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Pioneer PL-41 pitch control?

ekmanning5

ekmanning5

Time has told me...
Does anyone have this TT and know if there is a pitch control inside the base. Nothing outside. Mine is running a little fast. Thought I was hearing things at first, :scratch2: but the more I use it the more I am convinced. I'll do a CD to vinyl comparison later today.
Thanks.
 
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Doubtful, Ed, it's a synchronous motor so the speed is tied to the AC current. Might be the belt. In any case, you can download a strobe disc from vinylengine to check.
 
Going from memory here.....There is a switch under the platter to change between US and European electricity. There is also a separate motor pulley under there. It seems like there may have been another switch somewhere too, but I may be mistaken.

I assume you have checked to make sure you don't have black melted rubber goo on the spindle. I had this problem once which made a pioneer turntable run fast.
 
hakaplan said:
Doubtful, Ed, it's a synchronous motor so the speed is tied to the AC current. Might be the belt. In any case, you can download a strobe disc from vinylengine to check.
Click to expand...

Howard, will a belt that is loose cause this. The lady I bought this from said it needed a new belt. It appeared to me that the belt had fallen off. I put it back on and it worked fine...well almost.
 
jbpollock said:
Going from memory here.....There is a switch under the platter to change between US and European electricity. There is also a separate motor pulley under there. It seems like there may have been another switch somewhere too, but I may be mistaken.

I assume you have checked to make sure you don't have black melted rubber goo on the spindle. I had this problem once which made a pioneer turntable run fast.
Click to expand...

I'll double check under the platter. Thanks.
 
Well, buildup on the motor end would speed it up. Loose belt I think would slow it down. :scratch2:
 
I suspect Hakaplan is correct. As for pitch control, I know of none, and
sort of spent some time poking around mine when I got it. How fast are you
talking about?? I wouldn't think even buildup would make it terribly faster.....
noticable to a decent ear, surely, but not overly so. Belts are available from
a few sources online. Good luck, it isn't a bad table at all when you get it
running well. I merely cleaned a few things, put on a fresh belt(speed fine
here)and replaced the original headshell with a newer one and mounted the
Grado cartridge. It makes nice music, now!:music:
 
Ed,

Just a thought, but if I recall correctly, there were 2 pulleys provided for this model. One is for 50Hz and the other for 60Hz operation. You may have the wrong one installed. An intact 'table should have both. The one not in use is secured to a stud on the motor mount plate via the set screws near the base of the pulley. If you have both, swap pulleys and see if things improve.
 
eujohns said:
Ed,

Just a thought, but if I recall correctly, there were 2 pulleys provided for this model. One is for 50Hz and the other for 60Hz operation. You may have the wrong one installed. An intact 'table should have both. The one not in use is secured to a stud on the motor mount plate via the set screws near the base of the pulley. If you have both, swap pulleys and see if things improve.
Click to expand...

It's funny, I had some Pavarotti on today (God bless him) and it sounded fine. Yesterday was the Beatles Love album, which I also have on cd, and that just sounded a bit off. I think I will get a strobe disc so I know for sure.
 
PL-41 speed

Ed,

You aren't hearing things, these tables do run fast.

I ground down the drive pully with a small file while the motor was running (like a lathe).

Checked speed with a strobe disc.
 
Agree that this is a meaure that can't be undone, (destroy is little strong) but this was done after replacing belt with new, correct replacement, and still having the problem.

As I said, these tables are known for running fast.
 
I never realized that there was a speed/pitch issue with my PL-41 until I read this thread and checked with a strobe disc! What do you know - it was fast, quite fast actually. I couldn't believe I hadn't heard it previously. Even after checking with the strobe, I played a record and CD at the same time to re-check. It was several seconds out on a 4 min track. I think we're more sensitive to variations in pitch than we are to absolute pitch.

I researched the subject (largely with info from this forum), then I weighed up the options. I changed belts (I had 3), and I even had a spare pulley. All produced very similar results. So, with the safety net of a spare pulley in case things went bad, I got my needle files to work and trimmed the pulley down VERY carefully, measuring pitch after taking off small increments. The closer I got to the desired pitch the more careful I got of course. Then you have to repeat the procedure for the 45rpm part of the pulley. When I finished with the 45 I went back and checked the 33 again in case the reduced weight of the pulley had increased the rotational speed of the spindle/pulley! It hadn't, but if it had then at least you could trim again.

I was really pleased with the results and the pulley looks really clean now! :-)
At least I know it's spot on now. I have a feeling this must be a really common fault, and surely it must have been there by (poor) design? I thought about playing with the R/C values in the motor circuitry, probably with a pot' to see if that controlled the timing/pitch, but decided against this as I didn't have the schematics to hand.

In conclusion I would say that trimming the pulley produces great results as long as i) you have a set of needle files ii) you have a steady hand iii) you have the patience to do it carefully and keep measuring the pitch as you go. It took me about 2.5 hours to get both speeds bang on.

Thanks OBMG74 for the idea and confidence to give it a try. Worked for me.
 
OBMG74 said:
Glad it worked out well for you!
Click to expand...

seconded, but still, the whole idea of grinding the pulley down scares the bejeepers out of me. I still wonder if the issue wasn't the belt itself. I have on hand two replacement belts for mine, and they vary a bit in size. Not much, but perhaps 1 or 2 mm. Anyhow, just to test if MY PL-41 runs fast
(although I tested with a strobe disc back when I installed the current belt after purchasing the table used), I used the 'measure vs. song length' method. Choosing 3 songs, separately measured, I had a 6 second deviation from a total of 16 minutes, 13 seconds of stated time. I suspect human error entered into one timing, as one song was dead-on, one a second fast, the third 5 seconds fast, where I may have been a tic slow starting the timer.
Still a 0.6% error is hardly running all that fast. Any others out there with a PL-41, do you find that they tend to run fast??
 
TJLitt said:
Any others out there with a PL-41, do you find that they tend to run fast??
Click to expand...

Finally got around to completion of my thriftstore PL-41. Really beautiful table, someone had taken care of it (or at least not abused it). Still, it needed a headshell, cartridge, new belt, 'thrust' bearing and general cleanup and maintenance.

I recalled reading something here on AK about this model running fast, and sure enough, I could hear it. Printed a strobe and the evidence was obvious.

Seems that there MUST be a better way to get a more accurate speed than doing the lathe trick on the pulley. Any developments here?
 
Good to hear you got your PL-41 in good shape. If you'd like to try the "spindle slimming" trick then I have a spare spindle I'd be happy to send you (or anyone else with the same problem). You need to be careful and patient though - it took me a couple of hours.

Regarding the previous posts(s) about the length of belt having an effect on the rotational speed of the turntable. Isn't the rotation speed directly proportional to the ratio of the two pulley diameters (and not the length of the belt)? As long as the pulleys are in motion (ie. the belt is acting to couple the two pulleys mechanically), and the motion is steady (constant rotational speed, not accelerating, in which the elasticisty comes into calculations I guess) then I don't think the belt length should have an effect on the rotational speed of the turntable.
The belt has to be about the right length so that it makes effective contact, so the pulleys will turn, and so that it doesn't slip. We change belts because they don't grip as well as they did, or because they start to degrade mechanically (break up), not necessarily because they are a little too long or short.
Or does my dim and distant memory of rotational dynamics fail me?! :-)

Cheers.
 
I suspect that many of these tables have the 50Hz pulleys installed. They would be bigger by design and therefore drive the platter faster. If the USA pulley cannot be found, I'd lathe the Euro pulley and be done with it.
 
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