could someone explain the advantages of using an ancient designed directly heated triode such as the 300B or a PX25 when there are more available and recent (and cheaper) valves around?
Is it possibly a subjective thing, like the sound of one valve over another?
Speaking of DHT, I recently visited our local museum, where they have a Cinema equipment exhibition, one of the old (BTH I think) amps had 4 PX25 DHT in it, and the display case to the side, had NOS valves of PX4, PX25 and the much loved 300B, in sealed original boxes, dating from the 30's!
Is it possibly a subjective thing, like the sound of one valve over another?
Speaking of DHT, I recently visited our local museum, where they have a Cinema equipment exhibition, one of the old (BTH I think) amps had 4 PX25 DHT in it, and the display case to the side, had NOS valves of PX4, PX25 and the much loved 300B, in sealed original boxes, dating from the 30's!
Hi,
Maybe you should stick to the words you actually know: pentode, perhaps?
Curves are only useful to people that can read them properly, moreover they are only just an indication of what you can expect under the conditions those curves were drawn.
Make a circuit with the same tube and plot again, you'll see what's left of those curves once a load is attached.
Cheers,
Maybe you should stick to the words you actually know: pentode, perhaps?
Curves are only useful to people that can read them properly, moreover they are only just an indication of what you can expect under the conditions those curves were drawn.
Make a circuit with the same tube and plot again, you'll see what's left of those curves once a load is attached.
Cheers,
Alastair: Can you you give an exact location for your museum (and nearest police station)? I've got my wrecking bar, striped jumper, woolly hat and bag marked "swag" at the ready...
Sadly (I hate the prices), 300B etc have lovely linear curves. We might like our women to be curvy, but valves need to be flat as a board. That said, there is a huge fashion element, and my personal opinion is that 300B is over-priced, over-sexed, and not over here!
Another point worth bearing in mind is that making valves was/is a high technology business ideally served by mass production. It is much harder to achieve consistent quality on small production runs. In other words, modern valves tend to be more problematic than NOS ones, and this is why you will find people desperately trying to find ways to use obscure NOS valves with a still reasonable price.
Sadly (I hate the prices), 300B etc have lovely linear curves. We might like our women to be curvy, but valves need to be flat as a board. That said, there is a huge fashion element, and my personal opinion is that 300B is over-priced, over-sexed, and not over here!
Another point worth bearing in mind is that making valves was/is a high technology business ideally served by mass production. It is much harder to achieve consistent quality on small production runs. In other words, modern valves tend to be more problematic than NOS ones, and this is why you will find people desperately trying to find ways to use obscure NOS valves with a still reasonable price.
PX25
I used to run Cinemas, and I visited the museum and found a fellow enthusiast of cinema equipment was holding the exhibition!
It was around 10 years ago that I had a cinema in a local town, where the equipment was all original--Carbon Arcs and changeovers!--The arc-lamps were fed by Nevlin Rectifiers, with Mercury bulbs--These were great!! A wonderful purple-blue glow!
Due to reliability reasons, ( and the expense of carbon rods!) I changed over to a solid state rectifier and Xenon lamps.
The Gaumont Kalee Amplifier was the size of your average room door, a large cabinet affair, using 4 KT66 in the output, 6SN7 pre-amp/phase splitter, and as I remember EF37 as gain amps It was only mono, and rated (according to the data) at 30W RMS--It was even Bi-Wired!--Two secondaries from the O/P Tx! Smoothing was done by huge chokes and 8uF caps, and the rec was a large DH double diode--Cant remember the number though....U52?...
The Cinema was 503 Seater, built on a nice generous size and during ownership I used to have great fun playing my music through this, --Amazing bass for such a low O/P--Probably due to the huge folded horn speaker--Im 6'6'' tall, and I couldnt reach the top of the thing!--It took three people to move it for the occasional stage show presented there!
I never had any problems whatsoever with either the amp or the valves It had been fitted sometime in the Forties!, and looked all original, all the caps and resistors were as the maker had made it, and covered with a nice thick layer of carbon arc dust, It worked so well, I didnt dare touch it!
Sound pick-up, was done by a Photo-cell, A cold cathode valve with around 90 volts bias--This is the only thing I had a little trouble with, a strange rushing popping sound A NOS cured it completely--(Found a whole bunch of valves carefully packed out in the battery/ rewind room)
I closed the Cinema some ten years ago, Its still there, and I guess the amp and projectors are too!
I used to run Cinemas, and I visited the museum and found a fellow enthusiast of cinema equipment was holding the exhibition!
It was around 10 years ago that I had a cinema in a local town, where the equipment was all original--Carbon Arcs and changeovers!--The arc-lamps were fed by Nevlin Rectifiers, with Mercury bulbs--These were great!! A wonderful purple-blue glow!
Due to reliability reasons, ( and the expense of carbon rods!) I changed over to a solid state rectifier and Xenon lamps.
The Gaumont Kalee Amplifier was the size of your average room door, a large cabinet affair, using 4 KT66 in the output, 6SN7 pre-amp/phase splitter, and as I remember EF37 as gain amps It was only mono, and rated (according to the data) at 30W RMS--It was even Bi-Wired!--Two secondaries from the O/P Tx! Smoothing was done by huge chokes and 8uF caps, and the rec was a large DH double diode--Cant remember the number though....U52?...
The Cinema was 503 Seater, built on a nice generous size and during ownership I used to have great fun playing my music through this, --Amazing bass for such a low O/P--Probably due to the huge folded horn speaker--Im 6'6'' tall, and I couldnt reach the top of the thing!--It took three people to move it for the occasional stage show presented there!
I never had any problems whatsoever with either the amp or the valves It had been fitted sometime in the Forties!, and looked all original, all the caps and resistors were as the maker had made it, and covered with a nice thick layer of carbon arc dust, It worked so well, I didnt dare touch it!
Sound pick-up, was done by a Photo-cell, A cold cathode valve with around 90 volts bias--This is the only thing I had a little trouble with, a strange rushing popping sound A NOS cured it completely--(Found a whole bunch of valves carefully packed out in the battery/ rewind room)
I closed the Cinema some ten years ago, Its still there, and I guess the amp and projectors are too!
Hi,
Unfortunately this is impossible to do with a 300B.
This is, and probably always will be, a very labour intensive valve to build.
OTOH, with the advent of the Russian and Chinese 300Bs prices went down considerably over the past ten years.
You only need to compare these prices to the ones asked for the original WEs and Cetrons...
Cheers,
P.S. A good quality KT88 doesn't come cheap either...
Unfortunately this is impossible to do with a 300B.
This is, and probably always will be, a very labour intensive valve to build.
OTOH, with the advent of the Russian and Chinese 300Bs prices went down considerably over the past ten years.
You only need to compare these prices to the ones asked for the original WEs and Cetrons...
Cheers,
P.S. A good quality KT88 doesn't come cheap either...
Hi Steve,
While I don't know how the two compare labourwise, I do know of at least one particular aspect of building a 300B that deviates from standard practice, namely the way the heater wire is formed.
It is not spiralled regularly but unevenly as to avoid hot spots or cold islands if you like.
The building story of the 300B was published in one of the French "L' Audiophile" issues, I should still have a copy but if I remember correctly labour was about a months' worth of manhours per tube for a single worker.
This figure may be off so I'll try to look it up for you later tonight.
Also kee in mind that due to the WE factory move and some considerable investments made production effeciency is now much improved.
In the meantime here's some reading on the 300B:
NEW PRODUCTION WE 300B
Also very interesting is the WE factory tour which focuses on the production of the 300B:
The new Kansas City Works of WE
Keeping in mind the average lifespan of 40,000 hours and the fact that their customer was the military one more easily understand the relatively high asking prices.
As promised, I'll get back to you with more detail asap.
Cheers,
P.S. Jean Hiraga also published an article, again in French, when he visited the M.O.V. company together with the CEO of a major Japanese buyer of KT88s.
Suffice it to say that I was very impressed by the quality of labour that went into it as well.
While I don't know how the two compare labourwise, I do know of at least one particular aspect of building a 300B that deviates from standard practice, namely the way the heater wire is formed.
It is not spiralled regularly but unevenly as to avoid hot spots or cold islands if you like.
The building story of the 300B was published in one of the French "L' Audiophile" issues, I should still have a copy but if I remember correctly labour was about a months' worth of manhours per tube for a single worker.
This figure may be off so I'll try to look it up for you later tonight.
Also kee in mind that due to the WE factory move and some considerable investments made production effeciency is now much improved.
In the meantime here's some reading on the 300B:
NEW PRODUCTION WE 300B
Also very interesting is the WE factory tour which focuses on the production of the 300B:
The new Kansas City Works of WE
Keeping in mind the average lifespan of 40,000 hours and the fact that their customer was the military one more easily understand the relatively high asking prices.
As promised, I'll get back to you with more detail asap.
Cheers,
P.S. Jean Hiraga also published an article, again in French, when he visited the M.O.V. company together with the CEO of a major Japanese buyer of KT88s.
Suffice it to say that I was very impressed by the quality of labour that went into it as well.
typical
Yes Frank, I think your last two points, about the military and life span are a couple of factors dictating the price. The process is typical of Svetlana and others, except the time involved for evacuating the tube may be much longer than others, which costs money, so another reason. Measuring all the parameters and giving printouts also raises the price.
From what I understand, the higher the evacuation of the bulb, the "harder"/"dryer" the sound. Of course there are other factors too.
Thanks Frank.
Yes Frank, I think your last two points, about the military and life span are a couple of factors dictating the price. The process is typical of Svetlana and others, except the time involved for evacuating the tube may be much longer than others, which costs money, so another reason. Measuring all the parameters and giving printouts also raises the price.
From what I understand, the higher the evacuation of the bulb, the "harder"/"dryer" the sound. Of course there are other factors too.
Thanks Frank.
What do you say?
What reason do you give to your wife to spend $900 in a couple of bulbs?
Any ideas here?
Maybe we should address this question to the marketing people from Western Electric. If they've already made the telephone, vacuum cleaner, hair dryer and DVD player to be part of our homes, why not make every good family believe that a nice triode will enlight the life at the house?
What reason do you give to your wife to spend $900 in a couple of bulbs?
Any ideas here?Maybe we should address this question to the marketing people from Western Electric. If they've already made the telephone, vacuum cleaner, hair dryer and DVD player to be part of our homes, why not make every good family believe that a nice triode will enlight the life at the house?
Hi,
Hmmm...Maybe...But how does one know the amount of Tor the vacuumpumps are set to at the factory?
I know WE prides itself in applying the highest vacuum levels in the industry.
However I fail to see the sonic relationship as anyone would be hard pressed to describe the WE 300B as sounding hard or dry.
Do you happen to have any web based, or whatever, matter on this I can read up on?
BTW, I found the article regarding the WE300B but I only read part of it so far.
Publisher: Editions Frequence.
Issue #6, new series of "L' Audiophile" page 106-115
Title: Le Musee Imaginaire: 75 ans de tubes a la Western Electric.
Author: A.-R. Balaton.
It's well worth reading as the entire production process of the WE 300B is explained from A-Z.
Cheers,
Hmmm...Maybe...But how does one know the amount of Tor the vacuumpumps are set to at the factory?
I know WE prides itself in applying the highest vacuum levels in the industry.
However I fail to see the sonic relationship as anyone would be hard pressed to describe the WE 300B as sounding hard or dry.
Do you happen to have any web based, or whatever, matter on this I can read up on?
BTW, I found the article regarding the WE300B but I only read part of it so far.
Publisher: Editions Frequence.
Issue #6, new series of "L' Audiophile" page 106-115
Title: Le Musee Imaginaire: 75 ans de tubes a la Western Electric.
Author: A.-R. Balaton.
It's well worth reading as the entire production process of the WE 300B is explained from A-Z.
Cheers,
Vacuum
Hi Frank,
I just read what you read. You know how some tubes have that "wet, not clear sound. Wonder if it has partially to do with the vacuum. Others have posted theories at other chats, but nothing specific to mention.
Thinking about wire and how different materials, like steel etc, affect the sound. Different materials used inside the tube probably do the same thing.
Hi Frank,
I just read what you read. You know how some tubes have that "wet, not clear sound. Wonder if it has partially to do with the vacuum. Others have posted theories at other chats, but nothing specific to mention.
Thinking about wire and how different materials, like steel etc, affect the sound. Different materials used inside the tube probably do the same thing.
Hi,
Sure...I don't need any convincing in that department...
I'm just a little surprised no one mentioned the quality (composition and thickness) of the glass used for the bulb yet.
Or maybe they did?
The vacuum should affect the operation of the tube, sure...It just happens I never linked it to soundquality as it's usually an unknown factor.
Doing a simple gass test on the meter won't cut it I presume...
I mentioned this in another thread before but if you missed it; Philips did do some tests showing that too high a vacuum considerably shortens tubelife as the cathode literally gets bombarded with electrons till it's finally shot to pieces...
Ah, Starwars in a Bottle...
Cheers,
Sure...I don't need any convincing in that department...
I'm just a little surprised no one mentioned the quality (composition and thickness) of the glass used for the bulb yet.
Or maybe they did?
The vacuum should affect the operation of the tube, sure...It just happens I never linked it to soundquality as it's usually an unknown factor.
Doing a simple gass test on the meter won't cut it I presume...
I mentioned this in another thread before but if you missed it; Philips did do some tests showing that too high a vacuum considerably shortens tubelife as the cathode literally gets bombarded with electrons till it's finally shot to pieces...
Ah, Starwars in a Bottle...
Cheers,
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