[Harp-L] Sonny Junior 1 Output Transformer upgrade

["Don Z" <dzeller@xxxxxxxxxxx>]

As promised, here's the results of my output transformer upgrade on my Sonny Junior 1.  Thanks muchly to Gary Onofrio (Sonny Junior) and David Allen of Allen amps for your help and advice on the wiring.  In a quest for more output, and as posted here by Sonny a few weeks ago, I switched the original transformer for the heavier(by several pounds)/ beefier Allen output transformer model TO40MT, which is a 40 watt 4/8 ohm upgrade transformer for Vibrolux amps that retails for $59.00 plus shipping.( http://www.allenamps.com/parts.html )
The conversion was fairly simple and took under 1/2 hour( after removal of chassis and the VERY IMPORTANT BLEEDING of the CAPS which can deliver a dangerous shock from an unplugged amp if not shorted out to the chassis first: hire a qualified amp technician to do the work if you have no idea what I'm talking about here!):
The results are very good: the amp is substantially louder (could I estimate 20 % by my ear?) and preserves the tone of the circuit well.  Like a wild stallion, it is a bit more prone to feedback, as one would expect, but using a 12AY7 and a 12AT7 as the phase inverter and preamp tubes respectively I control feedback adequately.  (Going 12AU7 to 12 AT7 or 12AY7 eliminates the feedback almost completely but to my ear cuts the snarl factor a little more than I like.  Sonny suggested trying 12AU7 to 12AX7 but to my ear this wasn't as good as the above).
So, for the cost of a couple of power tubes, the upgrade gets my double-thumbs-up rating and endorsement for those SJ1 owners seeking more stage volume.  Any SJ1 ownwers who need more details on this are welcome to email.
Ahhh, the smell of solder resin!
Zig