PL2000 S2 Balance pot.

[George S.]

I was thinking of going with these, but they're logarithmic. Pretty sure I found same pots in linear taper somewhere. I have a good Dremel with a pile of those tiny round thin cutting discs so configuring the shaft should be easy, go slow and keep the heat low, no grinding.
https://www.ebay.com/itm/2-Precisio...-/202977004721?_trksid=p2349624.m46890.l49292

 

[Gepetto]

You have a PL2000 right? Balance pot is a single gang 100K pot in the 2000

 

[Gepetto]

I was thinking of going with these, but they're logarithmic. Pretty sure I found same pots in linear taper somewhere. I have a good Dremel with a pile of those tiny round thin cutting discs so configuring the shaft should be easy, go slow and keep the heat low, no grinding.
https://www.ebay.com/itm/2-Precisio...-/202977004721?_trksid=p2349624.m46890.l49292

That won’t work

 

[George S.]

You have a PL2000 right? Balance pot is a single gang 100K pot in the 2000

Yup, PL2000 S2, my balance pot is 50k 2 gang 6 total lugs. It's listed in the manual as part# 129-0037 Balance:50k:NL:dual. Right below it is listed another, 129-0027:Balance:100k:L. Weird. Here's a photo of it.

 

[Gepetto]

Series 2 used a single gang 100k pot

 

[Gepetto]

Series 1

 

[George S.]

Lee posted last week that he thinks maybe the issue with the DChristie 2000 S2 I guess he may still be working on may be related to the balance pot. Here's a photo of the wiring at solder pads. I take lots of photos before I take things apart.

 

[MarkWComer]

On the road working until this Saturday evening. When I get home I'll check for that disc I'm sure I have, try to rip it for a "personal backup". If successful I'll PM you for your address.

Will be returned within one day after I rip (depending on if I get it on a weekend).
THANKS!

 

[Gepetto]

Lee posted last week that he thinks maybe the issue with the DChristie 2000 S2 I guess he may still be working on may be related to the balance pot. Here's a photo of the wiring at solder pads. I take lots of photos before I take things apart.

Balance circuit around the pot is the same for the S1 or S2 so you should be able to configure it like the S1 and use a single stage 100K pot.

Do you have the circuit schem for the S1? They are both covered in the same service manual.

 

[Gepetto]

Your channel to channel imbalance may not be the fault of the balance pot, but rather the dual gang volume pot that precedes the balance pot.

Just as likely a culprit.

 

[George S.]

Joe, thank you. I have the S2 service manual on the phone. Going to check it out. Can always download a earlier manual if need be. Had no idea they used two different pots. I pulled that pot and checked on the bench with a ohm meter. Discrepancy I saw on the ohm meter matched what I was seeing on the scope. Thanks. Going to sketch those schematics out on paper this weekend and figure out how to go to a 100k single gang.

 

[George S.]

Will be returned within one day after I rip (depending on if I get it on a weekend).
THANKS!

No problem, no fun not having the complete set.

 

[George S.]

Had a morning free past weekend and pulled the balance pot. It's definitely logarithmic, has 150 deg sweep to either side from 12 o'clock, 300 deg total. Went overboard and mounted it on cardboard, then measured, plotted the graphs, trying to gain insight how this works. Think I have a handle on this now. Going to do some reading this week and looking at my data, then order some new dual gang pots to try out.
Also considering replacing the volume pot with a new high quality pot, getting rid of that on/off switch as I use power strips that have the switch.

 

[George S.]

Oh, and that last graph shows the tracks crossing at 15 percent of rotation, exactly what I was seeing on the scope. Yeah, I know, easily fixed by rotating the pot to where that point is 12 o'clock on the faceplate.

 

[George S.]

Then there's this, use the 2000S1 100K single gang linear taper, looks like best way.Hint: if you connect the wiper of the pot to ground, you get two variable resistances that are complements of each other.

 

[Gepetto]

Then there's this, use the 2000S1 100K single gang linear taper, looks like best way.Hint: if you connect the wiper of the pot to ground, you get two variable resistances that are complements of each other.

Yup, if they are manufactured perfectly...

 

[George S.]

PDA241 HRT02 104B0 is the pot you want. Nice feel Bourns pot.

Had a couple similar, PDB241 GRT02 104B0, same that Perry recommended for the WOPL attenuators. Solid shaft, so carved it to a D shaft with a Dremel and cutting disks, aluminum shaft so it was easy. Just cut it oversize and finish with a hand file, glad I had two as I cut too much off the side of the first. Those abrasive disks cut that shaft like butter.
I wired the new pot keeping the factory wire colors, same as the old double gang pot. Looks perfect on the scope as I fade channels in out out and raise and lower volume. The volume pot tracks perfect so not messing with it.
Thanks for everyone's help! May be my imagination, but seems like imaging is improved between the two channels.

 

[George S.]

So, after 5-6 hours of listening yesterday and last night, I can say the imaging between the channels is improved. Best way I can describe it with my very limited electronics knowledge is this. Seems like the original double ganged pot was causing phase or delay issues between the channels, or not passing the entire sound spectrum equally. Probably makes no sense at all to you engineers, but sounds better to my ears, like a more accurate soundstage.

 

[Gepetto]

So, after 5-6 hours of listening yesterday and last night, I can say the imaging between the channels is improved. Best way I can describe it with my very limited electronics knowledge is this. Seems like the original double ganged pot was causing phase or delay issues between the channels, or not passing the entire sound spectrum equally. Probably makes no sense at all to you engineers, but sounds better to my ears, like a more accurate soundstage.

Sometimes simpler is better

 

[Gepetto]

So, after 5-6 hours of listening yesterday and last night, I can say the imaging between the channels is improved. Best way I can describe it with my very limited electronics knowledge is this. Seems like the original double ganged pot was causing phase or delay issues between the channels, or not passing the entire sound spectrum equally. Probably makes no sense at all to you engineers, but sounds better to my ears, like a more accurate soundstage.

You replaced a dual log pot with a single linear pot correct? Did you measure in ohms where each pot measured to its ground terminal when the knob was centered on the original pot?