power tran buzzing

[sloblues]

hello all,
I have a Traynor Amp with a buzzing power tran. Just a mild buzz and when I place my hands around the casing with slight pressure the buzzing stops. When I run this amp around 75% of full power it occasionally spews out a sharp high pitched 'splat' sound.
Could the power tran be failing, and if so cause the splat sounds?
Traynor Custom Reverb
Model: YSR-1
Power Tran marking (Hammond ? ) 81384
Choke:68347
OPT: 68348

thanks

[Tom Phillips]

I can't comment on the "plat" sound without hearing it but as to the power transformer they can buzz. The buzz can be caused by loose covers, screws and windings. From what you describe ("...with slight pressure the buzzing stops") I suspect that the bell cover many be a little loose. If it were mine, I'd try tightening the four through bolts that hold the bell covers to the laminations and the nuts that hold it all to the chassis.
I doubt that this means that the transformer is failing.
Regards,
Tom

[Dave Curtis, dB AudioTech]

Concerning the high-pitched noise, how old are your tubes?

-DC

[Mars Amp Repair]

Also, how old is the amp? Might be time for re-cap job...glen

[sloblues]

buzzing stopped loose bell housing

funny how the simplest thing gets overlooked ..thanks Tom Phillips ..just needed a little tightening on the bell housing bolts and no more buzz...

as for the splatting ... I scoped out this amp and it is perfectly clean up to 5.5 on the volume at which I am putting out 40watts .... 17.88 VAC at speaker out jack into an 8ohm load ..only if I go to 7 on the Vol knob and hit a hard chord then it 'splats' FIlter and all caps brand new (Using a JJ ft style can 40/20/20/20/ at 500V) all the components are brand new as I put a loaded AB763 board in this amp.
Tubes are 2 TAD 6l6GC biased around 18watts (40 and 42ma at 436VDC on plates)
1 reissue Tung Sol 12AX7, the remaining 2 12AT7's and 3 12AX7's are first time used NOS.
Could it just be that these circuits are not meant to be run full out?
Could the JJ cap can be weak? Would Solen Fast Caps be better?
Could it just be harshness from the silicon rectifier? I have considered installing FREDS

thanks!!