing to it that sounds very vintage to my ears. Especially the upper mid-range. Really syrupy and creamy. Definitely not hifi

I would think a crappy 2N3055 with low bandwidth that is slow contributes to this but maybe not.

Either way, it's something I'm interested in and would like to learn more about.

I will say this... My AMS1073 Re-issue sounds pretty damn good. I've heard it next to vintage modules and it's pretty close... So close I doubt most would hear any difference. But there is still something the vintage units do. They are a little dirtier. Maybe it's the Marinairs? maybe its the 2N3055? Maybe it's the carbon comps that are always drifting? Maybe it's all those things but I swear the vintage units have a soul of their own and you can hear it!

 
Aaronrash said:
Maybe it's the carbon comps that are always drifting?
Carbon comps?  Most Neve gear of the era used carbon film resistors.
Back on the topic of 2N3055's, have read that the vintage pieces have higher base capacitance.
 
Aaronrash said:
These are my thoughts exactly.

There hasn't been enough talk about them for me to really understand what the differences are with a new one vs a vintage.

I suspect it is all about semiconductor process variability. Back in the day, the science of semiconductor process control was in its infancy. This means there was a lot of variation in even the basic parameters of transistors of the same type. The most obvious of these is gain banding which still occurs today. The two parameters that would most probably have been of greatest interest to Rupert were gain and gain bandwidth product. Both of these would probably have varied over quite a wide range in the 2N3055. Rupert is a great believer in NFB and to make it work best you need to maximise the open loop gain and bandwidth. I suspect these were the two parameters he selected for.

The funny thing is, that because of the wide variations in those days you could expect to find quite a few transistors that were much better than the standard specs. Modern versions, however, are subject to much better process control and it is entirely possible that most of them are quite close to the standard spec and there are few if any exceptional ones. This may explain why some vintage types sound better than their modern equivalants.

Cheers

Ian
 
It should not be that hard to bench test said vintage circuits with new or old 3055 to discern what is different. If it is audible it will also be measurable.  The old 3055 as I recall were less than 1 Mhz devices, new parts are multiple MHz ft.

I remember the 3055 fondly from back in the day as a cheap, slow, but hard to kill general purpose NPN to-3 power device, but not as something to use in a high performance audio path. At modest voltage swing and gain, probably not that bad, just not an obvious premium solution. 

When the original process became un-competitive to manufacture ('70s?) they did a new version using the newer (faster) technology. Since the 3055 was such a popular GP device they also made a complementary PNP (2N2955) device around the same time as the 2n3055 redesign.  Many early solid state amps used all NPN output devices in quasi-complementary topology for the PNP side.

They probably should have given the new 3055 a different part number but it was such a popular part, they were afraid of losing design-ins and sales,  if they changed the PN too.

JR
 
Here are some early (ca 1970-1971) BA183 cards with different types of transistors.
I doubt that Neve would select these transistors but i do of course not know for sure.
One thing i noticed though is that on some later cards all the other transistors were all at exactly 600hfe.
But the circuit works with lower gain transistors as well.

 

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The 3055 was initially a very 'general' device, made for jobs which needed a bit of muscle. -The primary requirement in audio applications seemed to be adequate 'brute force' across the audible spectrum. -Nowadays the devices seem to far exceed what is required of them and in particular with Rupert using decent amounts of NFB, if there's a significant measurable difference between older and newer devices, it's likely to be a 'limtation' of the older devices, rather than a limitation of the newer devices.

If you measure/hear a difference and prefer the older ones, by all means seek them out.

However, I'm reminded of the quite which I heard first from Bob Katz:

There are two kinds of fool in the world: -One who says "this is old, and therefore good" and another who says "this is new, and therefore better!"
 
I have just been checking out the data sheets of some 'modern' 2N3055s. There's an On Semi version with a 6MHz GBW product. However, it looks like some aspects of process control as not better today than they were back in the day. The On Semi 2N3055AG data sheet says its fT is 0.8MHz but the max is 6MHz so it would seem that selecting parts even today would pay dividends. Only hfe seems to be better controlled.

http://www.onsemi.com/pub_link/Collateral/2N3055A-D.PDF

Cheers

Ian
 
Great info.

I'm gonna try throwing the vintage  2N3055 in and see if I hear/measure any differences. It's looking like the biggest influence on that sound I love so much though is the transformers. Something special about the DC flowing through the primary of the output. But then again that's where the 2N3055 is! I also wonder where I can find the proper heatsinks for them.

I do know each first transistor is measured for above 600Hfe but I wonder if there is any benefit from making them all over 600Hfe? (for the BC184C, BC107, BC109)
 
Aaronrash said:
Great info.

I'm gonna try throwing the vintage  2N3055 in and see if I hear/measure any differences. It's looking like the biggest influence on that sound I love so much though is the transformers. Something special about the DC flowing through the primary of the output. But then again that's where the 2N3055 is! I also wonder where I can find the proper heatsinks for them.

I do know each first transistor is measured for above 600Hfe but I wonder if there is any benefit from making them all over 600Hfe?

I don't believe I have ever seen a "vintage" 2N3055 with hfe of anywhere near 600.  Maybe I'm doing it wrong????
Best,
Bruno2000
 
No I mean the BC184C, BC107, BC109.

An earlier poster was saying each transistor on his card was exactly at 600hfe

 
Does anybody know where I could find a early 2N3055 without actually buying a populated vintage 283 card? I'm not sure how old mine are that I have
 

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