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Tube warm up time technical measurements

Discussion in 'Portable and Other Gear Measurements' started by atomicbob, Jan 27, 2017.

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  1. Aklegal

    Aklegal Friend

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    Received my MJ3 yesterday. I don't have a fancy FLIR thermal camera, just a cheap infrared gun. Mine topped out at 151 degrees after more than two hours of operation. The MJ3 was sitting directly on top of a Audio GD Master 9 with internal heatsinks that reach temps of 120 on its own.

    My rig is in my basement and the ambient Temps this time of year are around 70 degrees.
     
    Last edited: Oct 11, 2023
    Aklegal, Oct 11, 2023
    #41
  2. Vansen

    Vansen Gear Master (retiring)

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    Initially, my MJ3 would reach about 165 degrees on a baby FLIR and Type-K thermocouple. I wasn’t concerned, but was curious due to this conversation. I have been able to get my MJ3 down to 155ºF from 165ºF with a couple of changes. I though I had my MJ3 on a double conversion UPS set at 115 VAC, but when I moved my music setup in September, I needed to do some work on the outlet and a GFCI circuit to make the UPS happy and still had the MJ3 power cord off the wall. I thought it was feeding from the UPS, but nope.

    I suspect the most significant factor is the drop from ~123 VAC to 115 VAC.

    [​IMG]

    At 165 degrees:
    • Mains at 123-126 VAC during the day, 119 to 123 VAC at night.
    • Ambient temperature at 24ºC.
    • Sitting on top of a powered on Rag 1.
    [​IMG]

    At 155 degrees:
    • Mains regulated to 115 VAC with a Vertiv GXT5 double conversion UPS.
    • Ambient temp at 22ºC in this image.
    • Still sitting on top of a powered on Rag1.
      • I might shut if off and post a follow up if the temp is lower.
     
    Vansen, Oct 14, 2023
    #42
  3. Vansen

    Vansen Gear Master (retiring)

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    I shut off the Rag1 and had the MJ3 on most of the day and was listening to music for an hour before taking this measurement.

    [​IMG]

    At 139ºF (maybe 141):
    • Mains regulated to 115 VAC
    • Ambient temperature at 21ºC
    • Sitting on top of a powered off and cold Rag1
     
    Vansen, Oct 15, 2023
    #43
  4. atomicbob

    atomicbob dScope Yoda

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    Vali 3 with GE JAN 5670W tube warmup time

    01 vali3_ge_jan5670w_small.jpg


    02 20241001_Vali3_OS136_C.png

    03 20241001_Vali3_OS136_F.png

    At 17 minutes 95% of thermal equilibrium achieved. At 30 ~ 40 minutes temperature becomes dependent on room ambient changes.
     
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    atomicbob, Oct 1, 2024
    #44
  5. Grattle

    Grattle Friend

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    Grattle, Oct 2, 2024
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  6. atomicbob

    atomicbob dScope Yoda

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    Valhalla 3 temperature measurements (stock tubes)


    Temperature measurement setup:
    01 DSC_0146_small.jpg
    Valhalla 3 (VH3) on 15mm high isolation feet for extra ventilation below the chassis.
    Stock 6n1p input and 6n6p output tubes
    Omega OS136 IR sensors + iFi iPower2 15V supply
    Picoscope 2205 + PicoLog data recorder

    IR Sensor One 85 mm above and aimed at Schiit Logo center.
    IR Sensor Two 95 mm away from right rear 6n6p at approximately 45 degree angle aimed at the center of the tube plate.

    VH3 settings:
    No feedback 10x gain
    Volume adjusted for system unity gain
    Impedance multiplier off
    Sennheiser HD800S headphones (300Ω load)
    No music playing, quiescent operation

    Power on (or off) one minute after start of data collection
    Temperature data collected at 30 second intervals

    02 20250531_Valhalla3_warmup_stock_tubes_OS136_deg_F.png
    Power on at minute 1.
    Observe 6n6p plate achieves very high temperature within 10 minutes.
    Note how chassis temp rise from transformer requires 100 minute to equilibrate.
    Also note how 6n6p plate temperature equilibrates in approximately 50 minutes.

    03 20250531_Valhalla3_warmup_stock_tubes_OS136_deg_C.png


    04 FLIR_6n6p_plate.jpg
    Left 6n6p plate temp.

    05 FLIR_top_logo.jpg
    Chassis top logo temp.


    06 20250530_Valhalla3_cool_down_stock_tubes_OS136._deg_F.png
    Power off at minute 1 for cool down measurements.

    07 20250530_Valhalla3_cool_down_stock_tubes_OS136._deg_C.png

    Valhalla 3 presents some challenges for measurements. First, there are numerous settings to accommodate a wide variety of headphones and their respective load impedances. For simplicity I chose settings for my listening preferences with HD800S. Second, with Holo Cyan2, Valhalla 3 and HD800S I find it difficult to halt listening sessions and begin measurements. Same for tube rolling. I’d rather roll through my music library and continue having frequent, strong ASMR experiences.
     
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    atomicbob, May 31, 2025
    #46
  7. Doug Sawyer

    Doug Sawyer New

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    Yep.....[​IMG]
     
    Doug Sawyer, Jun 1, 2025
    #47
  8. DrMorbius

    DrMorbius New

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    Well, I always turn on the Vali 3 and wait a minimum of 4 minutes before putting the signal through. It’s been working perfectly for the past year plus 5 months.
     
    DrMorbius, Jun 8, 2025
    #48
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