Wildly fluttering woofer

Atmasphere,
valid point, but I didn't know if the offending speaker was right next to the turntable or not. That's a great way to create feedback. I also didn't know if the speakers were in phase. If it happened to me I would have reversed channels via the interconnects between each component till I isolated the problem. Or try another tube as you suggested, but I got the impression the original poster wasn't very hands on.
As far as a noisy tube goes, I don't know how his preamp is designed (tubes carrying both channels or one). The problem seemed subsonic and only in one channel, which rules out the power supply (unless it's completely dual mono). There was no mention of how much volume, if any was required to cause the problem.
The problem actually sounded more like motorboating in one channel to me, which points to an amplifier's feedback loop, and a bigger problem than a noisy tube.
There just wasn't enough information to formulate a reasonable cause as there was no mention of a process of elimination.

I'm interested in the outcome.

Dear Heyraz, " I got the impression the original poster wasn't very hands on" is almost a compliment. I'm limited in knowledge and mobility due to a broken foot and a cast up to my knee and told no weight bearing. It was too difficult for me to reverse speaker cables which was my first thought. Somehow the tracking force was almost 2.6 gms which is strange since I'm the only person allowed to touch anything. I double checked the tracking force and set it to 2.0 gms. The arm is a Graham Phantom. Using a Yamaha C 60 preamp and correct tracking force there isn't any flutter. I'm hoping Art Ferris finds a problem with the preamp I sent him.
Thanks to everyone who offered their knowledge to "hands on". I'll post Art's comments when I hear from him. Katz1

Ouch! Wishing you a quick recovery. Enjoy the music while you're stuck inside.

Dear Heyraz, I've enjoyed reading you so much that I've tracked you down via other threads. A worthwhile way to spend some of my downtime. I've never rolled a tube or changed a capacitor and I'm envious of you folks who get into the nitty-gritty of this hobby. At age 72( I'm too vain to use my hearing aids) I'm resisting my life long search for absolute musical realism with any further upgrades. I have to finally settle for good enough and stop the chase and enjoy the music and searching thrift stores in Los Angeles for the big score!
Regards, Katz1

Katz1,

Sometimes you don't have to do anything major to improve the sound. Changing stock speaker crossover capacitors is one thing that can be done easily and reversed if not satisfied.

My favorite thing about changing capacitors (any capacitor) is listening to them as they break in. At first, new capacitors usually sound horrible. After about 15 minutes they bloom as though someone opened up the door to make things clear, it's really dramatic for me, like someone raised the lights. After that, as they continue to stretch out and break in, the sound continues to get clearer, more subtle and detailed.

Rolling tubes is a little easier, no soldering involved. Different tubes have their own sound. My preamp uses three 12ax7 types in the line stage. I started out with three Telefunkens but it seemed like the sound was over-driven and sometimes too loud. So I changed the first tube to a 5751 (70% of the gain of a 12ax7) thinking I might be over-driving the second stage and the sound became less congested and more subtle. I left the tele in the second position and put a nice low distortion 7025 in the third position to smooth over and finish the sound. Kind of like finishing scotch in a sherry cask. The sound took on a different flavor. That's what rolling tubes is like for me.

I'm not as big of a tinkerer as you might think. Once I like what I hear, I'm done and just enjoy the music. It's only when I get no pleasure from listening that I wonder if it's my ears or the equipment. I can't do much about my ears, so I check the equipment or go to a friend's house to compare.

I do have an extra set of speakers that I might experiment with. They're an extra set of Large Advent's and I'm thinking of removing the internal capacitors and passing the wires to the outside of the cabinet to some terminal strips. That way I can practically change capacitors on the fly till I find my favorite. Then, using another amp, I might "stack" them to see what all the fuss is about.

How's the leg coming along? I can empathize with you're plight because I broke my neck 10 years ago and was stuck in a halo for 3 months. Thank God I had Star Trek recordings to watch, I was so bored. After that, I got hooked on The History and Discovery channels and made it a point to watch all of Clint Eastwood's movies that summer.

One day at a time..each day over is a day closer to getting the cast off.

Good luck.

Rich