Yamaha CT-7000

Discussion in 'Tuners' started by stoutblock, Apr 10, 2018.

  1. stoutblock

    stoutblock If it sounds good, it is good... Subscriber

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    Got one! A lovely black version with rosewood. I've been looking for a nice one at a decent price for years but did not ever believe I would also be able to score a black one as I desired.

    Seller bought it from a widow and did not know the history. Looking inside I was not surprised to see the PS has seen some duress based on my research. I will consider my options here but for the near term I just removed the dreaded dis-bond glue, cleanup up the corrosion and re-soldered the associated caps. I will replace all the electrolytic on the PS with 105 deg versions. Yes, lots of heat coming off those TIP transistors! I will give the heat solutions some thought including considering one of Patrice's new PCBs that make room for heat sinks.

    I read somewhere that doubling the value of the filter capacitor just before the regulator will reduce ripple and allow the regulator to run cooler? I guess I need to determine which capacitor this is? Anyone who knows what they are looking at (I admit my limits) want to look at the schematic for me?

    Except for the PS, all the rest of the circuits look exceptionally clean with no signs of duress.

    I re-installed the cleaned up PS PCB, replaced all 12 bulbs (most were out) with some of dgwojo's fine bulbs and plugged it in. With just a di-pole it still performed beyond my expectations. Does it sound better than my T-2? Yes, same musical sound quality only better. Probably 10% better overall but bass is very impressive and probably 20% better.

    Most of the stations I listen to come in about the same strength as they do on the T-2 (both with di-poles). There is one exception, the KING classic station comes in much stronger on the CT-7000. About three times the signal on the CT as on any of my T-2 tuners. The CT-7000 captures KING at least as well as my C-85 did but with the musical quality of the T-2 (plus). This is worth the purchase alone as I love this station but this is the first time I have been able to really enjoy it in my main system.

    Purdy and the CD-S2000 matches it's classic design.
    IMG_0208 (net).jpg

    Some new functions including adjustable mute, ability to turn off the lamps and a really good headphone output. I do miss the T-2 digital station readout but not much...
    IMG_0209 (net).jpg

    They just don't make em like this anymore!
    IMG_0201 (net).jpg

    PS has seen some duress but all easily fixable.
    IMG_0198 (net).jpg

    I hate this crap! At least they only used it on the PS.
    IMG_0196 (net).jpg

    IMG_0197 (net).jpg
     
    Last edited: Apr 10, 2018
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  2. avionic

    avionic " Black Knights " Subscriber

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    That is a sweet looking tuner..
     
  3. ChristopherP

    ChristopherP AK Subscriber Subscriber

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    Nice, post. Keep us posted.
     
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  4. stoutblock

    stoutblock If it sounds good, it is good... Subscriber

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    Sure is a big impressive looking beast! Not sure it justifies the added size compared to the T-2? It does make you appreciate the T-2’s slimness and more elegant size. If you have the space to spare, it is one hell of a nice tuner!

    David, mind looking at the schematic to help me determine the filter capacitor for the regulator?
     
    Last edited: Apr 10, 2018
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  5. mgkfifty

    mgkfifty Active Member

    Very nice tuner.
     
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  6. Nick_G

    Nick_G Active Member

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    That looks fantastic stoutblock! IMHO the CT-7000 looks better in black. I bet it sounds good too. As Del Boy would say:

     
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  7. stoutblock

    stoutblock If it sounds good, it is good... Subscriber

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    Got caps ordered for the PS now I have to see if I can figure out something to suck the heat off those transistors.
     
  8. 39cross

    39cross AK Subscriber Subscriber

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    Nasty looking corrosion on those resistors, are the legs still solid?
    You can get heat sinks for those power transistors from Mouser, I can dig up some part numbers if needed. I wonder how that grey cap measures.

    I have a Sony ST-5950 that ran pretty hot inside; recapping the power supply made an audible impact, which was a first for me in a tuner.
     
  9. stoutblock

    stoutblock If it sounds good, it is good... Subscriber

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    The corrosion looks worse than it actually is. The legs are very solid. Dreaded conductive disbond glue! I will check the values on the resistors when I do the recap just to be sure. I assume they are fine because the tuner works quite well as is. Yeah, part number for the heat sinks would be great if you have them handy?
     
    Last edited: Apr 13, 2018
  10. rcs16

    rcs16 Super Member

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    Do not think so. The bigger the ecap filter, the avg DCV increases which means more V across the series pass reg. You want to lower the pass reg bjt Vce to drop the Pd. A "CRC" ckt has more ripple attenuation and more loss. Either you drop the power in a series R b4 the reg or in the series pass reg device itself.

    Well built unit, might want to measure the TO-220 device op temp and put heatsinks on them to help them, since everything looks like it is in a can.
     
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  11. Mark B

    Mark B Yamaha Fan Subscriber

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    The CT-7000 looks great in black. Congratulations!
     
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  12. rcspkramp

    rcspkramp AK Subscriber Subscriber

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    Gorgeous in that color. Congrats.
     
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  13. 39cross

    39cross AK Subscriber Subscriber

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    Here you go. these are Mouser parts:

    Heat Sink: 532-577304B00
    Mounting kit: 532-4880M

    The mounting kit is nice to have, screw, nut, washers and insulator all included. Good time saver.
     
  14. stoutblock

    stoutblock If it sounds good, it is good... Subscriber

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    I found some of these at Fry’s but I don’t think the narrow ones will fit? At least not in all locations. I ended up buying the wider ones which seem to avoid local components better. I still had to cut two in half for at least part of the heat sink to fit.

    Got the recap and heat sink done. I don't think I will touch the remaining caps on the other PCBs as they all look just fine and the tuner just sounds stellar. I think this beauty is good for another 40 years!

    IMG_0216 (net).jpg

    IMG_0218 (net).jpg
     
    Last edited: Apr 16, 2018
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