The tubes from H that I was testing earlier were from a batch of 100 of the $1 tubes.
These are mostly RCA, Sylvania, GE, but a smattering of just about everthing else. Like Triad, ITT, Raytheon, Zenith, IEC Mullard, Westinghouse, Lafayette LRE, Lindal, Dumont. Then a few made in Japan models under the those brands.
Here is the 6922 (E88CC) datasheet with curves, top of page 9 to compare with the tube from H with the same scales, or the "perfect triode" curves. The "perfect triode" tube only has a Mu of 10 in triode and is actually a dual DHP 1.5 Watt pentode, common cathode. The tube from H is a 10 Watt single pentode, Mu of 30 in triode. I would say the 6922 could retire as far as linearity goes. Just 2nd harmonic though.
http://frank.pocnet.net/sheets/009/e/E88CC.pdf
These are mostly RCA, Sylvania, GE, but a smattering of just about everthing else. Like Triad, ITT, Raytheon, Zenith, IEC Mullard, Westinghouse, Lafayette LRE, Lindal, Dumont. Then a few made in Japan models under the those brands.
Here is the 6922 (E88CC) datasheet with curves, top of page 9 to compare with the tube from H with the same scales, or the "perfect triode" curves. The "perfect triode" tube only has a Mu of 10 in triode and is actually a dual DHP 1.5 Watt pentode, common cathode. The tube from H is a 10 Watt single pentode, Mu of 30 in triode. I would say the 6922 could retire as far as linearity goes. Just 2nd harmonic though.
http://frank.pocnet.net/sheets/009/e/E88CC.pdf
So from the batch of 100 you got they were a mix. I guess if I get 20 of them I can just ask if they can send one brand or divide them into two brands, maybe that's common sense and they will do that anyway but it can't hurt to ask.
Does the 10M45S have any issues with no delay in B+ when tubes are cold? I plan on using a 5U4GB with a Hammond 373BX.
Does the 10M45S have any issues with no delay in B+ when tubes are cold? I plan on using a 5U4GB with a Hammond 373BX.
Stan at ESRC said no problem, send the questionable RCAs back for replacement with another brand.
I traced the curves for an RCA TFH with the 11HM7 like guts, so attached are triode and pentode curves for that. 10 mA/div Vert and 50V/div Horia., 0.5 V g1 steps.
Then I went looking for a real 11HM7 here, and darn'd if I couldn't find the ones I had seen before that look just like the odd RCA versions. I did find a GE 11HM7 which doesn't look like the previous 11HM7s, and instead looks like the TFH versions made in Japan! Curves attached for that one too. Took 165V on g2 for the real 11HM7 in pentode to match the pentode curves of the RCA TFH "11HM7" variant with 120 V on g2. Not the same tube obviously.
Finally, attached is the original Raytheon gray plate TFH triode curves for comparison. As it turns out from testing a bunch of the TFH, the Raytheon gray plate triode version is unusually nice. But the other TFH are not far behind. Better than the RCA TFH "11HM7" triode curves (or real 11HM7 in triode) for sure. Even those are fairly decent compared to most triodes around.
The one issue about the RCA TFH "11HM7" look alikes is that they have half the plate size of the normal TFH, and red plate at 10 Watts diss. So I'm going to return them still for "real" TFH tubes.
Man, once you have a curve tracer, you will never believe stories like "black plate this or that sounds better than grey plate that", or whatever. Only when I see the actual tube curves will I believe an individual tube is good. There ain't no such thing as consistency concerning most tubes.
I traced the curves for an RCA TFH with the 11HM7 like guts, so attached are triode and pentode curves for that. 10 mA/div Vert and 50V/div Horia., 0.5 V g1 steps.
Then I went looking for a real 11HM7 here, and darn'd if I couldn't find the ones I had seen before that look just like the odd RCA versions. I did find a GE 11HM7 which doesn't look like the previous 11HM7s, and instead looks like the TFH versions made in Japan! Curves attached for that one too. Took 165V on g2 for the real 11HM7 in pentode to match the pentode curves of the RCA TFH "11HM7" variant with 120 V on g2. Not the same tube obviously.
Finally, attached is the original Raytheon gray plate TFH triode curves for comparison. As it turns out from testing a bunch of the TFH, the Raytheon gray plate triode version is unusually nice. But the other TFH are not far behind. Better than the RCA TFH "11HM7" triode curves (or real 11HM7 in triode) for sure. Even those are fairly decent compared to most triodes around.
The one issue about the RCA TFH "11HM7" look alikes is that they have half the plate size of the normal TFH, and red plate at 10 Watts diss. So I'm going to return them still for "real" TFH tubes.
Man, once you have a curve tracer, you will never believe stories like "black plate this or that sounds better than grey plate that", or whatever. Only when I see the actual tube curves will I believe an individual tube is good. There ain't no such thing as consistency concerning most tubes.
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Hi all,
It's been a while since I last posted here. Parenthood has taken all my time. Anyway, this thread is very interesting and is great you're uncovering some gems out there.
This motivated me to do a quick trace of the 6GE5 and created a Spice model.
Would be great if someone can test them as I ran out of time. They seem to fit well to the sample I have which measures 113% despite the saturation at high currents.
6GE5 Pentode Model | Bartola Valves
Cheers
Ale
It's been a while since I last posted here. Parenthood has taken all my time. Anyway, this thread is very interesting and is great you're uncovering some gems out there.
This motivated me to do a quick trace of the 6GE5 and created a Spice model.
Would be great if someone can test them as I ran out of time. They seem to fit well to the sample I have which measures 113% despite the saturation at high currents.
6GE5 Pentode Model | Bartola Valves
Cheers
Ale
While uTracer's curves look ok, Ip is way too low when the pentode model is used. Vg2=150V, Eg1 from 0 to -40V.
An externally hosted image should be here but it was not working when we last tested it.
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I'm sad looking at all these wonderful compactrons (6GY5 is the prettiest; fat bottle AND a top cap!). Shipping to Finland is expensive, and if your order is over 23€ in value, you have to pay 24% ransom to the customs to get it.
Russian are cheap and I can get them inside the European economic area customs free. There's not much info though.
I guess the soviet union didn't have too much TV production? The 6P36S seems to be a real performer though. I'm going to buy 10 of those soon.
Russian are cheap and I can get them inside the European economic area customs free. There's not much info though.
I guess the soviet union didn't have too much TV production? The 6P36S seems to be a real performer though. I'm going to buy 10 of those soon.
Those triode curves for that 6P36S do look quite nice. No wonder it is in demand for DIY in Eastern Europe.
Ebayers seem to be equating them to EL500/6GB5, but the datasheets don't look the same at all. Does the 6P36S use 2 Amps or 1.38 Amps of heater current?
http://frank.pocnet.net/sheets/113/6/6P36S.pdf
http://frank.pocnet.net/sheets/030/e/EL500.pdf
http://frank.pocnet.net/sheets/049/6/6GB5.pdf
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I just heard from Stan at ESRC that the full size RCA branded (but made by Sylvania) TFH are cleaned out with someone's recent order of 200. (and the other TFH brands are already cleaned out too unfortunately) There might be some of the smaller size RCA versions available from returns. Apparently the smaller versions were actually made by RCA, and the bigger RCAs are rebranded Sylvania. The smaller (actual) RCA do have decent triode curves, they just measure more like the 7 Watt diss. of an 11HM7 (they actually look exactly like the 5 Watt pentode in a 6LQ8, but don't measure the same). So they could still be useful for driver tubes.
I had hoped there would be a huge # of the TFH available. Probably no need for concern then with some Hong Kong buyer cleaning out 10's of 1000s, like what happened with the 6HB6.
Ebayers seem to be equating them to EL500/6GB5, but the datasheets don't look the same at all. Does the 6P36S use 2 Amps or 1.38 Amps of heater current?
http://frank.pocnet.net/sheets/113/6/6P36S.pdf
http://frank.pocnet.net/sheets/030/e/EL500.pdf
http://frank.pocnet.net/sheets/049/6/6GB5.pdf
------------------------------
I just heard from Stan at ESRC that the full size RCA branded (but made by Sylvania) TFH are cleaned out with someone's recent order of 200. (and the other TFH brands are already cleaned out too unfortunately) There might be some of the smaller size RCA versions available from returns. Apparently the smaller versions were actually made by RCA, and the bigger RCAs are rebranded Sylvania. The smaller (actual) RCA do have decent triode curves, they just measure more like the 7 Watt diss. of an 11HM7 (they actually look exactly like the 5 Watt pentode in a 6LQ8, but don't measure the same). So they could still be useful for driver tubes.
I had hoped there would be a huge # of the TFH available. Probably no need for concern then with some Hong Kong buyer cleaning out 10's of 1000s, like what happened with the 6HB6.
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I started looking at Russian tubes as an alternative to the US sourced sweep tubes. Of course I could just get one of you to post me a box full for a suitable recompense but where's the adventure in that. In my travels I was linked to
Tube List (English)
The 6P44s seem worth a closer look as well, at 25W plate diss . 44S are a couple of quid each so same order as the 36s.
Tube List (English)
The 6P44s seem worth a closer look as well, at 25W plate diss . 44S are a couple of quid each so same order as the 36s.
Hell Busted Wide Open
One of the TFH had a crack in the glass, so an autopsy was in order.
Left side is the TFH, right side is a 6HB6 for comparison. The wires you see are the g2 wires. The g1 wires are too small to see, but there are 4 g1 wires per g2 wire for TFH, and 5 g1 wires per g2 wire for the 6HB6.
Some measurements:
TFH: cathode 4 x 15 mm active area, 32 g2 wires, 4x32 g1 wires
6HB6: cathode 3 x 25 mm active area, 29 g2 wires, 5x29 g1 wires
The datasheets for these do not give DCmax current or Ipeak
So using the 6BQ5 and 6GK6 as reference, which have the same size cathode as the 6HB6 rated 65 mA DC max and tyically 3.5x that for Ipeak at 225 mA
Then for TFH, using the cathode area ratio 60/75 gives 52 mA DCmax and Ipeak at 180 mA (the heater current ratio is also similarly 0.6/0.76 )
One of the TFH had a crack in the glass, so an autopsy was in order.
Left side is the TFH, right side is a 6HB6 for comparison. The wires you see are the g2 wires. The g1 wires are too small to see, but there are 4 g1 wires per g2 wire for TFH, and 5 g1 wires per g2 wire for the 6HB6.
Some measurements:
TFH: cathode 4 x 15 mm active area, 32 g2 wires, 4x32 g1 wires
6HB6: cathode 3 x 25 mm active area, 29 g2 wires, 5x29 g1 wires
The datasheets for these do not give DCmax current or Ipeak
So using the 6BQ5 and 6GK6 as reference, which have the same size cathode as the 6HB6 rated 65 mA DC max and tyically 3.5x that for Ipeak at 225 mA
Then for TFH, using the cathode area ratio 60/75 gives 52 mA DCmax and Ipeak at 180 mA (the heater current ratio is also similarly 0.6/0.76 )
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There was some speculation in the 6HB6 thread as to why there was so much difference between two versions of the same tube. I have several hundred 6HB6's, obtained from Radio Electronic Supply several years ago when they were 35 cents each.
At a casual glance they appeared to be of mostly two versions. The plates in the two versions look exactly like the plates in vintage 6BQ5's from RCA or Sylvania, and none that I have seen have the flat plate shown in your picture. Maybe there are 4 or more versions of this tube.
My tubes are stored in 2 or three cartons that haven't been opened in a couple of years. I looked at, tested, and played with only a few samples when I got the tubes. Guess I need to crack open a few more boxes when I get a chance.
Circumstance has pushed aside most tube testing for the last week, and this may continue for a while. My health insurance has expired, and I have spent days on the phone dealing with idiots. It seems that being born in the US, and working here and paying taxes for 45 years, is not proof enough that I an in fact an American. I need to verify my identity. A photocopy of a 62 year old birth certificate isn't good enough.....They want an original. If approved, its $1450 per month! I have resorted to using a 3rd party advocate to deal with this BS.
At a casual glance they appeared to be of mostly two versions. The plates in the two versions look exactly like the plates in vintage 6BQ5's from RCA or Sylvania, and none that I have seen have the flat plate shown in your picture. Maybe there are 4 or more versions of this tube.
My tubes are stored in 2 or three cartons that haven't been opened in a couple of years. I looked at, tested, and played with only a few samples when I got the tubes. Guess I need to crack open a few more boxes when I get a chance.
Circumstance has pushed aside most tube testing for the last week, and this may continue for a while. My health insurance has expired, and I have spent days on the phone dealing with idiots. It seems that being born in the US, and working here and paying taxes for 45 years, is not proof enough that I an in fact an American. I need to verify my identity. A photocopy of a 62 year old birth certificate isn't good enough.....They want an original. If approved, its $1450 per month! I have resorted to using a 3rd party advocate to deal with this BS.
Here are some pics of the 2 types of 6HB6 I have seen. Most of the ones I have are the right side (GE) type. The guts pictures are from that type. I only have a few of the left type, so I haven't "modded" one yet.
I myself skipped health insurance until medicare took over. Keep the money in the bank for your own insurance, I say. You would face another mountain of paperwork and frustration trying to get it back from an insurer anyway. Paying for health insurance these days, will just give you a heart attack. Get a kayak, bicycle and hiking shoes for exercise. You'll outlive the doctors.
I myself skipped health insurance until medicare took over. Keep the money in the bank for your own insurance, I say. You would face another mountain of paperwork and frustration trying to get it back from an insurer anyway. Paying for health insurance these days, will just give you a heart attack. Get a kayak, bicycle and hiking shoes for exercise. You'll outlive the doctors.
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Based on a small sample, most of my tubes are like the ones on the left, GE made. Some are Sylvania which have a different plate structure.
I'm in great physical shape for a person my age, run a few miles and hit the gym 4 or 5 times each week, but none of that will undo the skin damage that 61 years in the Florida sun did. I have had several recurring skin cancers over the last 20 years, one of which required 6 surgeries to finally get it all at a total cost of nearly $60K. The severity and frequency of these has been on the decline, but last year a minor wound from a collision between my leg and a trailer hitch turned cancerous and grew quickly into a lump the size of a large grape. A single surgery removed it without issue, but left the reminder that I probably need to pay the extortion until I can get Medicare, a little over 2 years.
Oh man. Sorry to hear that. I guess you are up against the wall there for insurance. I try to pay attention to medical news for some potential medical conditions of my own. Seems like every thing that might potentially help also has a dark side as well though. For example, some components of butter have recently been found to be protective of diabetes, but at the same time, the fat content is one of the major suspects of causing it.
Someone recently mentioned niacinamide to me with respect to skin cancer (kayakers spend a lot of time in the sun), but it has some questionable attributes too.
https://en.wikipedia.org/wiki/Nicotinamide
Then there's the old quip about all medicines are just dilute poisons. If there were an easy fix for anything, the body would already have it. The most annoying research I've seen lately though, found that the body shuts down a very important cell repair mechanism around age 20. We just coast down hill after that. Sure feels like it sometimes. Now that's a "program" that needs hacking into. But what do we get instead, idiots sabotaging our PC's instead, preventing progress.
Someone recently mentioned niacinamide to me with respect to skin cancer (kayakers spend a lot of time in the sun), but it has some questionable attributes too.
https://en.wikipedia.org/wiki/Nicotinamide
Then there's the old quip about all medicines are just dilute poisons. If there were an easy fix for anything, the body would already have it. The most annoying research I've seen lately though, found that the body shuts down a very important cell repair mechanism around age 20. We just coast down hill after that. Sure feels like it sometimes. Now that's a "program" that needs hacking into. But what do we get instead, idiots sabotaging our PC's instead, preventing progress.
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