Audiofanboy
100+ Head-Fier
- Joined
- Jan 2, 2013
- Posts
- 453
- Likes
- 20
I asked that question over at "I <3 Tube Amps" and got my arse chewed on hard by the pros there...
Lucky to make it out of there unscathed, but I did manage to get some info from the guru's while running away in sheer terror.
Two of them suggested to run both halves of the tube in parallel as opposed to floating or grounded.
Ponder it over and see what you think...
Lol, yeah, the internet can be a dangerous place to hang out (just look at the other threads here!).
I'd read that one of the options to use a double triode in a single channel gain stage is to parallel both triodes, but everywhere I looked, I saw that this would probably mean some degree of parts to change or adapt to work well (people suggest two separate grid stoppers for example). Besides, it's not like we need the extra current that would come from double dipping triodes. It's extra gain I'd like!
For a 12Ax7 tube, this isn't really a problem, since one side of the tube can be used with the other triode unpowered -unheated. On a ECC88, that's not possible. Apparently, the heated but idle triode would eventually get "cathode poisoning" from such a use over time (years, mind you), meaning that it wouldn't work well the day you decide to use it. Not that it matters, since it's easy to just use another tube altogether when the first triode starts to show signs of fatigue.
The real potential problem is just this floating triode... Which really should be grounded. Then again, I haven't seen or heard anything bad in my amp for the last 2 hours, so it is unlikely to be a huge issue. And I know that some -professional- amps use only one half of a double triode (with the other half grounded, obviously).