My turntable's too fast

August 15, 2012 2:03 AM

My turntable plays records too fast. It has no adjustment knob. How can I slow it down?

(found this older discussion, but it wasn't resolved)

So basically, I've been playing records on this thing for over a decade, and recently I realized it plays too fast. This could be a recent development; It could also be that I'm a moron and never noticed it before. I just tested it by playing the same song from an LP and on YouTube simultaneously. The LP went noticeably out of phase after just a few seconds. Also, as you might imagine, every LP sounds ever so slightly chirpier and lighter than it should.

It's a Sherwood PD-502, belt-driven turntable. I tried cleaning the little spindle that turns the belt; There was some residue there, but removing it didn't solve the problem.

That's it, I'm stumped. Any ideas?

posted by Silky Slim to technology (10 answers total)

A few thoughts on this sort of thing:

Turntable too fast - no speed adjustment

My Pioneer PL-514 TT plays a bit too fast

From those threads, it sounds like there may be some sort of unlabeled speed adjustment screw under the platter that you've missed, and/or there's crud on the drive pulley, and/or the belt is gummy or worn. Start with those and see if one offers a solution.
posted by mosk at 2:18 AM on August 15, 2012 [1 favorite]

You could put a resistor or potentiometer between the power source and the motor (example).
posted by Blazecock Pileon at 2:49 AM on August 15, 2012

Is the belt in the right place? My old flatmate and I discovered that our ancient belt driven turntable (can't remember model and old flatmate has it now) had slipped ever so slightly out of place and that was causing it to play faster, regardless of the speed setting we chose.

It may also be worth replacing the belt as they do get worn out, esp. if it has had more than one owner before you.
posted by halcyonday at 3:24 AM on August 15, 2012

The first thing I'd do is to find a few different versions of different songs and check whether they all show the same type of deviation.

Also, if your turntable is too fast, the most noticeable deviation isn't sound character ("chirpier and lighter") but should be the fact that the pitch is off: 'your' version ought to be irritatingly too high, (obviously).

If that's the case go try what mosk says.
posted by Namlit at 4:06 AM on August 15, 2012

Ideas above are good. Please also check against something other than Youtube. I've seen so many YouTube songs that are off-speed.

Perhaps measure against the timing of the track listings themselves, or of an entire LP to figure out exactly how much it's off? That might provide a clue to what's happening.

(That is, how much less than 43 minutes is Dark Side of the Moon?)
posted by rokusan at 4:16 AM on August 15, 2012

http://myvintagetv.com/strobe.htm will tell you if the turntable is in fact fast.

If it was at some stage working right and now it isn't, find out what changed. The belt is the most likely culprit.
posted by wrm at 5:01 AM on August 15, 2012

You might want to quit listening to one of the sources. You have no quantitative evidence which is wrong. (i.e., never go to sea with two watches... take one or three.)

If your hearing is perfect pitch, you should splurge on a turntable with a speed adjustment! Craiglist/ebay solution. Yard sales in most places yield good ones every weekend.

Not familiar with your model, but if it uses an AC induction motor, the resistor approach mentioned above will only get you a warm resistor and a motor that turns at the same synchronous speed it did before you modified it. its speed is independent of the coil resistance and only a line frequency shift will change the motor RPM. (You could buy a variable frequency drive for a few hundred bux, but the noises from them are exceedingly objectionable and you'd have spent more than you need to for a decent turntable with a speed control.)

if it's a DC motor, there IS a speed control somewhere. it's a small potentiometer on a circuit board somewhere inside the machine. it would also respond to a series resistor, but that would need to be very low value, stable, and multi-turn to have good adjustability.

these things are fairly stupid mechanically. they aren't meant to be studio quality for general use, and if you need studio quality, that always comes with pitch control. there are ways of making linkages that don't involve belts or conical pulleys, but i've never seen anything in the wild for such non-critical applications.

i just bought a used stanton TT from a friend for $75. not the be-all-end-all of TT, but a speed adjustment range of +/-12%.... and a stroboscopic scale for precision (as most even modest TTs have). does 33-45-78. does not do 16. good enough does not have to be expensive.
posted by FauxScot at 6:56 AM on August 15, 2012

Back in the day, we put pennies on ours...but we weren't really invested in optimal sound quality.
posted by JoanArkham at 8:06 AM on August 15, 2012

Pennies on the tone arm are there to prevent skipping (but they're a terrible idea — bad for the turntable, bad for the record).

My girlfriend's old turntable had a belt tensioner capstan that could be used as an ersatz speed control, but that wears out the belt pretty quickly. A new turntable ran about $75, though it doesn't have an obvious speed adjustment.
posted by klangklangston at 10:06 AM on August 15, 2012

Yeah, don't use Youtube as a speed reference. A lot of uploaders specifically change the speed of songs so that auto-analyzer software doesn't flag them for copyright violation.
posted by hwyengr at 10:34 AM on August 15, 2012