RGR Model 4 Pre Amp ....HUM QUESTION

Leave the tone button pushed in?

Which way is on? Are the tone controls turned way up when you engage the button? If they are turned up, set them to 0 or the flat position. Just a thought.

How long have you had this preamp? Have you made any power amplifier or other  changes? These are fairly old and have been known to have some cold solder issues.

Posted the same question twice and then don't respond to answers. 

Thank you for input,

I too have the same hum problem with my RGR 4. It is only on the right channel. For awhile I have been plagued by a right channel hum coming from my Sumo Andromeda amp. I was resigned to replacing one or both power supply caps. After reading your post I tried the RGR 4's tone button. Voila, pushed it in and hum GONE! That's a lot of worry gone! I really like the Andromeda with the DCM Time Windows and will continue to use it! The RGR 4 also sounds fine - as long as I leave the tone button pushed in! 

@rocky1313 : Thanks for your post! Otherwise I would have done an unnecessary cap job on the Andromeda amp - and still had the right channel hum problem!

Tone button IN means the tone control circuit is engaged. Just leave it IN to eliminate hum. Probably just a quirk of some of the RGR 4’s. Any other owners notice the same thing? My first RGR 4 back in 1980 was hum-free for all its life (20+ years). No.2 bought five years ago has the right channel hum problem with tone circuit OUT. 

The RGR 4 was in 1980 a giant-killer preamp designed by Robert Grodinski of pro-audio RG Dynamics fame. Sonically as good as - or better! - than the then- current champ - the $4500 Levinson ML7. So for $650 one could buy a SS preamp in the same sonic class as the Levinson.

After reading your post I tried the RGR 4's tone button. Voila, pushed it in and hum GONE! 

I nailed it on the first post, lol. On a preamp that old I don't think I would spend any money on a repair unless you were really married to it, not worth it.

Thank you for your repleys ,