Good source for belts on Pioneer CT91 tape deck

My Pioneer CT91 cassette deck needs a fresh set of belts. I haven't purchased any belts recently and would like to find a good source for belts, idlers, pinchrollers and other rubber parts. Many sellers only offer the thicker type belts which won't work. Consistency and quality are another issue. I often have to purchase more than one set of capstan belts to get ones which don't cause excess wow+flutter.

My open reel decks are easier to get rubber drive parts for, but cassette decks are so much harder to service these days due to lack of parts.

Any advice?
 
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Checking on ebay, I've found a few sets from oversees sellers, but I'm leery about the quality given how thick the capstan belts look. There is a Ukraine seller with transparent looking belts, which they claim to have custom made for them to a higher spec.

I used to have tons of belts from my service days, but they don't have a long shelf life. Most of them turned into goo by now, even having been stored in a cool dark place.
 
Re: "transparent belts"

Just avoid silicone belts. Very springy behavior. On my turntable, silicone belts vs EPDM. Silicone resulted in 2-3x more speed variation and wow. Plus they tend to snap up and down on a pulley, from a weird rigidity issue. I am not a fan.
 
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I did notice similar issues with a translucent type capstan belt on my tascam 22-4s. I had rebuilt one of them using the 2 different types of materials and noticed higher W&F on the clear belt. I have 2 of these tascam machines synced and the clear belt equipped machine would always have negative corrections on it to keep it synced despite everything else set the same. It was as if it speed up when it got warmer and never stayed 100% at reference speed. I switched both machines to identical black belts which cured the speed issue. The other thing I noticed was the deck with clear belts would sound rough and edgy, which turned out to be a W&F problem linked to the belts.
 
I wouldn't buy belts from Thakker or any of that transparent crap. The only current good source of belts for cassette decks and Walkmans I know of is fixyouraudio.com

They have Pioneer CT-777 and CT-979 belt kits, probably the same set, most likely should work OK for the CT-91. Try it, it is probably your best bet right now. You should also buy the spare idler for CT-91 from them.

Cheers

Alex
 
I ended up buying a set of belts from a Portuguese company on Ebay named webspareparts. The belts appear top quality, very close to the originals. The belt material feels just like oem and the fit is spot on.

The old belts turned into black goo, stuck to the capstan pulleys and transport mode drive.

It took a long time to get rid of all the residue and required acetone to fully clean up. This was by far the most labor intensive job I've done to a cassette deck.

Now I have to reduce the reel motor torque a little. The current amount of torque the reel drive exerts on the tape is too high IMO. It maxes out my test tape at 100g and should be in the 40 to 60g range for playback. There is no adjustment for takeup reel torque, but I can reduce the reference zener voltage on the drive circuit to reduce torque.

I'd rate this deck right behind the Yamaha K1020 I use for transfers of old material, but its not that far off in terms of SQ. A DBX encoded recording sounds almost as good as 7.5 ips on my open reel Tascam 22-4. Certainly a bit better than an average MP3.
 

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For those interested, I installed a 3.3 ohm 1/2w resistor in line with the reel motor. This dropped the take-up torque in play mode to 50 gm and wind torque to 85 gm. Both are in spec now to avoid stretching 90 min tapes. Not sure why they thought it wasn't too much torque before. That just stresses your precious tapes unnecessarily.