PX4 vs 2A3

[Paul Barker]

Just noticed PX4 filament consumes 4 watts 2A3 filament consumes 6.25 watts.

Manufacturer's suggested operating point Class A1 single ended. PX4 produces 4.5 watts with a THD of 4%, 2a3 produces 3.5 watts at a THD of 5%.

Just saying.

Chinese backed the wrong horse. should be propely making exact replicas of PX4 and PX25 instead of fobbing us off with slapped together attempts a an apprecntice at Osram would have been fired for even puting on paper..

By they way anyone who thinks I am a Chinese valve manufacturer basher for the sake of it or for reasons of racism. Wrong, if the country from which these sub standard valves came from was called zickywok I would be saying the zickywok PX25 is not a PX25.

My passion is the valve not the nation. It is what a manufacturer from a nation does to the valve which I am criticicing not what they do otherwise.

If we went back to the 1930's and one manufacturer, let's call it "elite valves" produced this pathetic excuse I would have as much to say as I do now. If the hat fits wear it. The hat fits the Chinese manufacturer. They put themselves into that snuggly fitting hat! I am just pointing it out.

I do of course realise that the commercial insentive is to make 2a3's and 300b's because of the much larger demand from USA, and once production is set up even people from UK will buy into as they have, the US types.

Just saying the modern manufacturer's are misguided by the USA economic dominance (which is not guaranteed to continue).

It reminds me of my studies in economics in the 1970's. The USA had an internationsal currency advantage known as Seniorage. Well they have Seniorage in the choice of which valve is made today. But only for the same position of power economics. Not for any other reason.

Not to say the 2a3 and 300b are bad valves. Just that there is better!

[andrew Ivimey]

What you say sounds about right to me. But having tried a Chinese. 50 it was not good. I've got loads of Shuaguang 2a3s and they are relatively chap after all. Paul, I believe was underwhelmed so far with his px25s. I he one pair of px4s and a couple of pairs of Chinese px4s (they look frighteningly similar to the 45s or the 2a3s, but I do like them. As you point out px4s and 2a3s are very similar to implement so why haven't I? No time! Russian valves are cheaper to abuse and px4s are precious... oh all right, I will. A px4se amp is built, but the psu has gone so it won't take too long - this summer then(?) America's hold on things too means that my English px4s have different bases to the yankee ones.

[steve s]

Paul, this is a subject that has made me wonder, even on this forum there is clear american bias... The original american valves are clearly not as good as the original Brits/ german valves, even when compared like with like the british valves command the highest prices, take the 6sn7 vs b65/ecc3?
it is also well documented the ml/mh 4volt valves are superior.

What has also surprised me is the differences are not subtle, but again on many forums where the goal, one would think, is to build the best one can, there are a lot of valves used that i would not even dream of using . And that was well known back in 1945

What is good for us lot is that if one wants to take the time and the outlay to get the very best valves, we can quite easily and relatively cheaply do that. And know that a pair of px4 are still a good long term investment as well as being amongst the best audio valves ever produced
I wish i could still pick new ones up for £60 as i did 15 years ago, although at todays prices they are terrific value compared to any new production output valve.
In isolation the 2a3 may sound very good, a-b'd but next to a proper audio valve?

[steve s]

If we went back to the 1930's and one manufacturer, let's call it "elite valves" produced this pathetic excuse I would have as much to say as I do !

That a fair point Paul, but in the 1930's no one would have bought them any way, funnily enough they new all about quality back then, in fact much more than todays customers know about quality. Around 5 years ago i bought a 1932 pa amp, 5 watts, for dance halls, the original instruction booklet explained the system requirements for the highest quality reproduction, things have not changed today

[JamesD]

Well it makes the point very well about the relative performance and ties up with the valves relative reputation in Asia where the PX25 rules supreme with prices to match...

I still remember the 4211E though will a real sense of awe about its sound, better than anything else I've heard...

J

[Paul Barker]

Well it makes the point very well about the relative performance and ties up with the valves relative reputation in Asia where the PX25 rules supreme with prices to match...

I still remember the 4211E though will a real sense of awe about its sound, better than anything else I've heard...

J

Yes and if I was rich I would be saying to the Chinese manufacturer, "make me a genuine PX25 and if you get that right I will consider buying your 212!"

[Nick]

Well it makes the point very well about the relative performance and ties up with the valves relative reputation in Asia where the PX25 rules supreme with prices to match...

I still remember the 4211E though will a real sense of awe about its sound, better than anything else I've heard...

J

Yes and if I was rich I would be saying to the Chinese manufacturer, "make me a genuine PX25 and if you get that right I will consider buying your 212!"

Yep, but why would they bother? if you paid them what it would cost + profit to make you a PX25, why would they bother if you bought the 212? They sell all the 212's they make (I asked), and they make enough to make a profit at the price. I am sure if they thought they could sell more at that price (without causing the demand/price to fall) they would make more. I can't help thinking the higher gain of a PX25 makes it a harder valve to make than a 300b or 2a3.

[Paul Barker]

I can't help thinking the higher gain of a PX25 makes it a harder valve to make than a 300b or 2a3.

I agree.

[steve s]

Well it makes the point very well about the relative performance and ties up with the valves relative reputation in Asia where the PX25 rules supreme with prices to match...

I still remember the 4211E though will a real sense of awe about its sound, better than anything else I've heard...

J

Thats interesting james, there is an awe about really clean power, and the 211 is a very powerful valve , i know exactly what you mean, but the px4/25 is a different animal, implemented correctly they let more of the finer harmonics through, you get a tone and a timbre that not many valves can achieve.
My 600v transmitter versions of the px25 show the same differences as the anode material changes, the tone is less .. Still very good but not as good as the audio version....

[Paul Barker]

My 600v transmitter versions of the px25 show the same differences as the anode material changes, the tone is less .. Still very good but not as good as the audio version....

Similar to my experience with the oxide coated filament 211 compared to the thoriated tungsten. There is something powerful and seductive about TT but I prefer oxide coated. You have described the sound I hear.

Darren had an oxide coated 212 which he said sounded great. I had one too but it burned up without me even listening to it. Poof, smoke filled the glass and that was that!

[Paul Barker]

I suspect the AD1 will sound better than the PX4.

Here is a curve trace of my one Ad1



Here is an average PX4

[steve s]

Do you have an old globe px4 to compare too paul? They are a very different valve to the later types

[Paul Barker]

In a word, no.

[JeanBeo]

Hi Paul
I did some listening tests a few years ago between PX4 (the old balloon shaped with sloping plates and the more modern straight bulb) and AD1 (Dario, French made).
The best by far was the balloon PX4 which has such a charming sound (maybe not entirely neutral).
The AD1 had a very fluid sound but les direct and bass were lacking a bit of control.
Third were the modern Px4, with a less even balance (tilted toward treble) and a more aggressive sound.
The Dario are not the best of the AD1. The German are supposed to be better. According to Jean Hiraga, the Loewe AD1 are one of the best sounding triodes ever made but the Japanese got them all in the eighties when nobody else was looking for them.
Jean-Noel

[Nick]

Do you have an old globe px4 to compare too paul? They are a very different valve to the later types

But if they measured that much differently, they would not be px4's

That AD1 set of curves does look rather nice though.

But I would have to argue that a 300b doesn't look that much worst.