[vc1187]

That sure is a beautiful sight for a tube addict, like myself 

 

[Xcalibur255]

 
Tyrell can you try this adapter in the small chassis?
One 6BL7 isn't enough power really in this amp.

 
At the moment I don't have enough of either tube, just a pair a piece.
 
I tried directly subbing 6BL7 in the 6AS7 sockets once, I remember us discussing it quite a while back.  Definitely didn't have enough drive, but I didn't have my 600 ohm DT880s at the time either it probably would have worked with them.
 
I moved my OTL over to my TV setup and have it hooked up to the McIntosh now actually.  Been using it to watch movies late at night and it sounds awfully good in that capacity.  This change is what finally prodded me into ordering an Yggdrasil for the PC setup, hearing one of my amps on the McIntosh made it clear just how long in the tooth my VDA-2 DAC has become.

 

[gibosi]

  Pretty cool. Looking forward to your impressions. What are the dimensions of the adapters? Just curious as my output tubes are offset towards the back of the unit.

 
http://www.ebay.com/itm/191792226144
 
They are about 35mm (1 1/3 inch) by 85mm (3 1/3 inch). Further, they can be rotated a bit if necessary as seen here in JazzVinyl's Elise:
 
http://www.head-fi.org/t/410326/for-6as7g-tube-rollers-here/3285#post_12318343

 

[JoelT]

^^^Excellent. Just placed an order for a couple adapters to try out for fun. Thanks for the info!

 

[gibosi]

  I like the flat plate Sylvania the best of all 6BL7s.
Does 2 of them sound better then 6AS7s??
I know that 3 of them in amps I made to take them sound better then any 6AS7 including the GEC.

 
Am I correct in thinking that if someone wanted to run low-Z cans (in your OTL), one could use these adapters to run four 6AS7? Two per side? In terms of heater current, no different than running a pair of 6336, yes?

 

[whirlwind]

 

  I like the flat plate Sylvania the best of all 6BL7s.
Does 2 of them sound better then 6AS7s??
I know that 3 of them in amps I made to take them sound better then any 6AS7 including the GEC.

 
Am I correct in thinking that if someone wanted to run low-Z cans (in your OTL), one could use these adapters to run four 6AS7? Two per side? In terms of heater current, no different than running a pair of 6336, yes?

Ken, wait for Glenn's to respond to make sure.....but I am pretty sure told me that I could do this.....very interesting too, could be a great option for low z cans.

 

[JazzVinyl]

Am I correct in thinking that if someone wanted to run low-Z cans (in your OTL), one could use these adapters to run four 6AS7? Two per side? In terms of heater current, no different than running a pair of 6336, yes?

I am not sure if two ST bottle 6AS7G's can fit on this adapter (might not have enough spacing, between the octal sockets?).

But for sure, a couple of 6AS7GA's could.

 

[2359glenn]

 

  I like the flat plate Sylvania the best of all 6BL7s.
Does 2 of them sound better then 6AS7s??
I know that 3 of them in amps I made to take them sound better then any 6AS7 including the GEC.

 
Am I correct in thinking that if someone wanted to run low-Z cans (in your OTL), one could use these adapters to run four 6AS7? Two per side? In terms of heater current, no different than running a pair of 6336, yes?

Yes and good 6AS7s might sound better then the 6336 if you can afford them 4 GECs

 

[Xcalibur255]

   
Am I correct in thinking that if someone wanted to run low-Z cans (in your OTL), one could use these adapters to run four 6AS7? Two per side? In terms of heater current, no different than running a pair of 6336, yes?

 
The 5998 achieves the same reduction in output Z without the added complication.  It has the added benefit of allowing the amp to run a lot cooler too.

 

[JazzVinyl]

What is the lowest recommended impedance for your cans, when using a Glenn OTL amp?

 

[gibosi]

This is all good advice. As I do all my listening through a pair of 150 ohm Senn 700s, my question was more for the good of the order than for myself. But for sure, I bet a pair of HE-6 would sound pretty good driven by a quad of GEC 6AS7. lol.
 
In my opinion, four 6BL7s seem to be more than up to driving my 700s. Bass is reproduced with very good power and control, and I think it is very safe to say that owners of the HD 800, Beyer TI and similar reasonably efficient high-Z cans would be more than happy with this configuration.
 
For those who have not experienced the sound of 6BL7s as output tubes, this review of one of Glenn's 6-tube units might be very helpful, especially the section on tube rolling.
 
http://www.tweak-fi.com/apps/blog/show/42754587-building-a-reference-system-part-2-glenn-s-headphone-amplifier
 
Like that reviewer, I find the sound of the 6BL7s to be very good but also very different than that of the 6AS7. And like that reviewer, I think I am going to need some time to "get" this sound. That said, I am currently using the GEC B36 as a driver, and I don't think I have ever heard this tube sound this good.
 
Cheers

 

[whirlwind]

  This is all good advice. As I do all my listening through a pair of 150 ohm Senn 700s, my question was more for the good of the order than for myself. But for sure, I bet a pair of HE-6 would sound pretty good driven by a quad of GEC 6AS7. lol.
 
In my opinion, four 6BL7s seem to be more than up to driving my 700s. Bass is reproduced with very good power and control, and I think it is very safe to say that owners of the HD 800, Beyer TI and similar reasonably efficient high-Z cans would be more than happy with this configuration.
 
For those who have not experienced the sound of 6BL7s as output tubes, this review of one of Glenn's 6-tube units might be very helpful, especially the section on tube rolling.
 
http://www.tweak-fi.com/apps/blog/show/42754587-building-a-reference-system-part-2-glenn-s-headphone-amplifier
 
Like that reviewer, I find the sound of the 6BL7s to be very good but also very different than that of the 6AS7. And like that reviewer, I think I am going to need some time to "get" this sound. That said, I am currently using the GEC B36 as a driver, and I don't think I have ever heard this tube sound this good.
 
Cheers

Man, I am trying to save up for an ether to use with this amp....but really want to hear the HD800 with the 6BL7 now  

 
I need a second job 

 

[JazzVinyl]

http://www.tweak-fi.com/apps/blog/show/42754587-building-a-reference-system-part-2-glenn-s-headphone-amplifier

Like that reviewer, I find the sound of the 6BL7s to be very good but also very different than that of the 6AS7. And like that reviewer, I think I am going to need some time to "get" this sound. That said, I am currently using the GEC B36 as a driver, and I don't think I have ever heard this tube sound this good.

Cheers

I am using the quad 6BL7's as powers in my Elise amp, on Glenn's suggestion. I agree fully with the reviewer on Tweak-Fi in his sound description.

I also noted that not only is the bass deeper yet more articulated, but it is apparent to me that careful listeners will also discover that the multi 6BL7's reveal more details in both mids and highs. Yes, it's different from what you are used to via 6AS7G as powers. But listen carefully to works that you know very well, and you will hear these subtle details that seem to be barely hunted at, via 6AS7's.

My 6BL7 quad are fine for my 300 ohm SENN 580's but I do think that my 600 ohm Beyers would like 3x 6BL7's per 6AS7 socket as in Glenn's amp. They don't quite have the drive to bring that bass authority I am getting with the Senns @ 300 ohms.

I am sold on multi 6BL7's as powers....for certain it elevated my amp beyond what is possible with 6AS7 as powers, in my opinion....

As gibosi always says....my ears, my gear YMMV....

Cheers to all....

 

[whirlwind]

Glenn, if I were to ask someone to make an adapter for my amp to use 3x 6BL7....what info would they need.....what is the current capacity of my amp ?

 

[gibosi]

  Glenn, if I were to ask someone to make an adapter for my amp to use 3x 6BL7....what info would they need.....what is the current capacity of my amp ?

 
Two 6336 draw 10 amps, four 6AS7 draw 10 amps and six 6BL7 draw 9 amps (6 X 1.5). So the current capacity of your amp is more than enough.
 
Very crudely, I suspect that you could purchase 4 of the adapters I have and simply plug adapters into adapters, piggy-back if you will, to provide two units with three sockets each. However, it may be necessary to put something underneath the heavy end of the piggy-backed adapter (with two tubes) in order to give it some support.
 
Optimally, I think it would be best to have something that was a good bit more rigid and designed to fit nicely into the existing space on top of your amp....