I replaced the volume pot on my tube preamplifier.

@mattw73  Interesting. Definitely worth trying out. 

Here's the link.

@noromance Thanks for posting the link. I tried to do a little research on the attenuator & found that they are used by a hifi tube component company in Ukraine named Phast. I found a couple internal photos of their preamp on the web & it looked to be of decent quality. 

I haven't compared this relay attenuator to anything of quality in the same circuit yet. But with my experiences of brands like TKD, GoldPoint, & Khozmo more recently, this Relay is legit good. Especially for the price. 

I originally bought a remote controlled RK27 with the control, attenuator, & relay input boards for like $65 bucks. I got a little discount on the Relay volume control by Serglobo & the version I purchased doesn't have the input switcher but for like $40 bucks more than the RK27 unit I got a huge upgrade in sound & stage perceptions. I initially used the 6v input off a transformer & all was good. Then switched to powering it by an external 5v Sbooster linear power supply. The preamp gained a whole new sense of air & space between notes & instruments. Also threw the widest soundstage that the bookshelves I had in place have ever displayed. I tried powering the volume control with a cheap-ish SMPS IFI Audio iPower X ($115) & the results were equally as good. I added a DC power jack at the rear of the chassis & ran the + & - straight to the volume board. The power & signal grounds on the relay PCB are separate. If you hear the relay clicks thru the speakers you have allowed the power ground to infiltrate signal ground. I only mention this because I did it lol. If hooked up correctly it's silent. 

I'm not trying to overhype this relay control. My subjective opinion is that it's an audible upgrade over the basic pot. And at a good price point.. especially for being remote controlled. 

My headphone amp comes with an ALPS RK50 stereo pot.  A friend who builds stuff liked the feel and inquired  about the price.  This was a long time ago when the dollar bought much more.  He was told by the distributor that the price was $850 each, with a minimum buy of 50 units.