Hi,
Please remember that the spec of this tube giving a peak current of 1.5A still doesn't guarantee in any way that this is valid for continous conditions, (oxide coated cathodes can sustain much higher currents during peak conditions with short pulses then for steady state).
Of course some people designs amplifiers and hope that it is possible to pull 1.5A trough one tube continously but there is no support for that in the manufacturers specifications.
For me this is not a professional way of design.
There is no guarantee whatsoever that it will be possible to source tubes in future that can sustain 1.5A continously even thougbh that there could be some tubes availlable today which support continous current requirements, therefore some of currently available designs using this tubes is quiestionable indeed.
Regards Hans
Please remember that the spec of this tube giving a peak current of 1.5A still doesn't guarantee in any way that this is valid for continous conditions, (oxide coated cathodes can sustain much higher currents during peak conditions with short pulses then for steady state).
Of course some people designs amplifiers and hope that it is possible to pull 1.5A trough one tube continously but there is no support for that in the manufacturers specifications.
For me this is not a professional way of design.
There is no guarantee whatsoever that it will be possible to source tubes in future that can sustain 1.5A continously even thougbh that there could be some tubes availlable today which support continous current requirements, therefore some of currently available designs using this tubes is quiestionable indeed.
Regards Hans
Peak vs. continuous
I think that Hans is mixing his nomenclature here.
I'm far from being an expert in tube specifications, but it seems to me that the specs for both the original EL509 (Amperex, Philips, RCA) and the more recent Ei EL519 refer to "maximum cathode current" as being the amount that the tube can pass over serveral seconds or longer, i.e., in a "continuous" mode, before (as George Kaye says) the tube "goes cherry." (Love that expression!).
"Peak" current is what you would get in an instantaneous, pulsed mode, with a duration of much less than a second. I agree that one should not design a circuit with pulsed or peak current in mind, as this is not a real-world spec.
It's something like the way consumer amplifiers are now almost universally rated in RMS, or continuous power, after the U.S. Federal Trade Commission began clamping down in the '60s and demanded more realistic ratings from manufacturers. Prioir to that, manufacturers could claim that any given power amp, originally designed for a few watts ouptput, was really a "200W amp", because they were able to gooch it that high for a few milliseconds!
Am I right here, guys, or not?
I think that Hans is mixing his nomenclature here.
I'm far from being an expert in tube specifications, but it seems to me that the specs for both the original EL509 (Amperex, Philips, RCA) and the more recent Ei EL519 refer to "maximum cathode current" as being the amount that the tube can pass over serveral seconds or longer, i.e., in a "continuous" mode, before (as George Kaye says) the tube "goes cherry." (Love that expression!).
"Peak" current is what you would get in an instantaneous, pulsed mode, with a duration of much less than a second. I agree that one should not design a circuit with pulsed or peak current in mind, as this is not a real-world spec.
It's something like the way consumer amplifiers are now almost universally rated in RMS, or continuous power, after the U.S. Federal Trade Commission began clamping down in the '60s and demanded more realistic ratings from manufacturers. Prioir to that, manufacturers could claim that any given power amp, originally designed for a few watts ouptput, was really a "200W amp", because they were able to gooch it that high for a few milliseconds!
Am I right here, guys, or not?
Ei Octal 519
Im in discussions with Edicron about supplies of standard Ei PL519 valves, When I next speak to them, Ill tell them, that an Octal version following the Svet. pinout would sell like nothing else--Who knows, it shouldnt take much for Ei to put a 519 in an Octal bottle!
Anythings possible--They even have stocks of Nuvistors!
Im in discussions with Edicron about supplies of standard Ei PL519 valves, When I next speak to them, Ill tell them, that an Octal version following the Svet. pinout would sell like nothing else--Who knows, it shouldnt take much for Ei to put a 519 in an Octal bottle!
Anythings possible--They even have stocks of Nuvistors!
I have proposed this exact scenario to the folks at Tubebuilder, that is, an Ei EL519 in an octal package with EL509II pinouts. Don't know if they can persuade the manufacturer though.
Given that the MK IIs are sold out worldwide (as best I can tell) and are in high demand, this seems like an easy win for them.
I'd buy sixteen of them tomorrow.
But, of course, these guys have to make sizeable production runs to make profits and I don't know what their financial calculations are. But, I bet they could make money fairly quickly.
Also, I agree with Chris. Getting 1A from a tube under short pulse duration is simply depleting the space charge cloud around the cathode and does not reflect the tube's ability to deliver the peak cathode currents needed to get power from OTLs. So, if Svet's curves come from a typical curve tracer, then Svet's will not make in OTLs.
If there is anyone from Ei on this forum, I'll buy octal EL509s or EL519s with the MK II pinouts from you right now. I need two matched octets (16 tubes). Tell me who to make the check out to
Given that the MK IIs are sold out worldwide (as best I can tell) and are in high demand, this seems like an easy win for them.
I'd buy sixteen of them tomorrow.
But, of course, these guys have to make sizeable production runs to make profits and I don't know what their financial calculations are. But, I bet they could make money fairly quickly.
Also, I agree with Chris. Getting 1A from a tube under short pulse duration is simply depleting the space charge cloud around the cathode and does not reflect the tube's ability to deliver the peak cathode currents needed to get power from OTLs. So, if Svet's curves come from a typical curve tracer, then Svet's will not make in OTLs.
If there is anyone from Ei on this forum, I'll buy octal EL509s or EL519s with the MK II pinouts from you right now. I need two matched octets (16 tubes). Tell me who to make the check out to
I dont think I mixing up any things but please prove me wrong if I am
According to the datasheets I have seen for PL509 and PL519 the max continous cathode current is given as 500 mA and peak cathode current as 1500mA, note that this is peak not continous current, see for instance Philips databook for "Receiving tubes" from March 1975
Oxide coated cathodes have the ability to sustain higher currents during peak conditions then during contionous conditions, this has not anything to do with depleting the space charge but is a condition valid for oxide coated cathodes but not for bright tungsten emitters and other type of cathodes, therefore it is not clear if the written spec of 1.5A peak is valid also for continous conditions, maybe it is OK maybe not.
For me the heater power of ~ 12W seems a bit low for 1.5A continous cathode current
Even if every EL/PL509/519 tube used so far have been able to sustain 1.5A continously there are still no guarantee that it will be so for new production, for me this is exactly what seems to be happening here, the newly produced tubes can sustain 1.5A peak but not continously and they will still fulfill the original spec.
The same problem exist when using any other tube for OTLs also , 6C33C is only specified for 550mA continous current and no spec seems to exist for short term or peak conditions but that tube at least have the heater power to make it credible that it can sustain high short term or peak currents.
In conclusion when building OTLs it will always be somewhat of a gamble if it will give the same performance when changing to a new set of tubes as the tubes are always used outside their max specified ratings, most of the time it seems that it is possible to get away with this but there is no guarantee that it will continue that way.
Regards Hans
Yes, you're correct. But the problem that seems to be confusing everyone (at least me) is as follows.
When the curves are traced and shown in the data books, how is that being done? I'm assuming a curve tracer of some kind with perhaps some manual tweaks.
If this is so, then the tube can put continous current at the bias conditions shown on the curves.
It may be true that the cathode cannot sustain the higher currents and will sag after a time or the plates will melt.
And, of course, the maximum sustainable Ik would be something like 500mA.
So here is my dilemma.
The Philips (and other) EL509 curves clearly show Ik of over 1A at Vs and Vp between 150V and 200V and Vg=0.
But, the Svetlana plate curves show only about 500-600mA for approximately the same bias conditions.
Now, what does this mean? How were these curves taken?
My take on this is that the Svet curves are accurate for what they are selling (which are not el509s) and that the curves say that they can't deliver peak currents over 1A. Because if the curves are taken with a tracer and the tubes could deliver the current, this would be reflected in the plate curves.
But, I would very much like to be proven wrong.
CB, they can have my first born child, just so I don't have to rip up and resocket and rewire my newly built OTLs.
When the curves are traced and shown in the data books, how is that being done? I'm assuming a curve tracer of some kind with perhaps some manual tweaks.
If this is so, then the tube can put continous current at the bias conditions shown on the curves.
It may be true that the cathode cannot sustain the higher currents and will sag after a time or the plates will melt.
And, of course, the maximum sustainable Ik would be something like 500mA.
So here is my dilemma.
The Philips (and other) EL509 curves clearly show Ik of over 1A at Vs and Vp between 150V and 200V and Vg=0.
But, the Svetlana plate curves show only about 500-600mA for approximately the same bias conditions.
Now, what does this mean? How were these curves taken?
My take on this is that the Svet curves are accurate for what they are selling (which are not el509s) and that the curves say that they can't deliver peak currents over 1A. Because if the curves are taken with a tracer and the tubes could deliver the current, this would be reflected in the plate curves.
But, I would very much like to be proven wrong.
CB, they can have my first born child, just so I don't have to rip up and resocket and rewire my newly built OTLs.
Hi,
Come to think of it, we do have Milwood as a member who's in banking, right?
Personnally I feel this kind of product would actually sell itself in record time...
If only I had the cash to spare...deep sigh...
Than there is George Kaye dying for a product like this too...he, he.
Bruce Rozenblit maybe too....??
There you are a couple of thousand sold already and that's just the OTL guys....
Somehow I don't think I could convince the Manley crowd into buying KT99 Supers...Oooops.
Anyhow, just thinking out loud...
Come to think of it, we do have Milwood as a member who's in banking, right?
Personnally I feel this kind of product would actually sell itself in record time...
If only I had the cash to spare...deep sigh...
Than there is George Kaye dying for a product like this too...he, he.
Bruce Rozenblit maybe too....??
There you are a couple of thousand sold already and that's just the OTL guys....
Somehow I don't think I could convince the Manley crowd into buying KT99 Supers...Oooops.
Anyhow, just thinking out loud...
I think it would be a big seller too. So how do we get the attention of the manufacturer to see if they'd be willing to consider it? I've had two OTL monoblocks on complete hold until all of this gets resolved.
The EL509s sold like crazy (so far as I know). These new Ei 509s would be real OTL material and are exactly what I was expecting to get when I built the amps around the Svet MK IIs.
I think they could sell 10,000 of them on a worldwide basis in way less than a year. MHO.
Using me as an example (maybe typical or not), I need 16 of them. To sell 10,000 tubes they only need 625 customers. Given the markets in the US, EU, and Asia, this seems easy to me. But I admittedly do not know their business.
The EL509s sold like crazy (so far as I know). These new Ei 509s would be real OTL material and are exactly what I was expecting to get when I built the amps around the Svet MK IIs.
I think they could sell 10,000 of them on a worldwide basis in way less than a year. MHO.
Using me as an example (maybe typical or not), I need 16 of them. To sell 10,000 tubes they only need 625 customers. Given the markets in the US, EU, and Asia, this seems easy to me. But I admittedly do not know their business.
I dont know if the curves where taken using the same method but if so the Philips EL509 and the Svetlana EL509 is clearly not the same tube, how Svetlana can claim that it is I have difficulty to understand.
It is not so difficult to take the curves using a curve tracer as long as it is setup to limit the time where the current draw is max, the curve would look almost identical if the sweep is done in 10us or 10mS as almost any tube can handle high frequencies quite well and give almost identical performance at 1kHz as for 100kHz or even 1MHz.
BTW in Philips tube data book it says that if a spec for peak current is not given it is safe to assume that max allowed peak current is 3 times the average current for not more then 25ms, so probably all Philips tubes are designed for those conditions.
Regards Hans
Hi,
From prewar experience, the main obstacle has always been bureaucracy and of course the language barrier played a major role as well.
I think I still have copies of correspondence with EI, a nightmare believe me.
BTW, here in Europe the EI EL519/509s are nothing new. Granted, during the Yugo war there were shortages.
What's so annoying is that they have all the Philips know how and licenses to make tubes, they have the TFK tooling and what have you.
I recall them making excellent EL34s for Siemens for instance back in the early Nineties.
In short they could make the best 6DJ8s, ECC85s, EF86s and a zillion of other tubes and make a bundle...
On their website they don't even mention the EL509s as they probably just see it as a TV sweep tube.
It just makes me wonder what else they still produce we're just not aware of...
Tesla also made fine EL519s but admittedly I've never seen any myself.
Ah well, enough nostalgia.
Cheers,
From prewar experience, the main obstacle has always been bureaucracy and of course the language barrier played a major role as well.
I think I still have copies of correspondence with EI, a nightmare believe me.
BTW, here in Europe the EI EL519/509s are nothing new. Granted, during the Yugo war there were shortages.
What's so annoying is that they have all the Philips know how and licenses to make tubes, they have the TFK tooling and what have you.
I recall them making excellent EL34s for Siemens for instance back in the early Nineties.
In short they could make the best 6DJ8s, ECC85s, EF86s and a zillion of other tubes and make a bundle...
On their website they don't even mention the EL509s as they probably just see it as a TV sweep tube.
It just makes me wonder what else they still produce we're just not aware of...
Tesla also made fine EL519s but admittedly I've never seen any myself.
Ah well, enough nostalgia.
Cheers,
Hi,
Hans,
This is mostly Svetlana USAs' fault, now defunct anyway.
The EL509 is not the only type they confused the customer with,
Remember?
6N1P = 6DJ8? Not even the datasheet is correct for this one.
Some other dealers: 6N1P = ECC85/6AQ8...Huh???
SV83 = 6BQ5? Well sort of, if you don't mind rewiring the socket etc.
And so on...
Best thing with Russian stuff is to have a copy of the original datasheets that come with the tubes and decypher the cyrillic.
They have great tubes still just sitting on shelves. I've seen some that I absolutely don't have a clue what they were made for but till we know what they are...Who's going to buy them?
Cheers,
Hans,
This is mostly Svetlana USAs' fault, now defunct anyway.
The EL509 is not the only type they confused the customer with,
Remember?
6N1P = 6DJ8? Not even the datasheet is correct for this one.
Some other dealers: 6N1P = ECC85/6AQ8...Huh???
SV83 = 6BQ5? Well sort of, if you don't mind rewiring the socket etc.
And so on...
Best thing with Russian stuff is to have a copy of the original datasheets that come with the tubes and decypher the cyrillic.
They have great tubes still just sitting on shelves. I've seen some that I absolutely don't have a clue what they were made for but till we know what they are...Who's going to buy them?
Cheers,
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