Time for POT? previously owned tubes


For several decades now, audiophiles have wondered whether or not, China and Russia will be able to produce new tubes that equal or exceed the quality of the NOS tubes, before we run out of NOS tubes.

After sampling some of the current production tubes, the answer is clearly no.

A better alternative to current production tubes, are POT tubes.
The supply of POT tubes is nearly unlimited. Many of our favorites are available at very reasonable prices

My system is completely custom. It is in the category of: If you have to ask;
How much? You probably can't afford it. Many of the NOS components are close to being extinct.

The question I get asked most often by people entering the high-end audio world for the first time is: What are the most critical components?
My answer is the speakers, because there is simply no way of correcting poorly designed speakers. I bought a pair of 15 year old speakers and completely gutted them. The first thing that had to go was the separate cross-over boxes. It was a fad that never made any sense. The terminators that connected the external cross-over boxes, were very poor. They dramatically decreased both the quality and quantity, of your signal.

I rolled in NOS drivers, moved the first order cross-overs to the bottom of the speaker cabinets, and hard wired them in place, after upgrading all the components. I had to add 3 inches to the bottom of the speakers to accommodate the cross-overs, which was a fairly simple task. Next I re-wired
using a four nines silver ribbon wire with a natural silk dielectric. I then reset the cross over points, to my taste. I grew up listening to the "Marshall" sound at live concerts, and tried to reproduce it.

Before entering the high-end world, I thought all good music started in the middle of 1964, when the Mustangs, first came out, and ended sometime in 1970. The music of that era contained a lot of distortion and special effects.
As manager of a high school band, I created a simple "fuzzbuster" by ripping a woofers cone until I got the sound, I was listening for.

Shortly after entering the high-end world, I realized that my favorite music was not suitable for reference recordings, too much distortion and other issues. I developed a good critical listening ability using CDs of female jazz singers. They were recorded with little, or no distortion. All the great female jazz singers needed was a couple of high quality mics, placed 20 feet apart.
I A/B'ed every single component using a knock-off rule. If a component sounded better than an existing component, it took it's place, in my reference system. I started with the speakers previously mentioned. I ended up with phase coherent four ways, using only first order cross-overs. They are 86db efficient. The rest of my system revolved around making the speakers sound as good as they could. To create a great high-end system, you have to learn not to lie to yourself, which is also a great way to live. My method of creating a great system is very simple to duplicate, I made every mistake possible.
I remember being able to laugh at myself, when an inexpensive Chinese integrated amplifier sounded like, it had more potential than my $40,000
worth of great looking gear. After listening to every type of output tube, I settled on a pair of 845s. I would agree that a 300B SET output system sounded better than my 845s, but they couldn't come close to driving my speakers. I then tried using four 300Bs, per channel in a push-pull circuit.
After tweaking it to the max and rolling in every NOS tube possible, I abandoned it, after I realized a did not like anything a push-pull amp could deliver.

My tube rolling addiction, led to a divorce, I then founded the first "Tube Rollers Anonymous" group.
To spare you our collective pain, I will tell you that no gray plated tube ever made into our reference systems. After talking to physicists and audio engineers, I understand it is completely absent logic that the color of the plates, make such a huge audible difference, but based on my not lying to myself rule, I will not buy another gray plated tube, which is why I am strongly recommending POT black plates, instead of current production gray plates.

I spoke with a guy who was about to go back into the production of audio vacuum tubes. After telling me that he could make purple plated tubes sound as good as black plates, I asked the obvious question. What color plates to you plan to produce? "Black plates", came the response. "There is too much consumer resistance to gray plated tubes"!

It is definitely time for POT!
128x128ws_trader
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I agree Brf, and I'm thinking he lives in a state where this particular type tube has been legalized, and may be slipping into non-acrophobia.
I purchase previously owned tubes myself, and while I gravitate toward "NOS lightly used" tubes that are on the expensive side, I look for very strong test results for the tubes offered and like new physical condition. One can't help wondering, and I missing something? Should I have bought new-in-the-box NOS tubes? LOL
Medical Marijuana , has been legal, by prescription, in Colorado, since 2009.
Last month recreational use of marijuana became legal, in certain counties.

It has led to a new term, "Marijuana Tourism".

Colorado experienced a surge of immigrants, but not the kind you are probably thinking of. It was primarily families with epileptic children, racing here after hearing some of the miraculous results of using marijuana to prevent seizures.

RE: High testing POT tubes.
The absolute readings vary from tester to tester.
I look for tight matching and balancing, more than the absolute readings.
It works because the sections rarely wear evenly.

Even more important:
Whenever I buy a large lot, I take the worst and most poorly matched and balanced pair, break them in and listen to them. I have yet to find an audible difference between the closest and furthest testing pairs.

My gut tells me, what we are testing for has a very small relationship to what we actually hear.

I strongly warn against doing any critical listening on pot, you probably won't be happy, when you re-assess your purchase straight.
I strongly warn against doing any critical listening on pot, you probably won't be happy, when you re-assess your purchase straight.
Definitely agree, even a jam box can sound great when one's attitude has been adjusted.

Ws_trader, curious as to what tube tester you are using, emissions or mutual conductance?
Easy WS,

these days mentioning the word 'pot' may cause some of our readers to start withdrawls...laughing...
I own a Hickok 752 A, but send out 5694s for AT1000 testing.
I still can't establish much of a relationship between test results and audio quality.
Has anyone out there been clearly able to hear an audible difference, between
great matched and balanced tested tubes, and poor testing tubes?
I can not tell how closely tubes are matched by listening to them either. I'm just guessing but it would seem that as long as they're not approaching "Bad" readings they would be able to produce the appropriate amount of electrons.

It also seems that spending a lot of $ to get a closely matched pair might be a mistake because triodes seem to lose strength at different rates, so they won't stay closely matched for long.

I have read a post from Jim McShane that said that the important match is materials and production, meaning tubes that were made at the same place at the same time.

Anyone who knows for sure what the truth about tube matching is want to chime in?
I have a hunch that unless one uses Herbies tube dampers differences among tubes are quite masked by the distortion. Of course there are a lot of other things that produce distortion and noise in audio systems that could mask differences among tubes.
I completely agree with Tomcy6.

Raytheon produced 4 different 5694 designs, in only 7 years of production.
THE SECOND BIGGEST LIE?

"Tests like NOS".

Since vacuum tube manufacturers never published a booklet, of how their new tubes should read / test, on a vacuum tube test meter, and since vacuum tube meters read out, using different scales (in many cases, even by the same company);

How do they know, what a particular, tube type, brand, factory, and year, is supposed to test like, when new?

If the answer lies within the spiritual realm, I plead total ignorance.

Keep on rolling...
Here in 2018 used vintage tubes are still the best choices - and prices keep rising!