Need a part for my Dynaco PAS4 pre

muncybob
muncybob Posts: 3,042
in 2 Channel Audio
The balance control is causing the right channel to cut out. The sound is restored if you apply pressure to the knob either up or down, so I am assuming it's not a simple matter of deoxit cleaning. I will need a repair shop to do the replacement since I have next to no soldering skills. I want to minimize the amount of time they have the preamp, so I am looking to acquire the part needed before taking it to the shop. Where do I look for a good control? What info would they need?
Yep, my name really is Bob.
Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub.
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Comments

  • [Deleted User]
    [Deleted User] Posts: 7,658
    In Dynaco's owner's manual it is described as a 25k dual balance potentiometer, but the dimensions of the mounting hole and the size and type of knob used will make a difference.
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  • muncybob
    muncybob Posts: 3,042
    S, that info probably cannot be determined until the potentiometer is removed?
    Yep, my name really is Bob.
    Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub.
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  • [Deleted User]
    [Deleted User] Posts: 7,658
    You can tell what the shaft diameter (usually 0.25") is and how the knob is attached. Look for a set screw on the side of the knob (you might have to turn the unit upside down to where it is located) and if you have some allen wrenches you can figure out which one takes the knob set off. If there's no set screw then the knobs pull off and look at the underside to see if there's a "D" shaped opening.
    Honestly it might be best to just bring it to a good repair shop and let them source the part. It won't add too much to the wait time.
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  • muncybob
    muncybob Posts: 3,042
    Probably what I'll do. Is this a part that one manufacturer is better than another? It's not something that will get used very often.

    There are also tape monitor and tape dubbing knobs. Perhaps have them replaced too while it's in for repair or leave well enough alone?
    Yep, my name really is Bob.
    Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub.
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  • [Deleted User]
    [Deleted User] Posts: 7,658
    Companies such as Bourns, Clarostat and Alps are the ones most often used in vintage gear. Clarostat has a mil-spec series that would have accurate tracking between the two channels. You'll want an audio taper control as opposed to a linear design. There seems to be an online Dynaco parts store, not sure what they might have available.
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  • mhardy6647
    mhardy6647 Posts: 33,801
    @muncybob: Are you sure the pot won't respond to cleaning?

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  • [Deleted User]
    [Deleted User] Posts: 7,658
    I had the same thought, it was the symptom of needing to put pressure either up or down that probably indicated the wiper wasn't in contact with the resistive track that led me to think it either needed taking the pot apart (if possible) or replacing.
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  • muncybob
    muncybob Posts: 3,042
    Since I really don't need a balance feature on the pre(can do this from the amp if needed)...could this pot be eliminated?
    Yep, my name really is Bob.
    Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub.
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  • [Deleted User]
    [Deleted User] Posts: 7,658
    Yes it could.
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  • muncybob
    muncybob Posts: 3,042
    So, any down side to this? I just figure 1 less item in the path, no?
    Yep, my name really is Bob.
    Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub.
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  • [Deleted User]
    [Deleted User] Posts: 7,658
    Outside of not having a way to adjust the channel balance (from the preamp) eliminating a component in the signal path is always a good idea. Looking for that proverbial straight wire with gain audio grail, sonus suavis.
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  • muncybob
    muncybob Posts: 3,042
    I guess it could hurt resale value or at least limit the potential buyers, but since I have no plans on selling any time soon I think this is the right choice for me. Also saves me a few days waiting on the pot to come in :)
    Yep, my name really is Bob.
    Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub.
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  • pitdogg2
    pitdogg2 Posts: 25,441
    hot1tinger reported
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