[thathertz]

Hi all

I recently purchased this amp which should arrive tomorrow (fingers crossed) :

http://www.head-fi.org/forums/f42/sold-431635/

The amp has (from the description) : Power Input adapter for 12Volt tubes

I'm trying to find out what this adapter actually is.

Is it a tube adapter, a switch or an internal modification (not switchable)
that allows the use of 12 volt tubes?

Hoping someone can help.

Many thanks
Mike

 

[takezo]

the 12v input adapter is just a power cord that's regulated to supply 12volts to the
heater elements of the drive/input portion of your mpx3. from the looks of your link, you
don't have any tubes that can be used with the adapter cord. the tubes listed are driven
by 6.3 volts. tubes that need the 12volts in the drive section are like these: 12sn7gt,
14n7, and 14af7. i think the 12sn7gt is a direct replacement and doesn't require
an adapter. but the others will need the same adapter that is used for the 7n7. (6sn7gt
and 7n7 are electrically identical but the pin-outs are arranged different, thus the need
for an adapter)

the power cord adapter doesn't have switches. you have to plug it in to the back of
the amp when you want to use it. be careful though. if you use the adapter cord
with a standard 6.3v tube it'll probably glow like the sun and die rather quickly.

 

[thathertz]

Quote:

Originally Posted by takezo /img/forum/go_quote.gif the 12v input adapter is just a power cord that's regulated to supply 12volts to the heater elements of the drive/input portion of your mpx3. from the looks of your link, you don't have any tubes that can be used with the adapter cord. the tubes listed are driven by 6.3 volts. tubes that need the 12volts in the drive section are like these: 12sn7gt, 14n7, and 14af7. i think the 12sn7gt is a direct replacement and doesn't require an adapter. but the others will need the same adapter that is used for the 7n7. (6sn7gt and 7n7 are electrically identical but the pin-outs are arranged different, thus the need for an adapter) the power cord adapter doesn't have switches. you have to plug it in to the back of the amp when you want to use it. be careful though. if you use the adapter cord with a standard 6.3v tube it'll probably glow like the sun and die rather quickly.

Perfect answer Takezo.
Just what I wanted.
Cheers!