I recently bought a set of Bentley FS-150s and a Rotel RB-985 five channel power amp to drive them as well as the centre and surround speakers. It's a brilliant combo, but having gotten over the initial euphoria, I was able to sit down and listen more critically to the system. There was something amiss somewhere, I couldn't quite put my finger on it, so I pulled out my NAD C320 and rigged it up in place of the RB-985 as the "power amp" and listened again. I immediately realised that the mids and especially the highs were dull and a bit muddy on the Rotel. The NAD was exceptional, it didn't have the bass authority of the Rotel, but the mids and highs were crisp and clear, pretty much exactly how I expected the huge upgrade to my system should sound.
The RB-985 is one of Rotel's earliest five channel amps, it's well over 20 years old now, so I decided that it probably needs the electrolytic capacitors to be replaced as they're old and this amp runs quite hot. I phoned up Nilam, the repair magician, and explained the situation to him. No problem he said, bring the amp in and he'll have a look at it. He phoned back a few hours later and said I can come pick it up in the morning, he just wanted to run it for 12 hours, just to be sure it was all 100%. Sheesh! I thought! That was quick to replace the 40 odd electrolytic caps that's in the amp. When I arrived the next day to pick it up, he explained that the caps were all still fine and didn't need replacing, but that the biasing on each channel was waaay off. The one channel was almost operating as a pure class B amp. There were also a few solder joints that needed reflowing, they weren't bad, but they might have been an issue in the future. He recommended that the amp should be checked every 5 to 10 years, depending on how often it's used.
I got the amp back home and rigged it all up again and WOW!!!! What a difference! The mids and highs were spot on, just as good as the NAD and now the bass was even more brutal. I was impressed before, but now I'm gobsmacked! Thanks Nilam, you're a genius! :2thumbs:
So if your amp is older than 10 years or so, I'd definitely recommend having it serviced, you might just be surprised with the result.
The RB-985 is one of Rotel's earliest five channel amps, it's well over 20 years old now, so I decided that it probably needs the electrolytic capacitors to be replaced as they're old and this amp runs quite hot. I phoned up Nilam, the repair magician, and explained the situation to him. No problem he said, bring the amp in and he'll have a look at it. He phoned back a few hours later and said I can come pick it up in the morning, he just wanted to run it for 12 hours, just to be sure it was all 100%. Sheesh! I thought! That was quick to replace the 40 odd electrolytic caps that's in the amp. When I arrived the next day to pick it up, he explained that the caps were all still fine and didn't need replacing, but that the biasing on each channel was waaay off. The one channel was almost operating as a pure class B amp. There were also a few solder joints that needed reflowing, they weren't bad, but they might have been an issue in the future. He recommended that the amp should be checked every 5 to 10 years, depending on how often it's used.
I got the amp back home and rigged it all up again and WOW!!!! What a difference! The mids and highs were spot on, just as good as the NAD and now the bass was even more brutal. I was impressed before, but now I'm gobsmacked! Thanks Nilam, you're a genius! :2thumbs:
So if your amp is older than 10 years or so, I'd definitely recommend having it serviced, you might just be surprised with the result.
