Hi All
I am currently looking at a refurb/ fix of an old (but immaculate conditiomn) magnum ai170 amplifier.
in short it sounds great , but occassionally has a bit of furry distortion on both channels -but one channel more than the other
- not being driven hard-
given its age - I wonder if it may be in need of recapping..
via a process of elimination the preamp appears ok - (tested via feeding tap outputs into another power amp) and bypassing the output stage (feeding outpuit transistors-(TIP 35C's) on the amp via their own power supply does not remove the "distortion""-- so i wonder if the issue is in the main power amp stage prior to output transistors..
Most listening has been via some old B&W DM4's or Stax electrostat headphones.
interstingly the power supply toroid after rectification and filtering putting out about 49.5 v on pos and neg rails
but
Main filter caps are rated at 50v... (!!)
at the very least i will be uprating the main supply caps to something above 60v or so......
i am seeking some schematics etc - despite trawling the net - i have been unable to find anything much on the amp.
far far too nice sounding to ignore.....any ideas out there...?
btw - internal construction is very nice 🙂
many thanks in advance
Cheers
I am currently looking at a refurb/ fix of an old (but immaculate conditiomn) magnum ai170 amplifier.
in short it sounds great , but occassionally has a bit of furry distortion on both channels -but one channel more than the other
- not being driven hard-
given its age - I wonder if it may be in need of recapping..
via a process of elimination the preamp appears ok - (tested via feeding tap outputs into another power amp) and bypassing the output stage (feeding outpuit transistors-(TIP 35C's) on the amp via their own power supply does not remove the "distortion""-- so i wonder if the issue is in the main power amp stage prior to output transistors..
Most listening has been via some old B&W DM4's or Stax electrostat headphones.
interstingly the power supply toroid after rectification and filtering putting out about 49.5 v on pos and neg rails
but
Main filter caps are rated at 50v... (!!)
at the very least i will be uprating the main supply caps to something above 60v or so......
i am seeking some schematics etc - despite trawling the net - i have been unable to find anything much on the amp.
far far too nice sounding to ignore.....any ideas out there...?
btw - internal construction is very nice 🙂
many thanks in advance
Cheers