Little Dot Tube Amps: Vacuum Tube Rolling Guide
May 27, 2014 at 6:40 PM Post #6,287 of 13,432
  Correction i'am using them as driver tubes.

 
6AS7-type tubes, used as drivers, do run hot, and very likely, too hot. The LD's driver tube circuitry is designed for tubes drawing .5 amps, at most, so running these 2.5 amp power tubes seems to me, not to be a good idea.
 
I ran my 5998 for about 30 minutes, just enough to satisfy myself that it was not defective, so that I could give the eBay vendor positive feedback. I do not intend to roll it again until I have an amp designed to use it as a power tube.
 
May 27, 2014 at 6:52 PM Post #6,288 of 13,432
I have tried seven different 6080 tubes and one 6AS7 tube as driver tubes with a separate 5A power supply and I did not notice anything untoward.
 
The tubes run hot, but not excessive, and the LD transformer housing feels a little warm (using 6SN7 tubes as power tubes). With other driver tubes drawing less current (0.6A), the LD feels cool to the touch with the 6SN7s,
 
The best of the 6080 tubes sound quite nice with strong bass performance, and I would like to try them as power tubes when the right pieces arrive.
 
May 27, 2014 at 7:41 PM Post #6,289 of 13,432
Actually 6080 driver tube for MK III and 1+ the amp did not even get warm same as 6SN7 driver tube but with 6H13C driver tube for MK III and 1+ it gets a little warm.Now for 6AS7 power tubes expect your amp to get HOT,Sure it does work for MK III but for how long.
 
May 27, 2014 at 9:21 PM Post #6,290 of 13,432
   
Of course, you are going to want to do both! Of course! :)
 
In my opinion, assigning improvement percentages to options 1 and 2 is very difficult to do, but it is clear that either will make a significant difference. My suggestion is to start with the cheapest option first, which is probably a nice pair of 6SN7's and adapters.
 
Cheers

 
 
 
 
   
Hi C.
 
gibosi is probably right re the order of things, but I would say -  from my own experience with the IV SE - that the C3G gives a greater percentage improvement. So you must save up for them (or give out hints for birthday etc.!). Unless, that is, you can keep trying to find some for silly money a-la-mordy...but I wish you good luck! in that lol...
wink_face.gif
.

 
Thank you guys for your inputs. My 6SN7 journey just started. I just got myself 3ea. early 50s Sylvania 2 holes bad boy 6SN7GT for  23 USD  .  And ordered  a pair of adapter for 22 USD.  Did I  pay too much or fair price? Wish me luck.
 
I will have to wait awhile for C3g and adapters. WOW! A pair of adapter cost as much as C3g.
 
May 27, 2014 at 9:49 PM Post #6,291 of 13,432
  Thank you guys for your inputs. My 6SN7 journey just started. I just got myself 3ea. early 50s Sylvania 2 holes bad boy 6SN7GT for  23 USD  .  And ordered  a pair of adapter for 22 USD.  Did I  pay too much or fair price? Wish me luck.

 
The price you paid for the 6SN7's and adapters sounds very fair to me. I assume your LD has rings around the sockets? If you cannot remove them, you will need two additional 9-pin socket-savers to clear those rings. The base of the 6SN7 adapters is too wide to fit within the rings....
 
May 27, 2014 at 10:05 PM Post #6,292 of 13,432
  I have tried seven different 6080 tubes and one 6AS7 tube as driver tubes with a separate 5A power supply and I did not notice anything untoward.
 
The tubes run hot, but not excessive, and the LD transformer housing feels a little warm (using 6SN7 tubes as power tubes). With other driver tubes drawing less current (0.6A), the LD feels cool to the touch with the 6SN7s,
 
The best of the 6080 tubes sound quite nice with strong bass performance, and I would like to try them as power tubes when the right pieces arrive.

 
I would agree that running these 2.5 amp tubes makes the LD about as hot as when we rolled 6AH6's. However, with the 6AH6's that heat was generated by the internal LD heaters and the associated driver tube circuitry. With these 6AS7-type tubes, which require external heaters, that same amount of heat is being generated only by the driver tube circuitry. And therefore, I have to believe that all the components and circuit board wiring associated with the driver tube are running much hotter than before.
 
Until someone is willing to open up their LD's and measure the temperature of critical resisters, similar to the testing Hypnos1 did while running 6AS7 as power tubes, I am not willing to take the risk....
 
Be careful out there....
 
May 27, 2014 at 10:23 PM Post #6,293 of 13,432
   
The price you paid for the 6SN7's and adapters sounds very fair to me. I assume your LD has rings around the sockets? If you cannot remove them, you will need two additional 9-pin socket-savers to clear those rings. The base of the 6SN7 adapters is too wide to fit within the rings....

Hi gibosi
 
Thank you. There are two screws holding the whole tube guard rings and base plate. Looks like I am good to go as soon as I get my tubes and adapters. This is my very first tube headphone amp. I was never really into headphone until last "black Friday" I got myself HD650 from sennheiser for 300 USD , DT880/600 for 230 USD and LD MK IV from David in Feb of this year. Until then I had Sony MDR 6 for the last 20 years and still alive and kicking but being ignored for last few months. I do have Fisher 500c for last 15 years but not in use for last few years because of humming problem. Now I am thinking about selling it and get a nice headphone amp or should I do restoration??? Decision decision. Fisher takes KT88/7591 tubes . Can we use them in LD? I've never done any TUBE ROLLING on my fisher 500c.
 
May 27, 2014 at 11:07 PM Post #6,294 of 13,432
  Hi gibosi
 
Thank you. There are two screws holding the whole tube guard rings and base plate. Looks like I am good to go as soon as I get my tubes and adapters. This is my very first tube headphone amp. I was never really into headphone until last "black Friday" I got myself HD650 from sennheiser for 300 USD , DT880/600 for 230 USD and LD MK IV from David in Feb of this year. Until then I had Sony MDR 6 for the last 20 years and still alive and kicking but being ignored for last few months. I do have Fisher 500c for last 15 years but not in use for last few years because of humming problem. Now I am thinking about selling it and get a nice headphone amp or should I do restoration??? Decision decision. Fisher takes KT88/7591 tubes . Can we use them in LD? I've never done any TUBE ROLLING on my fisher 500c.

 
The KT88 is a single beam tetrode and it will not work in the LD....  
 
You might want to simply put new tubes in the Fisher. After 15 years, I would say it is about time....  And as to getting a "nice headphone amp", if you follow Hypnos1's lead, your LD will in fact be a very nice headphone amp. :)
 
May 28, 2014 at 4:19 AM Post #6,295 of 13,432
Hey guys, I'm looking for suggestions for power tubes on a MKII ... In the guide he doesn't cover them at all.  I've settled on the Voshkod 6ZH1P-EV, and was wondering what manufacturer I should go for for the power tubes.  I was just going to get the Russian 6H6P-I from YenAudioStore figured I'd keep it Russian :p Would you guys say these work together, or is there a better power tube set. 
 
Btw, I did use the search button on this thread, but putting in the terms " power tubes " brought up just about every post on this gigantic thread haha, so sorry if this has already been covered. 
 
May 28, 2014 at 7:32 AM Post #6,296 of 13,432
  Hey guys, I'm looking for suggestions for power tubes on a MKII ... In the guide he doesn't cover them at all.  I've settled on the Voshkod 6ZH1P-EV, and was wondering what manufacturer I should go for for the power tubes.  I was just going to get the Russian 6H6P-I from YenAudioStore figured I'd keep it Russian :p Would you guys say these work together, or is there a better power tube set. 

 
Here is  pretty good review of the traditional power tubes for the LD:
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/3000#post_9823694
 
Now you should know that a number of folks have begun to use 6SN7's and some believe them to be better.
 
May 28, 2014 at 8:48 AM Post #6,297 of 13,432
   
Here is  pretty good review of the traditional power tubes for the LD:
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/3000#post_9823694
 
Now you should know that a number of folks have begun to use 6SN7's and some believe them to be better.

Sweet, thanks so much for that link.  So looking over it, he talks about how the 
6H30P-EV is faster and more neutral, while the 6N6P-IR sounds " tubier "... Well, I'd be using this amp mostly for Rock from the 70s through 90s.. So I'm a little torn, should I go with the nostalgia 
sound, or the faster sound?  
Also, just based off of the OP's recommendation I was going with the Voshkod 6ZH1P-EV... Now, I don't know if there's a tube that you guys have found since then that people like more?  Or if there's one that's maybe good with rock? The amp is being paired with a pair of Grado 225is if that means anything.  I'm mostly looking to upgrade the sound of the amp once, I'm not so much interested in having multiple sets of tubes. 
Thanks!
 
May 28, 2014 at 9:14 AM Post #6,298 of 13,432
  Sweet, thanks so much for that link.  So looking over it, he talks about how the 
6H30P-EV is faster and more neutral, while the 6N6P-IR sounds " tubier "... Well, I'd be using this amp mostly for Rock from the 70s through 90s.. So I'm a little torn, should I go with the nostalgia 
sound, or the faster sound?  
Also, just based off of the OP's recommendation I was going with the Voshkod 6ZH1P-EV... Now, I don't know if there's a tube that you guys have found since then that people like more?  Or if there's one that's maybe good with rock? The amp is being paired with a pair of Grado 225is if that means anything.  I'm mostly looking to upgrade the sound of the amp once, I'm not so much interested in having multiple sets of tubes.

 
I have an LD 1+, which is a hybrid, so I really cannot comment on the sound of power tubes.....
 
Of the EF-95-type tubes, the Voshkod 6ZH1P-EV are among the best. One tube that many people like more is the EI 6HM5, and it is pretty cheap. In the end, the only way to know which tube is your favorite is to try them all! lol  Or at least, you need to try a few. Everyone has different ears and different gear. And everyone has a different preferred sound signature. What one person loves another finds to be blah. So I encourage you to try as many as your wallet will allow. Cheers. :)
 
May 28, 2014 at 9:31 AM Post #6,299 of 13,432
   
I have an LD 1+, which is a hybrid, so I really cannot comment on the sound of power tubes.....
 
Of the EF-95-type tubes, the Voshkod 6ZH1P-EV are among the best. One tube that many people like more is the EI 6HM5, and it is pretty cheap. In the end, the only way to know which tube is your favorite is to try them all! lol  Or at least, you need to try a few. Everyone has different ears and different gear. And everyone has a different preferred sound signature. What one person loves another finds to be blah. So I encourage you to try as many as your wallet will allow. Cheers. :)

Thanks so much for the help!  Well I can't seem to find any 
6N6P-IR tubes on ebay, so I guess that decision made itself haha.
 
EI 6HM5.  Are these them? http://www.ebay.com/itm/6HM5-6HA5-EC90
Do I need to worry about balance? I see all these " matched " tubes on ebay, but I read somewhere in this thread that that doesn't really mean much.
 
May 28, 2014 at 9:42 AM Post #6,300 of 13,432
Sweet, thanks so much for that link.  So looking over it, he talks about how the 6H30P-EV is faster and more neutral, while the 6N6P-IR sounds " tubier "... Well, I'd be using this amp mostly for Rock from the 70s through 90s.. So I'm a little torn, should I go with the nostalgia sound, or the faster sound?  
Also, just based off of the OP's recommendation I was going with the Voshkod 6ZH1P-EV... Now, I don't know if there's a tube that you guys have found since then that people like more?  Or if there's one that's maybe good with rock? The amp is being paired with a pair of Grado 225is if that means anything.  I'm mostly looking to upgrade the sound of the amp once, I'm not so much interested in having multiple sets of tubes. 
Thanks!


Hi gravit!

After my long abstinence here, i have to say that i found my endgame tubes.
Many have now found that the Siemens c3gs as driver tube outrule most other tubes in areas like tansparacy and neutrality.
I also listen to much rock and i have to say, neutrality is not bad for rock at all! It might sound less "interesting" at first, but after a while you notice all the little details you didn't hear before.
Also the position of the instruments is much better defined.
So my advice is clear,try to get some c3gs!

As for power tubes, i tried the 6sn7 tubes, which seem to provide extra power and dynamics the amp was missing till then. In combination with the c3g, this is my endgame combo.
But i might try some 6f8g in the future... Who knows?


Btw, cheers guys, wasn't online a long time (yeah my profile says other, but everytime i open my smartphone browser, it logs into headfi, even if i don't surf there, so...)
Cool to see many others to try the c3g!
Did you try the 6f8g's eventually?
What where the results?
Haha i missed so much information! XD
 

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