I'd been considering adding a way to document tube life more than just based on my estimates (tube hour meter). I searched the forums but couldn't find anything.

Ideally I would just add a monitoring device inline with the power to each amplifier in which individual tube specifics could be recorded into the device. It would then monitor the hours in use for each of the tubes (based on "insertion date/time"). However, I couldn't find such a product, so I'll leave that invention to the PIC or Arduino fans out there. Perhaps it exists.. just couldn't find it.

I did find a product on Amazon (USD $12.79) that works well in a general sense-- has non-volitile memory (internal rechargeable battery), can measure within +/- 2% mains voltage, frequency, amps, watts (real time, min, max), power factor, cost, and cumulative time (only when there's a current draw. No backilight but models with it don't seem to have internal battery):
https://www.amazon.com/Electricity-Monitor-Voltage-Overload-Protection/dp/B07DPJ....

I haven't noticed any change in fidelity by having it inline.

I also included a short AC extension cord (USD $2.95) to get it off the power strip: https://www.amazon.com/CyberPower-GC201-Heavy-Duty-Extension/dp/B01JRLSPRW/ref=s....

Just install a fresh set of tubes and let it roll. In the Amazon product reviews others have claimed it's fairly accurate. I haven't tested this.

Here's the reported real-time power demand and approximate power factors for my two amplifiers at this time:

SE84UFO25: 58.7W, PF=0.98
CSP3 w/25th: 26.3W, PF=0.88

I also tested my DAC at 43.2W continuous draw, which is significant as it's recommended to just leave it on all the time to extend life. If you know your electricity rate, you can also enter it into each device for display.

If anybody has other solutions it would be interesting to know.

@CAJames, totally agree. Who knows though, perhaps this post is useful for others in terms other than tube quality (such as burn in monitoring time), used tube claims, or perhaps even failure prediction. Simple, inexpensive, with lots of utility and no known downside.

Here is a way

Arduino, some code, a clock with nvram, some simple ui lcd/rotary encoder..

You can sense is device is powered without using any of its power.  You would record tube position and times. Etc.

If you wanna go crazy use a PI and a touch screen. Would sit in same circuit as audio rack to sense power on of amp.

I’ve been maintaining an excel spreadsheet of my various tube usage over the past year but lately it’s becoming a major PITA to update. The thought of just giving up this madness has crossed my mind several times in the past month.

Not too short, but life is too long to do all that.


I look, sniff, thump, wiggle to see if there are any changes. Changes might mean something, so more watching.
Low tech here, but living a long life. I hope.