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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 326

post #4876 of 10574
Quote:
Originally Posted by mojorisin35 View Post

Anybody have a 1975 Voskhod 6n23p they would sell me? My Russian connection disappeared on me, I had 3 ordered but he close up shop. Thank you gary

Ever try 6BQ7A sound good and there cheap.

post #4877 of 10574
Quote:
Originally Posted by MIKELAP View Post
 

Hi Mikelap,

      since i'am using 12AU7 meaning my setup should be like what you have in the picture(12AX7)?Now i'm running 12AU7 on a 6DJ8 setup did i do any harm to my LD?THANKS!

post #4878 of 10574
Quote:
Originally Posted by i luvmusic 2 View Post
 

Hi Mikelap,

      since i'am using 12AU7 meaning my setup should be like what you have in the picture(12AX7)?Now i'm running 12AU7 on a 6DJ8 setup did i do any harm to my LD?THANKS!

Exactly, to be honest i dont know . do you have the tube list of the tubes we can use with  our different adapters they are on page 267 i printed that tube list theres the 6DJ8 types ,the 12AX7 and the 6SL7octals i always double check to make shure i dont  use the wrong tube .

post #4879 of 10574

Hi,

 

I am using an external voltage regulator. We have been told to shut off the LD amp and wait several minutes (5-10Min?) when changing tubes so that the capacitance of the amp dissipates.

 

Now, when I have an external source to power the tube heaters, do I have to wait, or can I just shut off the voltage regulator and change tubes right away?

post #4880 of 10574
Quote:
Originally Posted by MIKELAP View Post
 

Exactly, to be honest i dont know . do you have the tube list of the tubes we can use with  our different adapters they are on page 267 i printed that tube list theres the 6DJ8 types ,the 12AX7 and the 6SL7octals i always double check to make shure i dont  use the wrong tube .

THANK YOU Mikelap!Yes i will check out Page 267   i feel bad though that i can't used adapter on my LD 1+ due to Noise.I'am looking forward to make my octal adapter as soon as my parts arrive then i will Bug you guys for the schematic for octal adapter.I will stop using 12AU7 on a 6DJ8 adapter  again THANK YOU!

post #4881 of 10574
Quote:
Originally Posted by i luvmusic 2 View Post

 

      since i'am using 12AU7 meaning my setup should be like what you have in the picture(12AX7)?Now i'm running 12AU7 on a 6DJ8 setup did i do any harm to my LD?THANKS!

 

No, you have not hurt the LD or the tube. Nothing to worry about.

 

The only difference between these two configurations is the way pins 4, 5 and 9 are configured. In a 6DJ8 socket, pin 9 is tied to pin 8, the right cathode. But since pin 9 is part of the heater circuit on a 12AU7, you connected the heater to the right cathode!  And yes I can imagine that it was very noisy. lol

 

And if you will rewire your socket properly for your 12AU7, it will be much quieter. :)

post #4882 of 10574
Quote:
Originally Posted by mordy View Post

 

I am using an external voltage regulator. We have been told to shut off the LD amp and wait several minutes (5-10Min?) when changing tubes so that the capacitance of the amp dissipates.

 

Now, when I have an external source to power the tube heaters, do I have to wait, or can I just shut off the voltage regulator and change tubes right away?

 

I suspect that the reason for this recommendation doesn't have anything to do with the heater circuit. I think it has more to do with the 100 volts or so on the plates. If so, then this recommendation would still be valid. However, this is just a guess on my part.... Perhaps someone else who understands this better will lend his/her advice.....

 

That said, I have never waited..... 

post #4883 of 10574
Quote:
Originally Posted by gibosi View Post
 

 

No, you have not hurt the LD or the tube. Nothing to worry about.

 

The only difference between these two configurations is the way pins 4, 5 and 9 are configured. In a 6DJ8 socket, pin 9 is tied to pin 8, the right cathode. But since pin 9 is part of the heater circuit on a 12AU7, you connected the heater to the right cathode!  And yes I can imagine that it was very noisy. lol

re

And if you will rewire your socket properly for your 12AU7, it will be much quieter. :)

THANK YOU!I will build one for octal soon so no need for me to rewire.

post #4884 of 10574
Quote:
Originally Posted by gibosi View Post
 

 

I suspect that the reason for this recommendation doesn't have anything to do with the heater circuit. I think it has more to do with the 100 volts or so on the plates. If so, then this recommendation would still be valid. However, this is just a guess on my part.... Perhaps someone else who understands this better will lend his/her advice.....

 

That said, I have never waited..... 

What i do is shut off Littledot but let volume turned up until music fades away due to lack of current once i dont ear the music i remove the tube.

post #4885 of 10574

Here are all the schematics Artsi made for different adapters and page 267 with the tubes we can use on those adapters                                                                                                                                                                            

 

6V tube types
 
ECC88 6DJ8 6N23P CV5358 M3624        0.35A 33x
E88CC 6922 CCa CV2492 CV2493 9622  0.30A 33x
E188CC 7308 CV4108                         0.35A 33x
E288CC 8223                                    0.47A 25X
ECC85 6AQ8 B719 6L12                      0.44A 57X
ECC86 6GM8 6N27P                           0.30A 14X
ECC189 6ES8                                   0.36A 31X
ECC804 6GA8 6/30L2                         0.30A 18X
ECC812                                          0.44A 50X
ECC865                                          0.44A 58X
ECC180 6BZ7 6BQ7 6BS8 6T27           0.40A 36X
6N2P 6CC41                                    0.34A 100X
6BK7                                              0.45A 40X
6BC8 6BZ8                                      0.40A 35X
PCC88 7DJ8                                     0.30A 33X
6AU7                                              0.30A 20X
6AX7                                              0.30A 100X
6BX8                                              0.40A 25X
6CH7                                              0.40A 36X
6DT8                                              0.30A 60X
 
 
 
12V tube types
 
ECC83 12AX7 B339 95-127-01 6L13 CM1        0.30A 100X
ECC82 12AU7 B329 95-126-01 CC82E CV491  0.30A 17X
ECC81 12AT7 B152 CC81E CV455                 0.30A 60X
E81CC 12AT7WA CV6091 6201                     0.30A 60X
E82CC 6189 M8136 6189W                         0.30A 17X
E83CC 12AX7WA 6057                              0.30A 100X
E180CC CV8431 7062                               0.40A 50X
E181CC                                                  0.40A 32X
ECC186 12AU7WA 7316                              0.30A 17X
ECC802S                                                 0.30A 17X
5751 GL5751 CK5751 CV4017                      0.35A 70X
5814A CK5814-A                                      0.35A 17X
5963 CV3900                                           0.30A 21X
5965 6829                                               0.45A 47X
6679                                                      0.30A 60x
7025                                                      0.30A 100X
12AD7                                                   0.45A 100X
12DF7                                                   0.30A 100X
6680                                                     0.30A 20X
6211                                                     0.30A 27X
12AZ7                                                   0.45A 60X
12AD7                                                   0.45A 100X
12AV7                                                   0.45A 40X
12AY7 6N4P                                           0.30A 40X
12DM7                                                   0.26A 100X
12DF7                                                   0.30A 100X
12DT7                                                   0.30A 100X
12U7                                                     0.30A 20X
6072                                                     0.35A 44X
6681                                                     0.30A 100X

Edited by Artsi - 10/21/13 at 1:57pm

                                                                                                                                                                                                                                                                                                                                            

Here is small list of octal tubes that i could recommend to use with little dot.

 

Driver octals:

6SL7GT = VT-229     Classic type
= CV1985
6SL7W                    Sylvania
6SL7WGT                Rugged version with smaller parts
6SL7WA                  Military version
6SL7GTB                 Lower base
6SU7GTY                Better quality and balance? Tung-Sol
6SU7WGT = 6188     Ruggedized and bantam construction
ECC35                    European version with 0.4A heater
6N9S (6H9C)           Russian
6N9M (6H9M)          Russian mini version
1579                      Russian, better quality?
6N9P                     Chinese
6N9P-T                  Chinese, better quality?
6113                     Low microphonic?
5691                     Better quality? 0.6A heater

 

Power octals:

6SN7GT = VT-231     Classic
6SN7GTA                 More power?
6SN7GTB                 Like -A but with faster heating
6SN7GTY = CV1988   Better quality?
6SN7WGTA              Ruggedized and bantam construction
6SN7W                   Sylvania
5692                      Better quality?
6N8S (6H8C)           Russian
1578                      Russian, better quality?
6N8P                     Chinese
6N8P-T                  Chinese, better quality?

 


   

post #4886 of 10574

THANK YOU MIKELAP/ARTSI For Posting those schematics and tubes lists!I should be receiving all my parts within next week i ordered it locally this time so hopefully will be here in few days.

So if I'm going to make one for octal driver tubes adapter which PIN is for the separate Power adapter?

post #4887 of 10574
Quote:
Originally Posted by i luvmusic 2 View Post
 

THANK YOU MIKELAP/ARTSI For Posting those schematics and tubes lists!I should be receiving all my parts within next week i ordered it locally this time so hopefully will be here in few days.

So if I'm going to make one for octal driver tubes adapter which PIN is for the separate Power adapter?

use those types of adapters Gibosi nows this better than me.                                                                                                                                                                                                                                                                           

post #4888 of 10574

post #4889 of 10574
Quote:
Originally Posted by MIKELAP View Post
 

 

As you can see from the above pin diagram, you would connect your external heater power supply to pins 7 and 8.

post #4890 of 10574

THANKS! so it will work without separate power adapter reason i asked the Bravo audio Ocean power adapter is 24V-1.5A i'am thinking to used that as power adapter for 6SL7 and i ordered the regulator as will.

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