I own a Divided by 13 FTR37 that has an "half-power" switch which put the power down to 18w changing the power amp class operation from AB to A (cathode bias) AND according to some circuit scheme found around the web shutting off 2 of the 4 6V6 power tubes. In smaller 2 x 6V6 models as the SJT 10/20 where (I guess) it is no possible to shut off any tube it seems that just changing the power amp class operation to class A the power cuts down to 10w from full 20w. Just curious to know if in fact what we have here are different ways to achieve the same result (half power) or maye be there is something wrong in what I know about those amps (also I noticed on the FTR the switch is clearly labeled full/half-power while in the SJT the switch shows class AB/A instead). Thanks for any help on making this matter more clear to me. Ciao! E.