PSVANE - Let’s Talk All Things about Vacuum Tubes

[No Regrets]

Hmm, it's stories like this (and so many others already reported) that will stop me ever going down the Psvane path.

Believe me... I was very much stressed out when the first matched pair arrived with a defective tube. I thought..."how is this going to work out, trying to get replacement tubes from China, etc" But the gentleman at Psvane was very kind, understanding and responsive and made the process of getting the replacement tubes very easy.

For me... because their Acme 845 tubes sound so amazingly good, ( as I had said earlier - "the best that I've ever had in my amp") it was worth going thru the inconvenience of weeding out the defective tubes. They are that shockingly good sounding!

I just don't understand why they don't tighten up their quality control/testing of these tubes before sending them out to their customer base.

Best wishes,
Don

 

[mariovalvola]

I bought a pair of those 12AU7s before owning a good tube tester. After receiving the Amplitrex tester, checked these 12AU7s. The triodes in each are about 20% different, in both tubes. No way anybody would consider them matched triodes. The Amazon return period had long passed.

Triode 1 Triode 2

Tube 1
mA 8.0 10.4
Emission 76% 99%
GM 118% 145%

Tube 2
mA 10.2 8.2
Emission 97% 78%
GM 136% 122%

Gm tests must be performed with the same circulating current.

 

[oldvinyl]

I'm using the Psvane Acme 845 tubes in my single ended power amplifier as shown on the top shelf, middle in the photo below....
View attachment 160352

When you are able to get a pair that works as intended, they sound absolutely beautiful with rich tonality and wonderful micro/macro dynamics!

View attachment 160355
My first matched pair arrived with a defective tube (probably damaged in the overseas shipment from China).
That pair was returned and they sent a new matched pair.
I loved the sound of these tubes so much that I then ordered a second matched pair for back up.
Then another single tube went bad. They had me destroy that one, take a picture and they sent me a replacement tube.
Then another sigle tube went bad yet again. They again had me destroy that one, take a picture and they sent me a another replacement tube.

I currently have two pairs of the Acme 845 that are working as intended. They sound fantastic!!! Best I've had in my amp by a large margin!!!
The reliability or quality control seems to be under par... however, they are very responsive and getting a replacement is easy enough. I just wish they had a higher success rate/lower failure rate.

Best wishes,
Don

Unfortunately, this has been the situation with output power tubes for the past couple decades. As companies try to recapture the glory of NOS power tubes or move into new glories, most have had failures. It has happened with European and Asian companies; it is not specific to any country.

I went through the same thing about 25 years ago when I tried some new production 845 tubes and 300B tubes. Lots of spectacular failures after several hours of operation. They were all replaced and I eventually got working sets of tubes, but I lost interest in trying new ones.

I continue to hope that there will be a new Holy Grail 845 tube. It would help the industry and the consumers.

Someone must have lost the 845 recipe.

I feel your pain!

 

[spiritofmusic]

Would love to get the comparison of Audio Note 211s (more specifically Moly plate 242s) with Psvane Acme, especially re build and reliability.

 

[bmwr75]

Gm tests must be performed with the same circulating current.

What??

 

[mariovalvola]

The measurement of Gm and therefore the comparison of Gm between two tubes must primarily be carried out with Ia being equal, not with -Vg being equal. This is written in every handbook.

 

[bmwr75]

The measurement of Gm and therefore the comparison of Gm between two tubes must primarily be carried out with Ia being equal, not with -Vg being equal. This is written in every handbook.

My Amplitrex AT1000 tube tester is set up to test tubes in Fixed Bias mode. The mismatch between the triodes in each tube is my issue with the PSVane 12AU7s.

 

[mariovalvola]

My Amplitrex AT1000 tube tester is set up to test tubes in Fixed Bias mode. The mismatch between the triodes in each tube is my issue with the PSVane 12AU7s.

To work well with the Amplitrex, you must use it connected to your PC in order to make adjustments to the grid negative voltage.

 

[bmwr75]

To work well with the Amplitrex, you must use it connected to your PC in order to make adjustments to the grid negative voltage.

That's not going to happen.......just to make PSVane tubes look better. Nearly every, if not every, vintage tube tester tests in Fixed Bias mode per the research I've done. PSVane should just do a better job of testing and screening the tubes they sell.

 

[mariovalvola]

That's not going to happen.......just to make PSVane tubes look better. Nearly every, if not every, vintage tube tester tests in Fixed Bias mode per the research I've done. PSVane should just do a better job of testing and screening the tubes they sell.

I don't want to defend anyone, and I believe that better quality control is necessary.
However, when criticizing, even when justified, one must be beyond reproach. Time has caused us to forget some obvious premises, which I, as a long-time enthusiast, would like to reiterate.
I am attaching a handbook as an example

https://www.rsp-italy.it/Electronics/Databooks/Philips/_contents/Philips%20ElectronicValves%20Book%20II%20-%201949.pdf

Please read page 1
"
THE VALVE DATA
Properties such as the mutual conductance, internal resistance, etc., are given with respect to a certain value of the anode current, which is in each case such that optimum results will be ensured under normal conditions. Since the anode current should be regarded as the guiding factor, the grid voltage values given must be taken to be average values. All total values are the outcome of measurements at the working voltages and currents as specified and they should be looked upon as averages obtained from tests on a very large number of valves. Unless otherwise stated, data concerning pentodes having separately connected suppressor grid may be considered as having been obtained with this suppressor grid connected to the cathode. All voltages are given with respect to the cathode. In the case of battery valves, voltages are quoted with respect to the negative end of the filament, whilst the other data refer to the grid bias indicated.
"

 

[bmwr75]

Switched my Amplitrex AT1000 tester to auto bias mode a couple of days ago and retested the PSVane 12AU7-AT tubes. Same result, poorly matched triodes in each tube. Not quite as bad as in fixed bias mode, but still bad triode matching within a tube.

 

[spiritofmusic]

Sorry if it seems like I'm happy to benefit from all of you gentlemen's misfortunes, but your clear reporting on this company has saved me the same aggravation that has befallen most of you.