Yamaha CX-1 Thread

Discussion in 'Yamaha' started by Bratwurst7s, Sep 30, 2017.

  1. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Thanks for this information John. Odd about the Duorex/Muse thing but it's the cap values that's important to know. I guess that what I'll do is buy at least 2x 22µF ES Muse. I already have a bunch of Wima foil caps in 2.2µF. Then I can decide later what I'm going to do. Probably go with one of each like original. It just seems odd to me that they would use different value caps in mirrored positions left and right.

    Thanks again for looking,
    James
     
  2. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Cool that your CX-1 arrived so fast. Even more cool that it looks so nice. In the photos it looks perfect. Enjoy it!

    Cheers,
    James
     
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  3. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Agree strongly with this. I like the clean and simple appearance. Minimal and not busy looking. Let the music do the talking while the equipment stays in the background.

    In spite of not needing the remote I found myself wanting one of those originals just for the sake of completeness. Probably good that they don't/won't ship to Germany because I can't really afford to buy one right now anyway.

    Cheers,
    James
     
  4. 808_state

    808_state Active Member

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    Thankfully the Japanese take good care of their stuff and the line-in gives me no indication that anything needs redoing. Looking forward to running it with my good CD player once I get it back from repair.
     
    Last edited: Oct 19, 2017
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  5. Karl vd Berg

    Karl vd Berg Super Member

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    Wonderful thread, James. Very nice pictures, too! :thumbsup:
     
  6. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Thanks Karl! It's been a while. How have you been doing? All's well I hope.

    Cheers,
    James
     
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  7. 808_state

    808_state Active Member

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    Pulled the trigger on the remote and tracking says it may arrive tomorrow...looking forward to only getting off the couch to flip the record :rockon:
     
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  8. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Yeah, having a remote is a luxury that I've become adjusted to having. When I'm comfortably in the zone with my feet up it's nice to be able to jog the volume without having to disturb the pillows or set down the glass. :)

    Cheers,
    James
     
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  9. brutal

    brutal YamaHoarder

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    Ditto.
     
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  10. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Well, I believe that the CX-1 will be staying here. :) I have the feeling that it's feeling right at home here because it's been singing so sweetly.

    Unless something goes wrong I'm planning on putting it on the bench Friday to measure cap diameters, spacing and lead spacing. Then I can start making some final decisions on a buy list.

    Cheers,
    James

    edit: When I get started on my M-70 I'll be making use of your thread. Thanks for posting that.
     
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  11. 808_state

    808_state Active Member

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    So I did a little side by side comparison with both my early Mercury cd and lp copies of Def Leppard's High n' Dry and the lomc phono in the CX-1 is definitely starting to open up, though I do still hear a slight congestion in the mid-range. I didn't hear any distortions on 220 or 1000 ohms (plenty of high frequency to blow apart on) and the imaging and decay are really strong. Spinning my Gilbert Kong cut of Thin Lizzy's Jailbreak was far better after a few other records. Think I'm going to hook the CX-1 up to my M-85 this weekend and see how they get along with my NS-1000x's. The remote may ruin me for going back to the C-2x.
     
    Last edited: Oct 25, 2017
  12. mcgjohn

    mcgjohn New Member

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    The CX-1 is a sleeper unit. was Yamaha's last all out effort on an all analog 2 channel pre. I have worked on several of these.

    The biggest benefit sonically is adding a film bypass cap to all the interstage coupling caps; and replacing all shunt position resistors with Vishay bulk foil.

    The phono stage in these units is great. And the MC stage can be made more flexible by adding some extra resistors and a switch to offer more MC loading options.

    I would not be in a hurry to replace the OEM lytics unless they were shot. If you really want to make it sing, build an outboard PS and use a 500VA transformer to replace the original 30VA trans. Dynamics will be better, bass impact will improve, and the unit will develop an ease to the sound that it does not have in stock form.

    Have a few pics and some marked up schematics if there is any interest.

    best.

    J
     
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  13. 808_state

    808_state Active Member

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    Definitely interested, please do share. The tech who works on my stuff has done a similar switch mod on his C-2 and I may have him try it with my HA-1 stepup. I'm definitely looking forward to spending more time with it this weekend.

    I know this is a little off topic but have you ever experimented with adding an outboard power supply to a C-70? I'm wondering if that would boost the sonics and also increase the lifespan. Mine is in good shape but I've read that the heat from the PS over time is a killer.
     
  14. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Yes. There is interest. Please post any pics and schematics that you'd like to. And welcome to AudioKarma!

    Cheers,
    James
     
  15. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    OK. Today I took another look inside the control amp.
    First some photos of the "Main-PCB 2" daughter card for the phono section that I missed earlier.

    DSC04609.jpg DSC04610.jpg DSC04611.jpg DSC04613.jpg DSC04614.jpg

    Cheers,
    James
     
  16. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    And photo of the underside with the base plate removed. Like the AX-750, 890, 1090 etc all components are mounted on a fibreglass reinforced plastic frame. Many of the caps solder points won't be accessible without lifting the boards from the frame. Re-capping will take a lot of care.

    DSC04625.jpg

    Cheers,
    James
     
  17. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    And a couple of pics of the hidden cap in the standby/reset section.

    DSC04618.jpg DSC04619.jpg

    Cheers,
    James
     
  18. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Lastly photo wise are a couple of the main filter cap leads.

    DSC04620.jpg DSC04621.jpg

    The leads measure 20mm at the outside and 10mm between the inside.

    Cheers,
    James
     
  19. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    I measured cap diameters and lead spacing. Then I went back and edited all of the earlier posts to add this info where it's important.

    All of the 2200µF caps are 16mm dia and have a 7.5mm lead spacing. Nothing larger in dia will easily fit.
    All of the caps smaller than 2200µF have a 5mm lead spacing.

    The 1000µF/6.3v caps are 10mm dia and nothing larger in dia will easily fit.
    The 470µF/25v caps are 12.5mm dia and nothing larger in dia will easily fit.
    The 470µF/16v caps are 11mm dia and up to 12mm dia should fit.
    The 330µF/16v caps are 8mm dia and up to 10mm should fit.
    The 100µF/35v caps are 8mm dia and up to 10mm should fit.
    The 100µF/25v caps are 5mm dia and up to 8mm should fit.
    The 100µF/16v cap is 6.5mm dia and up to 10mm should fit.
    The 47µF/25v Muse are 6.5mm dia and up to 8mm should fit.
    The other 47µF/25v are 5mm dia and up to 8mm should fit.
    The 47µF/16v cap is 5mm dia and up to 6mm should fit.
    The 33µF/25v is 6mm and nothing larger will easily fit.
    The 22µF/25v Duorex is 5mm and up to 8mm should fit.

    All other caps are 5mm dia. I don't see any problems there. For the 10µF Muse there should be room for up to 8mm. I'm replacing all smaller values with film caps and don't see any size problems there.

    Now I can get serious about a Mouser buy list.

    Cheers,
    James
     
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  20. mcgjohn

    mcgjohn New Member

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    James / Guys, sorry for the late reply. Have not had a chance to post.

    Here are a few images of the marked up schematic that I used. H = Holco Copper end cap resistors
    V = Vishay VSR bulk foil resistor

    The other key area is the CX-1 is full of interstage coupling caps. I originally tried to eliminate them, but circuit changes were too involved, so left circuit stock and added film and foil bypasses to caps.

    The Power supply upgrade is the first thing I would do
    1. Fast recovery bridge rectifier
    2. bypass the main PS filter caps.

    In the next week or so, will try to find the images I took during the upgrade.


    best

    John
     

    Attached Files:

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