They were not new. They were "previously auditioned". That meant used. The price told me that they were probably returns that were not defective, but not resellable as new. The 6550 - KT88's had no obvious signs of wear. The EL34's had teeth marks on the bases indicating that they had been in a guitar amp, probably a Fender. The Svetlana 6L6's had teeth marks, and discoloration on the brown bases. This happens pretty quick in a Fender guitar amp because the tubes are mounted upside down so the heat cooks the bases.
I have been building amplifiers for resale for a long time, so I am always looking for tube deals. I visit a tube reseller that is about 200 miles away every time that I get within 50 miles of his store. These were part of a "one time deal" that he had purchased. After my initial purchase confirmed that the tubes were not junk, I bought most of the output tubes that were available. Another audiophile (and guitar player) got the rest of them. I have thouroughly tested each tube under "stressful" conditions to find any that would blow up in a guitar amp (worst case voltage stress) or a SE HiFi amp (worst case dissipation). So far I have only found one 6L6 that makes a crackling sound in the speaker when warming up out of 30+ used, Reflector sourced (Sovtek, EH, etc) tubes.
Based on this experience I would have no problem recommending these tubes (at TubeStore prices) in a SE HiFi amp, and I will consider them for guitar amps after I test them at 500+ volts. I have not used any Reflector sourced tubes since I got a bad batch of Sovtek 300B's several years ago and New Sensor said tough s***. The $10 deal is the only reason that I even tried these.
Yes the big toroid was an Antek. This is the 4th Antek that I have purchased. I have one of the 100VA (2 X 200 VAC) transformers with the windings in series feeding a bridge rectifier running an SE amp that uses 6L6GC tubes. This amplifier has been running almost continuously for 3 months. The transformer is running right at (or slightly above) the 100VA spec. It does not buzz, and it gets slightly warm. This is the only one of these transformers that gets used a lot. I have been using one of the 2 X 360 volt transformers for testing purposes (intermittently) and it also works good, but I have never had it near rated load. The 2 X 400 volt guy is even bigger physically, but I haven't powered it up yet.
The quality looks almost as good as the Maryland toroid unit (I have used 2 of these) but they are half the price (same size). My only complaint is the lack of a 5 volt winding. This gives you 3 options, SS rect, Damper tube rectifiers, or a big resistor in series with one of the 6 volt windings. I have used the resistor method with a 5AR4 in some tests, but I may use damper tubes in my next amp since I have a box full of them.
http://www.toroid.com/standard_transformers/rectifier_transformers/rectifier_transformers_tube.htm
Below is a picture of two EH KT88's operating at 45 watts of dissipation. Yes, that sounded like a lot in my earlier posts. It may not be evident in this photo, but there is No glow on the plate or screen grid at this power level. There is a lot of harmless blue glow. This happens in all of the EH 6550's and KT88's. The blue pulsates with the music and puts on quite a show in a darkened room. In fact, I have modified the front panel in my latest amp to include a Lexan window to view the show. It is better than reality TV.
Attachments
Quick update:
I wired the big Antek toroid into a SimpleSE in place of the original Allied power transformer. I wanted maximum voltage (and there is no 5 volt winding) so I selected the solid state rectifier. B+ is 530 volts under 200 mA load and 565 volts unloaded (not healthy on my 500 volt electrolytics). There is 470 volts across the tubes (EH KT88's). With the 560 ohm cathode resistor the current is 90 mA. No smoke, no sparks, no glowing tubes, just loud clean music. A lot of headroom with this much voltage (and a 5K load) but I haven't measured power yet.
I ran the amp for about 1 hour. The transformer made no buzz, and did not even get warm. The tubes remained calm, did not glow or arc, the blue glow danced around the glass in time to the music. I even flipped the triode - UL switch at full power several times , with no ill effects. I will test again at a higher current tomorrow, and "test" the 6L6WXT's.
I wired the big Antek toroid into a SimpleSE in place of the original Allied power transformer. I wanted maximum voltage (and there is no 5 volt winding) so I selected the solid state rectifier. B+ is 530 volts under 200 mA load and 565 volts unloaded (not healthy on my 500 volt electrolytics). There is 470 volts across the tubes (EH KT88's). With the 560 ohm cathode resistor the current is 90 mA. No smoke, no sparks, no glowing tubes, just loud clean music. A lot of headroom with this much voltage (and a 5K load) but I haven't measured power yet.
I ran the amp for about 1 hour. The transformer made no buzz, and did not even get warm. The tubes remained calm, did not glow or arc, the blue glow danced around the glass in time to the music. I even flipped the triode - UL switch at full power several times , with no ill effects. I will test again at a higher current tomorrow, and "test" the 6L6WXT's.
Hey Nixie,
New Sensor's tubes in general seem no better, no worse than most of the competition. (JJ/EI/Shuguang to name a few) I have used hundreds of them over the years and other than the short lived 12AX7WXT which failed rather quickly in use I've had no problems. (sounded great at first, lasted only about 100 hrs) Should ExpoPul go away I think we'll see a pretty big increase in prices across the board.
New Sensor's tubes in general seem no better, no worse than most of the competition. (JJ/EI/Shuguang to name a few) I have used hundreds of them over the years and other than the short lived 12AX7WXT which failed rather quickly in use I've had no problems. (sounded great at first, lasted only about 100 hrs) Should ExpoPul go away I think we'll see a pretty big increase in prices across the board.
We tested it, and when the smoke cleared, we tested it again!
Except that this is a SE amp, 50W+ in SE requires an 833A. I will measure it sometime this weekend. 530 volts is really too much for this amp since I have 500 volt caps soldered into the PC board already, and that is about the highest voltage caps that will fit. Even still, I have been listening to it all morning (it is raining again).
That was my opinion after the bad 300B's. I didn't buy any of his tubes for 4 years. Even if you don't like his tubes, you can do as I did, and not buy any. If he dries up and goes away, the prices of all new production tubes will go up.
Nixie said:
That's kind of unfortunate, as some of us took you seriously..
Mike has fought tooth and nail to hold onto that plant, and I hope he succeeds, although in the long term I can't see how he will.
Mike's a pretty straight shooter, I've talked to him and Owen more times than I can remember. Have always done right by me. In the past I bought quite a lot of tubes from them as they are the major north american importer for most currently manufactured brands.
When you do the tally you will suddenly realize that that one plant in Saratov produces quite a large % of the high volume tubes still in production.
Here are the others I know about:
Shuguang
TJ (Tian Jian Full Music)
JJ (formerly Tesla)
EI
Svetlana (St. Petersburg) AKA Winged C
Kron Labs
Western Electric WE300B, 274B
Richardson (Amperex, Cetron) limited production if any at all
Vaic is apparently gone?
Some military specialty houses. (U.S. only afaik)
As you can see it is a very short list, if I've missed anything please feel free to add.
Hey Nixie 
,
LOL!
One thing I didn't mention in my last post is that my list contains only current known manufacturers, not resellers/relabelers with this one caveat:
Richardson relabels milspec surplus tubes mainly from Sylvania/Philips ECG as Amperex after testing and burning in on an old Amperex jig, as if that really made any difference. Actually that's totally redundant, adds no value, and the tubes so labeled are not anything close to the real thing, however they are quite open about their origins. (If not the value added.) Unfortunately years ago an unscrupulous eBay seller sold me some of these, and the in auction implied that they were the real thing - I have never been so disappointed, and of course paid far more than they were worth.
Richardson makes Cetron tubes, these aren't relabelled.
, LOL!One thing I didn't mention in my last post is that my list contains only current known manufacturers, not resellers/relabelers with this one caveat:
Richardson relabels milspec surplus tubes mainly from Sylvania/Philips ECG as Amperex after testing and burning in on an old Amperex jig, as if that really made any difference. Actually that's totally redundant, adds no value, and the tubes so labeled are not anything close to the real thing, however they are quite open about their origins. (If not the value added.) Unfortunately years ago an unscrupulous eBay seller sold me some of these, and the in auction implied that they were the real thing - I have never been so disappointed, and of course paid far more than they were worth.
Richardson makes Cetron tubes, these aren't relabelled.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.