Sisterray

That’s interesting. I might hold out for a T1. There isn’t one on eBay right now that’s in North America. I’ve seen the listing for the Stax amp service. It does seem mandatory after so many years. Getting back to the original problem... I noticed the hum only after switching from an Onkyo C-7030 single-disc player to a Sony jukebox. The Sony has a plastic cowling or cover on the back, presumably with the power supply inside. (I haven’t popped the covers, yet.) I had my cables draped over it when I noticed the hum. So after rearranging the amp & cables, the hum has lessened, but it’s still there. About two-and-half feet separate the amp from the power supply section of the Sony now.

Good SRM-1/Mk-2 units pop up on eBay frequently.

I’ll have to check whether the unit can be grounded. I have rearranged the amp & cables, so we’ll see this afternoon. Regarding a new amp: Would an SRM -1/MK-2 be a good choice? How about a T1?

No fluorescent lighting, but there might an issue with the power supply of the Sony (a 400 disc changer) affecting the amp. It sits on top of the changer, and the various cables run parallel to each other. I’ll have to rearrange them & move the amp. However, I don’t think that would explain the change in the loudness of the hum as I move my head.

Any idea as to why the loudness of the hum changes as I move my head?

The amp I have now is probably not worth sending back to Japan for service. I bought the system from a fellow through eBay Canada for $425 USD. (I’m in the States.) He bought it new and had only used it for about 50 hours, until he developed a very serious hearing problem. Needing cash at Christmas, he accepted my offer. All the packaging was fresh, and the earspeakers & amp looked brand new. What are suggestions for pro bias amps? I’ve been interested in a T1 for a while. What about a 353X?

Spritzer - The hum, which is very low in frequency, came back this morning after about 15-20 minutes of use, and only in the left driver. It built up in loudness as time went on. Present, but only appreciably noticeable when moving my head side-to-side & front-to-back, especially when done rapidly. The hum persisted after the SRM-252S was switched off, but disappeared after I unplugged from the amp. The eqrspeakers are SR-207. The amp has always r7n warm. I threw out the plastic bad. I need a stand & dust cover. i appreciate your help.

I hope inserting here is appropriate. This is my first post here. I bought an SRM-2170 a couple months ago & listen every day, usually for an hour on average. Because of that, I’ve become very familiar with the sound signature of the earspeakers. The speed, resolution, sound stage, and lack of distortion have changed my music listening. I was about to settle for mediocre listening through electrodynamic phones & a terribly compromised speaker setup when I bought the Stax. Everything has changed. While listening this afternoon for an extended period, I noticed an electrical hum in both drivers. The loudness, but not the pitch, changed as I moved my head side-to-side & back-and-forth. It was never “loud” by any means. No cracklings in the drivers. I store them in a plastic bag & then placed in a box after every use. This phenomenon seems to build-up over time as I listen. It’s quite noticeable. My perception of details seems to have sharpened as I have used the earspeakers over time. Any ideas?