So the service manual I found online doesn't have a schematic diagram and the main amp section current adjustment says to to connect the ammeters + terminal to 27 and its - terminal to B1 in the schematic diagram?Is this the right way ?
AU-999
- Thread starter Willy6
- Start date
Ok so I did every modification I could find on here and set the bias current with the leads on each side of the fuse holder like the above pic and I also decided to do away with the protection board and just rely on 1 amp fuses for speaker protection and then I hooked up two sets of speakers and it runs fine with speaker A or B but when I turned the knob to speakers A&B both 1 amp fuses blew when I turned the volume up half way?
I read it on one of these AU-999 modification threads where there was some controversy over by passing the protection circuit and relying on the fuses for protection.
Yep I was thinking the same thing because the 1 amp fuse works just fine with 1 pair of speakers.
slimecity
Super Member
I dont have the manual in front of me but recall the original fuses may be 4 amp?
I have been thinking about this and wondering if those fuses will still blow, even when some of us have removed the crowbar circuit. As this removal would obviously change the performance of the protection quite a bit.
I have been thinking about this and wondering if those fuses will still blow, even when some of us have removed the crowbar circuit. As this removal would obviously change the performance of the protection quite a bit.
stereofun
Super Member
I think the fuses would blow regardless, based on their amp rating vs amp draw. The protection circuit as I understand it probes for excessive DC right at the terminal - well after the rail fuses.
I can't remember the numner, but I would stick with fuse amp rating as specified.
P.s ...and use tuner input for your primary source. AUX goes through a small diameter pot and a rotary switch
I can't remember the numner, but I would stick with fuse amp rating as specified.
P.s ...and use tuner input for your primary source. AUX goes through a small diameter pot and a rotary switch
Hopefully they blow if a problem develops cause I really like my klipsch chorus 2s.
So I think I'm gonna stick with 1 or 2 amp fuses just to give me a little reassurance.
I presume he’s not referring to the rail fuses but rather fuses added to the output line that goes to the speakers.I think the fuses would blow regardless, based on their amp rating vs amp draw. The protection circuit as I understand it probes for excessive DC right at the terminal - well after the rail fuses.
I can't remember the numner, but I would stick with fuse amp rating as specified.
P.s ...and use tuner input for your primary source. AUX goes through a small diameter pot and a rotary switch
Right
slimecity
Super Member
Yes these are the ones I was thinking of too - the two screw-in types on the back panel
Does it matter which emitter resistor to measure from?
kevzep
Its all about the Music
No can be either one....
Clip on and dial it up, or down as needed..
Will do Thank you for the input.One question do you change out the green I think Mylar caps?Or change them out?I left them all in place and it sounds pretty good the way it is but I'm always open for upgrades..
kevzep
Its all about the Music
I leave them if they aren't giving any trouble.
The last 999 I did sounds pretty nice, and that had the green caps....
Ok I left the green caps in place I set the bias at 14ma across the emitters and played it for a few hours last night and I must say with your mods in place it really woke this thing up!This just might be my new favorite amp.
