Marco Pancaldi
Active member
- Joined
- Feb 19, 2006
- Messages
- 36
Hello,
need help:
1 - line stereo channels have +4/-10 switches: when I use the -10 (more gain) option with an unbalanced input (tip-sleeve plug), after some time the channel "collapse" to very low level with awful distortion. I mesured huge (about +5V) DC present on the input jack with T/S plug. If I switch to +4 and back to -10 the channel "resets" to normal functioning for some time.
In other terms the -10 setting is not compatible with unbalanced plugs: this combination sets immediatly a 5V DC on the plug.
The problem is on all 4 stereo channels, so I suspect an error in design (I tried another identical mixer with same problem).
This is the channel input schematic: http://www.2shared.com/photo/_aFI1hn9/xenyx1622-linein.html
2 - the headphone out is broken in one channel. The other channel have big (more than 14V) DC, near to the positive power rail. I need new 4580 opamps to repair it but I don't know if there is a fault in the circuit in this case also. Schematics: http://www.2shared.com/photo/8iD5w3s1/xenyx1622-phonesamp.html
3 - in case someone is intrested, this is the switching complete supply: http://www.2shared.com/photo/NUT7FBJ3/xenyx1622-power.html. Any info about good simple modding welcome.
Thanks!
m.p.
need help:
1 - line stereo channels have +4/-10 switches: when I use the -10 (more gain) option with an unbalanced input (tip-sleeve plug), after some time the channel "collapse" to very low level with awful distortion. I mesured huge (about +5V) DC present on the input jack with T/S plug. If I switch to +4 and back to -10 the channel "resets" to normal functioning for some time.
In other terms the -10 setting is not compatible with unbalanced plugs: this combination sets immediatly a 5V DC on the plug.
The problem is on all 4 stereo channels, so I suspect an error in design (I tried another identical mixer with same problem).
This is the channel input schematic: http://www.2shared.com/photo/_aFI1hn9/xenyx1622-linein.html
2 - the headphone out is broken in one channel. The other channel have big (more than 14V) DC, near to the positive power rail. I need new 4580 opamps to repair it but I don't know if there is a fault in the circuit in this case also. Schematics: http://www.2shared.com/photo/8iD5w3s1/xenyx1622-phonesamp.html
3 - in case someone is intrested, this is the switching complete supply: http://www.2shared.com/photo/NUT7FBJ3/xenyx1622-power.html. Any info about good simple modding welcome.
Thanks!
m.p.
