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Hi, I want to install this 2\ 250k volume control on my Dyna PAS project. I want to get rid of the balance control. I have 3 wires, left/green, right/red, and black/ ground. I will move my speakers or listening position for balance. Should I use little jumper wires from the left holes to left and right to right. It looks like that's the way the black/ground is hooked up. Thanks so much.I want to double check before I continue...Mark Korda
Follow Ups:
The grounds (the low side of each pot) get tied together and connected to the black wire. There is no need for jumper wires anywhere else.
The
Have Fun and Enjoy the Music
"Still Working the Problem"
Hi, Palustris, that pot I showed is a 2/250K pot. that goes in the Dyna PAS.I took the old one out and bought this one.With the manual the hook up shown is with a balance pot. There are only 3 wires to deal with.Red, green,and black/ ground. I know how to hook up the grounds like Tre' explained but didn't understand the rest of his answer.My question is with 1 red/right channel wire and 1 green/left channel wire how do I connect them to this pot so I can omit the balance control.I don't need it. Palustris, the article I have on this uses this configuration, they stated 1 Allen/Bradley 2/250 k pot with no balance.The preamp was working fine,with a balance control until my experiment of throwing everything off the boat thats not needed.The David Vorhis Last PAS, which this is very close,is the mod my friend installed.I have the article from Audio Amateur,1982, part 1, but not part 2 which might show me the answer.Part 1 is 4/82 in Audio Amateur.Part 2 must be 5/82.Thanks Palustris...
J.Carney, I'm running a Dyna ST-35 that made a trip to Van AlStines. I also had him mod a Dyna SAQA-80Q amp that another friend is using now,late 80's.I was broke,I never wanted to part with that.I will send him the pot question after I smoke a little myself.
Tre', thanks but I don't really understand your answer.What do you mean by the low side?.....thanks you guys.I will call the modder of that amp tonight as we still keep in touch from 1985, Audiomart.Take care ,Mark Korda...P.S. with the manual I know where the 2 red/green wires go to but can't figure,without you guys, how the soldering on the pot should go....I'm off balance, literally.
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Have Fun and Enjoy the Music
"Still Working the Problem"
Hi Tre', thanks for the help but I didn't understand what that black line was on the schematic.It looked like the same as in my manual.A couple of days ago Van AlStine called me up out of the blue and needed some more info and left me his idea's in an email which I would like to forward to you. He still has me a little confused.
What will solve my problem is the Audio Amateur 1982 #5 issue.It will show just 1 pot for volume like the mod shows and how it is wired.
Tre, I know how to wire the volume with a balance but only having 3 wires, right,left and ground ,I'm baffled.I'll keep trying to send Frank V's answer and see if you can decipher it. Thanks you other guys for the help,present and past and future.......Mark Korda
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Your 'sort of' double posting this question on two different Asylums makes it a bit difficult for everyone who's trying to follow, but can't access the same information for what you're trying to accomplish.
As I posted to you in Vintage, here's the Last PAS volume control wiring diagram. There's more information I've posted over there, which shows which wires in the PAS go to which eyelets on your Alps pot board.
For those following, S1 is the source switch (in this case a simple DPDT toggle), and S2 is a stereo/mono switch, the diagram taken from the Last PAS article in Audio Amateur.
Mark, note above that the wires on #3 and #6 (the ground lugs) of the volume control are tied together, just as Tre' said. In the case of the Last PAS, that wire is taken to a star (single point on the chassis) ground.
I hope this helps.
Hi Shovel, I left you a message on another site, vintage. That was beyond help! I had a hard time grasping some other recommendations. The last piece to my puzzle before I solder is a 20K resistor in series with a 510K resistor as in the diagram near the preamps output jacks.I know the 510k's are there as they are still on the un-connected wires.I can't remember if I threw away the 20k resistors when I gutted the jacks before installing the new ones.I don't know if you remember or not if the mod kept that resistor, which I already ordered anyway.I want to send you something for helping me. It will probably have more meaning than value but you the man!, thanks for the help.Here's my email, I need your address (kordamark@gmail.com)...thanks again Shovel...Mark Korda
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Hi Mark,
By "diagram", do you mean the schematic? If so, the only resistor I could find close to 510K is the 475K, R26 as shown above. If so, as Tre' said, the 20K won't make any significant difference in that feedback level.
In later correspondence with Dave Vorhis, the author of The Last PAS, here's what he told me about that resistor:
"As far as the resistor values [of R26, 475K] go, the exact numbers are totally non-critical. The two channels should be the same value but other than that you can change them up or down by 20% or so with no effect. [570K/380K]
This circuit is sometimes called an Anode Follower. It basically has heavy feedback which reduces the gain and the output impedance. It's not used as often as other designs but nothing unique about it, and certainly nothing critical.
Like most things, I wasn't the originator of it. My inspiration was the ARC schematic for their old tube crossover. In the ARC design, the feedback was so much that the 12AX7 had unity gain, at least that's how I recall it. I basically just altered the feedback resistor values to give it a bit of gain. The feedback circuit actually includes the volume control so as the control is rotated the overall feedback changes. I remember saying in the article that this was not particularly elegant but it seemed to work ok, so there you go."
Dave Vorhis
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Hi Shovel, your the best! I do have a final couple questions before I get sawing and soldering. I got a CK switch,S series, that is going in like the diagram you sent.The picture shows it lying on the chassis near the rotary switch which I will take out. I have to saw the hole a little bigger for the CK switch. I think I need to see what is in the phono board as the PAS manual has 2 750 caps and 2 27K resistors in the pictorial in the manual. That's why in the picture I was going to install 2 5 point lug strips in case they are important in the new Last PAS. I don't know if they w ere in the circuit.I would of saved them but am a little foggy about where I stowed the old rotary systemOne more question Shovel, When your facing the preamp, Is the top green wire the input to the board and same with the top red wire? I owe you big time and I will make sure I get you back....thanks so much for your time and effort, sincerely Mark K.
20k ohms in series with 510k ohms is not going to make any difference.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Hi, Thanks Tre', that was important as now the questions have been answered that kept my project stalled are answered.I got all the pieces in place to get it going thanks to all of you.Thanks Tre'....Mark Korda
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Have Fun and Enjoy the Music
"Still Working the Problem"
My plan for the phono is to use 2 adjacent 5 lug strips to put 2 caps needed for the phono section.I got one installed already. If this works the Sheldon Stokes cap board goes in.I finally found the step by step instructions. Thanks for any ideas...Mark K.
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pAS
E-mail Frank at Audio by Van Alstine, he'll be able to answer your question.
JCarney
frank@avahifi.com
"Should I use little jumper wires from the left holes to left and right to right."
I don't know what you are asking. Maybe if you post a PAS schematic and refer to the schematic it might make more sense.
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