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,
I've been following the discussion of tube hours with some interest and wanted to share a recent surprising experience I had. I have ARC gear which counts hours and on my Ref 2SE phono have a set of tubes with 430 hours on it, well within the 3,000 hour life. Recently however I began hearing breakup on one channel, sounded just like mistracking so I put it down to dirt on the stylus or issues with my setup. However when the same channel finally dropped 20dB and I isolated the issue to my phono amp I realized I must have a tube issue. Replacing the set of four 6H30s cleared up all the problems

i do use herbies dampers so it may be that the extra pressure reduces tube life, or maybe it's as much how many stop starts you have as it is total hours (I tend to have shorter listening sessions)

moral of the story is hours is only a rough guide, a good preventative maintenance policy of replacing every 5 years or so is probably not a bad idea and using aggressive dampers like the herbies may impact life
FolkFreak,  I agree wholeheartedly!  However, in my case, and hence the idea for this project, I have absolutely no idea how many hours are on my tubes.  I know when I got them, so there is that, but now 3 years and 4 months later, is impossible for me to predict the hours.

I plan to use this hour counter as a guide.  Manufacturers such as Audio Research were of the opinion that it was a good feature to include on their later products, and I believe all of the amps from the Ref 110 and on include this function.

I of course agree that hours alone are not the only way to judge a tube or decide if an entire set should be replaced, but for me, this will be another piece of data that will enter into the evaluation of the situation.

A bonus feature, one can determine how long they fire up their systems per month, and if it is too infrequent, they will have a motivation to step it up!  Only 5 hours this month!?  I need to make my quota!  :-)
Cleeds - yes!  this is the idea.  However as my amplifiers do not have the 12v trigger, I am going to try the plan I described.  Also, I think mine is going to look a lot prettier :-)  Like a little piece of audio gear.  Thank you for that link - I may pick his brain a bit!
This is the case manufacturer I am looking at:

@folkfreak -folk (or freak)-- that's some low hours for a 6H30 to fail. Are these tubes supplied by ARC or a third party?
I use that tube in my line stage and sourced real Reflektor DRs--after several years of moderate use, I send the unit back to be updated and had the tubes checked by the manufacturer, who found them to be fine and "re-matched" them (FWIW). All of these older tubes are expensive now. I did just find some NIB GEC tubes for my vintage Quad II amps--I'm hoping the amp outlasts me. Tracking hours on most NOS isn't really going to help, but I could see it for gear that uses modern tubes. 
They were ARC supplied and installed tubes. Anyway I'm not terribly bothered as replacements are not too costly what bugs me more is the creeping degradation of performance in small signal tubes such that you're never sure if they are performing at their best. I think I'll follow a policy of biannual replacement from now on just to be on the safe side - at least with a power tube you know when it's failed!
i do use herbies dampers so it may be that the extra pressure reduces tube life, or maybe it's as much how many stop starts you have as it is total hours (I tend to have shorter listening sessions)

Indeed, nothing should be in contact with glass during operation of vacuum tube -- NOTHING. Everything else, as noted shortens tube life.

Starts-stops if done at interval, should not reduce life unless there's issues with gear that cannot bring tubes properly to the operating voltages.

All ARC units literally KILL tubes ultra-fast. That's how they're designed to operate -- as hot as possible and it's main contributing factor to short tube life (and maybe some extra ARC supplied tube sales as well so ain't no bad without good rite?).

I just realized my tubes were last changed in 2012, not 2015!  Record keeping is not my forte apparently.  No wonder I am beginning to hear a need for new tubes.  If only I had my tube hour counter already :-)
Indeed, nothing should be in contact with glass during operation of vacuum tube -- NOTHING. Everything else, as noted shortens tube life
it's main contributing factor to short tube life (and maybe some extra ARC supplied tube sales as well so ain't no bad without good rite?)

Hmmm, maybe that's why ARC ship all their amps with rubber damping rings then, trying to get those pesky tubes to explode 🤑

More seriously I'll take replacing the tubes every 500 hours for the improvements the Herbie's dampers bring, it's a no brainer

I’ll take replacing the tubes every 500 hours for the improvements the Herbie’s dampers bring, it’s a no brainer.

You ain’t just whistling Dixie!

More seriously I'll take replacing the tubes every 500 hours for the improvements the Herbie's dampers bring, it's a no brainer
+1  I have used these for many years.  Never had a problem or seem to have noticed any shorting of tube life.  Do like the improvement though...
Tube amp and preamp manufacturers had tube shields over just about every small signal tube in their products for years with little to no degrigation so the idea that nothing should touch a tube is not a valid idea. I’ve got tubes out of old Scott amps that still work. Friend has a dynaco tube tuner with original small signal tubes shielded still working. It’s how the tubes are used and how hard they are pushed not to mention how well it was made
tube shields do not touch glass
 What about designing an hours counter that uses a heat sensor instead of a 12 V trigger? 
Peter, I like the idea.  However, I did a little research at the industrial supplier's website (McMaster Carr) and found that route would add a fair bit of complication and a pretty significant cost.  I think the way to go is with as much simplicity as possible.  
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?

the 12v trigger could possibly work, and would be a perfect way to activate such a device. My amps unfortunately do not have 12v triggers :-(
so in my case, I will have to use a household plug and connect the hour counter to my power conditioner.

if you (or anyone else with 12v triggers on their gear) are interested in one of my yet to be built devices, I will do the appropriate research on the actual function of the 12v trigger and consider making a 2nd version, or enhanced functionality in one design to accommodate more users. I should be able to create a version that can be activated by the influx of current when I turn on the power conditioner that it is plugged into, and also have an option to activate it via 12v trigger.  I think that addition will not add too much complexity...
 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. 

what amplifiers do you have?  I am researching the possibilities of a design that would employ a toggle switch that would allow one to choose a mode where the simple connection to the electricity will activate the hour counter, as will be useful in my case.  Flip the toggle, and the alternate mode will be selected where the 12v trigger will activate the counter.

Here is a rough preliminary sketch that I made of the device.  There are 2 LEDs to indicate the mode of operation.

can you please tell me the model numbers on your amp and preamp so I can use them as a research starting point?  

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...
Peter, it's been a very interesting research process. I am looking back into a temperature sensor as a triggering option for my hour counter device.  I think if I could eliminate human error, and make the device fully automatic, this will be the best option. I am making progress!

I am also now looking to eliminate household voltage levels and design a more sophisticated device that will employ a circuit board and hopefully a battery for operation. We shall see.

i have a question for you about your vac phi 200 amps.  Obviously the  tubes get hot, but do the there large boxes on the back also get hot? I suppose these are the power supply and the output transformers.  I ask because if my device were to have an external temperature probe, be it a small wire or thin steel probe, I would need to devise a non-invasive, reliable, and not completely unattractive way to place and keep the probe in the heat of the amp.  

With my amp design style, I could attatch the probe end to the top of the amplifier case cover, and it would be just above the tubes, right in the heat.  With your amp style it may be possible to slip the probe, if it is thin enough, between the power supply and one of the output transformers - if they also produce enough heat.

what are your thoughts on this?

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...
 I'm getting closer. I'm looking for a point-to-point wiring solution with low voltage components and avoiding  a circuitboard.  More info to come!
Interested. Why not a small microcontroller with an LED display, that is resettable? You could do a current sensing "tap", so you know when that device under test is on; no need for a thermistor or to plug in to the power conditioner.  With battery backup. :-) 
I have had tube equipment for more than 15 years. My first tube amps were a pair of Antique Sound Lab Hurricanes.  Very cheaply built but they sounded great. After about 8 years I began to have a lot of crackling in one amp.  Customer support was excellent. They instructed me to clean the tube sockets and pins. I did and the problem was solved. My point is that before going through the expense of replacing tubes try the cheap solution:  clean the pins and sockets.
You can buy hour meters for cheap on Ebay for as cheap as $5. If you have a basic idea about simple wiring you can hook it up and it will run only when your gear is on. And will count up to 10,000 hours, plenty for any audio use.The link here is a good example but you will find many with subtle differences, colors and features. Although simple is best. 

Ediver, what an excellent suggestion!

are you referring to a device similar to this:

Do do you think there is any possibility of introducing any negative effects to the AC (think crazy audiophiles here) with a current sensor clamped around someone's AC cable?  Or do you think this will be fully invasive?

I was researching peter's temperature suggestion, and it still holds water, but sensing the current sounds even better. Perhaps I can design a simpler and cheaper device this way.  also, the temp probe was always looking to be an issue. How do you ensure it stays in place, etc.  the current sensor clips to the power cable, seems like a great way to go.

I am sure I can hack this thing together, but I actually want to design a thoughtful, attractive, high quality device at a reasonable cost. We shall see if anyone buys one, but I will be the first customer :-)

russ - agreed, replacing tubes is not the only answer, but I do feel that knowing how many hours one has on their tubes is useful data...

dark matters, indeed, I have been looking at the full gamut of hour counters from $5 cheapie all the way to $100 fancy ones. I found some in the $20 range that look quite good.

thanks for the input everyone! Please share any more ideas, they have all been inspiring!

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.

Get SS. You're worried about tubes lasting 4,000
To 5,000 hr.s.   with all due respect of course
Peter,  I am in the process of hiring an engineer to help me sort out the electronics specifics.  If I can get this thing to run on batteries, and have it last for years on a 9V or Lithium battery, that would be killer.  We shall see.  I have also looked into relays and switches that can possibly interface with the current sensor.

I made a mock up of how I may design it.  It is early days yet, but I love design, so here is my first real go at a product!  It has a rectangular blue LED that will illuminate when the current is sensing, and the hour timer is counting.

Link to my mock up:  http://www.marktomaras.com/4485090-tube#0

Twoch - I'm not worried.  I just like the idea of knowing how many hours are on my tubes.  I have a lot of respect for high end solid state, but I love my tubes :-)

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