Would anyone like a tube hour counter for amps that don't have this function ?


I am planning and designing a small,  attractive,  external tube hour counter,  and I would like to get a sense if anyone is interested in this for themselves. If so I may be compelled to make a batch of these at the same time Rather than just one.

 I have an audio research VT100 mkII and and LS25. I really like these amplifiers, but neither of them have a way of tracking tube hours. I know I can just listen to the tubes to determine shortcomings, but I'm also an analytical sort of guy, so having an accurate tube hour count would be useful to me.

my plan is to use a digital, non-resettable, industrial hour counter.  I am planning to recess this into a small aluminum enclosure with professionally machined openings for the  Digital counter as well as the power cable coming out of the back. The plan is to use a  Black anodized aluminum body with natural aluminum face plate and rear plate. A power cable coming  out the back and be terminated to a standard household grounded plug. There will be rubber deer on the bottom. The device will be small: perhaps about 4 inches wide, 2 inches tall, and 4 inches deep.

 I have a six outlet power conditioner with one outlet free. To use this hour counter, I will plug it into my conditioner, I will switch off the power on the conditioner when I'm not using the amplifiers.  When I switch on the Power conditioner and subsequently the amplifiers, The hour counter  Will begin its count. 

 For those of you who plug their power amplifier directly into the wall, I suspect that many of you will still plug your preamplifier or other components into a conditioner or strip of some sort. In that case this tube hour counter will still work for you,  unless you just turn on your power amp from time to time for fun! 

 Since I will be re-tubing my power amp soon,  this is a perfect time for me to add this to my system.  I plan to use my small label making machine (brother p-touch style) to put a label on the bottom of the aluminum enclosure that has notes on the install date, tubes, and hour counter numbers. 

For example,  I may just change the power tubes on my amplifier and not touch the signal or driver tubes in the power amp, or the preamp tubes in the preamplifier at this time. When I go to change those smaller tubes in the future, I will notate that change and log the hour count in a  small note on the Label Maker,  and stick it to the bottom of the enclosure.  The hour counter will be non-resettable to avoid tampering or mistakes.

I'm not yet sure about the price of something like this, I'm doing the research now. Since it has to sit on my audio shelf, I don't want it to look like a piece of junk or a children's science project. Because of that, I will use professionally sourced parts, quality machining, and thoughtful design,  planning,  and careful assembly. 

 I suspect the final selling price may be in the neighborhood of $100 - $200. But that's just a wild guess at this point. If anyone's interested please let me know and I will consider  making several of these instead of just one for me! 

Take care,
Mark
marktomaras

Showing 6 responses by peter_s

 What about designing an hours counter that uses a heat sensor instead of a 12 V trigger? 
Mark. My amps have 12v triggers, which I don't use. I turn them on and off manually. Would the 12v trigger input to the amps work with your device?
 It is worth checking out. In my case,  although produced by the same manufacturer, my amplifiers have 12 V triggers but my preamp does not. I'm assuming that the 12 the trigger on an amplifier only received instructions and does not send them. So I am not sure how it  would send information about on/off status.
I am guessing that most people would not want to have to plug their amplifier into some other device in order to achieve the time accounting.  That is why I was suggesting a temperature sensor. But a 12 V trigger could also do this job. 
Mark - my amplifiers are VAC Phi 200's.  I'm actually surprised that they have 12v triggers given the current rush I sense when I turn the beefy switches on! I'm actually also surprised that my preamp, a VAC Signature Mk 2a Signature SE preamp does not have a 12v trigger (one would think it would pair with the amps!).  You could call VAC (they are very helpful), though I doubt that the trigger input to the amplifier sends out a signal when the amps are turned on/off.  I don't know much about that since I've never used it. I could imagine that your device, if it passes the trigger pulse through it, could be used to count hours. I will keep my eyes open for further posts...
Hi Mark. I think a temperature sensor would be most flexible, and optimally something on a thin wire that could be placed near the base of a power tube or on a transformer (mine do get hot).  I was looking into making something like this for a totally different purpose but the design was too techie for what you are trying to accomplish (e.g. temperature probe, raspberry pi computer as a datalogger). I wonder whether an IR termperature sensor would work as well...

The question is how to get the split core current sensor to communicate with the hours counter.  I am unclear about what kid of signal the hours counter requires, and whether the current sensor would provide this signal or if there would need to be some sort of "translator" in between.  Thoughts on that?

If you make a reasonable looking device (not aluminum billet), I think this is an accessory you could sell online and perhaps through online companies (e.g. music direct).  Personally, I don't require anything fancy looking, just reliable.  I think most people would tuck it out of the way and only look at it from time to time to see how many hours they are putting on their tubes.