RD112-100 Noise on Distortion channel

I've had my RD112-100 (EL34's, EV speaker, solid state phase splitter and black logo background) for 15 years. I figure it was build in 1979 or thereabouts. It's only ever had home use and has been well looked after. The distortion channel has always been very noisy compared to the "clean" channel (which I figured was normal), however after finding this site with its availability of MM knowledge & resources, I'm now questioning whether this should be the case. Normally for home use, I have the gain on "4" and volume on around "1", so we're not talking about high volumes here. Is there anything unusual about this or am I becoming paranoid ....

Because the amp DOES have higher apparent gain in the Distortion mode, you WILL get additional noise... especially if your guitar has single-coil non-humbucking pick-ups.
Whether this is "normal" for your situation would depend on the nature and character of the noise. If you have the opportunity to try another amp of the same model with your guitar, does the second amp sound the same or is yours different?

Thanks Steve. I figured it was probably "normal" (it's always been the same and is no worse than when I first bought the amp), however you start questioning things when you read the various posts on this site ....