Yamaha CX-1 Thread

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

  1. mcgjohn

    mcgjohn Member

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    also forgot to mention, as long as you have the bottom cover off, look for cracked solder joints where the RCA jacks are soldered to the PCB.

    See attached pics.
     

    Attached Files:

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  2. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Thanks John! Looking forward to seeing more. And I have lots of questions. :)

    I probably won't be touching up every solder joint but will definitely be re-flowing all of them where there is mechanical or thermal stress. Jacks etc and regulators etc.

    Have you noticed the cap discrepancy concerning C206 & C211 in the 0DB-Amp section? Signal path coupling caps, schematic and parts list show 2.2µF. 1x 2.2µF & 1x 22µF installed. If so what did you do?

    What caps do you use to replace Elna Duorex? What special attributes do the Holco Copper resistors have?

    The bridge rectifier appears to be a long skinny affair. What did you use to replace it? I haven't looked at the pin-out yet. Is it possible to use 4x Vishay SBYV27-200 ultra fast/soft recovery diodes in it's place?

    Cheers,
    James
     
  3. Jygesq

    Jygesq Well-Known Member

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    when I was going to buy a Yamaha Preamp through sound saleman's discount. I talked to a tech person at Yamaha. He told me NOT to buy the Cx-1 , but the Cx-2. He stated Yamaha was having cold solder issues with C-x1. That was in 1997.
     
  4. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Before I bought my CX-1 I took the time to use the search function and look up all of the AK threads concerning it. Seems that sooner or later you show up in every thread and make that statement.

    Do you have a speck of personal experience to expand on that statement? As one person said earlier, I'd be far more ready to believe that your tech needed to sell of a backlog of CX-2's or had some kind of personal agenda than that specificly the CX-1 had more issues than any other piece of Yamaha gear. All electronics will eventually have solder issues, and a lot of Yamaha gear has them. I'm quite sceptical that this pre-amp is special in that regard.

    In any case, the CX-2 has all of the video through-put and DAC schnik-schnak that specificly I don't want. And the CX-1 is purely analog 2-channel audio oriented, which is exactly what I do want. And soldering issues can be dealt with with a soldering station, some solder and a few hours of work.

    Cheers,
    James
     
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  5. avionic

    avionic " Black Knights " Subscriber

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    Got the solder iron a little to close.:biggrin: upload_2017-11-4_17-35-16.png
     
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  6. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Heh heh. I found out with my AX-750 that that plastic frame melts very quickly. And that it blocks access to key solder points. There's really no good choice but to lift the boards.

    What I find more interesting is to compare the photo with the bottom photo of my unit. There are no component ID silk screen markings on my pre-amp.

    Cheers,
    James
     
  7. 808_state

    808_state Active Member

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    Spending more time with the CX-1 phono today and it continues to come alive. Listening to my Elektra dmm copy of Master of Puppets (not even the greatest pressing) and it shows some real fury and depth of sound with lots of slam in the drums. Very happy and can't wait to see what improvements Brat comes up with.
     
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  8. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    I've had mine for what, just over a month now? I've used it close to every single day. Very happy.

    I've been exploring different elco options. I see now that KZ's don't come in values greater than 1000µF, and with a max usable dia of 16mm for the various 2200µF choices are starting to get limited. Nichicon FG 2200µF/25v will fit, 35v won't. Panasonic FC 35v will fit, might be a good option to replace the Elna brown caps. I still have to look at Nichicon KL. Then I'll compare their specs and make some choices there. One thing about Nichicon FG's in larger values that concerns me is that in the past when I measured new ones a lot of them measured somewhat low fresh out of the box

    I don't picture getting into doing a bunch of mods with this unit, but am perfectly willing to look at the options. I probably will add 0.1µF Wima film bybass to signal path caps. I'm curious about why replacing the shunt resistors with metal film would help, rather than replacing signal path resistors.

    I do know from first-hand experience that replacing the bridge rectifier diodes in my CD player with ultra fast-soft recovery types gave audible improvements. I did an AB test with otherwise identical Denon DCD-1290 players and am a believer now. It remains to be seen if it's practical here, I haven't looked yet.

    I've also been looking at what options there are with Nichicon KG for the main filter caps. Looks like there are some options with 5600µF and 6800µF Gold Tune type 2 but availability is the problem. If I knew for a fact that I could squeeze a 50mm tall cap in that would expand the options but that would just about be pushing up against the case top. Again, with my CD players there were interesting SQ improvements when I upped the main filter caps values. It's worth looking into. It would be helpful if I could find some specs for the Nichicon "Great Supply" caps but I'm striking out there.

    I plan on making a partial parts order within a week, I need to order some caps to finish a cd player for my nephew so that he can have it somewhere near Christmas.

    Cheers,
    James
     
  9. avionic

    avionic " Black Knights " Subscriber

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    KG " Superthrough" I'm assuming.
     
    Last edited: Nov 5, 2017
  10. Jygesq

    Jygesq Well-Known Member

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  11. Jygesq

    Jygesq Well-Known Member

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    this was just a call I made to Yamaha , I called as a yamaha sound sales man and was told that the CX-1 had cold solder issues and he advised me to buy CX-2 instead,. I did and have no concerns with my CX-2 which I have had since 1997. The excess video features do not concern me, I do not use them. The call was to Yamaha Headquarters in the USA. I took his advise . I do not know his motivation, but took his advise one Yamaha professional to a yamaha sound salesman. I could have bought either at 50% discount from list
     
  12. mcgjohn

    mcgjohn Member

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    56
    yes, quite correct. It was a B_ _ _ _ _ to get to that joint and not remove the board.....

    There are a few other locations that are similar. On some solder points, you just have to remove the board to get to them.
     
  13. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    If that's the case the smallest SuperThrough is 6800µF/50v and is 80mm tall. There are a couple of Gold Tune Type II that look promising (5600µF and 6800µF) but have a 25 week back order time at Mouser. But if they prove to be the best choice I'll bite the bullet, order, and wait.

    Cheers,
    James
     
  14. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Now that I've used this pre-amp almost every day for the last 2 months I feel that there is a slight bias towards the right channel. It just seems to play a little louder than the left, the sound stage seems to be shifted slightly towards the right. This with pure direct engaged. This is not a big thing, I'm loving the sounds that I'm getting.

    I had a useful (for me anyway) conversation in DIY concerning finding a good replacement for the Duorex caps. While I still don't understand what the intended primary attribute of this particular series of caps is I'm getting comfortable with replacing them with Panasonic FC in most cases.
    http://audiokarma.org/forums/index.php?threads/elna-duorex-capacitor-replacement.797011/

    I'm close to finalizing a Mouser buy list. It will be expensive. Partly because I'm ordering some extras of some values and also some alternates so that I have some options in terms of final decisions. Today I did order a pair of Mundorf Mlytic AG 6800µF/63v for the main filter caps. I may still order a pair of Nichicon KG's to hedge my bets. I can always use them in a CD player later anyway.

    Cheers,
    James
     
  15. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    So yesterday I made a large (for me) Mouser order.

    The RY-12W-K relays,
    47µF/35v Nichicon ES,
    470µF/35v Panasonic FC,
    470µF/35v Nichicon KL,
    33µF/35v KL,
    330µF/25v Nichicon FG,
    330µF/25v ES,
    22µF/35v ES,
    2200µF/35v FC,
    2200µF/25v KL,
    2.2µF/63v MKS2,
    1µF/63v MKS2,
    10µF/35v ES,
    100µF/35v ES,
    100µF/50v FC,
    100µF/50v United ChemiCon KYB,
    1000µF/10v FC,
    Some assorted Vishay 1% CCF metal film and Yaego FRM flame-proof resistors,
    Other stuff. :)

    I also did some homework that I should have done earlier and compared stats for 2200µF/35v FC, 2200µF/25v FG and 2200µF/25v KL. They are all 16mm dia and so will fit on the boards (35v FG and KL are 18mm and won't fit). The FC's have at least double the ripple current rating over the other 2, better Df than the FG and similar Df to the KL. I've gotten pretty comfortable with using the Panasonic FC's throughout for the 2200µF.

    I ordered at least double what I need for all of the above and will be testing them to make up matched pairs. In a few values I ordered alternate choices so that I have options. For the 33µF/25v on the protection board I made a WAG that they used Muse because they wanted low leakage and ordered some KL but have some FC in 50v on hand so have a second option. In every case where they will fit I went up a voltage step.

    I'll make a complete documentation of the replacement parts later and post it. Starting the week after next I have 2 weeks off and hope to do the work then. That is if everything gets here by then.

    Cheers,
    James
     
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  16. Karl vd Berg

    Karl vd Berg Super Member

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    You did a nice job, James. I'd like to add just one more item for the tests and researches in the future: try also the Panasonic FM series caps for power supply section. I like the FC's a lot elsewhere, but I'm using the the FM's (and FR's, too) more often in the PSU. These have even higher ripple current ratings (nearly 50% higher) than FC's and lower ESR. The other parameters are very good, too.

    [edit] Also United ChemiCon KZN series are very very good.

    Cheers.
     
    Last edited: Dec 13, 2017
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  17. rottalpha

    rottalpha Yamaholic Subscriber

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    woo, those look "dry"
     
  18. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    OK. You convinced me. I just ordered some FM 100µF/50v and 22µF/50v for the PSU. And some FC 2700µF/35v. And 100 each of all of the Yaego FRM 1/4w flame-proof metal film resistors that are still available because they are now end -of-life! I'm unhappy that there are no more 10 ohm but I bought some of every value still there at Mouser.

    Cheers,
    James
     
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  19. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    With todays Mouser delivery I now have all of the parts to complete the project except for the main filter caps. Those I ordered from Bürklin, normally a reliable and fast outfit. They are kind of like a small Bavarian version of Mouser and are only a 20 minute drive from my apt. But the caps are back ordered. So now I wait.

    Cheers,
    James
     
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  20. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    I just found and bought an original service manual. :banana: Paid a premium price for it and shipping from the US but I'm tired of squinting at poor scans of the schematic and boards.

    Cheers,
    James
     
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