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For 6BL7 tube users
Feb 8, 2017 at 7:47 PM Post #436 of 608
gibosi said:
   
Don't be so sure. Some sellers just don't know what they have, and therefore, once in a great while, the most coveted tubes popup for cheap. But of course, these listings usually don't last long, maybe 15 minutes or so. lol :) 
 
While not $15 each, one of the sweetest deals I have ever come across was a pair of 1949 Marconi A1834 for $100. Again, the seller didn't know what he had....
 
 
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No way to reproduce the deal.  Everyone knows this and MWT now. 
 
Feb 10, 2017 at 1:42 PM Post #438 of 608
Awhile ago it seems the 6BL7 tubes were never approved for use in Woo amps did anybody ever get an explanation as to why we supposebly cant use these tubes in Woo amps and also just found out that they are not approved for use in the Elise amp either .Anybody ?
 
Feb 10, 2017 at 2:23 PM Post #439 of 608
mikelap said:
Awhile ago it seems the 6BL7 tubes were never approved for use in Woo amps did anybody ever get an explanation as to why we supposebly cant use these tubes in Woo amps and also just found out that they are not approved for use in the Elise amp either .Anybody ?
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I don't know about Elise amps however with Woo I would guess the 6BL7 tubes were not approved because Woo hadn't purchased up all the spare tubes. So it could drip them out to Woo owners at 10 times the real price.
 
Feb 10, 2017 at 3:31 PM Post #440 of 608
Hi Mikelap,
 
There are tons of beautiful sounding tubes that can be used in the WOO and the Elise amps. The problems the manufacturers are facing are that they have to use tubes that are easy to find and available in large quantities. That's the reason that mega dollar amps use the Russian Svetlana tubes. (BTW, I am not aware of a single producer of the 6AS7 family today).
 
There are still large numbers of Russian tubes available, and there are a few that are still being made today in the Soviet Union (don't remember what the correct name is today) as well as in China.
 
So the reason a manufacturer is a using a current production PsVane tube may not be that it sounds the best, but that it is easily available.
 
Feb 10, 2017 at 5:30 PM Post #441 of 608
mikelap said:
  Awhile ago it seems the 6BL7 tubes were never approved for use in Woo amps did anybody ever get an explanation as to why we supposebly cant use these tubes in Woo amps and also just found out that they are not approved for use in the Elise amp either .Anybody ?
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I suspect that the reason they are not approved for use in these amps is that the transformer cannot provide enough heater current. Of course, using one per side is not a problem for the transformer, but in terms of sonics, one is not enough...
 
Two or three per side requires considerably more heater current. For example, the Elise was built to supply about 7 amps, 5 for two 6AS7 and 2 for two 6SN7. In order to run four 6BL7, a total of about 8 amps would be necessary. And for six 6BL7 a total of 11 amps would be necessary.
 
Thus the Elise, and I suspect Woo amps, were never designed to run these tubes, and doing so runs the risk of significant damage. And since these tubes are not on the approved list, this allows the manufacturer to refuse to repair the amp for free under warranty.
 
Anyway, this is my best guess....
 
Feb 10, 2017 at 6:32 PM Post #442 of 608
That's what i had asked once ,knowing that 2- 6BL7 heater current is 3.0A , My WA22 is rated at 3.0A/channel would that be cutting it to close ? If you compare to a 6AS7 tube thats rated at 2.5A theres .5A to spare would that difference also apply to the 6BL7 ?
 
Feb 10, 2017 at 8:16 PM Post #443 of 608
mikelap said:
  That's what i had asked once ,knowing that 2- 6BL7 heater current is 3.0A , My WA22 is rated at 3.0A/channel would that be cutting it to close ? If you compare to a 6AS7 tube thats rated at 2.5A theres .5A to spare would that difference also apply to the 6BL7 ?
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It certainly seems to me that adequate heater current to run four 6BL7 is not an issue with the WA22. Perhaps their reluctance to approve the use of 6BL7 is due to the fact that adapters are required. Since they do not offer suitable adapters, customers have to purchase them from third-parties. And there is no way Woo can be sure that these third-party adapters have been designed correctly, and likewise, they can't be sure that the build-quality is up to their standards. So again, I think it comes down their reluctance to honor the warranty in the event an adapter is defective and damages the amp.
 
But as usual, this is just speculation on my part....
 
Feb 10, 2017 at 8:42 PM Post #444 of 608
gibosi said:
 
mikelap said:
  That's what i had asked once ,knowing that 2- 6BL7 heater current is 3.0A , My WA22 is rated at 3.0A/channel would that be cutting it to close ? If you compare to a 6AS7 tube thats rated at 2.5A theres .5A to spare would that difference also apply to the 6BL7 ?
Click to expand...

 
It certainly seems to me that adequate heater current to run four 6BL7 is not an issue with the WA22. Perhaps their reluctance to approve the use of 6BL7 is due to the fact that adapters are required. Since they do not offer suitable adapters, customers have to purchase them from third-parties. And there is no way Woo can be sure that these third-party adapters have been designed correctly, and likewise, they can't be sure that the build-quality is up to their standards. So again, I think it comes down their reluctance to honor the warranty in the event an adapter is defective and damages the amp.
 
But as usual, this is just speculation on my part....
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There's one thing i just remembered is that Woo has a new WA22SE prototype front tubes are 6SN7 but back tubes were said to be 6BL7 ?
 
Feb 10, 2017 at 9:50 PM Post #446 of 608
badas said:
I don't know about Elise amps however with Woo I would guess the 6BL7 tubes were not approved because Woo hadn't purchased up all the spare tubes. So it could drip them out to Woo owners at 10 times the real price.
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http://woo-audio-3.myshopify.com/products/rca-clear-top-12au7-ct-matched-pair-nos
 
vs
 
https://www.tubedepot.com/products/12au7-rca-clear-top-used
 
Feb 11, 2017 at 9:58 AM Post #448 of 608
mordy said:
  Hi attmci,
 
IMHO it is nice to know who made the tube because it could save you money in hunting down tubes.
 
Certain brands are very well known and fetch very high prices, but if you know who made a rebranded tube, you could buy the same one for much less. And if you are familiar with rebranded tubes you could avoid some scammers who sell fake tubes.
 
I believe that Gibosi was able to pick pick up some Bendix tubes under a different name for a fraction of the cost.
 
If a certain tube says GEC it might go for $180, but a rebranded one you may be able to pick up for $15 if you are lucky.
 
Just my 2c......
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Point taken:
 
http://www.ebay.com/itm/322416954497?rmvSB=true
 
Feb 11, 2017 at 11:20 PM Post #450 of 608
mordy said:
  Hi attmci,
 
I think that you made your point very clear - $40/pair vs $240/pair for the same tube.......
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Dear Mordy, that's your point.
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