kevinkr said:
Unfortunately, the list is too long. EI is out of business. There's talk of private ownership, ala Teslovak/JJ, but for now, it's just talk.
The tubes EI made before NATO got involved, were pretty darn good. The ECC83 and KT90 being prime examples. Post NATO military action, EI's QC fell off badly.
Penta Labs claims to make tubes. From their web site "Penta Laboratories is a Manufacturer and Distributor of vacuum tubes".
Several years ago I bought some Penta branded EL34's that were "made in the USA" and so labeled. Every one of them sparked out within a few months. One took out a few parts on the way. I have not used Penta since then. They currently show 3 versions of 833 type tubes including two graphite plate monsters with uprated plate dissipation ratings. One user that I talked to liked the 833C tubes, but he said that they were Chinese.
I used 6550WA's in guitar amps that would blow up the original Shuguang KT88's (a highly unreliable tube) without issue. I had always resisted the whole "boutique tube" thing building mostly push pull amps using 6L6GC's and EL34's (mostly guitar amps). I had heard a few "high end" tube amps, and decided that I would build one. I read an article by Kevin outlining the construction of a push pull 300B amp. I modified the design to use components that I had on hand, and bought 4 Sovtek 300B tubes from a local tube dealer. The amp was awesome, but one by one (right after the 90 day warantee expired) half of the filament went open in 3 tubes (the same half in all tubes). New Sensor would not help, and insisted that I should spend more money to buy their EH 300B, it had an improved filament. I tossed the amp into the closet, and started robbing it for parts.
About a year later I saw another tube dealer (the same guy who sold me the $10 tubes) at a hamfest. He had a box of 5 used Sovtek 300B tubes for $100, and he guaranteed that they would work. I put them in the amp, replaced the stolen choke, and it worked great. That was 4 years ago, and that amp still plays great with the same Sovtek tubes in it.
I have been listening to the TubelabSE with NX-483's (1.5 WPC) in it for most of today (it has rained all day). One of my neighbors is having one of his drunken Karaoke parties, and I can't hear my amp, so I am hooking up the 300Beast to my big speakers 25 WPC through 96db speakers should drown them out.
Clearly the problem with the Sovtek 300B's was batch related since 3 out of 6 of the original tubes died and all 5 of the (older) used tubes still work. If New Sensor helped, or would even admit that they had a problem, I might not have gotten so mad.
I have received email stating that some Sovtek rectifier tubes are prone to blowing up especially the 5Y3. I have Sovtek 5AR4's in my 845SE amp. There have been no problems and the Sovteks give the highest voltage of the rectifier tubes that I have tried.
I got about 30 tubes in the $10 each deal, all Mike Mathews brands. I have put all but the EL34's (I will get to those) through some strenuous (in excess of the ratings) testing, without any issues.
tubelab.com said:
A few years ago when I was working on an 833 project, I spoke to Penta engineers in California. They told me that the graphite 833 series was designed in the USA, and that manufacturing processes were split between the USA and Chinese factories. I don't know if that applies today. I was interested in very high voltage ratings for direct ESL drivers. One Penta engineer offered to make some slight mods to the internal structure to reduce the risk of arcing for me if I wanted to buy a lot. We discussed what elements would have to be changed and in what way, without affecting the basic tube characteristics. I did not buy a lot, but I thought it was interesting that they had that capability in California and were open to mods
Mike Mathews now owns the Svetlana name in the USA. He is free to put that name on whatever tubes he imports and the Svetlana's that are sold here now are relabled Sovteks. Another distributor is selling "SED" tubes as "Winged C" tubes in the USA. I suspect that this confusion has led to some cross lableing.
I have used Svetlana (pre Mike Mathews) tubes for years with good results. In fact when I swore off Sovtek, I used Svetlana tubes almost exclusively.
Recently I purchased a bunch of different brands of EL34's from a major US tube and component supplier. I tested and evaluated them for use in an upcomming amplifier project. I got 4 "Winged C" tubes, one was sick out of the box (several screen grid wires glowed at 300 volts) and one has since developed a runaway condition. None of these tubes were subjected to my stress testing, because they misbehaved at 300 to 350 volts. I don't know where or who actually made these tubes, but I don't want to buy any more of them.
Below is a picture of two tubes. On the left is a Penta Labs 6CA7 (I thought they were EL34's until I dug one out of a box) It is labeled "The Penta Laboratories Inc Santa Barbara, California MADE IN USA". I bought about 10 of these several years ago, all blew up! On a different note this is a 6CA7 and it is a true pentode, not a beam tetrode. That has been debated here several times, but the only beam tetrode 6CA7's that I have ever seen came from Mr. Mathews! (EH 6CA7)
On the right is an "Orion" EL34. It is "Made in Russia" I have seen the same "stuff" with several brands on them including "Star" I bought a bunch from a prominent Ebay seller in Hong Kong. The 6L6GC's (6n3C) work good, but the EL34's were so poorly assembled that I never tried them in anything that would tax their abilities. It is not obvious in a reduced resolution photo (to fit the file size limits) but the grid support rods are all bent, in different directions. The G3 rod has an "S" shape to it with several mm of curvature. All 3 grid rods and the cathode can be seen through the holes in the plate. They should all be in the same plane and G3 should be the only one visible. Would you want to crank 500 volts through one of these? I may try it just to see what happens.
I have used Svetlana (pre Mike Mathews) tubes for years with good results. In fact when I swore off Sovtek, I used Svetlana tubes almost exclusively.
Recently I purchased a bunch of different brands of EL34's from a major US tube and component supplier. I tested and evaluated them for use in an upcomming amplifier project. I got 4 "Winged C" tubes, one was sick out of the box (several screen grid wires glowed at 300 volts) and one has since developed a runaway condition. None of these tubes were subjected to my stress testing, because they misbehaved at 300 to 350 volts. I don't know where or who actually made these tubes, but I don't want to buy any more of them.
Below is a picture of two tubes. On the left is a Penta Labs 6CA7 (I thought they were EL34's until I dug one out of a box) It is labeled "The Penta Laboratories Inc Santa Barbara, California MADE IN USA". I bought about 10 of these several years ago, all blew up! On a different note this is a 6CA7 and it is a true pentode, not a beam tetrode. That has been debated here several times, but the only beam tetrode 6CA7's that I have ever seen came from Mr. Mathews! (EH 6CA7)
On the right is an "Orion" EL34. It is "Made in Russia" I have seen the same "stuff" with several brands on them including "Star" I bought a bunch from a prominent Ebay seller in Hong Kong. The 6L6GC's (6n3C) work good, but the EL34's were so poorly assembled that I never tried them in anything that would tax their abilities. It is not obvious in a reduced resolution photo (to fit the file size limits) but the grid support rods are all bent, in different directions. The G3 rod has an "S" shape to it with several mm of curvature. All 3 grid rods and the cathode can be seen through the holes in the plate. They should all be in the same plane and G3 should be the only one visible. Would you want to crank 500 volts through one of these? I may try it just to see what happens.
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I have always regarded Penta Labs to be nothing more than a glorified relabeler despite their claims otherwise.. Perhaps that is a bit narrow minded. 
My experience with their tubes has been disappointing.
Any Penta tubes I purchased in recent years were clearly of Chinese origin.
I was not aware that EI had totally ceased production.
My experience with their tubes has been disappointing.Any Penta tubes I purchased in recent years were clearly of Chinese origin.
I was not aware that EI had totally ceased production.
I found this on Pentas web site. I guess that this means that they either have "their own" plant in Shuguang, or they ues the same one that makes the Sino and Valve Art tubes.
"Penta / Shuguang is our brand of Vacuum Tubes Manufactured at our plant in Shuguang, China"
The 6CA7's that I got are at least 10 years old (I have had them that long) and they were surplus when I got them.
The ones that I got are "Winged C" branded tubes, not Svetlana. If you buy Svetlana branded tubes in the USA (I don't know about Canada) you can't be sure what you are getting. The old ones were made in the "Svetlana" factory in St. Petersburg, the new ones are made by Mr. Mathews in the Expo-Pul factory. The ones that I got look like the old Svetlana tubes, but have uncharacteristic reliability. I got them last August. It could have been from a bad batch.
This sounds like a challenge. I still have about 50 of the original Shuguang KT88's (Chinese fireworks!), 2 of the Penta EL34's, The Winged C EL34's, the Orion EL34's and a few other untrustworthy tubes. I also would like to find the limits of a few other tubes that I have lots of.
I don't mind blowing up some tubes, but I don't want to fry any OPT's or other expensive things. I thought about this for a minute, and I think I can rig up a method to "find the maximum power output available from a given tube" without damaging anything expensive. I have a Fluke 407D power supply, 0 to 555 volts, 250 or 300 mA no problem. I also have a monster 3KV rated power supply choke and a 7.5 KV rated cap. I could do a parafeed arangement to keep and DC out of the OPT when a tube arcs. I have the week off of work between Christmas and New Years, so some experiments are in order. My camera takes DVD quality movies but the files are huge.
Hi tubelab,
Imagine a CJ Premier 1 full of Penta Labs KT-88's. One came in like that. I watched several arc when I turned it on. It was satisfying, but I didn't like the fact that the customer had been ripped of. The >$10 fuses weren't very funny.
I even saw a Penta 12AX7A take out some resistors years ago. It was assembled every which way. The elements were all crooked.
Anyway, I was only half kidding. I figured a segment of "the moment" might be fun watching.
Just as a note, I found that Mikes 6CA7EH's sound great in my HF-87. Much better than EL-34's. I don't dabble in expensive tubes but his common stuff is very good as far as I'm concerned. I would really hate to see his factory go.
-Chris
Imagine a CJ Premier 1 full of Penta Labs KT-88's. One came in like that. I watched several arc when I turned it on. It was satisfying, but I didn't like the fact that the customer had been ripped of. The >$10 fuses weren't very funny.
I even saw a Penta 12AX7A take out some resistors years ago. It was assembled every which way. The elements were all crooked.
Anyway, I was only half kidding. I figured a segment of "the moment" might be fun watching.
Just as a note, I found that Mikes 6CA7EH's sound great in my HF-87. Much better than EL-34's. I don't dabble in expensive tubes but his common stuff is very good as far as I'm concerned. I would really hate to see his factory go.
-Chris
Is there any way to identify what I've gotten then? The boxes to say "Made in Russia", and the tubes are stamped with purlple 'OTK 2' and with a blue umbrella image, and the light silvery Svetlana symbol with "Svetlana Electron Devices EL34 Made in Russia 0209". On the plates there's what looks like a pencil scribbling, different on each tube.
i DO feel for Mr. Matthews, and I hope that it goes well for him, but really the only tubes from his empire that I would miss are the 12ax7-LPS and the EF86-EH... and maybe the Sovtek 6922. Everything else that I have tried has either ended up in smoke or bad sound. Some of the 6L6/5881 family are decent, but they vary in quality from batch to batch ao much that I can't trust them.
Hint.....as I tend to play loud with a tube amp on top of a bass bin, ask your tube vendor to tap(rap)-test tubes on tester before you get'em. Hopefully that will weed out the duff ones.
My bass amp (250W) currently uses KT88 C winged version Svetlanas and they have settled well in for a year without problems and the quiescent readings have stabilised at 65mA (500V). I've never had any problems with these and they have survived the shaki'n about. These are really HiFi tubes and sound a touch softer than others. The point is thev'e lasted.
richj
My bass amp (250W) currently uses KT88 C winged version Svetlanas and they have settled well in for a year without problems and the quiescent readings have stabilised at 65mA (500V). I've never had any problems with these and they have survived the shaki'n about. These are really HiFi tubes and sound a touch softer than others. The point is thev'e lasted.
richj
This thread just shows even the "unpredictable" can work ok. Take your pick ? The operating conditions, warm up all have a say in the life of a tube, esp heater volts.
Brousing over a slice of 10 year repair sheets , not a single 6550 WA/B/C series has internally failed in either MI or HiFi service.
richj
Brousing over a slice of 10 year repair sheets , not a single 6550 WA/B/C series has internally failed in either MI or HiFi service.
richj
I have not heard much about this issue of Mathews losing control of his factory in Russia as of late. But the prices of the tubes he sells have sure gone UP! I wonder if this is strictly a function of exchange rates or is production getting more difficult?
I've never been a huge Sovtek fan soundwise but their stuff was always reliable. I have been using some of the EH stuff recently and it's been quite good. I did not like their 12AX7's in a guitar amp but their 6V6's seem to sound good. I've also used their 6550's and EL34's in a few amps I've repaired with good results. I have their 300B Golds in my hifi amp and it sounds nice but I must admit that since 300b's of any type are rather expensive they are the only tubes I've used in that amp.
In the guitar amps that we use in my band for EL34's I use the JJ E34L's, KT66's I've used the Groove Tubes KT66HP Saratov tube. Now I've switched to using the Valve Art Chinese KT66's with great results in Marshall amps.
I just was wondering if anyone had heard any recent news about this subject.
I've never been a huge Sovtek fan soundwise but their stuff was always reliable. I have been using some of the EH stuff recently and it's been quite good. I did not like their 12AX7's in a guitar amp but their 6V6's seem to sound good. I've also used their 6550's and EL34's in a few amps I've repaired with good results. I have their 300B Golds in my hifi amp and it sounds nice but I must admit that since 300b's of any type are rather expensive they are the only tubes I've used in that amp.
In the guitar amps that we use in my band for EL34's I use the JJ E34L's, KT66's I've used the Groove Tubes KT66HP Saratov tube. Now I've switched to using the Valve Art Chinese KT66's with great results in Marshall amps.
I just was wondering if anyone had heard any recent news about this subject.
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