[mordy]

Hi R,

I cannot tell you if it will work in the Glenn OTL amp since I am not familiar with it. The 6SN7 draws 0.6A and the EL3N draws 0.9A. If the amp can use driver tubes that draw 1.8A it should not be a problem. A quad of EL3N would draw 3.6A which possibly is beyond the design parameters for driver tubes in this amp. You would have to check with the manufacturer if this is possible.

In the Elise amp we are using the EL3N as a direct substitute for the 6SN7 tube. I do not see the need for a dual EL3N as a driver since the results are so good.

The dual EL3N have been used as power tubes in the Elise with the same EL3N as drivers with very good results from what I have read. There are definitively sonic benefits from using certain dual power tubes, with greater drive,power and authority.

Personally, I have gotten excellent results from using dual 6BL7 power tubes. At this point I am very impressed, to put it mildly, by a dual set-up of 6BL7 and 6N7 power tubes. These two tubes draw 2.3A so they are compatible with any amp that uses 6AS7/6080 power tubes which draw 2.5A.

 

[mordy]

Hi h1,
 
Haven't taken the leap to 6 x BL tubes yet. All my tubes were sourced from the eBay bargain bins - don't know if they are new or used. My yard stick if the tube is new is if it changes in sound over time lol. Not one of them came with an original box - you get the idea....
 
The 6BL7 runs hot. It seems to me that after burn in they run cooler, but not 100% sure of this. On the other hand the 6080 tube runs very hot, and I do not hear any complaints from the many people using them.
 
A simple way to have the amp run cooler with inherently hot running tubes is to use an inexpensive socket saver, which acts as an insulator, as well as protecting the amp socket from excessive wear. The dual adapter will act like this by design.
 
At this time I am mesmerized by the 6BL7/6N7 combination that is sounding better and better - must be that my 1942 6N7 metal tubes are new, and are burning in.

 

[3083joe]

Hi m,

Look for this item on eBay:

1pc-Dual-Gold-plated-6BL7-TO-6AS7-tube-converter-adapter. It is made by Mrs Xu Ling and costs $22.50 + shipping.

As you can see from the picture, it has acrylic laser cut plates screwed on to the circuit board. I asked if there was a cheaper version, and Mrs Xu sold me a pair of adapters without the acrylic plates for $15 each + shipping $7.50 for two.

They work just fine - just remember not to touch the circuit board with the power on - you could get a nasty electric shock.

You have to email her to ask for this cheaper version.

Here is an action photo of the non acrylic adapter:

Question.
Can they be used on wa22?

 

[3083joe]

Sooooooo
Tempted to sell my round brown base GEC 6as7

 

[maheeinfy]

   
Hi maheeinfy.
 
Power tube shorts are not good news and can happen to any tube, if one is unlucky. It would appear the extent of the damage is rather unpredictable... depending on the cause, and the level of circuit protection within the amp. The sudden, "catastrophic" kind typified by extremely bright "arcing" can damage other amp components, and certainly headphones/speakers...and your eardrums won't be too happy either, lol!!...(just one reason not to leave a tube amp unattended - if you're lucky, you may just notice things beginning to go downhill before disaster strikes...like bad distortion and/or much brighter glows than normal within the tube).
 
As I mentioned, this is an unfortunate downside of tubes in general - but luckily a not too frequent one! Only time will tell if the 6BL7 is any more prone to this - or other problems - than others.
This tube appears to run VERY hot...and high heat is no friend to a tube's susceptibility. But once again, I personally would want to see much more long-term feedback from multiple users of different set-ups before feeling confident...others will differ of course, which is fair enough...we make our own choices.
 

Thanks, 
I have noticed that some of the power tubes i rolled glow differently. For example, when i had a pair of 6AS7G on the amp, one of them glows a lot, and the other not so much.
 
However i did not notice any popping sounds, distortion etc, so i guess this is normal

 

[mordy]

Hi m,
 
This is normal as you state, and it has to do with how the internals were assembled - sometimes there is a difference in how the heater wires are exposed.
 
If the tubes sound the same there is nothing to worry about.
 
Some tubes only have spectacular tube glow to advocate for themselves, and at other times tubes with very faint glow sound splendid.

 

[whirlwind]

deleted

 

[Badas]

Hi G,

I have some 25 6BL7 tubes. Many of them are rebranded, but there are only a few manufacturers.

Firstly, there are two major types: Older tubes have parallel plates; newer ones have plates in an X shape (cross plates). Older ones many times are labeled GT (both parallel and cross plates), and newer ones are labeled GTA (have only seen cross plates of GTA).

Some have double mica plates, some triple mica plates. All have top getters, round or rectangular, with the exception of the RCA  that has some side getter tubes as well.

The brands I have come across are GE, Sylvania, Tung Sol, Westinghouse and RCA. Now it gets complicated. Westinghouse and some Tung Sols have the tell tale GE sand blasted dots, so they must have been made GE. Some WE and TS look identical to the GE, but without the dots - don't know if they were made by GE or not. So it seems to leave us with GE, Sylvania and RCA as the major manufacturers.

Now, to answer your question: IMHO the best sounding ones are the GE/TS cross plate tubes with rectangular getters and GT/GTA designation from the mid 50's to early 60's. For some reason, running two 6BL7 can be just fine, but some people report that running 4 or 6 there may be problems with hum from one (or more) of the tubes. With trial and error it is possible to identify the culprit and substitute with another tube that does not cause hum.

At this point in time the BL tubes are great bargains with hundreds of offerings on eBay. According to some accounts, multiple 6BL7 tubes outperform some of the best 6AS7 tubes.

Again, all of the above are my personal observations, and I may be incorrect in my assumptions - feel free to add corrections or other opinions.

Very helpful. I'm moving to 6BL7's as well. Probably just stick with one per socket. I don't like the look of the adapters. I'm impressed with the sound quality improvement on 6080 / 6AS7G.

 

[MIKELAP]

 

Hi G,

I have some 25 6BL7 tubes. Many of them are rebranded, but there are only a few manufacturers.

Firstly, there are two major types: Older tubes have parallel plates; newer ones have plates in an X shape (cross plates). Older ones many times are labeled GT (both parallel and cross plates), and newer ones are labeled GTA (have only seen cross plates of GTA).

Some have double mica plates, some triple mica plates. All have top getters, round or rectangular, with the exception of the RCA  that has some side getter tubes as well.

The brands I have come across are GE, Sylvania, Tung Sol, Westinghouse and RCA. Now it gets complicated. Westinghouse and some Tung Sols have the tell tale GE sand blasted dots, so they must have been made GE. Some WE and TS look identical to the GE, but without the dots - don't know if they were made by GE or not. So it seems to leave us with GE, Sylvania and RCA as the major manufacturers.

Now, to answer your question: IMHO the best sounding ones are the GE/TS cross plate tubes with rectangular getters and GT/GTA designation from the mid 50's to early 60's. For some reason, running two 6BL7 can be just fine, but some people report that running 4 or 6 there may be problems with hum from one (or more) of the tubes. With trial and error it is possible to identify the culprit and substitute with another tube that does not cause hum.

At this point in time the BL tubes are great bargains with hundreds of offerings on eBay. According to some accounts, multiple 6BL7 tubes outperform some of the best 6AS7 tubes.

Again, all of the above are my personal observations, and I may be incorrect in my assumptions - feel free to add corrections or other opinions.

Very helpful. I'm moving to 6BL7's as well. Probably just stick with one per socket. I don't like the look of the adapters. I'm impressed with the sound quality improvement on 6080 / 6AS7G.

I have  been using only 1 -6BL7 per channel for the past couple of weeks and they sound good, and is within the 3A /channel MAX.for power tubes  I think for the extra limited  benefits 2 -6BL7 /channel brings ill play it safe .I also dont like the look of the adapters  but thats me ..

 

[3083joe]

  I have  been using only 1 -6BL7 per channel for the past couple of weeks and they sound good, and is within the 3A /channel MAX.for power tubes  I think for the extra limited  benefits 2 -6BL7 /channel brings ill play it safe .I also dont like the look of the adapters  but thats me ..

2 are fine, ran my amp for 8 + hours with them testerday and didn't get warm at all (2 is only 3A in wa22)

 

[maheeinfy]

Been wondering if there is a reason why 6BL7 is not recommended by amp makers like Wooaudio.
 
I had emailed them asking why this tube is not recommended, but did not get any response.

 

[MIKELAP]

 

  I have  been using only 1 -6BL7 per channel for the past couple of weeks and they sound good, and is within the 3A /channel MAX.for power tubes  I think for the extra limited  benefits 2 -6BL7 /channel brings ill play it safe .I also dont like the look of the adapters  but thats me ..

2 are fine, ran my amp for 8 + hours with them testerday and didn't get warm at all (2 is only 3A in wa22)

WA22 is rated at 3A/channel for power tubes its cutting it close .I forgot i had sent Woo an email regarding this but never got a reply ill send another one just to make sure ill let you guys know what they say 

 

[3083joe]

Mike you have a p.m.

 

[mordy]

One reason why manufacturers are not using the 6BL7 is because it is not available in large lots like new production tubes or Russian tubes. In addition, how much can you charge for a 6BL7 upgrade?
 
There is no bragging factor involved - "here are my $2000 Eltaka tubes" - wait till you hear them!

 
vs "Here are my $6 6BL7 tubes - wait till you hear them!
 
Have fun!

 

[MIKELAP]

  Been wondering if there is a reason why 6BL7 is not recommended by amp makers like Wooaudio.
 
I had emailed them asking why this tube is not recommended, but did not get any response.

Ok , me to i sent an email and never got a response i just sent another one because i want to know its simple as that .They usually always answer