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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 252

post #3766 of 5877

Hi Artsi,

 

The RCA tube has a date code BW - Feb 1968

 

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CC4QFjAA&url=http%3A%2F%2Fmysite.verizon.net%2Ftubetronic%2FPDF_FILES%2FRCA%2520DATE%2520CODES.pdf&ei=1sdzUvaRL7O_sQSQ8oDYBg&usg=AFQjCNEcbsMGwlSumKFcocuP4HLEcjBDjg&sig2=N_i3wBe8h8W2BbIY1KID4Q&bvm=bv.55819444,d.cWc

post #3767 of 5877

Hi Trolldragon and Mikelap,

 

Thanks for the advice and warnings about the open contacts on my temporary setup.

 

Is there less dangerous voltage on the EF95 setting which is what I am using for the 12A7 tubes?

 

If I always shut off the LD before I make any changes and wait a couple of minutes, does this make it safe to handle?

 

TD - how is your copper adapter coming along?

post #3768 of 5877
Quote:
Originally Posted by superdux View Post
 

i fell for tube mania and ordered the first Voskhod 6ZH1P-EV i saw on Ebay. Then while completing my mammut task of reading this entire thread i stumbled upon the same valves nearly half the price(they were just named differently i think without the Z and a J). damn how could i have not seen? guess the seller had a nice day as i paid him:)

Oh btw i ordered some

JHY-6AK5

from ebay.They are from 1945.They are also unmatched but same production year and month so i hope nothing goes wrong in my amp. So i was wondering about jumper setting?any help pls?

 

6AK5 = EF95, so the same setting as your Voskhod 6ZH1P-EV.

 

And I think JHY =  CBS-Hytron....

post #3769 of 5877
Quote:
Originally Posted by gibosi View Post
 

 

6AK5 = EF95, so the same setting as your Voskhod 6ZH1P-EV.

 

And I think JHY =  CBS-Hytron....


yes they are  CBS hytron

post #3770 of 5877
Hi mordy!

Doesn't matter which modes the amp runs in as long as the Anode wire is exposed it will have high voltage on it, in EF-95 mode the Anode is on terminals 5 & 6, in EF-92 mode all that jumper on the bottom of the amp does is short pin 7 to 5 & 6, then you have 3 terminals with the high voltage exposed.

Working with the power off and letting the amp discharge before doing anything is a safe way to be.

On the Copper adapter... I am still waiting for Chinese sockets delivered by rickshaw across the North Pole to Canada to arrive... I will post it all up with instructions when they do. If you guys havn't moved onto Octal sockets by the time they get here. biggrin.gif
post #3771 of 5877

Hi Gibosi,

 

Just to make sure I am doing things right in wiring for 6DJ8:

 

9 Pin socket                                 Left LD socket                    Right LD socket

 

1 plate triode 1                                     5

2 grid triode   1                                     1

3 cathode triode 1                                 2

4 heater                                                3

5 heater                                                4

6 plate triode 2                                                                                 5

7 grid triode 2                                                                                   1

8 cathode triode 2 and 9 tie together

               

Can I use a jumper for tying together pins 8&9, or do they have to be soldered to the tube pins?

 

Thanks for your input,

 

Mordy


Edited by mordy - 11/1/13 at 12:14pm
post #3772 of 5877
Quote:
Originally Posted by mordy View Post
 

Hi Gibosi,

 

Just to make sure I am doing things right in wiring for 6DJ8:

 

9 Pin socket                                 Left LD socket                    Right LD socket

 

1 plate triode 1                                     5

2 grid triode   1                                     1

3 cathode triode 1                                 2

4 heater                                                                                           3

5 heater                                                                                           4

6 plate triode 2                                                                                 5

7 grid triode 2                                                                                   1

8 cathode triode 2                                                                             2

9 Shield tied to pin 8 at the socket

               

Can I use a jumper for tying together pins 8&9, or do they have to be soldered to the tube pins?

 

Thanks for your input,

 

Mordy

 

No soldering is required.....

 

(My changes in red)

 

I believe that the heaters and the shield need to be on the same adapter, so I have moved the heater connections to the right adapter. (As mine is setup using the right adapter, I know it works). Since you have a breadboard 9-pin socket coming, you tie pins 8 and 9 together with a small jumper wire using the compression terminal blocks located adjacent to the socket on the breadboard. So no soldering is required.

 

And if you want to use 12AX7 tubes, you make the wiring changes using the compression terminal blocks. You do not have to touch the adapters.

post #3773 of 5877

Some relief for this serious tube rolling:

1000

1000

1000

1000

1000

have fun

post #3774 of 5877

If you have your LD set up to use 6DJ8s, but would like to be able to roll an occasional 12AX7, you could build a little adapter:

 

http://www.head-fi.org/t/549508/schiit-lyr-the-tube-rolling-thread/7185#post_9431142

post #3775 of 5877

I have a question about a socket saver if you would have a look if thats the right one for my LDMKIII (i´ve also contacted the seller).

http://www.ebay.de/itm/231071553119?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

i was wondering if i´d need such a socket saver if i would swap tubes maybe 20 or 30 times.

post #3776 of 5877
Quote:
Originally Posted by superdux View Post
 

I have a question about a socket saver if you would have a look if thats the right one for my LDMKIII (i´ve also contacted the seller).

http://www.ebay.de/itm/231071553119?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

i was wondering if i´d need such a socket saver if i would swap tubes maybe 20 or 30 times.

 

I cannot read German, but as it has 7 pins it looks fine to me.

 

But if you think you will swap tubes only 20 or 30 times over the life of your LD, then you don't need these. Some members of this forum have swapped tubes hundreds of times and their sockets are fine.

post #3777 of 5877

thx for the replys guys, i´m really enjoying this hobby!

post #3778 of 5877

For those looking for 6DJ8 RCAs, I don't think RCA ever made these and all I have seen a european rebadges at much less cost. They are therefore ag great bargain. Most are Amperexes, Siemens and I think Mullards.


Edited by Nic Rhodes - 11/2/13 at 6:19am
post #3779 of 5877
Quote:
Originally Posted by Edgard Varese View Post
 

 

It takes about a week or so, quite prompt service.  Good luck with your recovery!

Thank you very much my recovery is going well. It was very prompt service they arrived in 4 days Fed-x all the way. It was actually fun tracking it around the world. I don't know if you can tell but I'm new to computers & stuck in bed so you get your fun where you can LOL. But the good news wot a difference in the sound from the old op-amp i love it it's so much more alive.

    Thanks Bundy

post #3780 of 5877

The BOXZILLA! Got finally this son of a b**** work. And i can say that the box is pretty full of stuff. 

 

1000

 

I rolled to my lil dot mk2 some bigger tubes. All tubes are in use. 6SN7GT is a secret ingredient! Switches are for noval base doubletriode to switch between 6.3 and 12.6v heaters etc. Sound seems to be just like it should be.

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