12-02-2023, 03:12 PM
Thank's for your suggestions, yes could be a number of things. The S-99 uses a GZ34 for rectifier and I must admit I am using a 'cheap' (relative to a Mullard) brand normally for guitar amp use, you could say it is the 'hum' in the background before the band get's going!. I see you can get silicon/diode plug in replacement, I might get one and see what difference it makes. I cannot afford to be a purist!. It could well be a earth loop as I am using the S-99 in question driving a pair of Kef Concerto's, another S-99 with some Kef 104's, a pair of MA-12's with another pair of 104's and an old Sony receiver with Wharfedale Diamond 7's. I run these all at the same time from music off my computer, so the wiring does get a bit complicated. The hum from this particular S-99 is very low and quiet and admittedly the computer makes more noise!. I am renovating a Heathkit USC-1 pre-amp to go with the MA-12's, And another S-99 to go with another pair of Concerto's. I have, I don't think I will get all this in my 8ft x 10ft room!. I think I will have to bung some of this on Ebay, who knows, in the move the hum might dissapear!. Thank's all.
