Yamaha CX-1 Thread

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

  1. Karl vd Berg

    Karl vd Berg Super Member

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    Can also be, James. That's why I usually leave the unit "on" for a few days, melting the dried honey inside the cans...

    (Edit) A good way to check it could be by measure again the new cap after some 100 hours, but the repeated solder process could give you wrong (not actual) numbers.
     
    Last edited: Jan 15, 2018

     

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  2. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    OK. I just finished my parts list spreadsheet. I'm attaching it here at the bottom of this post.

    It is in a zipped LibreOffice ".ods" data format. I don't have or use any MS products. LibreOffice is a free download and this way anybody can us it without having to pay for an office program. I will be making an edit to the first post of this thread pointing to this post.

    I want to state clearly that in no way am I or would I try to say that I made all the best or perfect choices with what I bought and installed. This just a tool/contribution for anyone to use as a starting point. On the other hand, the pre-amp did turn out sounding better that before so one could clearly make some worse parts choices. :)

    I used Mouser part numbers and you can just copy/paste them right into the Mouser search field and save a little time.

    If anybody sees any errors Please PM me and I'll correct them immediately.

    Enjoy,
    James
     

    Attached Files:

    Last edited: Jan 15, 2018
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  3. Karl vd Berg

    Karl vd Berg Super Member

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    That happens to me in the value range of 220uF, 330uF, 470uF pretty often, no matter the voltage is with "fresh" new caps.
    Probably I'll buy caps from 270uF, 390uF to 560uF - whenever possible - when values don't have to be that tight/precise, like in the tone control, etc...
     
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  4. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Good to know. Thanks Karl.

    Cheers,
    James
     
  5. zaibatsu

    zaibatsu Well-Known Member

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    Great work, a very thorough job as always!

    That's funny - I recently bought some KZ 470uF 50V which all measured in-spec (slightly higher at ~480uF). I bought them because I was mildly annoyed at buying KZ 330uF 50V which consistently measured around 295uF, and figured the 470s would be out by a similar amount (and thus be close enough to +20% from 330uF), however that was not the case!

    Sometimes you can't win, I'll use them anyway. :)
    They were all from mouser for what it's worth.

    We can call it various things - but either way - numerous measurable changes happen to electrolytic capacitors (both in liquid electrolytic and solid polymer types) over their lifetime as a result of various factors: dormant storage (both initially, and/or after installation), application of soldering heat, and application of voltage + AC ripple.

    If you're interested I found these documents on the topic useful:
    http://www.tadiranbatteries.de/pdf/...perties-of-modern-electrolytic-capacitors.pdf
    http://www.ee.co.za/article/thermal-stress-capacitors-failure-prevention.html
    https://eu.industrial.panasonic.com/sites/default/pidseu/files/downloads/files/id_oscon1309_e.pdf (p.12)
     
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  6. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Thanks Zaibatsu!

    You and Karl usually stop by in one of my threads and always have something interesting to share. Always appreciated.

    That first link I discovered last month and had an influence on my cap selections, the other 2 are new to me. All are very interesting. Thanks!
    I think that I'm ready to start trying out some of your solid cap types.

    I'm starting to realize that buying new caps is a complete gamble in terms of what we receive on a batch to batch basis. One the one hand it's not good to have a lot of old caps sitting around, on the other it seems that the only way to get what we want (paid for actually) is to buy in quantity in different varieties. Almost a can't win situation unless one has a lot of money to play with.

    I have perhaps 10 hours of listening now with the re-caped pre and am very happy. I really didn't expect this much of a SQ improvement from a straight re-cap.

    Cheers,
    James
     
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  7. Karl vd Berg

    Karl vd Berg Super Member

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    You just did the best thing: measured EACH old and new caps, and replaced the old ones with the best possible substitutes.

    Yes, it cost you time, money, patience and a lot of research. But the reward is priceless, in terms of SQ and knowledge. And hey!, also shared with us all and for future projects... :music:
     
    Last edited: Jan 16, 2018
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  8. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Thanks Karl. :beerchug: Considering the thoughts that you and Zaibatsu and others have posted (ConradH also always has interesting/useful insights) about caps I've at least decided on a few general rules:

    Replace elcos with film caps whenever practical.
    Always use 105° caps when available for the application/position.
    Don't overheat caps when soldering.
    Go a step up or more in voltage when practical and size allows.
    For local filtering consider going a step up in µF when size allows.

    The cost in time and patience was actually fun, and well worthwhile. And in this case the money cost was irrelevant to me. It's not often that I can say that but when dealing with a pre-amp in this class there is no point in penny pinching.

    I still have the bridge rectifier replacement in my plans. I'll be dealing with that in the next few weeks.

    Cheers,
    James
     
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  9. mcgjohn

    mcgjohn Active Member

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    if you are looking for a fast recovery bridge, EDI makes them. saves a lot of time and looks cleaner than making a bridge out of 4 fast recovery diodes.

    http://www.e-edi.com/products_1.php

    best
     
  10. Karl vd Berg

    Karl vd Berg Super Member

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    James, good points.

    The step up in voltage when practical and size allows is what I do, too. Sometimes when there's room enough I put as large as it fits...

    [​IMG]

    Here's my Basic C1 preamp, once many times tested with all sorts of caps (MUSE, Silmic, Wima, Vishay, Panasonic FR, Nichicon PW, etc), opamps, Dale MF resistors, MBR1100G Schottky's, etc.
    Now pretty much stable... (IC2 opamp is 2604, my favorite, or 2228. IC1 is the 2068DD)

    Cheers,

    [​IMG]

    [​IMG]
     
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  11. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Thanks!
    I'll check it out.

    Cheers,
    James
     

     

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  12. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Hi Karl,
    A C-1? That huge thing that I see from time to time going for €3000-€4000? I'd be terrified to experiment with one because for sure I'd make a door stop out of it. Nice work. :)

    Cheers,
    James
     
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  13. Mr. Yamaha

    Mr. Yamaha Not so much Yamaha lately... Subscriber

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    I think that's a Kenwood Basic C-1 pre-amp ;)
     
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  14. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Oh. Well that's different. :)

    Cheers,
    James
     
  15. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    The schematic and PCB layout scans are too large to send to the database. I'm going to have to find a local print shop and have them scanned again. Stay tuned...

    Cheers,
    James
     
  16. brutal

    brutal YamaHoarder

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    Are they pdf? They might be able to be shrunk by removing support for older pdf viewers.

    I have tons of cloud storage available. If needed, I can put up a shared Onedrive folder and try to shrink them for you after upload.
     

     

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  17. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    The scans are jpg's. Actually the original scans are tif and even larger. It was probably a mistake to go with 600dpi, 300 would probably be good enough. Give me a little time to go over to a professional photo-shop/printer and see what I can get with a single scan that way. In the mean time I'll PM you about sending them to you.

    Things are a bit disruptive with me at the moment, getting things ready to go in the hospital next week for an OP. But we'll get it done.

    Cheers,
    James
     
  18. mcgjohn

    mcgjohn Active Member

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    Sorry it took so long to get the pics, but could not locate them on several flash cards, so took some new photos.

    The film bypass caps are nichicon YX series film and foil caps, availalble from several on line suppliers. The Vishay resistors are type VSR, ultra low noise.

    Preamp is super quiet, very resolving. Have got the upgrade itch a few times and compared it to 4 figure pre amps from various mfgrs, and so far the CX-1 has come out on top.

    If you are using a LOMC moving coil, spend the time and go through the phono stage. Its well designed and pretty tough to beat. I have used everything from a Benz Ebony to a Denon 103R and a few madrigal Carnegie ones (one of my fav carts). and the MC phono stage has plenty of gain and is super quiet.

    MM stage is pretty good too, but have not used an MM cart in years.

    cheers.
     

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  19. mcgjohn

    mcgjohn Active Member

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    sorry I missed your post....

    yes the larger PS trans will cut the heat drastically since the OEM transformers can run pretty warm. If you are pulling an amp or two out of a 30 or 50VA trans, not quite the same as pulling an amp or two out of a 500VA trans. Its akin to putting a V-8 in a Yugo, or in more modern times a V-8 in a Nissan Altima...The V-8 will be loafing no matter what you ask it to do. Same with the over sized transformerr

    All you need to do is measure your secondary AC voltages so you know what they are then go transformer shopping

    best

    .
     
  20. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

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    Thanks for the photos John. I don't know if I'll be going that far but it's good info to have. I'll definitely look into the VSR resistors. It must have been fun getting the bridge rectifier leads bent to fit the inline package spacing.

    I had some time yesterday and did some work on the schematic and layout scans. I was able to get them down to a much more reasonable size without any real loss of clarity. I'll see about uploading them to the database shortly. In the mean time if anyone wants them directly by email the schematics are now 11.3mb and 10.2mb, and the layout scans are now 15.3mb, 5.4mb, 7.7mb and 5.3mb. Should be doable with a few emails.

    Cheers,
    James
     

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