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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 356

post #5326 of 10504
Quote:
Originally Posted by TrollDragon View Post
 

Well I dug out the old 6H9C again and decided to give it another listen.

 

Changed out the ceramic B9A for a machined pin ceramic Octal socket.

 

Not one of the prettiest tubes when it comes to glow...

 

This Great Album was sent to me and I thought I'd give it a listen with the 6H9C.

I don't remember the 6H9C sounding this good for a cheap soviet tube.

 

Listening with the GMP 8.300D's this Jazz Fusion album has some ultra sweet bass lines, and the 6H9C is providing a really nice punch to the GMP's. I am seriously impressed, a totally different experience than what I remember when I first tried the tube.

:beerchug: 

Thats what i figure to for the price( $5.00 ) compared to the other 6SL7 they sound pretty good .                                                                                                                                                                                                                

post #5327 of 10504
Quote:
Originally Posted by mordy View Post
 

Hi mab1376,

 

If I understand correctly, you are running two 6SN7 tubes as power tubes and another 6SN7 as a driver tube?

 

Could you describe the difference between the IR power tubes and the 6SN7 power tubes? Is there a substantial difference that you feel will make it worthwhile to change from the IR tubes to the 6SN7 tubes?

I'm using a 6SU7GTY as the driver which is closer to 6SL7 tubes.

 

To me the difference seems like an all around extension on all frequencies and much warmer. The IR tubes seem thin sounding in comparison.

 

I would rate the IR tubes as a 7 out of 10 and the 6SN7 tubes as an 8.5 as far as overall SQ. The sound is very real and spacious, one thing that keeps happening with my HD650's is i keep thinking i have my speakers on by accident.

 

if you could do it for the price of some IR tubes or cheaper it's 100% worth it.

post #5328 of 10504

The 6H9C is a Russian 6SL7 tube. IMHO the LD MKIII sounds better with the 6SN7 as a driver tube. Has anybody tried the Russian equivalent 6H8C?

 

These tubes can also be found fairly inexpensive.

post #5329 of 10504
Quote:
Originally Posted by mordy View Post
 

The 6H9C is a Russian 6SL7 tube. IMHO the LD MKIII sounds better with the 6SN7 as a driver tube. Has anybody tried the Russian equivalent 6H8C?

 

These tubes can also be found fairly inexpensive.

Hi Mordy,

    Yes i have that tube compared to my Westinghouse 6SN7GTA i prefer the 6H8C, IMO it have a better sound than my 6SN7.

post #5330 of 10504

ECC40 -  Preliminary impressions:

 

I have been living in ECC40 land for some time now, with 6 tubes in house and 5 more on the way.  My thinking is these are essentially 6SN7s in a different bottle: that is, Philips 6SN7s if you will. The ECC40 was introduced by Philips in 1948 to replace the 6SN7GT. However, as the ECC40 was among the first of the all-glass construction vacuum tubes, the micanol octal base was discarded in favor of the glass rimlock B8A base. Evidently, the rimlock base never really took hold, as it was soon replaced by the ubiquitous B9A base used in the production of 12AUX7s, 6DJ8s and many, many others. Even so, Philips continued to manufacture the ECC40 on a rimlock base well into the 1970's.

 

I currently have tubes manufactured in Chartres, Sittard, Eindhoven and Hamburg, and notice the same country-specific sonic signatures we have noticed before. The ECC40 manufactured in Chartres, warm with rather punchy highs, is similar to the ECC88 manufactured in Suresnes. The Hamburg-made ECC40 has a similar sound signature to the Hamburg-made ECC88s, a bit dry, with nice airy highs, but not as punchy as the highs on the French tubes. And the Sittard-made ECC40 most strongly resembles the Heerlen-made ECC88 and E80CC. (I am told that Mullard manufactured the ECC40 in Britain, but have yet to get one.)

 

In the early 1950's it appears that there was a cluster of perhaps 9 distinct factories and/or production lines located Eindhoven, each with a distinct factory symbol. To date, I have seen ECC40s bearing 5 different Eindhoven factory symbols, and possess three of them. I have yet to spend any significant time with these Eindhoven tubes, as I have a couple more coming, and hope to evaluate them later as a group. However, based on first impressions, they appear to be similar to the Sittard tube.

 

While I am still in the process of evaluating the ECC40, I can say that the Sittard-made ECC40 is very comparable to the Heerlen-made E80CC and Sylvania 6SN7. In other words, it is already one of my favorite tubes. And for those with darker systems, the Hamburg-made ECC40 may well be spot on. Yes, you do need a rimlock adapter, but I think you will find these tubes to be well worth the trouble. Highly recommended.

 

1953 Dario (Sittard-made) ECC40

 

post #5331 of 10504

Sorry for the grainy cell pic

 

post #5332 of 10504

I am sure it sounds great! I too, would like to try a setup with 6SN7 as power tubes, but I do not know how to remove the decorating rings around the tube sockets. These rings do not allow the socket adapter to be seated in the socket. (I tried it with a different socket I have for octal to 12AX7)

 

The adapter rings on sale on Ebay look like they are screwed in from underneath with two screws.

 

Does anybody know how to remove the two rings from the chassis for the power tubes on the Little Dot MkIII?

post #5333 of 10504
My guess would be from inside, the MKIV has the cages screwed down from the top or you can remove the whole plate to take all 4 off at once.

Sorry, you'll have to probably disassemble the amp to take them off, and that is a little bit of work.

You could always add a couple of 9 pin socket savers to allow your adapters to plug in.
Edited by TrollDragon - 3/11/14 at 5:34pm
post #5334 of 10504
Quote:
Originally Posted by TrollDragon View Post

My guess would be from inside, the MKIV has the cages screwed down from the top or you can remove the whole plate to take all 4 off at once.

Sorry, you'll have to probably disassemble the amp to take them off, and that is a little bit of work.

You could always add a couple of 9 pin socket savers to allow your adapters to plug in.

Could those rings just be glued on because they seem to just sit on the chassis for mk3 anyways                                                                                                                                                            


Edited by MIKELAP - 3/11/14 at 6:16pm
post #5335 of 10504
It's possible, a little JB Weld and those rings would be there solid!

A quick tap with a hammer and block of wood will let you know if they are. biggrin.gif

I'll still bet on 2 little Phillips screws holding each on from the underside of the top.

If you took the faceplate off the MKIII you could peek inside and see, it might be just clips but I doubt it.
beerchug.gif
post #5336 of 10504
Probably not clips from looking at that picture, which I missed the first time through... Mobile browser...

Knowing the incredible lack of quality control that the Chinese have, if they did glue them I can guarantee every ring would be crooked and only half glued. biggrin.gif

Socket savers FTW!
post #5337 of 10504

No luck folks.

 

Scrolled through a bunch of 9 pin socket savers for sale. So far all are 27.5 mm wide and too wide to fit inside the decorative ring. Since it took me a week to put together a Vector adapter that I took apart, I would not entertain the idea of opening up the MKIII and put it together again.

post #5338 of 10504
Quote:
Originally Posted by mordy View Post
 

No luck folks.

 

Scrolled through a bunch of 9 pin socket savers for sale. So far all are 27.5 mm wide and too wide to fit inside the decorative ring. Since it took me a week to put together a Vector adapter that I took apart, I would not entertain the idea of opening up the MKIII and put it together again.

 

Well then mordy


All you need to do is buy a pair of socket extenders that are bolted together. Such as this one here (It was the first on that showed up)

http://www.ebay.com/itm/9-pin-tube-amp-tester-socket-savers-can-be-unbolted-/400653261220

 

Remove the bolt, cut the pins to the size you need and wrap a piece of tape around the solder parts. or shrink tube that is not shrunk too much so it bends the pins or a little hot glue to cover up the exposed solder tabs.

 

What ever works to keep it from shorting out against that ring.

:beerchug:

post #5339 of 10504
Quote:
Originally Posted by mordy View Post
 

No luck folks.

 

Scrolled through a bunch of 9 pin socket savers for sale. So far all are 27.5 mm wide and too wide to fit inside the decorative ring. Since it took me a week to put together a Vector adapter that I took apart, I would not entertain the idea of opening up the MKIII and put it together again.

Hey Mordy took the faceplate off and its like TD said theres at least 2 small screws holding the rings .  


Edited by MIKELAP - 3/12/14 at 6:10am
post #5340 of 10504

just ordered a pair of these socket savers:

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160622385954&ssPageName=ADME:L:OC:IE:3160

 

Hoping they will be small enough in diameter to allow them inside the rings!


Edited by samtheman - 3/12/14 at 9:38am
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