Mcintosh C22 Vintage Tube Preamp Motorboating Repair

Repair of a Mcintosh C22 tube preamplifier making noise like a running motor. The so called motorboating but this one sounded more like a Vespa scooter. The cause of the noise was dirty tube sockets but it also had dirty noisy trimpots. After cleaning the trimpots and tube sockets, the unit was no longer making noise but sounded dull because it need restoration so I could not enjoy a listening session as usual. If the owner allows me to, I will do a full restoration in a second video.

[@robertwear1675]

Looking good. I'm sure your customer will want to make such a fine piece as good as it can be.

[@Tinybench]

Thank you teammate, thank you very much!🙂🙏

[@drdyna]

Very nice, hopefully the owner gives the OK to replace those caps. I'm sure they will, I would!. It's amazing though, that someone just put the new caps across the old ones, like how is someone smart enough to know the caps are bad, but not smart enough to know they shouldn't just be in parallel with the old ones LOL

[@Tinybench]

Hello teammate! Thank you very much for watching liking and commenting. Lots of technicians do that. Actually, the way in which technicians work is the reason why I decided to learn to repair my own equipment.🙂🤚💥💥💥

[@mcgjohn22]

wow, sure is a clean unit. Looks almost as if it were just removed from the box!! Would leave the original coupling caps in place. They are part of the C22 sound. Some die hard MAC fans will replace modern caps on a unit that has modern coupling caps with NOS versions of these same caps. would agree the OEM power supply multi-section cap should go. Polishing the tube pins can also be done to improve conductivity.

[@Tinybench]

Hello Teammate! Sadly the bumblebee and blakbeauty caps leak DC voltage with catrastrophic effect. Most of them where Polyester anyway, not, paper, and oil like most people think. There are new capacitors that are so good that they sound like DC coupling. If a more vintage sound is desired, sealed can Russian paper and oil capacitors can be used. I have identical amps, that I compare and contrast polypropylene with paper and oil. My friends and I agree that they are different flavors, but no one can say one is better than the other. The paper and oil seems to have a dampening effect on the sound. The new polypropylene are incredibly transparent, three dimensional, clean, low noise, and holographic. I like them both. 🙂🙏

[@AudiophileStooge]

love it!

[@alexzildjian]

Your NEW SUSCRIBER 🎉 love Vintage Audio Gear❤ Hi from MÉXICO 🇲🇽🇲🇽😊

[@Tinybench]

Viva México!!!🇲🇽 Muchísimas gracias !!!!! 🙂🙏💥💥💥

[@danacrooker1282]

I've owned two C22 preamplifiers and they didn't look like that.

[@moodyga40]

The black cat caps go bad

[@Tinybench]

Hello teammate! Thank you very much for letting me know!!!! I personally don’t trust any old capacitor like that and I don’t have an issue making units sound good with capacitors available in the market today. And that’s without spending a fortune!!! 🙂🙏

[@johnbravo7542]

@@Tinybench I agree with you 100% I build my own tube amplifiers,with good caps available from Mouser or Digikey,some people that don't understand how electronics work believe the hype too much.