[triod750]

This is cheating, Luopal!!

I am very confused if your original adapters came from 'xulingmrs'. I bought mine from her a few years ago and they have been working perfectly. I have never had any trouble and my Little Dot has always been dead quiet (except from the music) when using them. My adapters from 6N6P to 6SN7 etc come from the same source and has that same quality. Since they are working well I will not butcher them to check their innards.

I am impressed by your solution!

 

[lupoal]

Yes they are the original Chinese stuff..... I’ve no idea, maybe I’ve been a little unlucky but, in any case, from mechanical point of view those adapters are pure rubbish... so use them gently, very gently

now talking about tubes... those C3G... what is the best match with them? RCA... Tungsol... Sylvania... ? now are playing with couple of 6H8C from year 52 and the sound is not as wide as expected... also in the low register the sound a little too dry...the same 6H8C with 6BE6 from RCA or Brimar sound completely different, with Brimar good low register but also fast and punchy, with RCA the bass go even deeper but a little bit slower, warmer... with both head stage is wider and deep and with more air between instruments, compare with C3G clearly... so suggestions about C3G matching?

 

[triod750]

It took quite some time before my C3g sounded any good. Don't remember how long but I was sceptical for a long while. But I have that same experience from my main tube amps for loudspeakers so I had patience. Still I sometimes jump to conclusions when trying new tubes. I only have Melz made 6H8C and they don't work that well with C3g to my ears. The combination is too much of a good thing. Both are very resolving tubes and together they tend to give much detail and less 'body'. I'm speaking of Siemens made C3g here. They are the only C3g I have experience of. So I'm only telling of my experience of this combination, my ears and my gear and mostly acoustical music. Resolving is good for my music but I'm looking for better balance to find the all important 'tone' I am searching for.

(We cannot be speaking of the same adapters since my adapters are very robust mechanically).

 

[MIKELAP]

Most of my adapters were made by that seller and a few others . In general they work good .i try to buy adapters that use the CMC sockets ,better quality .

 

[lupoal]

@triod750
you got the point... almost ( )... as my C3G are not new (the dealers declared they are still good, but as I remember the condition of the pins of those tubes I have some doubts they tested them) I think burn-in should not be required

my 6H8C are from Foton but have the same behaviour as yours Melz... togheter with Siemens C3G (mine are Siemns too) I have the same feeling there is not enough body... I will try today with a couple of 6SN7GTB RCA

 

[triod750]

There should be a lot of hours between burn-in and burnt-out. If you are comfortable with being adventurous you could go for external psu for the heaters and try 6BX7GT. They will give you a lot of body. I haven't tried RCA 6SN7GTB but a few others in that family, such as Ken-Rad 6SN7GTA, Brimar 6SN7GT, Sylvania 6SN7GTW, RCA 6SN7GT and a single Raytheon 6SN7GT tall bottle and a single Sylvania VT231 and maybe som I have forgotten.

I enjoy the ride and am looking for 'the right tone' but would not mind finding it. Even if I find it I am convinced that I will keep on experimenting for the fun of it. Right now I am listening to a choir work by Arvo Pärt, using EL42 as input via adapters from @Deyan and Melz 6H12C as output via adapters from xulingmrs. No external heater psu used for this. The music is beautiful!

 

[lupoal]

Ok, with RCA those C3G are much much much (not a typing error) better... let say still a little on the bright side especially with the piano, but that could also be matter of recording... this is the album (Qobuz) I’m using for test, very nice live session

now... I would like to investigate the possibility of 6AS7G/6080 with external power supply togheter with C3G... is it so good as declared here ?

 

[triod750]

I have just tried 6080 (Tung-Sol and Tung-Sol Chatham) shortly and also -62 Svetlana 6N13S shortly and wasn't impressed enough to take it any further there and then. Maybe I will revisit, I don't know. Two GEC A2293 single triodes (one A2293 is the equivalent of one half 6AS7G) per channel seems more promising to me. But sound and tone and presentation is a very personal thing and very little science when it comes to comparisons. I have to admit that I haven't tried 6080/6AS7G with EL42. Maybe they work better together?
In my opinion, 6BX7GT is a better alternative in Little Dot. Same psu and same adapters. A lot less heat to the components. Enough power (for my HD650).

 

[cddc]

after a bad experience with two chinese adapters with serious quality problems (and engineering problems that are defective already in design), that gave me a strong "hummmm" with the C3G, I decided to make myself a pair.
I disassembled this crap...



and then using cyanacrylate adhesive, to hold the pins in place in the pin-saver that sometimes comes with valves, and successivalent two-component epoxy resin, to lock everything in place and ensure electrical isolation, I assembled my adapters starting from a commercial bulb holder (cost 1 euro each).
The two conductors that carry the 6.3Vac are twisted and shielded, the shield is connected to the center pin of the valve, so the aluminum valve housing acts as an effective shield at his best, the shielding braid then crosses the mechanics and is connected to an external copper shielding, this is also connected a connector to connect shielding-circuit then this to earth through an independent cable (so not the ground conductor of the power cable and not even the shield of the power cable).





the piece of screw you can see in the middle is there to increase the coupling/holding force of cyanacrylate between plastic parts











The result of the work could be aesthetically better but from an electrical point of view is perfect .... no HUMMM even with maximum volume and in the absence of musical content. Very silent!

last but not least... thank you MIKELAP for precious help!

Nice workmanship, very handy man!

I like the way you ground the adapters.

Where did you find the base and pins for the miniature 7-pin socket? Are the 8 holes in the base spaced out exactly as the miniature 7-pin socket, and you just simply glued the pins to the base?

 

[TrollDragon]

Nice to see the modding active again in this thread. I remember the old days when we were trying dual triodes.

My Mk IV with a 6SL7GT in a DIY adapter.

 

[lupoal]

...
In my opinion, 6BX7GT is a better alternative in Little Dot. Same psu and same adapters. A lot less heat to the components. Enough power (for my HD650).

I’m using the same headphone... I will investigate about 6BX7GT, I don’t know anything about this... ok, let’s start searching info

 

[lupoal]

Nice workmanship, very handy man!

I like the way you ground the adapters.

Where did you find the base and pins for the miniature 7-pin socket? Are the 8 holes in the base spaced out exactly as the miniature 7-pin socket, and you just simply glued the pins to the base?

thank you

the base if one of those pin saver (hope is the right way to call them, I’m not sure as I’m Italian ) you get sometimes together with tubes... I received two of them with the last couple of Brimar 6BE6 I bought... so the pin position is already perfect... you should be able to find them also in eBay

the pins are from the Chinese adapter I cannibalized, same source for the octal socket... yes, first I glued the pins, already soldered to wires, with cyanacrylate... you have to use the gel one otherwise is too much thin and fluid and unable to fill the gap between pins and holder... after that you assemble the pin holder to the housing with some epoxy glue, at this stage I suggest to protect the pins with some paper tape... once the epoxy hardened then, if you use roughly the same housing I’ve used, you can inject additional/higher quantity of epoxy from inside and between wires using a syringe without needle

 

[cddc]

Ok, with RCA those C3G are much much much (not a typing error) better... let say still a little on the bright side especially with the piano, but that could also be matter of recording... this is the album (Qobuz) I’m using for test, very nice live session



now... I would like to investigate the possibility of 6AS7G/6080 with external power supply togheter with C3G... is it so good as declared here ?

Thanks a lot for explaining where you got the bases, they are from pin protectors/savers, that explains why they match so well with the miniature 7-pin socket. I was thinking it's a miracle to find some rubber base that happened to have 7 holes matching exactly with the 7-pin socket.

My experience with Melz 6H8C tubes matches yours and @triod750's , they have clean & detailed sounding but a little bit lean to my taste, I guess that could be the "house sound" of Melz, so Melz 6H12C could have the same signature.

If you like the warmth from RCA 6SN7GTB, you can possibly try the RCA 6SN7GT grey glass or VT-231, they come with the RCA warmth but with better resolution than the RCA GTB's.

If you can run 6080/6AS7 tubes with external heaters, I think you will get much more power from them. Worth a try in my opinion.

 

[triod750]

I would not suggest that you try either 6080/6AS7G or 6BX7GT. Try both. Same external psu, same adapters. But I am sure that 6BX7GT and 6BL7GT are much kinder to the components in Little Dot. @mordy used a computer fan to evacuate hot air from the tubes, not to overheat the amp. I don't believe 6BX/BL7 runs any hotter than 6N6P but 6080 makes the amp very hot. (The adapters and heater input adapters elevate the 6BX7 tubes from the chassis so they don't transmit as much heat to the chassis as 6N6P does. This goes for 6BX7 but 6080/6AS7 produces so much more heat that the distance isn't enough). But if they are good for the music, your phones and your ears....

If you don't try it you will never know. But HD650 don't need as much power as some other phones.

 

[lupoal]

well... heat and capacitors are declared enemy, I'm happy that with 6SN7 the LDII remain quite cold compare to the use wth 6N6P so 6BX7GT are more reassuring to me ... but before to proceed one question (maybe stupid): from 6SN7, or 7n7 with adapter (cheap and very good), to 6BX7GT is the gap in performance worth the efforts? or is mainly matter of fun in doing that (that is also important)?
I'm also wondering if, at this stage, is now better to put attention in, maybe, changing output capacitors... but this is argument for different thread