I am looking for mods for my aging RA980BX. I changed the U bridges with silver coaxal wire and decent plugs and now has a far more palpable sound to listen to but I feel there should be more lurking inside.
- Has anyone tried using Vishay resistors in the pre amp section?
- would black gates for small caps be an upgrade?
- Should I take care of the smoothing caps?
I am not very technical and it makes a bit harder because I don't have schematics or anything. Does anyone know a site for schematics?
Last question, would changing the bias in the output section change the sound dramatically and is it potentially dangerous
for the amp. (I live in an area with a very bad power grid, and I mean bad as in huge swings, constant static and blow outs.)
Well enjoy the music.
Giskard
- Has anyone tried using Vishay resistors in the pre amp section?
- would black gates for small caps be an upgrade?
- Should I take care of the smoothing caps?
I am not very technical and it makes a bit harder because I don't have schematics or anything. Does anyone know a site for schematics?
Last question, would changing the bias in the output section change the sound dramatically and is it potentially dangerous
for the amp. (I live in an area with a very bad power grid, and I mean bad as in huge swings, constant static and blow outs.)
Well enjoy the music.
Giskard
. Well the message above was at least very helpful, thanks for the info.Hi,
in my opinion, most of Rotel's amplifiers has well-balanced design. Regular tweaks aren't lead to significant improvements (and easy to get something wrong).
I have RA971Mk2. Only one mod really help to me. This is lowering gain at input stage. With typical CD output level and medium-sensitivity speakers, there is situation when for comfortable listening volume knob must be in positions close to beginning. At middle position - just overloading. After some research found: signal goes through mech.selector and volume control to input amp.stage, based on OPA2604 with gain about 6.
So, need to change feedback resistors for lowering gain, now I live with gain 2.
in my opinion, most of Rotel's amplifiers has well-balanced design. Regular tweaks aren't lead to significant improvements (and easy to get something wrong).
I have RA971Mk2. Only one mod really help to me. This is lowering gain at input stage. With typical CD output level and medium-sensitivity speakers, there is situation when for comfortable listening volume knob must be in positions close to beginning. At middle position - just overloading. After some research found: signal goes through mech.selector and volume control to input amp.stage, based on OPA2604 with gain about 6.
So, need to change feedback resistors for lowering gain, now I live with gain 2.
Hi, audiotux & hienrich,
Greetings to you from India.
Thanks for the feed back. I found 991 was somewhat on brighter side (in 2ch stereo) but powerfull especially in the bottom end. It's excellent for HT applications. IMO found not that satisfactory for pure 2ch stereo. Anyway listening tastes are different from person to person & I'm not supposed to commnet much on that
.
I wish to carry out some minimum tweaks as suggested by audiotux. audiotux my sincere thanks to you for this.
rgds
Raj
Greetings to you from India.
Thanks for the feed back. I found 991 was somewhat on brighter side (in 2ch stereo) but powerfull especially in the bottom end. It's excellent for HT applications. IMO found not that satisfactory for pure 2ch stereo. Anyway listening tastes are different from person to person & I'm not supposed to commnet much on that
. I wish to carry out some minimum tweaks as suggested by audiotux. audiotux my sincere thanks to you for this.
rgds
Raj
Hi;
I've read your responses and they are all very helpfull; the 971 MK2 is a nice balanced little amp which I would not try to tamper with either, unfortunately the 970 and 980 integrated amps are a bit different in that especially the 980 is very harsh and pinchy on top, the U bridges are not so good and I have a feeling that a change of resistors in the preamp (this should only be a few in the signal path) would do wonders in opening the top end a bit.
Diodes, opamps are all great ideas to tinker with. Upgrading internal wiring is good, what wire do you use??
The biggest problem I have right now is the schematics so I know the values.
Well thanks for the input.
enjoy your music and don't strip your soul
Giskard
I've read your responses and they are all very helpfull; the 971 MK2 is a nice balanced little amp which I would not try to tamper with either, unfortunately the 970 and 980 integrated amps are a bit different in that especially the 980 is very harsh and pinchy on top, the U bridges are not so good and I have a feeling that a change of resistors in the preamp (this should only be a few in the signal path) would do wonders in opening the top end a bit.
Diodes, opamps are all great ideas to tinker with. Upgrading internal wiring is good, what wire do you use??
The biggest problem I have right now is the schematics so I know the values.
Well thanks for the input.
enjoy your music and don't strip your soul
Giskard
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