The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Share

    8xlaxx

    Posts : 18
    Join date : 2016-12-10

    Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by 8xlaxx on Sat Dec 10, 2016 11:37 pm

    I'm a newbie to the site.  Extremely informative website!  An asset to the audiophile community, thank you.

    Maybe I haven't searched this topic thoroughly on this site but I think, I might not be entering the correct search.  I have a PAS 2 that is unmodified.  Has original tubes inside and it works.  It is driving an unmodified ST-70 (Bias caps and selenium rectifier replaced with diode).

    My PAS 2 volume control starts out pretty evenly as I increase gain,...it's not super loud at all through the range until it hits about 12-1 o'clock position then it starts to crank and really show the expression of my speakers.  I saw a brief thread on this topic on another site but no luck on the remedy.

    Can a member here assist me in diagnosing what the issue might be?  The control pot is smooth with no crackle, catch, hiss, or pop.  I can live with it but its a little frustrating when I want to hear something at a moderate volume level but not too low.  If the answer is already posted in a thread on the website, please post the link.  

    Thank you in advance.
    avatar
    peterh

    Posts : 837
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by peterh on Sun Dec 11, 2016 2:40 am

    8xlaxx wrote:I'm a newbie to the site.  Extremely informative website!  An asset to the audiophile community, thank you.

    Maybe I haven't searched this topic thoroughly on this site but I think, I might not be entering the correct search.  I have a PAS 2 that is unmodified.  Has original tubes inside and it works.  It is driving an unmodified ST-70 (Bias caps and selenium rectifier replaced with diode).

    My PAS 2 volume control starts out pretty evenly as I increase gain,...it's not super loud at all through the range until it hits about 12-1 o'clock position then it starts to crank and really show the expression of my speakers.  I saw a brief thread on this topic on another site but no luck on the remedy.

    Can a member here assist me in diagnosing what the issue might be?  The control pot is smooth with no crackle, catch, hiss, or pop.  I can live with it but its a little frustrating when I want to hear something at a moderate volume level but not too low.  If the answer is already posted in a thread on the website, please post the link.  

    Thank you in advance.

    replace the pot.
    See http://www.tubenirvana.net/pas3-spare-parts.html
    for parts.
    avatar
    arledgsc

    Posts : 459
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by arledgsc on Sun Dec 11, 2016 8:33 am

    You may have the wrong type "taper" of volume control.  A linear taper control would give you limited headroom where an audio (log) taper seems more smooth to your ears.  

    Google "linear vs log taper potentiometer" for additional information.  To measure set the pot to mid-range (power off).  Using an ohmmeter a linear control will measure equal resistance from wiper to other sides of the pot.  A log taper pot set to mid-range should measure much lower on one side versus the other.  Wired up in the circuit may interact with the meter reading so you may have to isolate the pot (pull off a wire temporarily).  

    A log taper pot wired up incorrectly or a "reverse log" taper pot will only compound the problem.
    avatar
    Peter W.

    Posts : 463
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by Peter W. on Sun Dec 11, 2016 8:52 am

    8xlaxx wrote:I'm a newbie to the site.  Extremely informative website!  An asset to the audiophile community, thank you.

    Maybe I haven't searched this topic thoroughly on this site but I think, I might not be entering the correct search.  I have a PAS 2 that is unmodified.  Has original tubes inside and it works.  It is driving an unmodified ST-70 (Bias caps and selenium rectifier replaced with diode).

    My PAS 2 volume control starts out pretty evenly as I increase gain,...it's not super loud at all through the range until it hits about 12-1 o'clock position then it starts to crank and really show the expression of my speakers.  I saw a brief thread on this topic on another site but no luck on the remedy.

    Can a member here assist me in diagnosing what the issue might be?  The control pot is smooth with no crackle, catch, hiss, or pop.  I can live with it but its a little frustrating when I want to hear something at a moderate volume level but not too low.  If the answer is already posted in a thread on the website, please post the link.  

    Thank you in advance.

    Let me put this in a way that will help your diagnosis:

    a) If the pot is original, and if this behavior is recent - both are necessary conditions - then the pot is defective.
    b) If the pot is original, and if this behavior is ongoing, it may be that you do not understand the function of an Audio Taper pot. Audio taper pots 'come on' very slowly. At 50% of the turn, an audio taper pot may be only at 25% of full volume, and then start to come on far more directly thereafter. So, if the sudden onset at 1:00pm is happening evenly on both channels, that is most likely the issue. Try cleaning the pot and see if that brings back a little bit more moderation.
    c) If the pot is after-market, repeat a) and b) - or it may be that the after-market device is not suitable for your application.

    But the odds of a simultaneous failure of both sides of such a pot are not large. Certainly possible, but not likely. With the pre-amp off, unplugged and the top off, you could test both sides of the VC using a VOM, even in-circuit. And you could observe for yourself how the taper works. In any case, willy-nilly replacing of the pot without a more specific diagnosis may only repeat the issue, but with a new pot.

    There are, also, stepped volume control kits out there that would allow you to custom-taper a pot for your specific needs. One of many sources is linked below.

    http://diyparadise.com/stepped_atten.html  

    And don't apologize. All of us here are in different stages, and all of us are capable of learning something new, and all of us have 'been there' at one time or another.

    Peter Wieck
    Melrose Park, PA
    avatar
    tubes4hifi
    Admin

    Posts : 1364
    Join date : 2008-11-30

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by tubes4hifi on Sun Dec 11, 2016 2:34 pm

    this is a very common problem with old PAS preamps. They used low quality parts, and now after 50 years, the old one hasn't gotten any better! Replace it with a new volume control.
    This one from Radio Shack is a close enough sub . . . . https://www.radioshack.com/products/radioshack-100k-dual-ganged-stereo-volume-control
    avatar
    PeterCapo

    Posts : 431
    Join date : 2008-12-05

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by PeterCapo on Mon Dec 12, 2016 9:49 am

    8xlaxx wrote:I'm a newbie to the site.  Extremely informative website!  An asset to the audiophile community, thank you.

    Maybe I haven't searched this topic thoroughly on this site but I think, I might not be entering the correct search.  I have a PAS 2 that is unmodified.  Has original tubes inside and it works.  It is driving an unmodified ST-70 (Bias caps and selenium rectifier replaced with diode).

    My PAS 2 volume control starts out pretty evenly as I increase gain,...it's not super loud at all through the range until it hits about 12-1 o'clock position then it starts to crank and really show the expression of my speakers.  I saw a brief thread on this topic on another site but no luck on the remedy.

    Can a member here assist me in diagnosing what the issue might be?  The control pot is smooth with no crackle, catch, hiss, or pop.  I can live with it but its a little frustrating when I want to hear something at a moderate volume level but not too low.  If the answer is already posted in a thread on the website, please post the link.  

    Thank you in advance.

    This characteristic is typical for original PAS volume pots.  Have a look at the following discussion, especially Post n°19, here: http://dynacotubeaudio.forumotion.com/t3113-audio-analogue-bellini-as-pre-amp-for-st-35

    8xlaxx

    Posts : 18
    Join date : 2016-12-10

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by 8xlaxx on Tue Dec 13, 2016 3:06 pm

    Thank you for all the replies to the symptoms and remedy for the volume controller!  Very, very helpful.  

    The link that PeterCapo copied is exactly what is happening with my PAS 2.

    peterh and tubes4hifi,...

    Is the Radio Shack volume controller an exact drop-in replacement for the stock Dynaco controller?  I ask because you never know what problems one will run into upon installing an after-market part.  In particular 1) the shaft length and 2) 'if' the original, plastic, brown w/ gold in-lay Dynaco knob will fit onto the Radio Shack shaft.

    Please reply if you have experience with the Radio Shack 100k gang controller installation.  There seems to be quite a difference in price between the Radio Shack controller $4USD and the Tubesnirvana controller at $12USD +shipping.  I have a Radio Shack right around the corner and they do have 5 of these controllers in stock!  Much easier just to run out and get it,...

    Thank you for all the assistance.
    avatar
    Peter W.

    Posts : 463
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by Peter W. on Tue Dec 13, 2016 3:51 pm

    The original control is a tapped 250K dual-pot *AUDIO TAPER* volume control.
    There are several schools-of-thought on 100K vs. 250K. With 100K, you sacrifice the very lowest volume settings, but according to the literature, you get a bit more stability in return. Writing only for myself, when I replaced mine, I used a 100K tapped audio taper unit and kept the loudness control on my PAS3X. No worries, good results.

    If you have soldered before and have decent fine motor skills, it is not a difficult job. I have done it in 20 minutes, from top-off to test.
    avatar
    peterh

    Posts : 837
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by peterh on Tue Dec 13, 2016 5:21 pm

    8xlaxx wrote:Thank you for all the replies to the symptoms and remedy for the volume controller!  Very, very helpful.  

    The link that PeterCapo copied is exactly what is happening with my PAS 2.

    peterh and tubes4hifi,...

    Is the Radio Shack volume controller an exact drop-in replacement for the stock Dynaco controller?  I ask because you never know what problems one will run into upon installing an after-market part.  In particular 1) the shaft length and 2) 'if' the original, plastic, brown w/ gold in-lay Dynaco knob will fit onto the Radio Shack shaft.

    Please reply if you have experience with the Radio Shack 100k gang controller installation.  There seems to be quite a difference in price between the Radio Shack controller $4USD and the Tubesnirvana controller at $12USD +shipping.  I have a Radio Shack right around the corner and they do have 5 of these controllers in stock!  Much easier just to run out and get it,...

    Thank you for all the assistance.

    I would go for a 250k from tubenirvana.
    100k will load the riaa amp , and in addition to anything connected to tape out it will ruin
    vinyl quality

    8xlaxx

    Posts : 18
    Join date : 2016-12-10

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by 8xlaxx on Tue Dec 13, 2016 11:02 pm

    I would go for a 250k from tubenirvana.
    100k will load the riaa amp , and in addition to anything connected to tape out it will ruin
    vinyl quality[/quote]

    Thank you for the advice.  There are no 250K volume pots at this site, that I could see, except for the balance pot.
    avatar
    peterh

    Posts : 837
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by peterh on Wed Dec 14, 2016 2:32 am

    8xlaxx wrote:I would go for a 250k from tubenirvana.
    100k will load the riaa amp , and in addition to anything connected to tape out it will ruin
    vinyl quality

    Thank you for the advice.  There are no 250K volume pots at this site, that I could see, except for the balance pot.[/quote]
    Thats strange ..
    Myself bought 2 pieces of 250k "ALPS" on ebay some years ago .
    Ask tubesnirvana about 250 pots, they should know.
    avatar
    peterh

    Posts : 837
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by peterh on Wed Dec 14, 2016 2:45 am

    peterh wrote:
    8xlaxx wrote:I would go for a 250k from tubenirvana.
    100k will load the riaa amp , and in addition to anything connected to tape out it will ruin
    vinyl quality

    Thank you for the advice.  There are no 250K volume pots at this site, that I could see, except for the balance pot.
    Thats strange ..  
    Myself bought 2 pieces of  250k "ALPS" on ebay some years ago .
    Ask tubesnirvana about 250 pots, they should know.[/quote]
    A quick search on ebay :
    http://www.ebay.com/itm/DYNACO-OTHERS-REPLACEMENT-POTENTIOMETER-/371811769465?hash=item5691b55c79:m:m9Lff2XDNmnM_iMRT-caTfg
    ( you need to inform seller that you want 250k )

    http://www.ebay.com/itm/5pcs-Dual-Deck-MN250K-Blend-Balance-Pickups-Guitar-Potentiometer-/272414342809?hash=item3f6d28fe99:g:aLgAAOSw8w1YAfrB
    ( lacks loudness tap )

    http://www.ebay.com/itm/Japan-ALPS-RK27-VOLUME-Pot-Stereo-audio-taper-potentiometer-Dual-250K-ROUND-/131281361277?hash=item1e90fa997d:g:VXAAAOSwxH1T~qll
    ( looks like the "ALPS" i bought )

    and that was a quick look...
    avatar
    PeterCapo

    Posts : 431
    Join date : 2008-12-05

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by PeterCapo on Wed Dec 14, 2016 10:11 am

    There is another point that should probably be mentioned - and I am not entirely clear on this, due to some apparently conflicting information.  But, over time, I know I have read a number of reports of a taper problem when replacing the volume control in a PAS with a pot that does not retain the loudness taps and loudness resistors.  Without the loudness taps and loudness resistors connected, some have reported the volume getting too loud with too little rotation of the volume control.  This might vary depending on the value of the pot, but I'm not sure.  Note this all applies to the original Dynaco PAS circuit.

    Suggest reading through the Full Thread associated with the post at this link http://audioasylum.com/forums/dynaco/messages/1/14144.html
    avatar
    peterh

    Posts : 837
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by peterh on Wed Dec 14, 2016 2:45 pm

    PeterCapo wrote:There is another point that should probably be mentioned - and I am not entirely clear on this, due to some apparently conflicting information.  But, over time, I know I have read a number of reports of a taper problem when replacing the volume control in a PAS with a pot that does not retain the loudness taps and loudness resistors.  Without the loudness taps and loudness resistors connected, some have reported the volume getting too loud with too little rotation of the volume control.  This might vary depending on the value of the pot, but I'm not sure.  Note this all applies to the original Dynaco PAS circuit.

    Suggest reading through the Full Thread associated with the post at this link http://audioasylum.com/forums/dynaco/messages/1/14144.html

    This is most likley a non log pot used. Volume pots ( and PAS3 ) is logaritmic to
    adopt to human hearing.

    GP49

    Posts : 778
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by GP49 on Wed Dec 14, 2016 3:29 pm

    There was a prior thread here about an inexpensive stepped attenuator, available through an EBay vendor.  It is of very high quality...as mentioned in the thread, it's the volume pot used by Ed in the tubes4hifi  SP12 & SP14 preamps.  

    http://dynacotubeaudio.forumotion.com/t2931-user-report-dact-type-21-stepped-attenuator-250k-for-tube-amp?highlight=DACT

    The EBay reference has changed in the meantime, but that's OK, it was for one without the loudness tap.  The current 250kΩ one with the loudness tap:

    http://www.ebay.com/itm/LOUDNESS-tapped-250K-DACT-Type-21-Stepped-Attenuator-Potentiometer-FREE-PCB-/201655037416?hash=item2ef393ade8:g:p8gAAOSw6n5XwZ7k\

    There are other alternates, different impedances, with/without loudness tap, splined vs. D-shape shaft...search by seller name.

    This attenuator tracks very accurately, better than the Radio Shack one (which is the wrong impedance anyway, instead of the correct 250kΩ it is 100kΩ which will roll off the bass in the PAS phono stage) and sounds better than the ALPS pots.  The prior thread explains what you may wish to do to ease installation, since this attenuator is smaller than the stock Dynaco pot you are replacing.


    Last edited by GP49 on Wed Dec 14, 2016 5:27 pm; edited 1 time in total
    avatar
    PeterCapo

    Posts : 431
    Join date : 2008-12-05

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by PeterCapo on Wed Dec 14, 2016 3:46 pm

    That 250K one with the loudness taps looks like a pretty good solution.  As you mentioned, the remaining challenge is the physical fit.

    Did not look at this in detail, but there might be something to help at the following link, or the O.P. could contact Kevin directly: http://www.dynakitparts.com/dynakit-products/pas-chassis-parts/PASControl-Hardware

    8xlaxx

    Posts : 18
    Join date : 2016-12-10

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by 8xlaxx on Thu Dec 15, 2016 10:04 am

    Just wanted to thank everyone for the replies so far.

    I must admit that I am a very confused over 'what' to install.  Some here have suggested the replacing of the current 250K pot with a 100K pot from Rat Shack (I have already purchased one).  While some others have said replacing with a 250K pot so as not to lose vinyl quality sound (which I do listen to 99.9% of the time!).

    Yesterday I secured a black box 100K ALPS pot with six connections on it, no loudness tap.  I would prefer installing this over the Rat Shack product.

    I also read the information at Mr. Curcio's website on replacing the volume pot.  I cannot post the .pdf link here as this site manager will not allow new members to post links until after 7 days.

    Mr. Curcio suggests and recommends replacing the original 250K pot to 100K.  What 'gives' on all these different choices and recommendations?

    Thanks again for the assistance.
    avatar
    Peter W.

    Posts : 463
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by Peter W. on Thu Dec 15, 2016 10:42 am

    8xlaxx wrote:Just wanted to thank everyone for the replies so far.

    >>Snippage<<

     What 'gives' on all these different choices and recommendations?

    Thanks again for the assistance.

    Welcome to the hobby!

    Each circumstance is different.

    You have a PAS-2 (early version) which has issues that were addressed in later versions, up to and including the last PAS-3X with the center-out tone controls and a different output impedance that more easily matched both tube and solid-state amps. On that version (my version), going to a 100K, tapped volume control is far less problematic and has little or no effect on the phono section.

    On your version, I would suggest (and should have initially, sorry) that you stick with the 250K, audio-taper option. And, that you continue to use the center-tap for tone controls. My general advice is *one thing at a time* with modifications. You can always opt out of tone controls later.

    And "fixing" the phono board is also pretty simple:

    http://www.curcioaudio.com/Dynaco%20PAS%20RIAA%20EQ%20Correction%20Mod.pdf  

    The X-mod (output impedance only) from Dynaco:  

    1. Obtain two 100,000 ohm, 1/2-watt 10% tolerance resistors.
    2. Unsolder and discard the two 510,000 ohm (green-brown-yellow)
    resistors connected to the audio-output sockets on the back panel of
    the preamplifier and replace them with the 100,000 ohm resistors.
    Solder all connections.
    3. Snip out and discard the two 62,000 ohm (blue-red-orange) resistors
    on the PC-5 circuit board adjacent to eyelets 8 & 18. This completes
    the modification.


    Given the relative difference in cost, I would use 5% resistors and
    screen them as well.
    avatar
    PeterCapo

    Posts : 431
    Join date : 2008-12-05

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by PeterCapo on Thu Dec 15, 2016 11:23 am

    At this point I suggest limiting your work to replacing the volume pot and leave other matters such as the line level output stage, tone controls, etc., for later.

    With regard to the Radio Shack pot, perhaps others will agree that it is very much a budget replacement.  Nothing terribly wrong with it (unless you get a sample with bad tracking), but some of the other pots under discussion are likely "better."

    IIRC, the black box pots are Alps knockoffs made in China, I think?  You might try taking a meter and measuring the resistance of each channel with the pot rotated to different positions throughout the likely listening range to see how closely the channels track, including the lower end of the pot’s range if you intend to listen at lower volume at times.

    But, then, your black box pot is lacking loudness taps.

    I recall Mr. Curcio saying that the PAS has slightly better high frequency response using a 100K pot vs. 250K, but I do not think he elaborated on this.  Is this what you found in his literature? http://audioasylum.com/forums/dynaco/messages/1/13482.html

    A 100K pot will roll off the bass from the phono section a bit, but I tend to doubt it’s enough to be audible http://www.audioregenesis.com/documents/PAS_Phono.pdf   By the way, this Audioregenesis study demonstrates that the PAS phono section does not require "fixing."  If you go to the Audioregenesis home page, you’ll see a collection of the best studies anywhere of the original PAS.

    I vote for a pot like the one GP49 posted from ebay seller "lasercollection," either 100K WITH loudness taps or 250K WITH loudness taps.  I’d try messaging lasercollection to discuss any issues with the physical fit.
    avatar
    PeterCapo

    Posts : 431
    Join date : 2008-12-05

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by PeterCapo on Thu Dec 15, 2016 11:42 am

    On the other hand... looks like that pot sold by "lasercollection" would have its connection points on the front wafer really close to the inside front panel.  Mounting a pot like this might require extra care to make sure nothing shorts to the panel while leaving enough shaft to secure it to the panel and to the faceplate, although the nut on the outside of the faceplate might be expendable.  Again, suggest discussing with lasercollection before purchasing.

    Aside from any issues related to the physical fit, I would prefer the kind that lasercollection is selling to any thus far discussed.  But, if the fit ends up being too much of a problem, I was able to fit the following into my PAS a little while back: http://www.ebay.com/itm/1-X-MADE-JAPAN-ALPS-RK27-SERIES-100K-STEREO-VOLUME-CONTROL-POT-LOUDNESS-/301910555710?hash=item464b457c3e

    "hkseller8" might have it in 250K with loudness taps if you want to inquire.

    GP49

    Posts : 778
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by GP49 on Thu Dec 15, 2016 1:56 pm

    PeterCapo wrote:On the other hand... looks like that pot sold by "lasercollection" would have its connection points on the front wafer really close to the inside front panel.  Mounting a pot like this might require extra care to make sure nothing shorts to the panel while leaving enough shaft to secure it to the panel and to the faceplate, although the nut on the outside of the faceplate might be expendable.

    Yes, that is a possible issue, discussed in the prior thread.  If you solder to the backside of the connecting points and not the front, and clip off surplus wire, it fits.  That was no problem for me.  A larger issue was that the new attenuator being smaller, meant the original Dynaco wiring couldn't quite reach the connecting points, so for me the solution was to solder longer wires to the attenuator while it was on the workbench, then remove the old wiring and solder the new longer wires to where they connected in the preamp, one by one to avoid confusion, after the attenuator was physically installed.  It was no big deal; in fact I didn't even remove the PAS chassis from its place on the shelf while installing the new attenuator, with new wires attached.  I installed it in situ after removing the cover.

    I continue to be positively impressed with the performance of the new attenuator.


    Last edited by GP49 on Thu Dec 15, 2016 2:06 pm; edited 1 time in total
    avatar
    PeterCapo

    Posts : 431
    Join date : 2008-12-05

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by PeterCapo on Thu Dec 15, 2016 2:06 pm

    GP49 wrote:
    PeterCapo wrote:On the other hand... looks like that pot sold by "lasercollection" would have its connection points on the front wafer really close to the inside front panel.  Mounting a pot like this might require extra care to make sure nothing shorts to the panel while leaving enough shaft to secure it to the panel and to the faceplate, although the nut on the outside of the faceplate might be expendable.

    Yes, that is a possible issue, discussed in the prior thread.  If you solder to the backside of the connecting points and not the front, and clip off surplus wire, it fits.  That was no problem for me.  A larger issue was that the new attenuator being smaller, meant the original Dynaco wiring couldn't quite reach the connecting points, so for me the solution was to solder longer wires to the attenuator while it was on the workbench, then remove the old wiring and solder the new longer wires, one by one to avoid confusion, after the attenuator was physically installed.  It was no big deal; in fact I didn't even remove the PAS chassis from its place on the shelf while installing the new attenuator, with new wires attached.  I installed it in situ after removing the cover.

    I continue to be positively impressed with the performance of the new attenuator.

    That gets my vote!

    8xlaxx

    Posts : 18
    Join date : 2016-12-10

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by 8xlaxx on Thu Dec 15, 2016 5:02 pm

    With that eBay 250K pot and PCB board, are they both connected or can I directly connect the wires from the PAS 2 to the 250K pot? or do they go directly to the board?
    avatar
    Peter W.

    Posts : 463
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by Peter W. on Thu Dec 15, 2016 5:10 pm

    You may connect directly to the board - and it should fit. Or, you can go directly to the control off the board. Note that the board has positions for the associated caps and/or resistors as well.
    avatar
    peterh

    Posts : 837
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by peterh on Thu Dec 15, 2016 7:17 pm

    I agree with above ( use 250k pot )
    Happy X-mas

    Sponsored content

    Re: Volume Control on PAS 2,...at 1 o'clock it starts getting loud

    Post by Sponsored content


      Current date/time is Sat Sep 23, 2017 11:19 pm