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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 316

post #4726 of 10489

Nic, the 6F8G will be fine with the 6SN7 power supply.

 

The BL63 will need 1.3A heater current.

post #4727 of 10489

I know :grin: interesting to see other peoples DIY travels amid tube rolling. Still loads of compatible tubes for not much money with great performance / value to go at. The 6N7 (sort of like 6A6) is fun as are the xx series tubes :) (the 53 is like the 6N7 but different heater).


Edited by Nic Rhodes - 1/19/14 at 11:37pm
post #4728 of 10489

Received some Refektor 6N23P tubes different presentation than octals but very nice nonetheless will listen to other similar tubes like 6DJ8 6BQ7A to see how they compare to each other .year of tubes are 1970 1971 and 1974 meanwhile a  picture.                                                                

post #4729 of 10489
Quote:
Originally Posted by MIKELAP View Post
 

Received some Refektor 6N23P tubes different presentation than octals but very nice nonetheless will listen to other similar tubes like 6DJ8 6BQ7A to see how they compare to each other .year of tubes are 1970 1971 and 1974 meanwhile a  picture.                                                                

 

Very Nice!

I like the 6Н23П except mine is a Voskhod.:D 

post #4730 of 10489

Hi,

 

Here is an update on the GE 6CG7 tube. Trying to wake it up after some 50 years of hibernation. It has been on slow simmer for about 15 hours now.

 

Compared to it's Japanese Raytheon cousin it is darker sounding and not as quick, but the bass is fuller and more hefty. The mid range is good with a lot of detail. Timbre excellent and no sibilance in the treble. Sound stage is impressive. Both the bass and treble are more recessed in the background compared to the Raytheon that is more forward and open sounding.

 

Feel that it may need more time to wake up - will leave it on meanwhile. At this point it sounds very good, but not at the wow level.

 

rosgr63: Welcome to the Little Dot thread - we can all benefit from your expertise and knowledge! Looked up the 6F8G tubes on Ebay. Seems that they need a special adapter with an anode cap, and then this adapter fits into a 6SN7 octal socket. In your opinion, do the 6FG8(BL63) tubes offer better sound than the 6SN7 or 6CG7 tubes?

 

Re the 6CG7 type tubes I have about half a dozen varieties, but all have gray plates. So far I have just listened to two, Raytheon and GE.

 

The little voltage regulator I got can accommodate voltage sources from 4V to 40V and is rated 2-3 amps. I am using an old PS that puts out 20V and 2.5 amps so I think that this setup will accommodate almost all tubes that can be used with the Little Dot. The voltage coming out of it is always about 2V less than what goes in. (This PS won't work for 20V tubes, but it was free)

 

Waiting for my first 8V tubes. Will report when they arrive and compare to the 6V version.

 

Happy tube rolling!


Edited by mordy - 1/20/14 at 10:01am
post #4731 of 10489

Thanks.

 

You'll need an adapter but the 6BL3 is taller and will need a longer cable than the 6F8G.

I am not sure if the top contactor is the same diameter I've never used BL63 tubes.

 

Some 6F8G sound better than their 6SN7 cousins.

 

Try the 25SN7, even cheaper than the 12SN7 the Brimar 13D1 been one of the best.

post #4732 of 10489
Quote:
Originally Posted by mordy View Post
 

The little voltage regulator I got can accommodate voltage sources from 4V to 40V and is rated 2-3 amps. I am using an old PS that puts out 20V and 2.5 amps so I think that this setup will accommodate almost all tubes that can be used with the Little Dot. The voltage coming out of it is always about 2V less than what goes in. (This PS won't work for 20V tubes, but it was free)

 

Yes! Your 20V/2.5A adapter puts out 50 watts. Dividing 50 watts by 6.3 volts, it is capable of delivering almost 8 amps to a 6.3V tube! lol :)

post #4733 of 10489

Now what I want to see is some ELROG 211's rolled here... :D

The tube looks gorgeous!

post #4734 of 10489

Hi G,

 

Since my background is lacking in electronics, is this PS suitable for this application, or should I look for something else? Seems to me that only a small part of the capacity of it is used, which might not be bad at all.

post #4735 of 10489

HI TD,

 

Here is a link to Elrog and the history behind the first German tube manufacturer in 60 years:

 

http://www.6moons.com/industryfeatures/elrog/1.html

 

How much do they cost? If you ask u can't afford them....

 

Elrog makes displays for commercial airliner instruments and utilized their state of the technology in manufacturing these tubes.

post #4736 of 10489
Quote:
Originally Posted by mordy View Post

 

Since my background is lacking in electronics, is this PS suitable for this application, or should I look for something else? Seems to me that only a small part of the capacity of it is used, which might not be bad at all.

 

Yes, your PS is perfectly adequate, and in fact, having more power than you need is certainly not a bad thing. And except for tubes with a heater voltage of 20 volts or higher, you can easily handle any tube you desire. :)

post #4737 of 10489

The 13D1 and 25SN7's draw 150mA so you should be fine running them at 20V.

post #4738 of 10489
Quote:
Originally Posted by TrollDragon View Post
 

Now what I want to see is some ELROG 211's rolled here... :D

The tube looks gorgeous!


I'm down... I'll need 2 of them at.. OMFG no that's expensive lol

post #4739 of 10489
Quote:
Originally Posted by rosgr63 View Post
 

The 13D1 and 25SN7's draw 150mA so you should be fine running them at 20V.

 

His 120VAC to DC adapter puts out a maximum of 20 volts. The voltage regulator reduces this to 18 volts. Is it really OK to run a 25SN7 at 18 volts? But of course if so, his PS has more than enough amperage.

post #4740 of 10489

You can run a 12SN7 at 6V and you never know its not a 6SN7.

I assume (not sure) that 18V would be fine for a 25SN7.

There will be no harm done to the tube, so I would just go ahead and try.

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