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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 237

post #3541 of 7565

Alright... Now that you girls have all mastered the Dual Triodes, I want to see someone roll one of these T-1610's in the LD... :D

 

*


Kronzilla hand made in the old Tesla plant in Prague, 128 hours per tube to make...

Nice tour of the plant here.

:beerchug:

post #3542 of 7565
Quote:
Originally Posted by TrollDragon View Post
 

Alright... Now that you girls have all mastered the Dual Triodes, I want to see someone roll one of these T-1610's in the LD... :D

 

*


Kronzilla hand made in the old Tesla plant in Prague, 128 hours per tube to make...

Nice tour of the plant here.

:beerchug:

Hot Dogs anyone, you can get a sunburn with one of those!

post #3543 of 7565

I was able to make a commitment and went ahead with an order for tubes today.  The Voshkods are what I'll get first to try, then take it from there.

 

post #3544 of 7565

My Yugoslavian Ei 6HM5 tubes finally arrived after 17 days. They are easy to use; just set the amp for EF95 and plug them in.

First impression is that they sound good with strong bass and that the tubes are very musical. Full review has to wait until they are burnt in.

 

What is most impressive however, is the fireworks display every time I turn on the amp. There is a huge flash that could scare you if you did not expect it, and then the glow dies down to a normal level.

 


This flash-up happens in a second or so. Set my camera for burst mode to take six pictures at a time. I am apologizing for the blurry pictures but you get the idea.

 

The other thing is that the build quality seems to be less precise than other European tubes but the sound does not seem to suffer.

 

Interesting tube.....

post #3545 of 7565
Quote:
Originally Posted by gibosi View Post

 

This is great news!! But I want to be sure I understand correctly. All I have to do is tie tube-pin 9 to the cathode in both sockets?

 



I first connected only left channel B7G socket pin 7 to B9A pin 9 and electro-harmonix 6922 right channel humms. But if i connected same pin from right channel too, all extra noise stopped.
Edited by Artsi - 10/17/13 at 2:50am
post #3546 of 7565
Quote:
Originally Posted by mordy View Post

What is most impressive however, is the fireworks display every time I turn on the amp. There is a huge flash that could scare you if you did not expect it, and then the glow dies down to a normal level.

 

 

Interesting tube.....

I found this in another forum on Filament Inrush.

 

Quote: VacuumVoodoo @ The Gear Page
There are tubes (some of the SQ and mil spec class) with guaranteed warm up time 11 sec to 80% of the cathodes operating temperature. This was required on tube based tactical equipment that had to have minimal warm up time.
The initial light flash from the filament is a result of its design. There are also filament designs with guaranteed warm up time that do not flash.

 

It is a normal function of the tube.

:beerchug:

post #3547 of 7565
Quote:
Originally Posted by Artsi View Post
 
Quote:
Originally Posted by gibosi View Post
 

 

This is great news!! But I want to be sure I understand correctly. All I have to do is tie tube-pin 9 to the cathode in both sockets?

 

I first connected only left channel B7G socket pin 7 to B9A pin 9 and electro-harmonix 6922 right channel humms. But if i connected same pin from right channel too, all extra noise stopped.

 

I am still not sure what you mean by "B7G socket pin 7". Pin-hole 7 in the LD socket is not used for these 6-volt double triodes. Are you using modified adapters with pin 7 tied to pin 2?  If so, then I think you are actually connecting tube-pin 9 to adapter-pin 7 which is rerouted to adapter-pin 2 (cathode) in both sockets?

post #3548 of 7565
Quote:
Originally Posted by Artsi View Post

I first connected only left channel B7G socket pin 7 to B9A pin 9 and electro-harmonix 6922 right channel humms. But if i connected same pin from right channel too, all extra noise stopped.

If you are connecting the Dual Triode's internal shield to the Pin 7 on the LD's B7G socket then I would be real careful. In EF95 mode pin 7 connects to nothing, in EF92 mode there is plate voltage on that pin and that would probably not be a good thing to connect to the internal shield.

post #3549 of 7565
Quote:
Originally Posted by TrollDragon View Post
 

If you are connecting the Dual Triode's internal shield to the Pin 7 on the LD's B7G socket then I would be real careful. In EF95 mode pin 7 connects to nothing, in EF92 mode there is plate voltage on that pin and that would probably not be a good thing to connect to the internal shield.

After some investigations i have come to conclusion that DO NOT CONNECT pin 7 from B7G to anywhere! Electro-harmonix 6922 works with no humming if little dot is in EF92 mode or EF95 and 2-7 strap.

post #3550 of 7565
Quote:
Originally Posted by TrollDragon View Post

 

 

It is a normal function of the tube.

:beerchug:

 

If I had such a pair of tubes, I would also want my regular house lights to dim when the amp was powered on, too ... along with the fireworks of the tube.  Oh wait ... my Grados can only handle about 100mW.  On the other hand, scratch the idea of my house lights dimming when I would power on the amp.

 

On another note, I had mentioned a few times in posts how the current tubes for my Little Dot I+ were experiencing some noise issues.  I pointed out that I had used a small bit of emory cloth to clean the pins on the tubes.  To a degree, this did make a difference.  However, some noise could still be detected when I used the headphone amp in my bedroom on the night stand.  Next to the amp was my Squeezebox device, along with another electrical device.  When I moved the amp down to my office area, the noise completely disappeared.  Thus, for those who might experience this issue in the future, keep in mind that some interference can be introduced with the tube amp depending on which other electrical equipment might be near it.

 

Enjoy!

post #3551 of 7565

Here is a photo of this hell-machine adapter that allows to use 6.3v and 12.7v heater double triodes (6DJ8 and 12AX7 at least). It could need some finishing and paint. Filled with epoxy and waiting for drying.

700

post #3552 of 7565
Well done!
post #3553 of 7565
Quote:
Originally Posted by kvtaco17 View Post

Well done!
+1 Very Nice!
Now we just need to see the innards. smily_headphones1.gif
post #3554 of 7565
Off to pick up some cold war 6Ж5П's at the post office this AM. Made by Svetlana and probably pulled from the SS-18 Satan ICBM guidance spares... Or would be great to imagine the usage behind these Russian tubes. biggrin.gif
post #3555 of 7565
Quote:
Originally Posted by Artsi View Post
 

Here is a photo of this hell-machine adapter that allows to use 6.3v and 12.7v heater double triodes (6DJ8 and 12AX7 at least). It could need some finishing and paint. Filled with epoxy and waiting for drying.

 

This looks great, but we would really like to see the inside of your adapter.

 

In my LD 1+, it does not make any difference if the amp is in the EF92 or the EF95 configuration. Sometimes, there is a ground hum and sometimes there isn't. And it seems to be related to pin 9. When there is a hum, I can usually make it go away if I hold the pin with my fingers. So I think I need to find a way to run a wire from a good chassis ground inside the amp and connect it to pin 9.....

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