PX4 vs 2A3

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Romy The Cat
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#31 Re: PX4 vs 2A3

Post by Romy The Cat »

Paul , yes and now. The 2A3 is a fine universal tube, easy to get, easy to use, easy to drive everything with easy to understand sound. So, the 300B and even type 45. There are of because more sophisticated tube with much more complex sound: RE604, AD1, PX4/25, YO186 and many others. It does not mean however that any amp with "advanced tubesâ€￾ would sound better and in fact I did heard fantastic amps with 300B. What you all guys forget when you talk about the quality of those low power tubes is that they all are very low bandwidth tube. You get a watt of two out of let say KL71403 with 24-18K bandwidth but it is not where the tube is shining. No tube of 1.5W would shine in deep class A as there is nothing you can drive with this power, unless you are listening in closet. So, I think the more lucid is not to think/talk bout tubes generally but rather to look at "exotic: tube in context of specific application. The name/brand of the tube is irrelevant - it is what I have learned. When I am trying to evaluate the sound of a tube I consider the following factors, all of them:

1) Type of the driver and driver application that drive the tube
2) How the tube loaded and via what kind transformer
3) The specific bandwidth of the given DSET channel (I do not believe in low-power full-range SET with DHT)
4) Type of the speaker the amp is driving
5) Biasing implementation of the DHT
6) Ability of the amp owner to understand and to demand sonic complexity and to use audio methods to get right sound out of any output stage.

The point is that let say AD1 is "betterâ€￾ then 2A3 but it itself means very little. BTW, there are single plate 2A3 - very differently sounding then regular 2A3....
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#32

Post by Paul Barker »

Thanks Romy I fully comprehend all of that and find the same conclusions.

Sit in closet with weedy system is where a lot of us have consigned ourselves. Or trying to make weedy amps due to our love of that special tube shine outside their capable range by puting outlandish efforts nobody else is bothering with in speaker design. But to some the end result is not coherent across the spectrum.

It's a lifetime of failure, might be less painful to go to the abetoir and ask them to shoot us in the head.

Anyway your comments on my threads are always welcome, even if I don't agree right now I may find your words haunt me later, and if I shun you for your manor I never get to know what you thought of my ideas, and when my ideas are stupid it is better to find out sooner. Which isn't an admission that you are always right and I am always wrong, but an expression of a desire to share knowledge perspective and experience openly.

I occupy a working life where if you move someone's plasterboard they start a fight with you, or if you ask a guy to quote for a part of a job but then in the event you decide to do it yourself, he comes round and knocks your door and when you answer you greeted by a punch in face. no talking.

I must say it is so refreshing compared to the world of work where I was only man among women. All nicy nicy to your face meanwhile behind your back planning your ultimate demise, a few years on theiur schemes and plans come to frution and you find they have weaved a web of lies and deceipt and trechory you could never have imagined and the fist time you know they are actually your enemy not your friend as they have appeared to be, you are lying on the floor with a hole in the back so big from the knife you r blood all poured out in seconds.

I prefer the punch in the face at first sign of conflict!

Best thing I ever did was stop working as the only man among women.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
Alex Kitic
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#33

Post by Alex Kitic »

Paul Barker wrote: Sit in closet with weedy system is where a lot of us have consigned ourselves. Or trying to make weedy amps due to our love of that special tube shine outside their capable range by puting outlandish efforts nobody else is bothering with in speaker design. But to some the end result is not coherent across the spectrum.

It's a lifetime of failure, might be less painful to go to the abetoir and ask them to shoot us in the head.

...

I prefer the punch in the face at first sign of conflict!
I really like your comments, and your way of looking at things :D

I do not second every notion, though - some of that is exactly what I am trying to rebel against and prove as not necessary true.

I must say, on the other hand, that given rather inefficient speakers, the 30 or 35W per channel produced by an amp like the RH813 open new possibilities. I feel able to sense what other people get with my "more common" amps on their efficient speakers.

It is not an issue of power bandwidth, rather efficiency. What 35W is for me, 3.5W is for someone (more fortunate?) on his pair of La Scala or similar speakers.

As for the issue of PX4 vs 2A3, or similar questions, more than anything else this is a matter of intrinsic values. While not paramount, the type and make is all but "unimportant".Of course, from a perspective as objective as possible, like what my RH-TTA offers. After all, it could be used without additional modifications, except socket (maybe with adapters) and of course heater voltage. The PX4 is rare, expensive, and unavailable in my part of the world, but there is no doubt in my mind that it would show its worth!
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#34 Re: PX4 vs 2A3

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Romy The Cat
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#35 Re: PX4 vs 2A3

Post by Romy The Cat »

Alex Kitic wrote:I fail to grasp the meaning of what said under 3) ?! What would the term "bandwidth" mean or imply? What is a DSET? Why would the SET or SEP amplifier, directly or indirectly heated, implicitly dis-illude the listener with it's limited bandwidth? Maybe the power/sensitivity issue is relevant, but it foes not imply limited bandwidth.
DSET comes from Dedicated SET, a little searching at my site would help. DSET implies a SET amplifier works in a limited bandwidth and in context of multi-amplification where multiple design criteria, decisions and methods are optimized for the given very limited bandwidth. The DSET configuration is particularly effective in case low power tubes...
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#36 px4 versus 2a3

Post by Steptoe »

Dear Paul, I have nothing useful to contribute to this topic but fully concur with your comments re the dangers of working with women, although for me it is not so much their spiritual nature as their physical attributes that are the problem and which inevitably result in the arrangement going down the pan sooner or later. This is as much a law of physics as w= I2R and although we wish it was otherwise there's nothing to be done. The only remedy is to stay well away unless you want to marry one but even that is not absolutely guaranteed to keep you out of trouble. Yours sincerely, Steptoe.
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#37

Post by Paul Barker »

Yes mate, that is a worse temtation at different stages of your own relationship and your own position on the human lifecycle. Sometimes I am much closer to the thin line which demarkates me from adultery, but I haven't "yet" crossed it.

To err is human, I am human through and through.

I had a whole career axed by a lying bitch, and it began with her trying to french kiss me when we were working a nightshift together over Christmas. before I knew what was happening she has her tongue halfway down my throat. Get out of that one without enjoying the experience or jilting the woman. You loose both ways. I jilted her and it took her two years but she wove her web of deception and lies in secret until the day of her anouncement that I was effectively an axe murderer of the worst kind.

Get out of that when you are a specially trained children's nurse and a man.

Put my career, livelyhood, reputation and freedom in the hands of a female again? NEVER! And that is why so many men have fled children's work, it's a mass exodus. It takes nothing more than an opinion voiced from a female colleague and you are marched off the premises by security suspended and visiting a Forensic Psychiatrist. The unions turn their back on you the personnel department closes it's door of access, the occupational health department look at you in fear as if you are about to get out an AK47 and shoot them all down dead.

Fortunately for me the Forensic trick cyclist and his registrar saw in the first sentence of my speaking with them that this was the vicious attack of a lying bitch. They completely exhonerated me.

So did occupational health unison personel and trust management, read the report and say "sorry son you have been done a great disservice?

Did they buggery, every last one and especially the union said right here is what you are geting "one months pay there is the door".

that was it out on my arse. The bitch still comfortable at work.

Went to see a private solicitor "you don't have enough to gain, not worth fighting" because I wasn't in the pention plan nothing to fight for over "unfair dismisal"

No problem today, moved on long ago. 2002 this process began.

Would I even want that job now if I could get it? NO.

So all's well that ends well, and learned a lot about men in children's work.

Give me the punch in the face for moving a blokes plasterboard every time!

To be fair half the women I worked with were fully on my side, but at least one of those was only so she could try and get me off my wife as the first bitch was really all about. Better not encouraging relationships with women, you might think it's an innocent friendship, they are planning to wreck you wife's life and improve theirs. Then once their home improvements are complete you are surplus and out on yer ear.

No thank you.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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#38

Post by steve s »

I can't disagree with many of romys comments, I like the term descibing some of the old valves as a more complex sound, my take is they take less away which is the same thing?

My goal is a to achieve what i consider a lifelike sound and the old valves help in achieving that
Bandwidth is were i would disagree, as romy has listed, all valve amplifiers are only as good as the sum of parts, i've heard modern production valves that struggle in the bass and the top end but the 'right' old valves should not struggle anywhere. And if an amplifier does, its not the valves to look towards, except that applies to new production valves too!, but the diffences are still there never the less....
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
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#39

Post by Romy The Cat »

steve s wrote:Bandwidth is were i would disagree, as romy has listed, all valve amplifiers are only as good as the sum of parts, i've heard modern production valves that struggle in the bass and the top end but the 'right' old valves should not struggle anywhere. And if an amplifier does, its not the valves to look towards, except that applies to new production valves too!, but the diffences are still there never the less....
Well, it of cause has nothing to do with "sum of parts", you need to look at the subject wider than just a characteristic of a given tube of a characteristic of a given amplifier . There is no bandwidth limitation in whatever tube it would be. The bandwidth limitations in low power DHT comes from the application of the tube in context of a given playback installation. Any person who dealt with practicality of multi-amp configuration would not be able to disagree or disregard it.

Me
Alex Kitic
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#40 Re: PX4 vs 2A3

Post by Alex Kitic »

Romy The Cat wrote: DSET comes from Dedicated SET, a little searching at my site would help. DSET implies a SET amplifier works in a limited bandwidth and in context of multi-amplification where multiple design criteria, decisions and methods are optimized for the given very limited bandwidth. The DSET configuration is particularly effective in case low power tubes...
Well we all have the right to make our own acronyms, I guess... just like the TTA means Tube Tester Amplifier, and TWA will probably mean The Welding Amplifier (the name given to my RH813, most probably it will stick).

While multi-amplification is always an interesting perspective for one who has inefficient speakers and is capable of building lots of amps in a short time-span -- I strongly disagree with the limited bandwidth of SE amps, be they SET or SEP.

The bandwidth limitation, if there is any, does not come from using one particular tube (i.e. 2A3) or another (i.e. PX4), but from the associated circuitry, including output transformers. After all, bandwidth is down to the circuit values and composition - not to the tubes. The tubes are capable to amplify the whole audible spectrum and beyond in either direction (this is not about RF amplification) but might be impaired with an inadequate circuit which filters the output on either end of the bandwidth... something that does not happen with RH amps for sure.

As for multi-amplification (dedication, as you call it) - that is one field of application where you need precisely modified bandwidth. But it does not imply that a 2A3 would be inferior for the bass amp compared to a 6C33C - unless it is power that you need for the task, which is going to be easier to extract from the latter. That said, how much power does one need for pair of "crossover-less" Klipschorns, or Nineteens?!

Dedicated amplifiers (multi-amplification) might be a good idea with relatively inefficient speakers - but once you connect them to an amplifier powerful enough (like the RH813, or similar) the whole idea to multi-amplify slowly fades into oblivion. Power may be important, thus the adequately powered amp for a given sensitivity loudspeaker... but that has nothing to do with bandwidth - particularly "tube type related".
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#41 Re: PX4 vs 2A3

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Alex Kitic wrote: While multi-amplification is always an interesting perspective for one who has inefficient speakers and is capable of building lots of amps in a short time-span -- I strongly disagree with the limited bandwidth of SE amps, be they SET or SEP.
You are perfectly within you constitutional right to disagree but it does not make you to be right. Put in this way: disagreement does give you opportunity to try DSET cones practically and not all people understand a subject enogh to be able extrapolate the benefits on purely theoretical base.
Alex Kitic wrote:As for multi-amplification (dedication, as you call it) - that is one field of application where you need precisely modified bandwidth. But it does not imply that a 2A3 would be inferior for the bass amp compared to a 6C33C - unless it is power that you need for the task, which is going to be easier to extract from the latter. That said, how much power does one need for pair of "crossover-less" Klipschorns, or Nineteens?!
Well, it is about practicality and applications. There is difference between 2A3 and 6C33C. If you have let day some kind of Klipschorns or Nineteens type of speaker and let say 20 sq miter room then you have two channels and HF might be driver by anything you want - 2-3W would be more than enough and any DHT would do it. The bass channel for a ported cabinet in case you amp has no feedback, 3 stage and let say 26dB gain is problem if you want to keep the amp in A1. It will just not happen, BT it will not happen even with 15W of 6C33C. To make your bass DSET to react properly to the Altec 416 driver run accros current reaction at the time when port of Nineteens hit resonance you would need very low amp impedance and very "decoupled" operation. In case of 6C33C you would need to ide the tube insanely, let say loading it to 2000R-2500R, erectly killing all power of the tube and getting from 6C33C perhaps 3-4W... which would not be enough for you. Mind you that severally idled 6C33C will not be sounding even remotely similar to 2A3 driving 808 driver of your Nineteens and you will be little getting horrible sound. You need to know how to deal with all of the situation and DSET concept has all of it factored in, read my site, I had written about it somewhere. Do not forget that to very high degree Power is Bandwidth ( and vise versa) in context of any SET amplifier with output transformer. In my view a DSET concept is good tool to deal with matching need of a given specific channel to the capacity of a given amplifier. Probably the case of Nineteens is too extreme and there is no amplifier that could help to that MF horror but as an illustration I think it was appropriate.
Alex Kitic wrote:Dedicated amplifiers (multi-amplification) might be a good idea with relatively inefficient speakers - but once you connect them to an amplifier powerful enough (like the RH813, or similar) the whole idea to multi-amplify slowly fades into oblivion. Power may be important, thus the adequately powered amp for a given sensitivity loudspeaker... but that has nothing to do with bandwidth - particularly "tube type related".
Well, any sub 150Hz is inefficient speaker. You can't get unfortunately manageable (key word) 110dB sensitivity for you let say midbass. Yes, it might look like it has nothing to do with bandwidth - particularly "tube type related" thinking but the reality is that I use word "bandwidth" (and it is very obvious if you read my site) as a synonym to the word "channel". Each channel (or bandwidth part) in let say my playback has own meaning, own expressive aspects and own means to accomplish those expressive aspects. You would not be able to handle those expressive aspects by means of one single amplifier, it is juts impossible (even if you forget about innermodulations and current roll back from drivers). Let me to give you an illustration to better understand what I am taking about. Pretend a symphonic orchestra with winds for some mystery reasons are not one "single driver instruments" but a division for number of different groups. Let take 4 of them: trumpets, contra-bassoons, tubas and clarinets. They all are the members of the same brass family and they all take air in and publish sound out. We would not deny that all of them has own spectra, harmonics and zillion other aspect that make the instruments different but we also would not deny that each of those instrument would requires different type of " air in", in other words liping techniques on trumpets would not be very different then bassoons. The point is that "type" of air that is sent to brass instrument in a way is a type of amplification you submit to a given channel of your entire installation.

Rgs, the Cat
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#42 Re: PX4 vs 2A3

Post by Alex Kitic »

Romy The Cat wrote: The bass channel for a ported cabinet in case you amp has no feedback, 3 stage and let say 26dB gain is problem if you want to keep the amp in A1. It will just not happen, BT it will not happen even with 15W of 6C33C. To make your bass DSET to react properly to the Altec 416 driver run accros current reaction at the time when port of Nineteens hit resonance you would need very low amp impedance and very "decoupled" operation.
1) My amps have rather low output impedance and are perfectly able to do what you are putting as impossible.
2) If that is because they are neither 3 stage, nor 26dB gain, nor "no feedback"... well, that is just proof that it is not about the tube, but the circuitry.
Romy The Cat wrote: Mind you that severally idled 6C33C will not be sounding even remotely similar to 2A3 driving 808 driver of your Nineteens and you will be little getting horrible sound.
Again, you confirm yourself that the tube type is not unimportant for the sound, regardless of power output.

Regardless of taste, few would reduce their Klipschorn or Nineteen to multi-amplifiable crossover-less boxes.
Romy The Cat wrote: Do not forget that to very high degree Power is Bandwidth ( and vise versa) in context of any SET amplifier with output transformer.
I am sorry, but this is the first time I hear of such a thing... I tought that there are rather exact definitions of what is power and what is bandwidth?!
We might eventually use the term "power bandwidth"... ? ... but power is not the same as bandwidth (not at all!).
Romy The Cat wrote: Probably the case of Nineteens is too extreme and there is no amplifier that could help to that MF horror but as an illustration I think it was appropriate.
This is again about taste... I would probably very much oblige if someone would be so kind as to give me a pair of these horrors as a gift. But I guess that is not going to happen.
Romy The Cat wrote: ...but the reality is that I use word "bandwidth" (and it is very obvious if you read my site) as a synonym to the word "channel"...
I guess you are free to use words as you like, but that does not imply that the use of words is correct and understandable to us all. Again, from what I know, bandwidth is not a synonym for channel.

This is beginning to resemble to the so called "word salad" (http://en.wikipedia.org/wiki/Word_salad). No pun intended, no offence meant.
Romy The Cat wrote: With my limited experience of using pentodes (primary as phono corrector first stage) I think that the most mysterious in them is power supply of bias to "other" grids. Looking at the Milq schematics it is obvious that I pay too much attention to the bias power supplies and I very much see the difference. With pentodes, which has a suppressor grid and screens, I find the sensitivity of those secondary grids to PS is critical. If somebody did find a good configuration of powering those grids then it would be wonderful.
Pardon me for quoting a post from another forum (http://www.goodsoundclub.com/Forums/Sho ... 0847#20847)

I guess the supressor grid (g3) or beam former plates (similar or same task in beam tetrodes) is not at all sensitive to PS?! Usually it is grounded (internally connected to the cathode) or it should be grounded (i.e. directly connected to ground) and very seldom someone dares to give this grid some potential other than 0V - due to the fact that it can have influence on the appearance of the kink in the curves.

Anyway, it is very difficult to "power" g3... maybe this is another synonymous use of the word, or some idiomatic expression that eludes me (powering = grounding, or powering = giving adequate potential).

This reminds me of the "Hazen mod"... or how to turn a pentode/kinkless tetrode into a plain tetrode with kink in the curves... no wonder there is a difference in sound (clarity?!).

What I am trying to say is that QUANTITY IS NOT QUALITY.
You cannot try to answer to a theoretical question without theoretical knowledge, drowning the answer in too much text that discourages the reader... regardless of all the experience with taming Nineteens that you might or might not have ;)
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#43 Re: PX4 vs 2A3

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*** 1) My amps have rather low output impedance and are perfectly able to do what you are putting as impossible. [/quote]
It depends what you recognize as a definition of success for YOU

*** Regardless of taste, few would reduce their Klipschorn or Nineteen to multi-amplifiable crossover-less boxes.
Well, among those who would even use Nineteen all bet are off and they can do anything they want, there is nothing that would help them anyhow
.
*** I am sorry, but this is the first time I hear of such a thing... I tought that there are rather exact definitions of what is power and what is bandwidth?!
This is very basics I have no idea why you do not get it. Your let say 6C33C SET would have 5Hz to 70kHz at 1/8 of full power 20-20K at 10 power and 25-18K at full power. If you have a OPT with huge inductance, no sections, do not care about capacitance and wind it with low impedance wire then you will have upper range of your OPT at let say 600Hz but you will get 22W at 10Hz. From DSET perspective power is bandwidth.

*** This is again about taste... I would probably very much oblige if someone would be so kind as to give me a pair of these horrors [Nineteens] as a gift. But I guess that is not going to happen.
Of cause it is about taste and reference points.

*** I guess you are free to use words as you like, but that does not imply that the use of words is correct and understandable to us all. Again, from what I know, bandwidth is not a synonym for channel.
Well, some people learn when they read forums.

*** I guess the supressor grid (g3) or beam former plates (similar or same task in beam tetrodes) is not at all sensitive to PS?! Usually it is grounded (internally connected to the cathode) or it should be grounded (i.e. directly connected to ground) and very seldom someone dares to give this grid some potential other than 0V - due to the fact that it can have influence on the appearance of the kink in the curves. Anyway, it is very difficult to "power" g3... maybe this is another synonymous use of the word, or some idiomatic expression that eludes me (powering = grounding, or powering = giving adequate potential).
You are right partially. I meant the second grid. However, the powering of the second grid is related to HOW you power plate and HOW you ground suppressor grid.

***You cannot try to answer to a theoretical question without theoretical knowledge, drowning the answer in too much text that discourages the reader... regardless of all the experience with taming Nineteens that you might or might not have ;)
Well, I do not insist of having theoretical knowledge. I also do not tame Nineteens. Discouraging the audio-type readers is however is what I have a hell of experience. I wish somebody have discouraged them long time ago...
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#44 Re: PX4 vs 2A3

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Romy The Cat wrote: Discouraging the audio-type readers is however is what I have a hell of experience. I wish somebody have discouraged them long time ago...
Well, I certainly know better than to loose any more time trying to discourage you, and looking bad in the eyes of people participating in the only forum where I feel comfortable - just like home ;)

There are far more interesting ideas to pursue and exchanges of opinions to have.
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#45 Re: PX4 vs 2A3

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Alex Kitic wrote:Well, I certainly know better than to loose any more time trying to discourage you, and looking bad in the eyes of people participating in the only forum where I feel comfortable - just like home ;) There are far more interesting ideas to pursue and exchanges of opinions to have.
It is OK. I appreciate your deep caring about me but I do not need audio forums help to be discouraged or encourage. So you might save your appearance in the eyes of people who scab your back in finish sauna. When you get tired to do aimless and meaningless soldering and start thinking about sound instead of being occupied with idea of how to make your back scabers happy then you might in your mind reevaluate the DSET concept and then you suddenly discover that what I have already said might keep your head and hands busy for next 4-5 years.
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