[metamorph63]

Hi and Good day to all. I have a question about MKVIIISE: on the circuit board, the sockets of 12AT7 tubes is at 6,3V or 12,6V? I need of an adaptor for install the 6SN7/CV181 tubes instead of 12AT7's and so it's important to know what is voltage...

 

[Maxx134]

Hi and Good day to all. I have a question about MKVIIISE: on the circuit board, the sockets of 12AT7 tubes is at 6,3V or 12,6V? I need of an adaptor for install the 6SN7/CV181 tubes instead of 12AT7's and so it's important to know what is voltage...

6.3v
I tried about $2k worth of the tubes, and already went there with tube rolling of every kind, and feel the best selection was using 6SL7, or 6c8g tube, both with adapter...
If you look at my pic, I am using those type.

 

[metamorph63]

6.3v
I tried about $2k worth of the tubes, and already went there with tube rolling of every kind, and feel the best selection was using 6SL7, or 6c8g tube, both with adapter...
If you look at my pic, I am using those type.

Thank you very much, I will try those tubes...where did you bought the adapters?

 

[Maxx134]

Ebay..
The 6c8g is the prettier bottle type over the 6SL7..
Both are the higher gain version of the 6sn7.

I still have my mk8 amp but now have another more neutral reference amp in my link.

And for desktop level portability, which is what I am focused on currently, is the Sony WM1A/WM1Z

 

[metamorph63]

Ebay..
The 6c8g is the prettier bottle type over the 6SL7..
Both are the higher gain version of the 6sn7.

I still have my mk8 amp but now have another more neutral reference amp in my link.

And for desktop level portability, which is what I am focused on currently, is the Sony WM1A/WM1Z

I've bought the adaptor for 6sn7/6SL7, I have not found an adaptor from 12at7 to 6c8g, but only from 6sn7/6SL7 to 6c8g...anyway, I'm satisfied. I have also an other amp, not a tube amp, a SS, more neutral and powerful, but the sound of the tubes is very interesting...thanks for the advice...

 

[baronbeehive]

And for desktop level portability, which is what I am focused on currently, is the Sony WM1A/WM1Z

I used to be heavily into my IPOD classic 5 or so years ago! Mainly for work, it was permanently glued to my ears. At the time I used to discuss with friends about the lack of a high res portable player, now they are all over the place! Very interesting, I don't really have a need for such a player now though. These Sony's look very high end.

BTW are you doing any work on the other 2 amps now, I know you said you were thinking of finishing the upgrades to your satisfaction. I've not had any need to do anything to mine now, it's good to just be able to enjoy them without having to fault find all the time for a change lol.

 

[baronbeehive]

I've bought the adaptor for 6sn7/6SL7, I have not found an adaptor from 12at7 to 6c8g, but only from 6sn7/6SL7 to 6c8g...anyway, I'm satisfied. I have also an other amp, not a tube amp, a SS, more neutral and powerful, but the sound of the tubes is very interesting...thanks for the advice...

Anything like this will do: https://www.ebay.co.uk/itm/6SN7-To-...758378?hash=item286536706a:g:TrkAAOSwBqpdpY~Z

12Au7 can be substituted for the 12At7 but has lower gain, 12Ax7 could also be used with this adapter as it says.

 

[metamorph63]

Anything like this will do: https://www.ebay.co.uk/itm/6SN7-To-...758378?hash=item286536706a:g:TrkAAOSwBqpdpY~Z

12Au7 can be substituted for the 12At7 but has lower gain, 12Ax7 could also be used with this adapter as it says.

But the bottom pins are for 6SN7/6SL7 tube sockets (correct me if I'm wrong). I have already bought the adapter from 12at7 (bottom socket, Mk8se mount 12at7 sockets) to 6SL7/6SN7 tubes...

 

[baronbeehive]

But the bottom pins are for 6SN7/6SL7 tube sockets (correct me if I'm wrong). I have already bought the adapter from 12at7 (bottom socket, Mk8se mount 12at7 sockets) to 6SL7/6SN7 tubes...

OOPS.... sorry!

You must have used the link I posted before I corrected it. The link in my post above is correct now. Your adapter is correct.

 

[Maxx134]

BTW are you doing any work on the other 2 amps now,

I haven't had time to finish but I already know the preferred caps I want to change all the cathode caps the same nichion and keep the WCF caps same as coupling caps .
Keeping them same and using those nichion for the cathode s should give me most transparency.

The choice of cathode caps was actually from testing various caps on another tube amp, the EC Aficionado.
It's a more straight forward design to test caps..

 

[metamorph63]

OOPS.... sorry!

You must have used the link I posted before I corrected it. The link in my post above is correct now. Your adapter is correct.

Don't worry....

 

[baronbeehive]

I haven't had time to finish but I already know the preferred caps I want to change all the cathode caps the same nichion and keep the WCF caps same as coupling caps .
Keeping them same and using those nichion for the cathode s should give me most transparency.

The choice of cathode caps was actually from testing various caps on another tube amp, the EC Aficionado.
It's a more straight forward design to test caps..

Yes, right, good luck with that! Good quality caps should do well in those positions. Personally I feel the advice on page 1 for bright sounding caps in WCF position is ideal to push out those higher frequencies so I feel the Mundorf is good there but your opinion is good also. I am interested to see if you can get both amps performing similarly like I managed to do, when you get around to it. I feel that your higher end gear might show up the deficiencies that do not register so much with mine.

I see you are still working on the HD800S mod, this is something I might be interested in future, not now though. The priority is to finish with the silver output wires to see if I can squeeze the most transparency out of the amp. That will be the last thing I do on the LD when I get around to it!
.

 

[Maxx134]

The silver plated wire both I used and the designer had as an upgrade was used, but ONLY in the input stage, which is a high impedance input.
The wire I used I placed in beginning thread had also shielding which, like stock wire uses.
This is the suggested method for input wire... A shielded one.

Different job than output amp section which I used twisted OCC copper.

The output wires are a shorter run to output Jacks, and you don't have to go from back there to front.
You can run straight from board to front too.

Anyways you are correct to try brighter/leaner or faster WCF caps in that section.

 

[baronbeehive]

The silver plated wire both I used and the designer had as an upgrade was used, but ONLY in the input stage, which is a high impedance input.
The wire I used I placed in beginning thread had also shielding which, like stock wire uses.
This is the suggested method for input wire... A shielded one.

I used silver plated unshielded for input wires, maybe shielding is an option there when I also finish the output wires, I didn't realise the stock wire was shielded. I concentrated on pure copper originally for output wires and changed partially to pure silver on the basis that the signal from the output tubes was the more important to preserve maximally. I don't know if sound is affected by the input wires, probably is if it was shielded but there are no EMF effects or the like that I can hear, only a completely black background, maybe there is some signal degradation though.

 

[Maxx134]

If you have quiet background then it should be fine.
The chassis is a good shield too.