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    CD player behavior when used with PAS 2

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    F.Sheng.WuChi

    Posts : 7
    Join date : 2016-12-20

    CD player behavior when used with PAS 2

    Post by F.Sheng.WuChi on Sat Jul 08, 2017 5:10 pm

    Hi, I recently acquired a "discman" type, portable CD player, and attempted to connect it to my system, a Dynaco PAS 2 and ST-70. Unfortunately, the performance was not without issue.

    While I cannot fully rule out the disc-player (intermittently it is unable to read a disc), there is one specific issue that I wondered if someone here may be able to illuminate why it occurs: While playing, if I place my hand near the rear of the disc-player, the playing is interrupted. It begins to fail altogether if I touch the player.

    It does not exhibit this phenomenon while listening with headphones.

    It makes no difference whether it is powered solely by batteries or connected to the AC supply.

    The proximity of my hand causes this effect to reach a peak whereupon the cd-player cuts out altogether.

    I have stopped attempting to utilize the cd-player just because I found the behavior annoying; but I suppose it may be possible that damage to any of my components could be a result of my Frankensteining. Could someone confirm that it may/may not be a good component choice for my existent system. I chose the player because of my space limitations. It was very cheap. I'm considering purchasing another for test purposes. Perhaps this is unwise?

    Is this phenomenon related to the mismatching of impedances?

    Thank you for your advice!
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    Peter W.

    Posts : 502
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: CD player behavior when used with PAS 2

    Post by Peter W. on Sat Jul 08, 2017 7:15 pm

    No, it is not - well, not exactly anyway. Most portable CD players *do not* have a fixed line-level output. So should the user choose to use such a device, they come off the headphone output, running at a low level.

    This will not work, full stop. The PAS is designed against a 2V (max) output from a conventional source as contemplated back in the 1960s. What comes out of a hand-held CD player is not that. So, whereas the actual failure is impedance-related, the cause is more that the components were never designed to be compatible.
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    peterh

    Posts : 859
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: CD player behavior when used with PAS 2

    Post by peterh on Sat Jul 08, 2017 8:32 pm

    It seems very strange.
    Try to rule out mains AC FIELDS, by grounding the PAS . Initially it could be a single wire
    connected with one screw on the backside and connected to a grounded item.

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    Kentley

    Posts : 431
    Join date : 2015-03-06
    Age : 65
    Location : Worcester, MA

    Re: CD player behavior when used with PAS 2

    Post by Kentley on Sat Jul 08, 2017 10:17 pm

    Never having utilized a PAS pre, i can't vouch for this, but I do believe that both Peters have a point.
    Those portable little CD players are generally junk to begin with.
    I've done what you are doing in the distant past with no issue. But that was long ago and far away, with crap equipment all round.
    Rest assured that you will not do any harm in your schemes.
    Have you tried all the inputs on your PAS?
    Heck, you can get a decent elderly CD player now on E Minus Baby for $40. Some of them are built into a half-chassis. If you want to listen to CDs properly you owe it to yourself.... santa

    GP49

    Posts : 781
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: CD player behavior when used with PAS 2

    Post by GP49 on Sun Jul 09, 2017 3:02 am

    I know that this will be of absolutely no help in answering the original poster's question...

    My Sony Discman, a D-EJ611, exhibits no such behavior into a stock Dynaco PAS-2x. It plays, and very well.

    It also has a line output...on the opposite side from the headphone output is a stereo mini-jack, clearly marked, "LINE OUT."
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    Peter W.

    Posts : 502
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: CD player behavior when used with PAS 2

    Post by Peter W. on Sun Jul 09, 2017 7:46 am

    GP49 wrote:I know that this will be of absolutely no help in answering the original poster's question...

    My Sony Discman, a D-EJ611, exhibits no such behavior into a stock Dynaco PAS-2x.  It plays, and very well.

    It also has a line output...on the opposite side from the headphone output is a stereo mini-jack, clearly marked, "LINE OUT."

    Yes, it does. Sony made some quite-serious portable disc players back in the day. And they also made docking stations for them so as to use AC power and provide an RCA output pair. I keep one to this day just as a collectible.
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    j beede

    Posts : 408
    Join date : 2011-02-07
    Location : California

    Re: CD player behavior when used with PAS 2

    Post by j beede on Sun Jul 09, 2017 10:49 am

    A few thoughts:

    -I have (personally) never seen a CD player (portable or otherwise) without a line out. That is not to say that they do not or cannot exist.
    -There was a time when the Optimus 3400 portable CD player's transport was viewed as high(est) performing. Do a search for Dick Sequerra and Optimus if you are curious. It may be "junk" but it still sounds good.

    To the original poster, try running the line output of your portable player through a passive attenuator (100k-250k stereo pot) straight into your Stereo 70. Radio Shack sells a junky inline attenuator for about $10 that should work. Catalog #4201352. You will need a 3.5mm stereo to RCA breakout adapter too. Catalog #4201354.

    GP49

    Posts : 781
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: CD player behavior when used with PAS 2

    Post by GP49 on Sun Jul 09, 2017 3:46 pm

    Peter W. wrote:Sony made some quite-serious portable disc players back in the day. And they also made docking stations for them so as to use AC power and provide an RCA output pair. I keep one to this day just as a collectible.

    The Sony D-EJ611, with its siblings having different model numbers, in different colors, and with different accessories included in the package, but all with identical and inerchangeable "guts", was a great advance in tracking ability and vibration resistance in a portable player.  It combined a new, best-tracking CD laser system with much faster-operating servo electronics than previously, and a large storage buffer.  At the time, nothing else could touch it.   Little can, even now.  I still use mine for its intended purpose, as a portable.  It is difficult to make it mistrack, even if I try!

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