Hi
I have just bought a quad of premium grade Shuguang CV181 treasure tubes.
I see there is a classic grade available also, is there any way to tell the difference between the two grades?
It is my understanding that the premium come in at least pairs in a fancy box and that the classic grades can be bought singularly in a not so fancy box.
Also I see the ones advertised on eBay which are sold singularly have three upside down "A" markings as shown in the image below
https://www.aliexpress.com/item/4001028661529.html
Whilst those sold as premium having the writings on them as shown below;
https://www.hotroxuk.com/psvane-black-treasure-cv181-z-gold-grid-matched-pair.html
Can anyone confirm that the ones with the three upside down "A" markings are classic grades only?
Any help greatly appreciated.
I have just bought a quad of premium grade Shuguang CV181 treasure tubes.
I see there is a classic grade available also, is there any way to tell the difference between the two grades?
It is my understanding that the premium come in at least pairs in a fancy box and that the classic grades can be bought singularly in a not so fancy box.
Also I see the ones advertised on eBay which are sold singularly have three upside down "A" markings as shown in the image below
https://www.aliexpress.com/item/4001028661529.html
Whilst those sold as premium having the writings on them as shown below;
https://www.hotroxuk.com/psvane-black-treasure-cv181-z-gold-grid-matched-pair.html
Can anyone confirm that the ones with the three upside down "A" markings are classic grades only?
Any help greatly appreciated.
Unless you’re testing the tubes yourself for whatever qualities have supposedly been selected for, I wouldn’t trust that one is better than the other. Quality control is not something you can inherently count on anymore.
I won't entertain Chinesium valves. They are not made with any quality control and differ in specification widely.
Nothing wrong with Eastern Block 6SN7s or if you can get them, the superior Svetlana 6H8c.
Be careful purchasing through unvetted sellers! Always use PayPal or your Credit Card, to guarantee money back, if they are not the real deal.
Most of, if not all, early valves that performed extremely well, didn't have 'gold plated grids'. There is no way of finding out how many molecules of gold there is deposited on the grid wires, if indeed, there is any at all.
Nothing wrong with Eastern Block 6SN7s or if you can get them, the superior Svetlana 6H8c.
Be careful purchasing through unvetted sellers! Always use PayPal or your Credit Card, to guarantee money back, if they are not the real deal.
Most of, if not all, early valves that performed extremely well, didn't have 'gold plated grids'. There is no way of finding out how many molecules of gold there is deposited on the grid wires, if indeed, there is any at all.
I used eBay and Paypal for purchases.
I have used classic grade and premium grade Shuguang CV181-Z tubes before and there was a difference to my ears anyway.
I have used classic grade and premium grade Shuguang CV181-Z tubes before and there was a difference to my ears anyway.
Soapbox moment.
Sorry but I have always been sceptical about salesmen tactics.
I have found, over the last 50 years, of customers "Tube rolling", most of the outcome has no scientific grounding but more, 'the head making the extra money spent a worthwhile project', in which the owner of the glitzy component truly believes that it makes a difference, when actually there is non.
Not all cases of course but the vast majority do. A valve of a particular specification must equal another valve of the same type and specification, otherwise, they must be allotted a different part number; ECC83, ECC83s, 12AX7, 12AX7WA etc. All different valves that have similar but not the same characteristics.
All this 'burn in' stuff I have heard about over the years is down to nothing but perception. What is actually happening is the ears are adjusting to the sound the amplifier makes and over time, the brain gets used to it. Some call it burn in, I call it getting used to it. Why would you, in the worst case, want to fit part worn components to your equipment ... I wouldn't and don't.
Just like Ford would have you believe, that a new 'fly by wire' electronic engine management unit, in your new car, will learn how you drive. Exactly the opposite, as the driver learns how the engine no longer has the instant performance that a mechanical fuel pump had.
That description "High polymer carbon coating" is just sales talk. There is no such thing. What it actually is, is the Getter gas that has evaporated and coated the inside of the glass. A normal fuction when evacuating a valve before sealing the envelope.
It is mainly salesman designed to play on the mind.
Whatever floats your boat, be my guest.
I can make some cryogenic valves if you want some. Put them in a freezer for a few hours. It does nothing but apparently puts an extra 80% on the selling price and people 'believe' it improves their performance.
Sad isn't it.
Sorry but I have always been sceptical about salesmen tactics.
I have found, over the last 50 years, of customers "Tube rolling", most of the outcome has no scientific grounding but more, 'the head making the extra money spent a worthwhile project', in which the owner of the glitzy component truly believes that it makes a difference, when actually there is non.
Not all cases of course but the vast majority do. A valve of a particular specification must equal another valve of the same type and specification, otherwise, they must be allotted a different part number; ECC83, ECC83s, 12AX7, 12AX7WA etc. All different valves that have similar but not the same characteristics.
All this 'burn in' stuff I have heard about over the years is down to nothing but perception. What is actually happening is the ears are adjusting to the sound the amplifier makes and over time, the brain gets used to it. Some call it burn in, I call it getting used to it. Why would you, in the worst case, want to fit part worn components to your equipment ... I wouldn't and don't.
Just like Ford would have you believe, that a new 'fly by wire' electronic engine management unit, in your new car, will learn how you drive. Exactly the opposite, as the driver learns how the engine no longer has the instant performance that a mechanical fuel pump had.
That description "High polymer carbon coating" is just sales talk. There is no such thing. What it actually is, is the Getter gas that has evaporated and coated the inside of the glass. A normal fuction when evacuating a valve before sealing the envelope.
It is mainly salesman designed to play on the mind.
Whatever floats your boat, be my guest.
I can make some cryogenic valves if you want some. Put them in a freezer for a few hours. It does nothing but apparently puts an extra 80% on the selling price and people 'believe' it improves their performance.
Sad isn't it.
An other annoying thing: Why did they name this tube "CV181" while it has the specifications of a 6SN7 (atleast that is how it is advertised)? The 6SN7 has an amplification factor of 20. The original CV181 is the military equivalent of the ECC32, which has an amplification factor of 32.
A comparable example is the "ECC99". The first "9" in the name should indicate that the tube is 7-pin miniature but the ECC99 is a noval tube.
A comparable example is the "ECC99". The first "9" in the name should indicate that the tube is 7-pin miniature but the ECC99 is a noval tube.
The ECC99 is a modern twin triode. The first 9 should indicate a B7G base according to the classical naming convention but here the valve is on a B9A base. So classically it would have been an ECC89.
The design use of the ECC99 is as driver for power valves or as an output valve in headphone amplifiers etc. The anode dissipation is 3.5 Watts and the control grids have heat sink fins on the tops of the support rods. At 800 mA the heating power is substantial. The 12BH7A also has an anode dissipation of 3.5 Watts but the anode current is 11.5 mA whereas this driver valve has a current rating of 18 mA.
Taken verbatim from The Valve Museum.
Everyone is allowed their opinions, but there is real science to back these up.
Ask anyone with a large selection of the same tube (same/different manufacturer, US/Chinese/Russian/Anywhere) as well as access to a way to test them... and they will all tell you there is a huge variance in tubes strictly from scientifically measuring them. There are changes in geometry of plates, grid spacing and structure across brands and years and from manufacturing deviation. There are different materials used at different times of production. These all have real audible effects, from lower gain, to frequency imbalance or colorations.
On burn in, if you search on this forum, there are real curve traces of new tubes out of the box and after 24 hour burn in. The curves are very different. No listening needed. All science.
Your freezer is 0 °C or maybe just under. Liquid Nitrogen is −210 °C. There is scientific proof the molecular structure of materials change when cryo exposed. Just like heating and cooling steel in different ways gives different properties. This is not fiction. The first Google result says, "The temperatures metals are heated to, and the rate of cooling after heat treatment can significantly change metal's properties." Temperatures affect metal. That's a fact.
Now everyone is free to make their own opinion on just how much it affects the sounds properties or if it is worth the time and money, but all of these are real measurable science. They are not just 'salesman tactics' or 'audiophoolery.'
My opinion is these things do matter, and to the original poster, a premium selected tube should be a better part and worth the extra money. As anchorman said though, you have to be able to trust the seller actually did the work. On the markings, I am not sure on this specific tube, but thinking big picture, they change over time or for customer. In this case, why not ask the seller(s) what the markings are for?
My guess is that JJ needed a new design. As the original tube naming committe is no longer available JJ was
forced to invent a name that did not conflict with anything else, "99" was choosen, but the convention
of ECC was kept intact.
They could for example have chosen ECC184 to stay within the naming convention for noval tubes.
As an aside, I bought two matched pairs of the cheapest Shuguang 6550A-98 tubes I could find. The pairs also matched meaning I got a matched quad. I paid under 200$CAD shipped. They run in UL or triode with cathode bias, and a B+ ~500V and a Pd of ~38W. So far they are working just like they should.
Tubes would crack if dipped in liquid nitrogen. Pyrex, quartz ones might survive.
At the very least, the glass to metal seals around the pins would develop micro-cracks and leak. I believe this cryo BS was a ruse to prove how gullible tube buyers are. Just like "sea salt", heavy metal contaminated salt. Arsenic, cadmium, chromium, lead, mercury, .... "essential" trace minerals for the gullible.
And now you get car engines that shut down at every stop, with a tiny engine with an un-reliable turbo booster. Starter burns outs, bearing surfaces wear down, cylinder surfaces scrape away. A "premium $$" car that you will have to replace early. Manufacturers love it.
I -have- seen tube curves change after running them for a few dozen minutes on the curve tracer. Most likely the getter is removing some residual gas. The cathode surface may be re-forming in some way too. Maybe a thin film of cathode material evaporating, some of it thin film coating the grids.
At the very least, the glass to metal seals around the pins would develop micro-cracks and leak. I believe this cryo BS was a ruse to prove how gullible tube buyers are. Just like "sea salt", heavy metal contaminated salt. Arsenic, cadmium, chromium, lead, mercury, .... "essential" trace minerals for the gullible.
And now you get car engines that shut down at every stop, with a tiny engine with an un-reliable turbo booster. Starter burns outs, bearing surfaces wear down, cylinder surfaces scrape away. A "premium $$" car that you will have to replace early. Manufacturers love it.
I -have- seen tube curves change after running them for a few dozen minutes on the curve tracer. Most likely the getter is removing some residual gas. The cathode surface may be re-forming in some way too. Maybe a thin film of cathode material evaporating, some of it thin film coating the grids.
Last edited:
I doubt that the cryo treatment of metal came from vacuum tubes used for high quality audio playback. Not a lot of interest or $ in that subject? However, if you search for "cryo treatment of metal research paper" you will find no shortage of real, scientific papers on the subject that are quite applicable. The only way you won't find them is if you don't click the search button.
My thoughts on this are simple:
- If you don't realize everything matters, you haven't pushed your understanding or the technology yet. Because every single thing matters. This is photography, audio, woodworking, cooking... literally anything.
- In audio terms, my 24 year me old stereo wouldn't reveal any differences that we are discussing. You'd literally listen and say they are all the same.
- In audio terms, my 50 year me old stereo which I have spent a 25 year career working as an professional engineer, musician and audiophile doing everything to make it better, would easily make these differences notable even to such as my wife, who has 0 interest in my electronics or anything we are talking about and whose phone is still her #1 listening device.
If you think it doesn't matter, that's fine... you'll spend less money and worry less. Good for you. That doesn't mean in any way, that it's not real or doesn't matter to others. So please express your opinion, but please don't say that anyone that doesn't agree with you is a 'snake oil salesman.'
Different sound . . .
Decades ago, some double blindfold listening tests were performed.
The "players" were a few solid state amplifiers, and one OTL tube amplifier.
There was no statistically significant sound difference in the sound of all of those amplifiers.
All of those solid state amplifiers, and the tube amplifier had 2 common design similarities . . .
Totem Pole Output Stage ('vertically' stacked output devices).
A Lot of Global Negative Feedback.
Hmm, food for thought?
Now to be fair, there are other possible causes:
Poor quality recordings
Poor playback signal sources
Poor loudspeakers
Perhaps this test should be carried out with modern recordings, modern playback signal sources, modern loudspeakers.
Decades ago, some double blindfold listening tests were performed.
The "players" were a few solid state amplifiers, and one OTL tube amplifier.
There was no statistically significant sound difference in the sound of all of those amplifiers.
All of those solid state amplifiers, and the tube amplifier had 2 common design similarities . . .
Totem Pole Output Stage ('vertically' stacked output devices).
A Lot of Global Negative Feedback.
Hmm, food for thought?
Now to be fair, there are other possible causes:
Poor quality recordings
Poor playback signal sources
Poor loudspeakers
Perhaps this test should be carried out with modern recordings, modern playback signal sources, modern loudspeakers.