Hi y'all.
Recently I was able to buy a Luxman C03 preamp with a Luxman M120a power amp for a bargain (€150).
The sound with my Visoniks was better compared to the sound of my Naim nait XS. Don't get me wrong the Naim is great, but the bass was too much with my speakers.
So the Luxman combo sounded good but needs some love.
In the C03 there were clearly some issues with two power supply capacitors. See pictures.
I replaced them by thexe nichicon caps: LLS2A332MELA
Specs: https://be.farnell.com/nichicon/lls2a332mela/cap-3300-f-100v-alu-elec-snap/dp/8813329
The M120a was really heating up and was smelly. I cleaned it thoroughly and set it's bias correct. It was out of control: up to 200mA instead of a stable 70mA.
Although there was something unclear in the schematics about the testing points for the fuse 801, in the end I did find the correct testing points, zo the bias should be okay right now.
Now: after hooking it all up again, letting it play for a few hours: I do find the bass again somewhat overwhelming.
Kind regards!
Gr
Will
Recently I was able to buy a Luxman C03 preamp with a Luxman M120a power amp for a bargain (€150).
The sound with my Visoniks was better compared to the sound of my Naim nait XS. Don't get me wrong the Naim is great, but the bass was too much with my speakers.
So the Luxman combo sounded good but needs some love.
In the C03 there were clearly some issues with two power supply capacitors. See pictures.
I replaced them by thexe nichicon caps: LLS2A332MELA
Specs: https://be.farnell.com/nichicon/lls2a332mela/cap-3300-f-100v-alu-elec-snap/dp/8813329
The M120a was really heating up and was smelly. I cleaned it thoroughly and set it's bias correct. It was out of control: up to 200mA instead of a stable 70mA.
Although there was something unclear in the schematics about the testing points for the fuse 801, in the end I did find the correct testing points, zo the bias should be okay right now.
Now: after hooking it all up again, letting it play for a few hours: I do find the bass again somewhat overwhelming.
- Could the new ps capacitors of the C03 pre have something to do with it?
- Do they need some break in?
- Are they the right ones?
- Something else I'm missing?
Kind regards!
Gr
Will
Attachments
I am going to answer you because you have shown perseverance with your PMA 2000.
Start by checking that your preamp is set to the correct mains voltage.
Then, with the service manual, check the voltage before and after the regulators.
It will be a good start.
Start by checking that your preamp is set to the correct mains voltage.
Then, with the service manual, check the voltage before and after the regulators.
It will be a good start.
Maybe there is nothing wrong with the power supply capacitors.
They look like they are bulging, could be only the plastic top cover that is deformed, as mostly is the case.
Before replacing these I would check them with a good capacitor meter.
Will check later on! But is this relevant? As I’ve only replaced these power supply capacitors?
Could really be true! Check these measurings… but why are they bulging then.. might be a last warning? …
Aside the originals being good/not good. Are the replacements any good?
I have seen the bulging of the plastic top plate of these capacitors many times, the capacitor itself being perfectly flat.
I think it is caused by the higher temperature inside the amplifier.
I do not think it damages the capacitor.
Recapping sometimes can change the sound of the amplifier.
I only replace electrolytic capacitors if they are really defective.
I have tested 40 year old ones that measured better than new ones!
I think it is caused by the higher temperature inside the amplifier.
I do not think it damages the capacitor.
Recapping sometimes can change the sound of the amplifier.
I only replace electrolytic capacitors if they are really defective.
I have tested 40 year old ones that measured better than new ones!
I would rather expect 0.05Ω ESR from an old but good enough 3300uF/50V. This type of component tester isn't as precise for ESR as dedicated 100kHz meters nonetheless. For example on one same tester I just tried a 1000uF/25V Nippon Chemi SL pulled from an Akai tuner made in 1979. Reads 986.1μF 0.00Ω ESR and 0.8% Vloss. This capacitor returns a more realistic 0.045Ω with a Bob Parker's Blue2 ESR meter.
As a conclusion do compare alike known good caps on this component tester finding what to expect as passable for the questionable caps ESR readings.
As a conclusion do compare alike known good caps on this component tester finding what to expect as passable for the questionable caps ESR readings.
There are 4.7uF and 47uF bipolar coupling caps at the phono and flat amp's outputs. Old BP tend to go bad. Higher on ESR, leaking, etc.
Even if slightly bad they can still affect the passing through signal. Better refresh those with Nichicon ES or alike. C2027,2028,7027,7028.
Few 10uF polar coupling caps in the tone amps inputs & outputs to maybe also check. C4005,4006,4007,4008,4013,4014.
