Little Dot Tube Amps: Vacuum Tube Rolling Guide
Oct 27, 2015 at 1:13 PM Post #9,916 of 12,704

hypnos1

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  Hi hypnos1, glad you are enjoying that great Amp, have read a lot about it! Unfortunately I havent been able to run the C3Gs with a decent pair of powertubes, the adapters I ordered didnt work, my big shame, well, as I am expecting a shipment from china that carries the adapters Mike sugested, along with some 9 pin socket savers. I have been reading this thread a lot and now I wonder if you could assist me in running some Tung-Sol 6080 (already got them), As I could see you ran this project before! Well the thing is that I made a diagram and just want to make sure everything is in order, will be a very fun weekend project anytime soon. :) Please check the image and tell me what would you suggest in case something is missing, Help will be very much appreciated cheers!
 

 
Hi WeirdChild...very impressive! And glad you already know about gibosi's mention re disconnecting from the LD's heater supply.
 
I hope you have no problems with hum from the external PS - if you do get any at all, try connecting the DC neg. out to a mains Earth point.
 
And I wish you all the best with your project - you will be amazed at the difference! But I'm so sorry about your C3gs....I do hope the new adapters work OK - these tubes will also take your amp to whole new levels...CHEERS! 
beerchug.gif

 
Oct 28, 2015 at 6:12 AM Post #9,919 of 12,704

hypnos1

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  Thank you guys for going down the road and coming back with buckets of knowledge for others to learn. It is a sweet ride. I appreciate it. :)

 
Hi WeirdC.
 
That ride was sometimes a real 'hairy' one, lol! A whole bunch of great guys did some unbelievable (crazy, actually!
wink.gif
) things that went in all kinds of directions...but which achieved amazing results without having to do major surgery inside the LDs - and which has come in very handy since!
 
Good luck once again in your own efforts...
 
ps.  Are your C3gs still in the canisters? If so, you presumably wouldn't know if the heaters at least were working? Did you have to 'work' the tubes hard into the adapters' sockets?...some of us lost tubes because of this (as you probably read) - the base of the tube's glass is so fragile, any undue stress on the pins (especially from a side-to-side 'rocking/rolling' motion) can easily crack the glass. If still canistered, it can be difficult to tell if the tube has actually gone or not!  These tubes MUST be inserted/removed ONLY with a straight action, and preferably without having to use too much force.
 
Oct 29, 2015 at 4:49 AM Post #9,920 of 12,704

WeirdChild

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Hi WeirdC.
 
That ride was sometimes a real 'hairy' one, lol! A whole bunch of great guys did some unbelievable (crazy, actually!
wink.gif
) things that went in all kinds of directions...but which achieved amazing results without having to do major surgery inside the LDs - and which has come in very handy since!
 
Good luck once again in your own efforts...
 
ps.  Are your C3gs still in the canisters? If so, you presumably wouldn't know if the heaters at least were working? Did you have to 'work' the tubes hard into the adapters' sockets?...some of us lost tubes because of this (as you probably read) - the base of the tube's glass is so fragile, any undue stress on the pins (especially from a side-to-side 'rocking/rolling' motion) can easily crack the glass. If still canistered, it can be difficult to tell if the tube has actually gone or not!  These tubes MUST be inserted/removed ONLY with a straight action, and preferably without having to use too much force.

Hi! hypnos1 Sorry I did not make myself clear, the adapters that didnt work were for a couple of 6SN7! Problem is I do not have another pair of these tubes to check what is wrong, anyway, I decided to go for the 6080 route and try the new adapters (still waiting for them) The CSGs are working wonderfully and waiting for the 6080s to join the party! Please tell me, what can of an improvement should I wait for, in your own experience?
 
Oct 29, 2015 at 5:38 AM Post #9,921 of 12,704

hypnos1

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  Hi! hypnos1 Sorry I did not make myself clear, the adapters that didnt work were for a couple of 6SN7! Problem is I do not have another pair of these tubes to check what is wrong, anyway, I decided to go for the 6080 route and try the new adapters (still waiting for them) The CSGs are working wonderfully and waiting for the 6080s to join the party! Please tell me, what can of an improvement should I wait for, in your own experience?

 
Ah...that's good news then - re. the C3gs at least!
wink.gif
But sorry for the 6SN7 problem...However, no big deal, because once you have the 6080s in place (or some nice 6AS7Gs even!) you can forget the 6SN7 lol!... With the C3gs in the driving seat, you are in for a real treat, basically!! There is an overall boost in dynamics and authority, which helps to balance out a bit more the C3g's bass in relation to its treble that can sometimes - depending on gear/ears - be a tad OTT!. The resultant powerful presentation is quite remarkable, especially for such a modestly priced amp - the C3g just cries out for this family of power tubes, and rewards you handsomely... they highlight this driver's amazing qualities such that if you found the C3g wonderful before, you will be searching for even more superlatives when you treat these little wonders to their new partners!...a marriage made in Heaven, basically!! 
bigsmile_face.gif

 
So in effect, WC, just imagine all that you love about the C3g... magnified!!!...(Already I'm feeling excited for you, lol!
biggrin.gif
). CHEERS! 
beerchug.gif
 
 
Oct 30, 2015 at 7:44 AM Post #9,922 of 12,704

northendjazz

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So I read the thread after buying a mkII and enjoyed working my way up to c3g's.
They started with problems, I was thinking I spent money for a horrific buzz with the 5687 power tubes I had running so I went back to 6N6P Novosibirsk power tubes. That solved the problem If I gave the amp 30 mins warm up.
I wanted to try 6sn7 as power tubes and I'm happy I did, all quiet no buzz so I can relax and enjoy the c3g's magic with no warm up needed but given anyway.
 
I'm now running and enjoying Onkyo CD - Beresford Bushmaster DAC - Little Dot mkII - Siemens C3g - 6SN7GTB Sylvania Chrome dome -  DT880 600's.  With some Sylvania 6SN7WGTA on the way.
 
One thing I have noticed with this combo is the running temp of the amp has dropped,  any clues as to why this happend?  
 
Oct 31, 2015 at 9:42 AM Post #9,924 of 12,704

hypnos1

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  So I read the thread after buying a mkII and enjoyed working my way up to c3g's.
They started with problems, I was thinking I spent money for a horrific buzz with the 5687 power tubes I had running so I went back to 6N6P Novosibirsk power tubes. That solved the problem If I gave the amp 30 mins warm up.
I wanted to try 6sn7 as power tubes and I'm happy I did, all quiet no buzz so I can relax and enjoy the c3g's magic with no warm up needed but given anyway.
 
I'm now running and enjoying Onkyo CD - Beresford Bushmaster DAC - Little Dot mkII - Siemens C3g - 6SN7GTB Sylvania Chrome dome -  DT880 600's.  With some Sylvania 6SN7WGTA on the way.
 
One thing I have noticed with this combo is the running temp of the amp has dropped,  any clues as to why this happend?  

 
 
  This also happened to my MK 3 also after I upgraded to C3Gs and 6SN7s.  I suspect it is from having the adapters and socket savers lifting the hot tubes above the chassis.

 
Glad to see you guys are also enjoying the magic of the C3g. And that you've also gone for different powers...the things we did with our poor LDs - and they just kept asking for more, lol!...amazing!
wink.gif

As mordy has often mentioned, another benefit of socket savers/extenders is that extra cooling effect....which certainly comes in handy with the mighty 6AS7G/6080s!! But even though our amps ended up running very hot, they still didn't seem to object...even more amazing!!!
 
Nov 1, 2015 at 1:28 AM Post #9,926 of 12,704

gulakpi

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I experienced serious distortions at higher volume after switching to 6SN7 as power tubes.  I'm using a pair of AKG K712  62 ohm cans, and that might have been the cause.
 
If I played at lower volume, the sound from the 6SN7 is silky smooth though!
I rolled different driver tubes with the 6SN7 to try to find a match. My beloved 6ZH1P was the worst one, followed by the 6HM5, EF900, 6915A and EF94.  To my surprise, the stock 5654W behaves quite nicely.  I can still hear the distortion, but they are almost gone unless I turn on the volume loud.
 
I do not have a pair of the C3g, and I wonder if this will solve the problem?!!
 
The temperature on the chassis is barely 1 or 2 degrees above ambient with the 6SN7!  It's amazing!
 
Nov 1, 2015 at 6:46 AM Post #9,927 of 12,704

northendjazz

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Makes sense, so my MkII will not be a room heater this winter. I have yet to try the 6sn7's with anything other than c3g's yet, I'll roll my way through my tube collection again. 
 
If I have understood the info on page 585  6sn7's "classic high end tube, not compatible with low impedance cans" .
 
Also Mullard EF95 cv850 (marked on tube) I found them better than the cv4010 I'm new to discribing the SQ of tubes so better will have to do and I only have one Cv850 left as the other failed.
 
Nov 1, 2015 at 8:59 AM Post #9,929 of 12,704

MIKELAP

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I just remembered i had 2 pairs of the CV850 was wondering if anybobody has the date codes for these i think there Mullards     the codes are 2E2 R9C1                                                                                                                                             

 
Nov 1, 2015 at 10:03 AM Post #9,930 of 12,704

MIKELAP

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Finally i used the search this thread function was forgetting about that and gibosi you gave me the answer to my question on the 6/16/2013  page 104 post 1547  date was 10 week 1969
 

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