Tweet
I have an amp that was originally built for 2X6L6, and the OT is bassman-size at 4.5K. I've been playing around with 6V6 in it, however, to cut the volume a bit; with 6V6, it puts about 400V on the plates but it's cathode biased, so actual working voltage iirc is somewhere down around 375 at idle. I suspect that running a 16 ohm speaker off the 8 ohm tap to reflect 9K is probably more 'classic' tweedish 6V6, but if I stick with 8 ohm/8 ohm for 4.5K, can I be creating some kind of problem? About the lowest 6V6 impedance I'm aware of are the DR at 6.6K. Any thoughts, anyone?
-
-
The danger is that you will exceed the maximum plate dissipation limit. With a 4.5k OT primary (1.1k to each tube) I'm pretty sure you will. With a 9k impedance it will be close. The best way to check is to plot the load line on the composite characteristic curves. You'll also need to bias the tubes so that the quiescent dissipation is under the limit. Look for red-plating... -
The lowest 6V6 Primary Z I am aware of is what you have: ~4.5K, Masco used this.
That DR primary you mention is often nearer 7K, however with an 8ohm extension speaker installed is ~3.5K...not that I recommend doing so, but Fender clearly though it was OK to.
If your OT is really 4.5K (measured) then I'd try it with 8 & 16ohm speakers and see which you prefer.Comment
-
Thansk for responding guys. This one actually measures just a hair under 4.600 ohms when using the 8 ohm tap. Usually, when I use this OT with 6V6, I run the 8 ohm tap into a 16 ohm speaker but at the moment all I have left are 8 ohm and honestly I really like how it sounds. A touch cleaner, but I swear there is more "harmonic content" or something like that. I just like it. The OT is bassman size, not really worried about that, so as per Translucid's suggestion I'm keeping an eye on the tubes. I have them idling at 11.6W dissipation. So far, running it cranked for 1/2 hour to 45 min., no signes of redplate and no problems... (they are old JAN tubes, though)Comment
Comment