L-65&Others-Variable Pots,Bypass or restore?

[wallstdrifter]

The pots on my L-65s are an annoying source of distortion. The distortion seems to come and go and fix itself when I screw the pots to right or left finding a good spot. I understand they have a hard room /soft room attenuating effect but after 30 years are they really worth it if they can't be restored?

I say bypass the little fu@#ers. Can I do that myself?

Looking for other various views and fixes.

May I remind the board that my equipment will go with me to the grave. Mods are welcome! (I will have them all around my bed in the old age home.)

P.S. Correct me if Im wrong but it is my understanding that spraying them with a cleaner only works sometimes. I guess that's a start (pending the boards permission.) How do I open the pots from the front?

I run 150 watts continuous Harmon Kardon Citation 16A Amp w/ Citation 17 pre-amp.

[4313B]

Just replace them with new pots. Use the 50W units because they are better than the old 15W units.

http://www.partsexpress.com/pe/showd...number=260-255

I say bypass the little fu@#ers. Can I do that myself?

If you want. Just substitute in a fixed resistor pad set to the same attentuation you like the L-Pads set at.

http://www.lalena.com/Audio/Calculator/LPad/

[3dbdown]

Unfortunately, you will need to remove the foilcals from the cabinet baffle board to remove the pots for proper cleaning OR replacement. Best to just replace them. You might find new foilcals on E-bay, but they will be un-serialized. As I understand you though, that's not an issue, since, like me, your L65's will be interred with you! You might get lucky and be able to remove them with sharp putty knife, heat, and lots of care, then re-install them afterwords. I tried cleaning mine, didn't care for the results, and replaced them with Partsexpress pots.

[wallstdrifter]

I'm thinking to mount two new parts express pots to the crossover board next to the replaced binding posts. Where did you mount yours? Pictures would set the mssg board on fire!

Unfortunately, you will need to remove the foilcals from the cabinet baffle board to remove the pots for proper cleaning OR replacement. Best to just replace them. You might find new foilcals on E-bay, but they will be un-serialized. As I understand you though, that's not an issue, since, like me, your L65's will be interred with you! You might get lucky and be able to remove them with sharp putty knife, heat, and lots of care, then re-install them afterwords. I tried cleaning mine, didn't care for the results, and replaced them with Partsexpress pots.

[wallstdrifter]

http://www.partsexpress.com/pe/showd...number=260-240

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Open to the board for other thoughts/comments

Just replace them with new pots. Use the 50W units because they are better than the old 15W units.

http://www.partsexpress.com/pe/showd...number=260-255

If you want. Just substitute in a fixed resistor pad set to the same attentuation you like the L-Pads set at.

http://www.lalena.com/Audio/Calculator/LPad/

[3dbdown]

Wallstdrifter....

Sorry, I should have edited my post to clarify that the ones I changed were on my 4430's, not the L65's........My point was that cleaning didn't work. The foilcals on the front of the 4430 are really thick, and were fairly easy to get off without damage. But, I bought those used, and the pots were at some point overloaded to the point of melting into the plastic mounting board! Although they both still worked, one of them had the proverbial "dead zone" in the taper. Cleaning did not help.

My Jubals, however, have been mine since the day they were built, in 1975. Believe it or not, for the past 33 years, I have simply cycled them through their entire range, once every couple of weeks or a month, and they still sound fine, with no distortion or scratchiness. Also, I have had them in many different rooms and listening environments during that time, so the pots have not just been sitting in the same "spot" so to speak. One of the advantages to having worked at JBL was knowing the weak spots of certain components over time, and how best to avoid certain issues.

I think your idea of mounting the new ones at the terminal board is just fine.

Sorry for any confusion,

Rick

[Doctor_Electron]

"If you want. Just substitute in a fixed resistor pad set to the same attentuation you like the L-Pads"

Or, you could switch through, say, three or even more, to taste, sets or L Pad-configured resistors (0 db, -3 db, -6 db etc.), being sure that the 0 db setting is "bright" enough for any enviornment you may use them in.

I have 4310's & 4410's with original pads, and rotate them through their ranges each time I use them. They can get a bit scratchy but this way I know they are "fixed" on each usage.

[short_circutz]

Are they damaged or dirty?

If dirty, you'd be amazed at what Caig De-Oxit will do.

http://store.caig.com/s.nl/sc.2/category.188/.f