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crooner's new Hour Meter (tubes and turntable) project PICS!!!

Discussion in 'Audio Hardware' started by crooner, Feb 11, 2007.

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  1. crooner

    crooner Well-Known Member Thread Starter

    Hi fellas!

    I spent the whole day working on my latest project. A single box housing hour meter displays for both my tube amp/preamp and turntable.

    Previously I had a cheap ABS box housing a single hour meter for my tube amp. This meter works off the 12V output of the preamp. This output is intended to work as a trigger signal to turn on a power amp. It's ideal to power the hour meter as well.

    After I had my tube amp hour meter up and running, it occured to me: why not have another similar meter to record estimated stylus/cartridge hours?

    The ideal way to do this would be by means of the turntable motor. I usually turn on the motor only when playing records. I very rarely keep the platter spinning for no reason. Therefore, it made perfect sense to have the hour meter register only when the motor was running.

    To do this, I added an extra switch to AC voltage going to the motor. The switch powers two AC receptacles. One for the motor and the other for the hour meter. The switch on the turntable itself would permanently stay in the "on" position.

    Originally I was going to use a 120V rated hour meter. This unit could be connected directly to the AC line. However, this kind of meter has an internal switching power supply. This would add hash and distortion to the AC signal going to the turntable. Not good.

    I decided to go for a 5-12 volt DC unit. This required the use of a small wall-wart transformer. I used a spare Nokia unit from an old cellphone. It puts out 8.3 volts, so it's within the range of the hour meter.

    Today I went to Fry's and found a nice extruded aluminum compact enclosure for my project. Much nicer looking than the ABS plastic I was using before.

    I got some other parts I needed including a switch, two AC receptacles, a IEC inlet with built in EMI filter, and a couple of 3.5 mm jacks.

    To drill the holes I used a Dremel tool. First time I used the thing, so there are some imperfections.:o

    In order to protect the finish from scratches, I made a template and then used clear tape to place it over the faceplate.

    The internals were wired with some spare Kimber Kable I had on hand. Not sure if it will make a difference sonically :winkgrin: but it does look nice.

    Some pics for your enjoyment!

    Attached Files:

  2. crooner

    crooner Well-Known Member Thread Starter

    rest of the pics...

    The top meter is for the tube amp. Since I have been using it for two weeks, it already had 31.8 hours on it. The bottom one is still "zero". I haven't played a record yet, the electronics are still warming up!

    The switch only controls the bottom meter and the TT motor. I have to get used to switching off the turntable this way.

    Attached Files:

  3. DaleH

    DaleH Forum Resident

    Thanks crooner, I really appreciate the you taking the time to post the details of your project. That's a fine piece of work. You've inspired me to make my own hour meter. Do you recall the part# for the timer units and the source?


  4. crooner

    crooner Well-Known Member Thread Starter

    Hi Dale,
    Thanks for your kind comments. I took pictures of the project as I went along and prepared the thread while warming up the system :D

    Here are the part numbers for the meters I used:

    Curtis 701TR00101248D2060A (12-48 V DC version)

    Curtis 701TR001O0512D (5-12 V DC version)

    There are other voltages available as well. For audio applications, it's best to get the DC versions to avoid the internal switching rectifier. The 5-12 V DC version is ideal since the wallwarts in this voltage range are plentiful and cheap. They are also much more compact. If you are using a wallwart, make sure it's transformer based.

    I got the meters from www.tecknowledgey.com. Price was less than $30 each.

    If you have any other questions don't hesitate to ask!

    Best regards,
  5. Tony Plachy

    Tony Plachy Well-Known Member

    Pleasantville, NY
    crooner, This is sooo cool. Thank you so much for the post. Have you considered that there could be a market for these (not huge)?

    P.S. I see you use the same VTF guage that I do, I really like it.
  6. hifi_nut

    hifi_nut New Member

    What a cool and great idea. Thanks for sharing.

    As Tony Plachy said there might be a market niche for this kind of accessory. I wouldn´t be surprised if some manufacturer pickep up on your idea.

    Congrats, this is what really makes our hobby so much fun.

  7. crooner

    crooner Well-Known Member Thread Starter

    Hi Tony!
    Thanks for your reply and comments.
    Yeah, I thought about it!
    Perhaps I should make a small run and sell it via Audiogon! :winkgrin:

    I bought the Expressimo Gauge after reading your posts here in SH Forums. It's a great device, and what a world of difference compared to the ancient Shure!

  8. crooner

    crooner Well-Known Member Thread Starter

    Hi Jorge!

    Yes, Indeed. I believe this is a device many tube/vinyl owners would love to have. Thanks to improvements in solid-state technology, it's now possible to have really accurate and reliable time pieces to measure hours. Very compact enclosures as well.
    The non-volatile memory lasts for up to 20 years and it's resettable, meaning that you can put the counter back to zero after retubing or changing cartridges.

    Thanks for the kind words Jorge. That custom Thorens TD-124 of yours is quite possibly the finest I have ever seen. And I've seen quite a few! :winkgrin:

  9. Tony Plachy

    Tony Plachy Well-Known Member

    Pleasantville, NY
    crooner, If you decide to make a small run, be sure to offer them for sale here, I think you might have a few takers. :thumbsup:
  10. crooner

    crooner Well-Known Member Thread Starter

    hahaha, I sure will! :righton:
  11. LeeS

    LeeS Audio Research Fan

    Very nice!
  12. crooner

    crooner Well-Known Member Thread Starter

    Thanks Lee!
    It's a great feeling to have some idea in your head and make it into a real device. Fortunately, the case turned out to be good looking not some ugly thing that would need to be hidden from view!

    I bought an identical box for my Squeezebox DIY linear power supply. Right now it's on a simple, cheap, thin metal case. It should look much nicer when I transfer it to this enclosure.

  13. boead

    boead New Member

    So how does it sound?

    My guess is it affects the sound in a significant way. Is it better or worse?

    Or have you not listened with and without?
  14. crooner

    crooner Well-Known Member Thread Starter

    I tried to make it as transparent as possible, specially for the turntable. That's why I used the IEC inlet with EMI filter. The Kimber Kable wiring should help to keep any losses at a minimum. Remember no audio signal goes through here. It's the AC voltage that goes to the turntable that is routed and switched inside the unit.

    The hour meter assemblies themselves have some digital electronics, obviously, but they behave like a low voltage LCD based digital clock. No audible "grounge" that I can detect. I placed a portable AM radio next to it, and it didn't pick up any additional noise.
    My squeezebox unit generates much more interference!

    The first record I played after I added the switch and hour meter was my pristine copy of Revolver (late 70s black Parlophone label).

    Perhaps it's the "placebo effect" but oh man the sound was very smooth and revealing. This is supposed to be a 60s compressed (Fairchild 670) recording with no "audiophile approved" soundstaging or such. But there was a lot of "air" and sense of space on it. The special effect voices and sounds on "Yellow Submarine", for instance, were literally floating between the speakers, with real body on them!

    It is therefore safe to say that the device seems not to harm the sound at all.
  15. Tony Plachy

    Tony Plachy Well-Known Member

    Pleasantville, NY
    crooner, I want to me sure I understand a few things and ask a couple of questions and then run by you how I would do this in my system. First the questions.

    1. What are the little red and blue pig tails that seem to be attached to the 120V AC outlet sockets in your first picture? They do not seem to be in the pictures where the outlets are wired into the circuit.

    2. I looks like you use a DPST rocker switch for on/off. That is what I prefer because then you know off is really off. Do you have a P/N and source for it?

    3. You said you used an IEC inlet with an EMI filter on it, do you have a P/N and source for it as well?

    Obviously I am thinking about building one of these, but given that I have had my TT down for 4 weeks now trying to get it tuned-up, it will probably take me 2 years to build the hour monitoring box. :sigh: If only I was retired.

    Now just to be sure that understand all of the wiring in your box is for the TT monitoring except the 12V DC input in the lower left hand corner of the back panel which takes the trigger signal from your preamp and drives the upper hour monitor with it.

    So OK, here is my situation. My c-j gear does not have any trigger outputs, however, I just got a new PS Audio PPP that powers my two monoblocks. I allows me to switch on both amps remotely when I power it up with its remote. I has three totally isolated zones on it output, I have one monoblock in zones 1 and 3, zone 2 is free. I can put a wall wart in zone two, any electrical noise from it will not reach the monoblocks and I can use the output of the wall wart to run the clock that will measure tube on hours for my preamp and power amps since I do not leave my pre on all the time I only power it up when I have the power amps on. All I need is a wall wart that has a long output cord because the PPP and monoblocks are by my speakers which are not close to my front-end rack.

    My TT I would handle almost like you except since I have an SDS with my TNT-HR I would use the hour box switch to turn the SDS on an off because the SDS is a power regeneration unit just like the PPP is and even if the power going into it has some crud from the box it does not matter, the SDS produces an almost perfect sine wave for the TT motor. This will cut down a little on the estimate of stylus use because I switch the TT motor on/off when I lower and raise the stylus not the SDS, however, it will give me a very good estimate of the hours on my phono stage tubes. :)

    I have an unused PS Audio dual outlet that I can use in the back of the box for the another wall wart to drive the TT hours monitor and the power cord to the SDS. Again I do not care if the use of a dual outlet adds a little more crud from the wall wart to the power into the SDS because the SDS cleans it all up anyway.

    Now if I can just find the time to do this, but first I have to finish the TT tune-up.
  16. crooner

    crooner Well-Known Member Thread Starter

    Ok Tony here I go!

    I bought the sockets and pretty much all the components, except the case and hour meter themselves from a local surplus electronics outfit called Gateway Electronics.

    The AC sockets came with very thin high gauge cable attached to them. I disconnected those when wiring the unit with double runs of Kimber Kable.

    Yeah, that's what I used. It's a standard common unit also from the surplus store. Don't have any part number on hand, but most similar switches will work fine. They are rated much higher than the actual currents involved. This one was rated for 15A max.

    One thing I did want in the switch was a positive but gentle action. I didn't want a switch that was too stiff since the case is relatively light in weight and it could cause the whole thing to slide around. I did add some rubber feet to help in this regard.

    I got this too from the surplus place. It's made by Delta Electronics and probably NOS. I liked the chromed case construction, pretty high quality.

    Yes, that's correct. There are actually two 3.5 mm mono minijack sockets in the rear. The first one is for the tube amp Hour Meter and the second for the turntable. I inserted the cable coming from the preamp on the first jack and the DC coming off the little walwart (plugged in the back) on the second one.

    Looks like you got it all figured out!
    Yeah, you can power the hour meter from the switched outlet on the power conditioner. It will power on simultaneously with the rest of your tubed gear. You should have no problem finding a suitable wall wart. In any case, you can custom add a longer cord to reach your components.

    Those that have switched AC sockets on their preamps can use them to power the hour meter.

    That would be the way to do it. Nice that the SDS is able to provide a clean AC signal to the motor, regadless of AC line conditions. You may want to switch off the SDS via the hour box instead. Depending on your rack, you may be able to place the hour box close to the TT motor for ease of access.

    There are obviously several seconds between the moment the motor starts running and the stylus hitting the record. Depending of course, on your habits. But this way of counting the hour usage seems to be the best yet. Accurate enough methinks.

    I usually warm up my phono stage for at least an hour before playing records, so I won't be able to keep track of the hours there. No biggie, since the Amperex Bugle Boys appear to still test very strong after almost 2 years!

    The main concern I had was the power tubes. They are more likely to cause problems if they go. Best to keep track of their usage and replace them at 2000 hours as ARC recommends, for greater peace of mind!

    I was quite surprised I was able to finish this thing in a day's work. I did wear out the two dremel cone bits I used to drill the faceplates. But I can't imagine doing this without the tool. A great buy for the DIY'er!
  17. crooner

    crooner Well-Known Member Thread Starter

    I forgot to mention, the DC input jacks must be isolated from the metal faceplate which is at ground potential. I had to makeshift a solution by adding some mica spacers to them.
  18. intlplby

    intlplby New Member

    São Paulo, Brazil
    you could switch on the needle timer by making a contact that is below the arm lift. that way it is in no way touching the arm and only measures when the arm is down
  19. crooner

    crooner Well-Known Member Thread Starter

    That's a neat idea. Perhaps a manufacturer might offer something like that in the future. The Hour Meter device itself could easily be incorporated to the plinth.

  20. OvenMaster

    OvenMaster New Member

    Crooner, hi!
    Putting an hour meter in the TT plinth?? What a great idea! My Dual's PlastiCrap base would be a great trial project for this... it would be pretty easy, I should think.
    Nicely done, pro-look work, my friend. Congrats.
  21. crooner

    crooner Well-Known Member Thread Starter

    Thanks for the kind words Tom, much appreciated!

    And post pics of that Dual if you decide to put a meter in it! :righton:

  22. ZenArcher

    ZenArcher Well-Known Member

    Durham, NC
    This is really nice work!

    I wonder if an hour meter could be devised that simply clamped over an AC power cord. The meter could detect current running through the cord by induction, and count the hours current is running. That way, there'd be nothing in the circuit at all. Unless the induction might "confuse the electrons" or something ;)
  23. crooner

    crooner Well-Known Member Thread Starter


    The induction hour meter is a great idea!
    Remember those little devices electricians use to detect if a cable is live? It doesn't touch anything it just turns on a LED indicator at the proximity of electricity. This principle could be used to trigger the Hour Meter!

  24. Oyama

    Oyama Active Member

    crooner, great job and thanks for sharing your hour meter project with us.

    Would you by any chance have a wiring schematic?
  25. Oyama

    Oyama Active Member

    I thought about this too! Tecknowledgey has a battery powered switch type (non-voltage) hour meter that could be used with a self powered current status switch.

    Actually, I have a spare current switch that I could use and it turns on at 150 mA, but I would have to see how much current my TT draws first.
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