I recently acquired the Dynaco ST-70 set, which was serviced,
power plugs replaced to new, capacitors renewed in preamp.
Amp showed suberb graph on spectrum analizer.
There are original Western Germany made tubes.
(Didn't looks at what exact model number yet).
When I connected it to old speakers Sansui x6700 it worked perfectly
(Sensitivity about 94-96).
After connecting amp with Klipsch KLF-20 with sensitivity 100,
there started constant 'zzzzzzzzzzz' sound.
Like ground sound or I felt it was like sound from tubes buzzing.
Overal sounds amazing, but hum sound is pretty big.
Wondering what it might be and how to fix it.
Do you have any ideas or advices?