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Old 15th March 2016, 03:18 PM   #1
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Default OLD vs NEW tube amplifier circuits

Is there much of a sonic difference between older (Williamson, GEC, Western,etc.)circuits than new (Tubelab, Millet, etc.)?? Is there really any inherent superiority or just personal preference? Do any circuits stand out above the rest?
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Old 15th March 2016, 03:20 PM   #2
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Yes and no.
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Old 15th March 2016, 04:10 PM   #3
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Yes and no.
Thanks for the information.
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Old 15th March 2016, 04:15 PM   #4
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Thanks for the information.
With such a broad question, that is what all answers will boil down to. To answer it fully, you would have to write a book.
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Old 15th March 2016, 05:13 PM   #5
DF96 is online now DF96  England
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And then someone else would write a different book!

The quick answer is that there is not much difference between the performance of a good design from 60 years ago and a good design from today, and any changes would be near or below the limit of likely human perception. There may be huge differences between a poor design of then and a poor design of today, as tastes in sound effects have changed somewhat: then people wanted 'good tone' but today they want 'slam' or 'soundstage'.
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Old 15th March 2016, 05:26 PM   #6
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Originally Posted by lugnut View Post
Is there much of a sonic difference between older (Williamson, GEC, Western,etc.)circuits than new (Tubelab, Millet, etc.)?? Is there really any inherent superiority or just personal preference? Do any circuits stand out above the rest?
I am no expert, but I have built 10+ different 300B SE amps for the last 25+ years.

To me, biggest sonic difference came from (1) output transformers and input or interstage transformer if there's any in the amp (2) tubes (3)power supply design. Even simplified WE91 style circuit and Tubelab constant current circuit did not sound much different.

I don't have proper measurement electronics, so I do not know about difference in THD, SNR, etc.
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Old 15th March 2016, 05:46 PM   #7
GoatGuy is offline GoatGuy  United States
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After reading this site for years and years, and remembering back to the days when slide rules were the bomb in calculating things for amplifiers… I'd say that most of the differences between the eras can be boil'd down to:

• economics of various parts
• esthetics of design choices
• fads and magical elixers
• sentimentality and purism

Economics is one of the 'real deals': inductors used to be cheap, now they're expensive. Capacitors used to be really expensive, now they're cheap. Commodity tubes used to be dirt-cheap, now they can be scores of Euros. Even solid-as-tanks resistors once were pretty expensive, then they got cheap. Now they're even cheaper, but no longer 'tanks'.

esthetics clearly is an evolving thing, but it is also does guide generational differences. Today, we have open-frame blue underlit tubes; people use gas regulators not for their practicality, but their telltale glow. Bespoke volume controls are au currant, but once it was silver-plated speaker banana jacks, and before that bakelite knurled knobs.

fads & magic has always been part of what defines the generational differences. Today the Aikido design (which is admittedly both novel and esthetically cool) is on the wane. Its still very good, but times change. Once it was SRPP (which no one can remember what the acronym means/meant). Before that there were cascodes and fairly unique common-grid designs lifted from the HAM folks. Times change. E'n the decision as to whether input or middle stages benefit from pentodes versus triodes (or FETs!) is contentious… and fluid.

sentimentality remains perhaps one of the most influential factors though. If we are honest, building tube equipment is a man's hobby, mostly. (Sorry, Katje! - you're extraordinarily special!) Just like rebuilding turn-of-the-century automobiles and trucks. (19th to 20th, not the recent one!). Design choices are very often rooted in original spec sentiments, then gradually 'honed' with decidedly later innovations. Sometimes openly, sometimes hidden below the hood.

Intellectual avocation (not in the bullet list) is also another significant factor. Many of the people who congregate here have both remarkable intellectual talent and the desire to dig deep, deep into the analytic underpinnings of abstract electronic engineering and physics theory. For many, just to understand, to 'grok', and to then design from the ground up - NOT depending on copying others' designs - is hugely satisfying. Evidence that all that studying, noodling, calculating, driving the wife nuts, is worth it.

Just like (mostly) gentlemen who are maybe bankers or attorneys, or civil construction generals, but who in private life have cultivated a life-long hobby of fine cabinetry and woodworking, or musicianship, or photography and printmaking, or crafting something really oblique like fountain pens, or cuckoo clocks, or distilling whiskey on a tiny scale. It consumes the wan hours of a lifetime, and the results, the creations are tangible. Evidence of intellect. Good stuff.

And guess what … all those things are also influenced by the prior 4 bullets.

So that's what influences the generation-to-generation designs of … everything.

GoatGuy
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Old 15th March 2016, 06:00 PM   #8
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Originally Posted by DF96 View Post
And then someone else would write a different book!

The quick answer is that there is not much difference between the performance of a good design from 60 years ago and a good design from today, and any changes would be near or below the limit of likely human perception. There may be huge differences between a poor design of then and a poor design of today, as tastes in sound effects have changed somewhat: then people wanted 'good tone' but today they want 'slam' or 'soundstage'.
Very correct...basically the old schematics remain true..Having built many powerful MI/HiFi UL amps from 1960 to ?; the biggest significant change on my bench is boxes of under performing New Edition made power tubes, poor materials, poor annealing/outgassing and worst, their sales flannel claim the performance as their predecessors could do; but no; the 6550 is a good example of a tube NOT to push. That dupe tube is closer to a 6L6, though there are many who use 6L6's way above 470V B+ in UL.
Electrolytic caps have definitely improved; as has the understanding of the CCS in designs; but those of us who use GNFB, will soon realise how accommodating and powerful the closed loop is, in trimming so many evil parameters. Component tolerances, Hum & noise; thd; damping factor; and so on.
I suffer from Tinnitus; but can still hear what'ain't right....
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Old 15th March 2016, 06:25 PM   #9
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The old advice, or admonishment, to "linearize first, before applying feedback" has entered a new dimension:

1) old grid 1 drive
2) new (g2 and g1 hybrid or "Crazy drive")

No amps using it yet however. Will someday be realized.
(after doing taxes, clearing deadly trees from nearby river for kayakers, after clearing brush from some property I need to sell, to pay those taxes, after solving high blood pressure problem .....) Well, maybe next year.
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Last edited by smoking-amp; 15th March 2016 at 06:28 PM.
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Old 15th March 2016, 06:35 PM   #10
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Originally Posted by smoking-amp View Post

No amps using it yet however. Will someday be realized.
I still reckon the enhanced triode mode that Tim deP used back in the mid 90s was a form of hybrid drive. Just not enough round tuits to work out what he did.
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