Marantz 1030 hiss

[Maxxarcade]

I have a Marantz 1030 amplifier that I have recapped, and it sounds great with one exception- The left channel has much louder background hiss than the right. It varies with volume level, so I'm guessing there is a noisey componenet in the preamp. The transistors cross to NTE 85. Anything I should know before I start troubleshooting further?

I also have a Sansui 1000X with the same problem, though not quite as severe.

 

[Maxxarcade]

Well, it ended up being the first transistor I checked on the preamp. I changed all of them out to 2SC2240's, and it sounds amazing now. Almost no noise at all.

 

[Arkay]

That's great that you found the problem.

I was going to suggest that aging resistors sometimes add a bit of hiss/noise, so you might check them, too, and replace any that are drifting away from spec to quieten it further. Modern resistors tend to be quieter, anyway, due to better quality control in production.

 

[Maxxarcade]

I was just thinking about that too. Are the metal film resistors the quieter ones for audio use? I'm not sure what the originals are made of.

Another thing I'm going to do next time, is gain match the transistors. It seems to be fine though.

But I can't believe how much better this little thing sounds on my PC in comparison to the Altec Lansing ACS56 computer speakers I had before. Those things hissed constantly because of the design, and they sounded muddy too. Even with a cheap pair of Sony SS-MB100H bookshelf speakers, it sounds great!