New Motor Capacitor for the Thorens TD-165

Recorded on August 27th, 2014

I’ve been obsessed with the turntable again, and chores around the house and other projects have suffered. The Thorens TD-165 can sound really good, but it’s not a “trustworthy” turntable, at least mine isn’t. It will turn on you. Still, the potential is there if the stars are aligned, the suspension is tuned, the bearing well is in good shape, the belt isn’t too loose or too tight, you have the right oil, and you think pure thoughts. If any one of those is wrong, you go down a dark road.

In addition to the crazy list above, you also want your motor to be quiet. After 35 or so years, the “motor run” capacitor can degrade and fall out of spec. It’s the capacitor that gives one of the motor windings the precisely right voltage in precisely the right 90-degree offset phase from the regular wall current, so when it’s not right after decades, or wasn’t perfectly tuned to the motor to begin with, the motor will knock and introduce noise into the turntable chassis, and/or cause flutter in the music. I heard flutter on sustained piano notes and it began to bother me. A lot.

In this video, you can see Hanze Hifi demonstrate the rather striking benefits of tuning a capacitor specifically to a particular motor. That was enough to put me on the quest for the perfect capacitor for my motor. Or at least prove that the capacitor wasn’t the problem causing the flutter.

As far as I know, this 0.33µF 400V capacitor was the one that shipped with my Thorens: original 0.33µF capacitor

The other side of the capacitor said “ERO MKT1813”. Some googling revealed that the best match for that was made by Vishay Roederstein. It had to match everything else exactly, and the only place I could find that had those in stock was Banzai Music in Germany. I decided to order two 0.33µF caps. Since they were made within a 10% tolerance, there could be a lot of drift in the actual values of the manufactured capacitors. One of the two new ones was bound to be no worse, and maybe better than the existing 0.33µF one in the turntable.

I also wanted to get two more copies of capacitors on either side of 0.33µF. The closest ones were 0.22µF and 0.47µF. That would give me six capacitors to choose from. I hoped I wouldn’t have to go outside that range. In the same way that Otter in Animal House was practically pre-med by being in pre-law, I’m practically an electrical engineer since I studied industrial engineering. (Not really—I never got how to bias a transistor properly.)

So the six new capacitors arrived and I made up a test jig with some alligator clips and heavy-ish wire. (Banzai called them “crocodile clips”.) I wanted to be able to easily swap the new capacitors in and out of the circuit and record the resulting motor noise. I unsoldered the original capacitor and put it in the test clips, which stood in the air just outside the turntable plinth: original capacitor in test leads

And then I recorded the noise from the motor, with a tie clip mic held onto the subchassis with Blu Tack (which I forgot to take a picture of, but here’s the Tascam about to record the sound): Tascam audio recorder Sound of motor running with original 0.33µF cap (mp3)
The knocking is pretty obvious. It sounds like a sewing machine.

Then it was time to bust out the new capacitors. Candidate #1, the first 0.33µF: capacitor #1 Sound of motor running with capacitor #1, 0.33µF (mp3)
Wow. That actually sounds a little better. The knocking is quieter.

Next up, Capacitor #2, the second 0.33µF: capacitor #2 Sound of motor running with capacitor #2, 0.33µF (mp3)
Very good. Even less knocking than Capacitor #1.

Now, Capacitor #3, the first new 0.22µF. In retrospect, I wish I had numbered the capacitors in order of increasing value, but it was late and I wasn’t thinking straight: capacitor #3 Sound of motor running with capacitor #3, 0.22µF (mp3)
Less hum, but the knocking is still there.

Capacitor #4, the second new 0.22µF: capacitor #4 Sound of motor running with capacitor #4, 0.22µF (mp3)
Sounds about the same as #3.

Capacitor #5, the first new 0.47µF (listed as 470n, as in “nanofarads”): capacitor #5 Sound of motor running with capacitor #5, 0.47µF (mp3)
Hum was a little louder than #4, but the knocking is the quietest yet. This is good.

Capacitor #6, the second new 0.47µF: capacitor #6 Sound of motor running with capacitor #6, 0.47µF (mp3)
Very close to #5. Hard to tell which is better.

When I was doing the experiment, I thought that #6 was just slightly knockier than #5, so I picked #5 (the first 0.47µF) as the winner and soldered it in. Now that I listen back after a few days, I’m not so sure, but I’m too lazy to dig back into the turntable and change anything more (at least related to capacitors).

I don’t have audio samples ready yet of an actual LP recorded before and after. That would be the ultimate demonstration to share to show whether any of this helped. But I did do some quick recordings of actual music, and have been listening for the past few days. Once I got Capacitor #5 wired in, all albums sounded cleaner and more straight—the flutter was almost gone. And the high end was cleaned up and extended significantly, because there wasn’t this awful smearing of the highs all the time. Unfortunately, there’s still a slight wow problem, and the rather loose belt I’m using (to not magnify whatever imperfections there are in the bearing well or the spindle), means everything is very relaxed sounding, and not in a great way. But those are fairly easy to overlook now that the flutter is just about gone. Ah well, a Dual 1219 idler wheel drive will take care of all of that someday…

Here’s Capacitor #5 in its new home. Don’t know why I got the weird dark lines from the flash on the iPhone: capacitor #6

Thinking about Eric Meyer

Recorded on June 12th, 2014

I’m thinking about Eric Meyer and his family today. Their daughter Rebecca was diagnosed with cancer last year and she passed away last Saturday.

Eric’s posts to his blog over the past year are devastating and beautiful. More than he realizes, by writing about the family’s research, their questions, their impossible choices, and their love for each other, he helped a lot of people who are going through similar health crises with their loved ones. All of it is a lesson in how to live.

If I were going through anything like that, I would shut down entirely, closing off all but the closest friends and family, with no energy left for writing or documenting. Eric opened up to the world and his tribe answered by buoying his family with love.

Jeffrey Zeldman encourages everyone to show their support on Twitter today with the #663399Becca hashtag, inspired by Rebecca’s favorite color: purple.

Eric and Kat, we’re with you.

Surprise Tape

Recorded on June 8th, 2014

photo of Phil with headphones Before I became a jaded music fan, I spent a lot of time with 8-tracks and FM radio. This was back when what we now know as “classic rock” was just “rock”, which would make me 3–7 years old. My parents gave me an Electra Radio Corporation AM/FM/8-track stereo for the Christmas of 1974, after I hassled them endlessly for something better than a pack-and-play phonograph. All the time I spent in my bedroom was also time with the stereo on. Occasionally, Mr. Rogers or Winnie the Pooh records would play through that system, but the vast majority of time the receiver was set to 96 Rock FM in Atlanta. Before my future loves R.E.M and The Fall and The Smiths and Joy Division even existed, I would get my foundation in the form of Peter Frampton, Led Zeppelin, Boston, Fleetwood Mac, Heart, the Allman Brothers, and Gary Wright. I knew none of these artists by name, but I knew the songs cold.

Second to FM, in terms of hours spent, was the 8-track tape player. Dad got an 8-track recorder for his stereo and we got busy making copies of “Jesus Christ Superstar”, Peter, Paul & Mary, Cat Stevens, The Beatles, and The Eagles. A stack of home-recorded 8-tracks piled up on my Dad-built, wooden, blue-painted stereo shelf. Those tapes and 96 Rock were the soundtrack to me making Lite Brite art, drawing other stereos, and testing the conductivity of metal scissors in the wall outlet. (Metal scissors conduct electricity well.)

Of course I wanted to share this musical bounty with the world, “the world” being any neighbors within earshot of our backyard. Maybe Misha, my playmate next door, Shane, the boy behind us whose ownership of a BB gun scared me, or Beverly and Jeff, the couple on the other side of our yard. On a warm day, I would open my bedroom window, put one or both of the stereo speakers in it facing outward, turn up the volume, and yell to no-one, “SURPRISE TAPE!!!”, as if that would awaken a community of latent music lovers and soon-to-be Philip-worshippers out of their doldrums. Why wouldn’t people come running when they heard that I had a Surprise Tape ready to play?

The same thing happened every time. I shoved in an 8-track, it started to play, and nobody came. Nobody said, “Thank you so much—this is brilliant!” It was just a loud stereo and me, looking out the window, amazed at what people were missing.