[gibosi]

Has anyone with an external heater PS tried 6BL7's as output tubes?
 
Judging from this review, they just might be pretty good:
 
http://www.tweak-fi.com/apps/blog/show/42754587-building-a-reference-system-part-2-glenn-s-headphone-amplifier

 

[mordy]

Hi G,
 
Don't remember if I tried the the 6BL7 as a power tube, but I tried it as a driver tube. It is an 1 1/2A  tube. However, IMHO a tube that performs well as a driver tube (and has enough power to work as a power tube) will perform well as a power tube.
 
The 6BX7 is similar to the 6BL7 and I found that I liked the sound of the 6BX7 better. The 6BL7 has an amplification factor of 15 and the 6BX7 an amplification factor of 10; otherwise they seem very similar. In the Glenn amp you are dealing with 6 tubes instead of two - don't know how this changes the dynamics. Maybe we should ask the the user if he tried the 6BX7 tubes as well?
 
At the present time I am so happy with my set up that I really don't want to change - 2 Sylvania 6080WA and a GE 5687 as driver.
 
Saw several sellers of the GE 5687 state that it was made by Tung Sol (even though the pictures show the EIA # of 188 which is the GE factory code). Don't know the basis how they can state this....

 

[hypnos1]

 
Wow...you may be on to something, vic2vic!
 
I counted them in this fashion:
 

 
Hi JV...and everyone else assisting here. Sorry I myself have been a bit lax coming in, but things have been very hectic recently...my upcoming (soon!) pictorial would have clarified things somewhat, but gibosi et al have hopefully answered all your queries and provided the correct pin order/placement.
Now that you are reading pin order correctly - both from the bottom of the upside down tube, and as it appears looking down on the target socket (reversed of course but yes, can sometimes get confusing and catch you out!) - hopefully all should be well. I personally have found it helpful - nay essential! - to mark the bottom target socket/pin aligner-holder of the adapter with the reverse numbering, as below...
 

 
ps...The end result is the same, but I personally connect pin 2 (grid 3) to pin 7 (cathode) at the C3g end, and pin 5 (cathode) of C3g to pin 2 of 6AK5...
 
Hope all goes well for you now...

 

[hypnos1]

  I asked a guy on ebay that sells those sockets he's saying 26.5 m.m. also so thats 1.035 approx , so  i guess its around there  and thats good my copper fitting is that size so its looking good . Once finished adapters hopefully will be about 11/2 inch tall or less will have to cut that's for shure.                                                                                                                                                                                                                                                                                          
                                                                                   
 
                                                                                   

 
Hi again M.
 
You're probably sorted by now, but it looks like different makes have different specs...mine (below) are indeed the 25mm mentioned...
 

 
ps... Hope you're going to give folks a full pictorial on how to make 'em...

 

[MIKELAP]

   
Hi again M.
 
You're probably sorted by now, but it looks like different makes have different specs...mine (below) are indeed the 25mm mentioned...
 

 
ps... Hope you're going to give folks a full pictorial on how to make 'em...

Will do ,i ordered my parts and will try and find a 1 piece housing if not will modify parts in picture above so that in the end adapter is shorter

 

[hypnos1]

  Just read the last 30 some pages out of curiosity; nice work people! I can't believe how many tube possibilities we now have for our LDs! I also can't believe my name is still being mentioned after such a long absence, thanks for not forgetting about me and those first monstrous experiments with hanging double triodes...
 
Like Mikelap said a few pages back, I am in Japan and had been virtually "gear-less" for many months, hence my disappearance. Now that my lifestyle here is getting more stable, I'm getting back in the hobby, piece of equipment by piece of equipment! Most of my gear is still in Europe--and 220V anyway--so I have to start from scratch here. I have the speakers, DAC preamp/headamp, and power amp, but I'm still missing the headphones--anybody say HE-560?--and tube headamp, but I'm getting drawn back pretty quickly and should be using my next paycheck or two to get some cool toys! My wallet is weeping already haha...
 
Anyway, just a heads-up to say I'm still alive and intend to get back in the game at some point! In the meantime, happy rolling!

 
Hi AFB (if somewhat belated!)...great to hear from you, and hope life is good for you in that fascinating country (channel NHK is one of my favourites on SKY TV!).
 
As you may have gathered already, the C3g driver has proved to be a real winner, for myself and a good few others now. If you hadn't tossed that into the mix of alternatives - some good while ago now! - I wouldn't have been tempted to adapt it for the LD (even though I previously liked the fact that Yamamoto uses the 20V C3m version in one of his fabulous amps). Its synergy with the 6AS7G/6080 (my rather expensive GEC CV2523/6AS7G especially!) is quite extraordinary, lol!!

 
So, mon ami, we must all say to you...merci bien; vielen dank; grazie mille; muchas gracias!...don't know any Japanese, I'm afraid.
 
Good luck with your return to the wallet-emptier...it will be interesting to hear what gear you end up with!!

 

[natra084]

I

 

[bbmiller]

  Well guys, looks like you just might not be free of me after all lol!
 
Have decided to let my local repair man, who does a lot of work on old "valve" radios, have a look at my LD. So hopefully we will get some idea of just what happened and what needs to be done...as per lemonjelly's postings. My feller mentioned anode resistors and possible caps/coupling caps as well as cathode resistors...it looks like he's gonna give it a good going over at least. And if the bill isn't too steep, I just might have my beloved amp back in my arms!
 
Too bad the Little Bear is on its way, but it should be a fun project and a not-too-expensive one...
 
Will keep you all posted...

Sorry if I missed it. This enormous thread sometimes can get away from you. But can hypnos1 report or can I be pointed to the report if I missed it of just what hypnos1 repair man reported went wrong with hypnolittle1's little dot amplifier ?

Can I also get a rehash of what possibly caused the need for a repair in the first place of his little dot amp?

 

[TrollDragon]

  Right guys, here goes...
 
First, the BAD news...I'm a first class idiot (which some may have gathered by now lol!).

 
Second, the GOOD news...my LD hasn't been nuked after all!!! (I am fairly sure).
 
Before carting her off to the repair man, I decided to do just one last complete check. This time, it occurred to me to use the meter and confirm there was no signal at the headphone connection inside the amp...lo and behold, THERE WAS!

 So I unplug at the 'phone, test the plug and...yes, you've got it...NO READING...doh...! I pull it apart and..

..both (thin) silver wires (+) detached...
 
The one thing I hadn't really considered, as I was SO careful when putting it together...sealed with resin, and generously covered in insulating tape - those tiny plugs (on the HD650) are the devil to work with.
 
So, folks, although I haven't re-soldered yet - after dinner project! - that's 99% sure to be the culprit, no?!! Will confirm later this evening.
 
But even if all is well, from mordy's near-miss, it would appear mods ARE needed so I shall go ahead and see what my local valve/tube man suggests.
 
Sorry to have been premature, but at least it has been a wake-up call to stop taking such a big risk and try to get it sorted...something I'm sure mordy now agrees with, lol!

 
 

  Sorry if I missed it. This enormous thread sometimes can get away from you. But can hypnos1 report or can I be pointed to the report if I missed it of just what hypnos1 repair man reported went wrong with hypnolittle1's little dot amplifier ?

Can I also get a rehash of what possibly caused the need for a repair in the first place of his little dot amp?

 
His headphone wires had broken and there was nothing wrong with the Little Dot.

 

[bbmiller]

 

  Right guys, here goes...
 
First, the BAD news...I'm a first class idiot (which some may have gathered by now lol!).

 
Second, the GOOD news...my LD hasn't been nuked after all!!! (I am fairly sure).
 
Before carting her off to the repair man, I decided to do just one last complete check. This time, it occurred to me to use the meter and confirm there was no signal at the headphone connection inside the amp...lo and behold, THERE WAS!

 So I unplug at the 'phone, test the plug and...yes, you've got it...NO READING...doh...! I pull it apart and..

..both (thin) silver wires (+) detached...
 
The one thing I hadn't really considered, as I was SO careful when putting it together...sealed with resin, and generously covered in insulating tape - those tiny plugs (on the HD650) are the devil to work with.
 
So, folks, although I haven't re-soldered yet - after dinner project! - that's 99% sure to be the culprit, no?!! Will confirm later this evening.
 
But even if all is well, from mordy's near-miss, it would appear mods ARE needed so I shall go ahead and see what my local valve/tube man suggests.
 
Sorry to have been premature, but at least it has been a wake-up call to stop taking such a big risk and try to get it sorted...something I'm sure mordy now agrees with, lol!

 
 

  Sorry if I missed it. This enormous thread sometimes can get away from you. But can hypnos1 report or can I be pointed to the report if I missed it of just what hypnos1 repair man reported went wrong with hypnolittle1's little dot amplifier ?

Can I also get a rehash of what possibly caused the need for a repair in the first place of his little dot amp?

 
His headphone wires had broken and there was nothing wrong with the Little Dot.

But even if all is well, from mordy's near-miss, it would appear mods ARE needed so I shall go ahead and see what my local valve/tube man suggests.
 
Sorry to have been premature, but at least it has been a wake-up call to stop taking such a big risk and try to get it sorted...something I'm sure mordy now agrees with, lol!
 

So did local valve/tube man suggests any mods to make the little dot amp more rope plus or less likely to burn out? Is there anything that you all would suggest?

 

[hypnos1]

  So did local valve/tube man suggests any mods to make the little dot amp more rope plus or less likely to burn out? Is there anything that you all would suggest?

 
Hi bbm.
 
It would appear the cathode bias resistor needs to be uprated, but then its accompanying capacitor may also need changing - according to lemonjelly. If you punch up his postings a while back, you will find more info on this...but later he seemed to think the plate draw problem, and hence extra load on the transformer, (as a consequence of uprating said resistor) might not be so serious after all. So all is still not too clear, I'm afraid. And as I didn't need to visit my local man after all - especially given the upcoming Feliks-Audio unit - he hasn't been able to investigate/modify the LD itself.
 
All I can say is that my MKIV SE has not yet shown any ill-effects from the punishment, and the resistor concerned never reached an alarmingly high temp. when I monitored it for some hours' continuous use...but this apparently doesn't necessarily mean all is well!!
 
So in the end it comes down to personal choice as to what path to take, I'm afraid...I personally think the best thing is to just keep going until the amp says 'enough is enough' (making sure you don't jump to conclusions as I did, and check EVERYTHING else first before blaming the resistor!) and simply confirm if the resistor(s) needs replacing and if so, use slightly higher rated ones...we are always having to take slight risks when veering a good way off the stock configuration, lol!

 

[Acapella11]

The pin numbering inversion happened quite a few times back when we started with non-EF91/92/95 driver tubes.
 
Received now AK5-vector socket extender, C3G-AK5 adapter and a while ago already the Siemens C3GS tubes (thanks superdux).
 
Just listening to it and it sounds very promising with the HD800s. Larger stage than with the 6HM5 for sure and the first impression is quite nice. Will come back once they are further burnt in. Took a shot from the big tube adapter assemblies put together. Not the most beautiful setup but sounds good as far as I can tell.
 
 

 
For reviews of 6N6P standard compatible driver tubes, look at this post #3007. It includes impressions from Mordy, Audiofanboy and myself.

 

[MIKELAP]

  The pin numbering inversion happened quite a few times back when we started with non-EF91/92/95 driver tubes.
 
Received now AK5-vector socket extender, C3G-AK5 adapter and a while ago already the Siemens C3GS tubes (thanks superdux).
 
Just listening to it and it sounds very promising with the HD800s. Larger stage than with the 6HM5 for sure and the first impression is quite nice. Will come back once they are further burnt in. Took a shot from the big tube adapter assemblies put together. Not the most beautiful setup but sounds good as far as I can tell.
 
 

 
For reviews of 6N6P standard compatible driver tubes, look at this post #3007. It includes impressions from Mordy, Audiofanboy and myself.

Thats good to know sounds promising .Was looking for that post just the other day Thanks alot .

 

[mordy]

Hi bbm.
 
I have been using the LD MKIII with 2.5A power tubes with an external power supply for many many hours, and IMHO these tubes are perfectly safe to use with the LD amp with the provision that the amp is also cooled by an external fan.
 
Previous posts show how to assemble an external power supply and how to arrange simple cooling with inexpensive computer fans.

 

[mordy]

Hi A11,
 
I notice that you use the OEM family 6N6P power tubes. If you would switch to plug and play 6SN7 type tubes (only requiring adapters) the sound would improve further, especially the bass.