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Low Hertz Low Hertz is offline
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Default Advise wanted on new well made Tube Integrated Amp, or Combination of

I am looking to replace my current solid state unit.

I see some tube units on EBAY, made in China. A friend tells me they would be good if the tubes were all replaced. I have read reports that the units
are cheaply made, with bad solder connections and such.

I also am a professional musician, and can not tolerate distortion, even
if it's the natural harmonics associated with tubes. I remember hearing
a Fisher or Scott unit years ago, and the distortion was horrible to me.

I want a well made unit that does not require modifications to keep for the rest of my life.

I can't afford vintage McIntosh, though they are clean and free of distortion. Obviously, one is paying for the name.

As a musician, I have always preferred the sound of warm tube amplifiers, but most prefer the sound of acoustic instruments.

Thank you

Bob C

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Peter Wieck Peter Wieck is offline
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Default Advise wanted on new well made Tube Integrated Amp, or

Please note the interpolations and semi-rant at the end.

On Sunday, November 23, 2014 7:06:19 PM UTC-5, Low Hertz wrote:
I am looking to replace my current solid state unit.

I see some tube units on EBAY, made in China. A friend tells me they would be good if the tubes were all replaced. I have read reports that the units
are cheaply made, with bad solder connections and such.


Yes, and yes-and-no. Yes, Chinese tubes are suspect. Yes, Chinese tubes have been known to melt down with spectacular results far more often than tubes from other sources. No, I would not put a Chinese tube in anything I own for front-line use. Yes, I have a few Chinese tubes that I reserved for testing purposes - never outside my immediate sight, however.

As to wiring and component quality: spotty, very spotty. _EVERY_ Chinese-made piece of (finished) tube equipment I have seen has had some QC and management problems. Many pieces of other-source equipment has had the occasional QC and management problem. I would be prepared to entirely re-solder anything from a Chinese source, and I would replace every tube rectifier out-of-hand with something from somewhere else. The output tubes I would watch like a hawk, but allow to stay until they fail. The small-signal tubes vary from OK to wretched, but seldom fail such that they take out everything.

Bottom line: there is enough legacy equipment out there that I would NOT purchase Chinese iron new or used.

I also am a professional musician, and can not tolerate distortion, even
if it's the natural harmonics associated with tubes. I remember hearing
a Fisher or Scott unit years ago, and the distortion was horrible to me.


There are some issues with the early Fisher and Scott units out there - some blame the voltage-doubler circuits, some blame the lack of a choke, some blame this and that. But the bottom line is that you might consider giving them another go-round as they are reasonably well thought of these days.

I want a well made unit that does not require modifications to keep for the rest of my life.


Lets you out of _every_ piece of legacy equipment in OEM condition out there, full stop. And now will boost the cost of this quest to at least four (4) figures, if not five for that level of reliability.

I can't afford vintage McIntosh, though they are clean and free of distortion. Obviously, one is paying for the name.


Yes, and no. If you are accepting legacy McIntosh, that will be much cheaper than some of the US/Euro tube stuff new these days. Given your other parameters, that is where I suggest you start, and likely finish.

As a musician, I have always preferred the sound of warm tube amplifiers, but most prefer the sound of acoustic instruments.


Here is the thing (and others here will throw up their hands in horror): that Rodney Dangerfield of tube amps - the Dynaco ST70, tweaked and modded such even rank amateur capable of following a cook-book recipe and using a soldering iron could do it in a relatively few hours, combined with a PAS3X (tweaked/modded the same) will give you excellent and blameless results at a relatively low cost. Not only that, but every part and piece of those beasts is available in the after-market such that lifetime maintenance is not an issue. Nor will you ever lose money on one assuming you purchase wisely in the first place.

So, if your budget is under $1,000 - go with Dynaco, bite the bullet and learn a little about the beasts, make your choice(s) of mods and go there.

$5,000 - $10,000: Look for vintage McIntosh.

No Limit: Audition some of the presently-in-production tube systems, US or Euro origin.

$1,001 - $4,999: you will have many opportunities but will have to know your stuff and be willing to make repairs, clean, upgrade, and so forth.

Whatever you do and wherever you do it, make sure that you get to audition whatever it is _AT HOME_ with a guaranteed return policy. You will not be easy to please, and so you need to insure yourself against an unhappy commitment. The exception being Dynaco - if the iron (transformers)is good, the rest will follow as the options are many.

Peter Wieck
Melrose Park, PA


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[email protected] jennconducts@gmail.com is offline
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Default Advise wanted on new well made Tube Integrated Amp, or

On Sunday, November 23, 2014 4:06:19 PM UTC-8, Low Hertz wrote:
I am looking to replace my current solid state unit.


You might take a listen to the PrimaLuna integrates. I love mine.

Jenn (fellow pro musician)
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steveaudio steveaudio is offline
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Location: Cleveland, Ohio
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Default

Quote:
Originally Posted by Low Hertz View Post
I am looking to replace my current solid state unit.

I see some tube units on EBAY, made in China. A friend tells me they would be good if the tubes were all replaced. I have read reports that the units
are cheaply made, with bad solder connections and such.

I also am a professional musician, and can not tolerate distortion, even
if it's the natural harmonics associated with tubes. I remember hearing
a Fisher or Scott unit years ago, and the distortion was horrible to me.

I want a well made unit that does not require modifications to keep for the rest of my life.

I can't afford vintage McIntosh, though they are clean and free of distortion. Obviously, one is paying for the name.

As a musician, I have always preferred the sound of warm tube amplifiers, but most prefer the sound of acoustic instruments.

Thank you

Bob C
May I give you a short tutorial on vacuum-tube high fidelity amplifiers? This discussion applies only to a class A push-pull amplifier, not one of those single-ended, no-feedback things that were a fad a few years ago. The most critical component in a tube amp is the output transformer. It must pass the audio range, 20Hz to 20 KHz with minimal loss at either end of the audio spectrum. That means Tthe transformer must be physically large, or low frequency saturation (and resulting distortion) will result. It must have high quality, 29-gauge laminations, stacked 100% interleaved. The primary turns must be tapped exactly in the center of the winding, and the two halves should be physically symmetrical, so that two halves are of equal resistance. The primary and secondary windings must be sufficiently interleaved or high frequency loss will result. Now the tubes: The output tubes must be capable of the power expected of the amplifier. The tubes should be selected as a matched set. There should be a bias adjustment for the output tubes, as well as a balance adjustment. The idea is to operate the tubes within ratings, and make sure that the two tubes have equal quiescent current, to prevent saturation of the output transformer with resulting distortion. If the output tubes are not matched, there could be balanced quiescent current, but unbalanced dynamic current, resulting in output transformer saturation and distortion when in use. The second reason for having bias and balance adjustments is to keep proper bias and balance as the output tubes age, which they will. The amplifier should have about 20 dB of negative feedback from speaker output to input. The first truly practical high fidelity tube amp design was the "Williamson," (not a brand, but a circuit design) followed by the "Ultra-linear" design.
What I have tried to do is to take the magic out of tube amps, and look a the engineering.
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