Take up reel rumble on K-1020

[perry]

I know a number of THers here have K-1020s. I have 2, one in need of an idler. The other one is in pristine shape, but the W&F was in the .08% range. I removed the pressure rollers and de-glazed them with 1500 emery. The supply roller came out perfect.... nothing but matte rubber. The take up roller came out very good, but still a very fine set of surface checks...but very pliable with no cracking when pressed. I set the azimuth, which was WAY off, and had never been adjusted before, 15kHz went from 15mV to around 80mV. Tapes really sound amazing on it now, and the W&F dropped to the .06% range. The only issue is that when I play a blank tape and turn the volume up with headphones in the tape deck headphone jack, I can clearly hear the take up reel rumble. The K-1020 has milled edges on the motor hub and the reel hubs, for idler traction, and I believe that rumble is the milling vibrating through the cassette. If I flip the tape over with the majority of the tape on the supply reel to begin with , the rumble frequency decreases to match the rotation of the take up reel. Now, let me say that if I were to listen to music at a volume that makes that rumble clearly heard during quiet passages, the music would be deafening, so it's not a deck breaker. But I find it hard to believe it is normal, as it CAN be heard. Anyone else listen to a blank tape and notice it?

[tcp100]

Perry, as I mentioned in PM to you - my newly recieved K1020 that I'm working on does the EXACT same thing - so it seems it is not unique to yours.

I work out of town during the week, but when I get home on Thursday afternoon I'll check the SN on mine and we can compare.. Perhaps it's something that was revised and fixed in later runs, or maybe it's a symptom of a cap near the end of its life somewhere?

Perhaps someone else has seen this and knows of a fix?

You're right in that it's hardly a dealbreaker; you need things turned up all the way to hear it, and at least on mine, any use of NR pretty much cut it out. It seems to happen on playback only; this rumble does not get recorded.

[perry]

I hadn't tried to listen for it on record, yet..that's good to know. I still have all the EQ and FR checks to do on it now that you got the SM to me. Bad thing is I honestly don't know if it was there before I tweaked the azimuth, but it is the kind of thing I sure think I would have noticed. (Did you notice it at all before you tweaked your azimuth, or was it not operational enough?) It could be that is what made it more audible. I do know that the azimuth was so far off that the overall volume out the line and of the headphone jack went WAY up across the whole FR. I could never get the K-1020 level to match the Naks, with them at 50% volume out, which I though was very strange. Now it's much higher than the Naks are! We'll see, maybe it was an intentional detune from Yamaha to hide that noise. I have the other one to get working, its never been tweaked and I'll check it out before I make any adjustments, other than fixing the idler.