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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 429

post #6421 of 10495
Quote:
Originally Posted by i luvmusic 2 View Post
 

Just wanna say wow a bit more power in bass would be perfect setup.

These tube setup makes me thinking of butchering my MK III put it in a bigger case similar to what i did to LD 1+ and install a case fan.

post #6422 of 10495
Quote:
Originally Posted by kvtaco17 View Post
 

I though the Tung-Sol/Chatham tubes all had top getters and earlier examples had grey glass bottoms and new examples had clear bottoms?

 

I suspect that over the years, as with most tubes, the construction changed. However, I have a pair of Chatham 6AS7's that look very similar to i luvmusic 2's. Mine have two bottom D getters, and of course, clear tops. And unlike the RCA's, no shields below the bottom mica. I am beginning to believe that of the American manufacturers, only Tung Sol and RCA manufactured these tubes. All the GE, Sylvania, Westinghouse and Raytheon that I have seen so far appear to my eyes to be rebranded versions of these two. There are also quite a few rebranded Russian 6AS7G's out there and these look quite similar to the Tung-Sol. However, the top shield is taller and of course, they have the flying-saucer getters.

 

For example, my guess is this GE was manufactured by Tung Sol:

 

http://www.ebay.com/itm/151300296001?

 

And these two Amperex. The one of the left may well have been manufactured in England but it has the tall top shields (and probably saucer getters), and is likely of Russian origin. And the one on the right with bottom shields is likely an RCA:

 
 

To be clear, I am speaking only of the coke-bottle 6AS7G. The 6AS7GA appears to have been more widely manufactured.

post #6423 of 10495

Hi G,

 

Which re-branded Coke bottle 6AS7G tubes are most likely to be Tung Sol tubes?

post #6424 of 10495
Quote:
Originally Posted by mordy View Post

 

Which re-branded Coke bottle 6AS7G tubes are most likely to be Tung Sol tubes?

 

I don't know.... It appears that RCA manufactured many more 6AS7's than Tung Sol, so most of the rebrands I see were made by RCA. In the end, all you can do is look at the construction. If it has shields below the lower mica, it is very likely an RCA. If there are no shields below the lower mica it is likely Tung Sol or Russian.

post #6425 of 10495

 I took TD's advised about connecting the heater wires in series and it workout well the Desktop PS 12V output is now divided into two sections one for MK III's power heaters in series(6AS7/6080 and 6S.. tubes) and the other section is for the 12A regulator for driver tube and something else it free up some load for 12A regulator.  Again Thank You Mr. TD! Oh and the sound is amazing the bass is really extended  deep and the details are superb nuh JUST KIDDING!:atsmile:

post #6426 of 10495

Anyone here from GTA area wants to buy a one 5A and one 3A step down regulator with display?

post #6427 of 10495
You are most Welcome ILM2! basshead.gif
post #6428 of 10495
Quote:
Originally Posted by gibosi View Post
 

 

The driver and power circuits are separate and the heaters are powered externally, so it should work. But I don't know that anyone has tried it yet.

Thanks G! i've tried this last night it's a nice setup.:beerchug:  

post #6429 of 10495
Quote:
Originally Posted by i luvmusic 2 View Post
 

These tube setup makes me thinking of butchering my MK III put it in a bigger case similar to what i did to LD 1+ and install a case fan.

 

Sure was a sad loss re your Chatham...they are seriously good tubes. But fear not, vacuumtubes.net have them for $20 ea.

 

And if you do butcher your MKIII, do your fellow MKIII owners a big favour and try to see if there's any (relatively) easy way you can get rid of those pesky rings, so y'all can do away with those even peskier extenders, lol! -  I'm sure the tubes would say "thank you", and make things look neater...GOOD LUCK. ( Mind you, mordy's trick of drilling through the extenders to take the heater wires is really neat!).

post #6430 of 10495
Quote:
Originally Posted by mordy View Post
 

Here is a little update on using the 6080 2.5A tube as a power tube. At this point I am waiting for a second 5A voltage regulator from China, but couldn't resist trying out one channel with a 6080. Picked a 6080 RCA that only earned a so-so rating as driver tube (my notes say 'murky") just in case Something Would Happen.

 

In order to use it in the LD MKIII it is first plugged into an octal to 9 pin adapter; then into a 9 pin extender to fit inside the ring surrounding the socket. This extender was taken apart and pins #4 and 5 were de-soldered and removed and replaced with two wires going to the external voltage regulator. This necessitated drilling a hole in the side of the extender socket to allow for the two wires to exit neatly.

 

The tube complement features an all star set up of the 1957 subminiature 6832 as driver (using the built in LD power supply), a 1957 Tung Sol 6SN7GTB as power tube for the left channel (LD powered) and the 1962 RCA 6080 as power tube for the right channel, using the external 5A PS.

 

A trial run indicated that the amp was getting warm. After an hour it was quite warm, but  not too hot to touch. Out of caution I installed a fan to cool off the amp. Here are a couple of pics:

 

Here is a close up of the extender showing the two wires coming out and teeth #4&5 missing. Used a little piece of white sticker to mark off the right pins and a little piece of blue to line up with the indentation on the top so that it goes together correctly.

 

 

Here is the fan assembly. The fan comes from a an old PC power supply and was picked for being fairly quiet. The power supply is a 12V wall wart that once powered a router. The plastic fasteners are used to tie the fan to my equipment rack in such a way that the fan sucks away the hot air instead of blowing directly on the amp. If you touch the 6080 you could burn yourself (ouch, just did), but the fan lowers the temperature of the amp chassis significantly.

 

Here is the triple dual triode (tongue twister?) line-up. The 6832 is swinging to the music like a buoy on the ocean. (Finally got the nail polish insulation but have yet to decide on fire engine red or turquoise blue.)

 

The sound is fabulous with a glorious bass and treble (and this is with the worst sounding 6080 I have!). Will have to try to better sounding 6080s and the coke bottle 6AS7 RCA as well. Meanwhile I am just enjoying the sound. Did I mention that this set-up is very quiet as well?

 

Here I have to quote hypnos 1 on the achievements of the members on this forum:

 

Unorthodox?...AGREE . But I would also venture to add : resourceful; pioneering; fascinating; educational; rewarding, BRAVE...and not a little MAD! But isn't this precisely what so often results in the greatest quantum leaps in any endeavor? (And, no doubt, been a source of a little amusement for the 'purists', lol!).

 

Whatever, hopefully what has been achieved is proving to be of great benefit to those LD owners who are now enjoying a level of sound from their lowly machines way beyond what may have ever been thought possible (well, it is for me anyways!). And hopefully also for those yet to come...

 

Maybe alternating red and blue? LOL......

 

Hey mordy.

 

Sooo glad you have finally managed to see/hear for yourself what this move can do...just wait 'til you get TWO really good 6080s/6AS7Gs in the hot seat!..I am smiling for you already, lol! :beerchug: 


Edited by hypnos1 - 6/7/14 at 9:15am
post #6431 of 10495
Quote:
Originally Posted by hypnos1 View Post
 

 

Sure was a sad loss re your Chatham...they are seriously good tubes. But fear not, vacuumtubes.net have them for $20 ea.

 

And if you do butcher your MKIII, do your fellow MKIII owners a big favour and try to see if there's any (relatively) easy way you can get rid of those pesky rings, so y'all can do away with those even peskier extenders, lol! -  I'm sure the tubes would say "thank you", and make things look neater...GOOD LUCK. ( Mind you, mordy's trick of drilling through the extenders to take the heater wires is really neat!).

 I did opened my MK III halfway.Back when i was butchering the 1+ IMO no other easy way to removed those rings without removing the MK III's PCB if you removed the PCB you can access those two screws per ring holding the rings from the bottom of the case..

post #6432 of 10495
Quote:
Originally Posted by i luvmusic 2 View Post
 

 I did opened my MK III halfway.Back when i was butchering the 1+ IMO no other easy way to removed those rings without removing the MK III's PCB if you removed the PCB you can access those two screws per ring holding the rings from the bottom of the case..

 

Oh dear...looks like you MKIII guys are well and truly bu*****d, lol!...I did tell you to go get yourselves a MKIV SE :wink_face:...they do sometimes seem to appear on the 2nd-hand market (but not often! :().

 

Ah well, it seems you can all still get GRRREEAT results, regardless...:popcorn:.

post #6433 of 10495
Quote:
Originally Posted by hypnos1 View Post
 

 

Oh dear...looks like you MKIII guys are well and truly bu*****d, lol!...I did tell you to go get yourselves a MKIV SE :wink_face:...they do sometimes seem to appear on the 2nd-hand market (but not often! :().

 

Ah well, it seems you can all still get GRRREEAT results, regardless...:popcorn:.

How did you removed yours?The BH Crack would be my next amp.


Edited by i luvmusic 2 - 6/7/14 at 11:47am
post #6434 of 10495
Quote:
Originally Posted by gibosi View Post

 

And these two Amperex. The one of the left may well have been manufactured in England but it has the tall top shields (and probably saucer getters), and is likely of Russian origin. And the one on the right with bottom shields is likely an RCA:

 

 

The one on the left is clearly a Svetlana. Note the distinctive bottle shape.

post #6435 of 10495
Quote:
Originally Posted by i luvmusic 2 View Post

How did you removed yours?The BH Crack would be my next amp.
The gold anodized plate with the tube guards comes off the MK IV from the top. smily_headphones1.gif

Crack with Speedball, will be a sweet amplifier.
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