Kalamazoo model 2 sound issues

[UnluckyFett]

Hi all, im fixing a Kalamazoo model 2 and im encountering some problems. when i got it the 6X4 socket was trashed so i replaced that and because i dont have a 6X4 i wired in diodes for the rectifier. after that the amp sounded really nice. clean chimey but when turned up got a nice crunch and grit too it. the only problem was that the trem didnt work. i found an open electrolytic (it goes from pin 3 of both 12ax7s to ground) i replaced it with one of equal value and now the trem works great but the amp sounds horrible. it almost sounds like a blown speaker theres so much flabby distortion. i dont think its the speaker but im going to sub it out eventualy. the only thing i changed was that cap. this is the second Kalamazoo model 2 ive heard with this problem. any ideas? atached is the schematic. i suppose it might be the filter cap but i dont hear the usual ghosting from a bad filter

Thanks,
Frankie

[trobbins]

Frankie, does the sound change if you stop the tremelo oscillator (S2) ? Can you measure the DC voltage across the C5-R13 (the cathode voltage)? The trem signal gets injected in to the amp via that common cathode voltage. For fault finding, you could try removing C5, or changing it to say a 0.1uF film cap, or another electrolytic cap.

Ciao, Tim