Name:    Steve Kennedy
Email:   steve@pacair.com  
Subject: 112-RP-100 tube question
Thread:  206
Time:    Fri, 19 Oct 2001 22:51:56 UTC

Not necessarily. For instance, a 112RD-65 made in 1979 would have 6CA7/EL34 tubes in it, but one made in 1980 or 1981 would have 6L6GC tubes.


If your amp was an early 100 watt model it is fully possible that it came from the factory with 6CA7 tubes. If you look at the schematics for the 2100-RP chassis you will notice that earlier amps ("GD-1" circuit) used 6CA7 tubes and switched control sets via a mechanical relay.


The later "GD-2" and "GD-2A" circuits use 6L6GC output tubes and fully solid-state switching.


If yours is a GD-1, I would leave it alone and continue to use the 6CA7 or EL34 tubes. If you really want to switch types it isn't rocket science but careful attention to the details in the schematics will be required to ensure a clean and correct substitution and rebias.


Steve