Silk thread belt / braided fishing line belt BFLB

Silk thread belt / braided fishing line belt BFLB

Postby krytoxlub » Tue Apr 03, 2018 10:03 am

I have a VPI Aries II (12 Inch acrylic platter and 300Hz motor) My black belt was long in the tooth. After reading a thread in this forum, I made a belt for my Aries from approx 10lb Power Pro braided green line. The braided fishing line has no stretch and good traction. It is known to eat groves in fishing eyelets over time.

I ballparked the length of the Aries belt to be 40". Made a simple overlap knot. Next, I made a 41" and a 42" version. I had to adjust my SDS to 63.28 HZ to get the right speed for all 3 belts, length of the belt is not a factor to consider for speed adjustment. I assume the diameter of the line is. Not a problem using the SDS controller. The VPI motors is heavy and being standalone (set on a sheet of Sorbothane) it is easy to adjust for a taut thread type belt. In relationship to motor placement with a standard rubber belt. the 40" belt is shorter and 42" belt longer.

It works well, speed is stable. Table sounds brighter now with tighter bass, more detail top too bottom. The detail is such that it sounded harsh to my ears accustomed to an older well stretched black belt. Tension on the thread is crucial for a natural sound. It is a test of patience and tenacity. Once you hit the correct tension, spot on detail with bloom and bass slam that rules.

This experiment evolved from the boiling the existing black rubber belt in my steamer pot for 2 minutes (Internet wisdom) to refresh it. That worked well, the belt was shrunk to a circumference small enough to hug the platter. A privilege only a virgin belt has. The sound was better than the stretched belt (approx 2" stretch). The boiled belt sounded fuller than the thread belt for a lack of a better term.

FYI: The stock rubber belt is 2.0 mm thick. The 10 lb braided fishing line I used is 0.12mm diameter (measured with a digital caliper) extremely small. In comparison, No. 2 silk thread is 0.45mm, No. 4 silk is 0.60mm, and No. 6 silk is 0.70mm. I am ordering all 3 silk threads to test.
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Re: Silk thread belt / braided fishing line belt BFLB

Postby Brf » Tue Apr 03, 2018 10:46 am

krytoxlub wrote:It is a test of patience and tenacity. Once you hit the correct tension, spot on detail with bloom and bass slam that rules.


Yes, this modification is not for everyone and it does require a more precise setup. In most instances, you will need to give the platter a gentle push to get it started.
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Re: Silk thread belt / braided fishing line belt BFLB

Postby krytoxlub » Tue Apr 03, 2018 11:44 am

Platter starts up immediately. Braided fishing line had good traction.
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Re: Silk thread belt / braided fishing line belt BFLB

Postby Brf » Tue Apr 03, 2018 12:48 pm

krytoxlub wrote:Platter starts up immediately. Braided fishing line had good traction.


Does your line initially slip on start-up?
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Re: Silk thread belt / braided fishing line belt BFLB

Postby krytoxlub » Tue Apr 03, 2018 3:47 pm

Yes, the pulley slips at the start, 4 seconds to full speed.

I went to Scheels and bought a 100m spool of Suffix Performance Braid. 80lb version (0.45mm). Equivalent to Silk thread No. 2 os (0.46mm) diameter. I made a 41" belt with a single loop knot. Frist impression is that it sounds similar to the thinner 0.10mm belt I made. Setting tension is easier with 80lb braid, almost a go no go setting. Slip or not slip.
SDS was 63.78.

Detail galore, Some records are too bright to my ears. May have to do some cable swapping to take advantage of excessive detail.
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Re: Silk thread belt / braided fishing line belt BFLB

Postby krytoxlub » Fri Apr 06, 2018 9:01 pm

Update on this modification.

I have used the 80lb braided line belt for 4 days. As earlier stated, I noticed the sound is bright. So I did some further testing on the 4th day.
I use a radio shack sound meter set microphone flush on the plinth to measure chassis noise. I use this method to tune my Thorens TD 124 for minimum motor/mechanical noise.
FYI, The Thorens has 62 DB measured with platter spinning.

I measured the noise to be 72 DB on the Aries using the BFLB 0.45 belt with the platter spinning. Switching to the standard rubber belt, the noise measured is less than 50db, the lowest the meter measures.

So the bright artifacts I hear is mechanical noise transmitted from the motor to the platter/bearing than to the plinth via the BFLB belt. 22+DB increase in mechanical noise.

I have ordered the silk thread for further testing. For now, I have switched back to using the stock rubber belt.
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Re: Silk thread belt / braided fishing line belt BFLB

Postby Brf » Sat Apr 07, 2018 7:33 am

Love reading your journey.

I am surprised that you are getting repeatable and correlated results using a radio shack spl meter which is really not designed for that purpose. Have you considered purchasing an accelerometer to measure the rate of change in velocity in your plinth? As an alternate, you could also use an stethoscope to help detect vibration noise that are localized on the plinth.

One of the benefits of using a rubber belt to drive the platter is it’s natural damping properties but at a performance cost of being elastic. I would try using 1 silk thread as oppose to multiple threads. Silk thread is inelastic but has less damping when compared to a rubber belt. The more silk threads, the greater the path for vibration/noise transfer from the motor to the platter. This is one of the reason why people play with the silk diameter in an attempt to further reduce the vibration path.

Have you tried a rim drive? Keep us posted.
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Re: Silk thread belt / braided fishing line belt BFLB

Postby krytoxlub » Sat Apr 07, 2018 11:03 am

Radio Schack sound meter set to weighting C and slow response will give an averaged reading.
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Re: Silk thread belt / braided fishing line belt BFLB

Postby Waxxy » Sat Apr 07, 2018 11:50 am

krytoxlub wrote:Update on this modification.

I have used the 80lb braided line belt for 4 days. As earlier stated, I noticed the sound is bright. So I did some further testing on the 4th day.
I use a radio shack sound meter set microphone flush on the plinth to measure chassis noise. I use this method to tune my Thorens TD 124 for minimum motor/mechanical noise.
FYI, The Thorens has 62 DB measured with platter spinning.

I measured the noise to be 72 DB on the Aries using the BFLB 0.45 belt with the platter spinning. Switching to the standard rubber belt, the noise measured is less than 50db, the lowest the meter measures.

So the bright artifacts I hear is mechanical noise transmitted from the motor to the platter/bearing than to the plinth via the BFLB belt. 22+DB increase in mechanical noise.

I have ordered the silk thread for further testing. For now, I have switched back to using the stock rubber belt.


Great work! Thanks for sharing your experiences.

I'm curious, have you tried multiple rubber belts? I've gone back and forth a few times but I found motor noise introduced by the additional belts trumped any gains in speed control. I'd be curious to know if adding additional rubber belts would show a measurable noise increase.
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Re: Silk thread belt / braided fishing line belt BFLB

Postby krytoxlub » Mon Apr 16, 2018 6:23 pm

Received my new VPI belt. Ran it for a couple of days now. The new belt is excellent, I feel a bit silly-stupid, and or senile. Simple fix to sloppy sound. I am now removing the belt from the pulley and resting it on the platter when not in use to preserve the elasticity of the belt.

I am waiting till my silk thread arrives and enjoying the music for now.
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