tube burnout

Sounds allot like either a filament or high voltage supply design flaw or defect due to a blown part. It would not be difficult to modify or repair.

Hi Guys,

Thanks for all the responses!
The last time I listened to vinyl I was plagued by the same problem. That is,on turn on I would listen to vinyl at low volume and everything was OK for the first fifteen minutes. Then, a low level distorted sound that got intrusive very quickly would appear. On FM everything sounded fine.

Today, I replaced the phono section tubes with a set from the line stage and replaced those with a known set of good ones. Upon turn on there was distortion right away on phono but not on FM.

I believe that there has to be something up in the circuit like Lamphear says.

One other thing. Phono sounded good before with a Shelter 501. Now I have a Shelter 9000 and it is a LOT better ( when the phono stage is not acting up).
I use a step up transformer to the MM section of the pre. The sound has a lot of the audiophile attributes we look for. But, how come with a cheap Kenwood tuner from the seventies the sound is more 'pleasing'?
It sounds fuller, richer. Not deeper bass or higher highs and air all around,
just a more relaxed sound. And this is I presume with CD's broadcast from across town. I have not had this sound on vinyl. Would loading and capacitance have something to do with this? As I don't have any options in this regard.

Chears

If your cartridge is not properly loaded, you are missing a bet with LPs. Proper loading can take out a lot of harshness and improve detail.

If the cartridge is a few years old, the cantilever suspension can perish (like bad shocks in a car) and the cartridge can get a lot harsher and not track as well. Of course, proper arm setup is *crucial*!

Hi Atmasphere,
The cartridge is new with maybe twenty hours on it. Still, it is a vast improvement on the Shelter 501 I had before in the same set up.
I think you are right, it has to be the loading of the cartridge.
It is hooked up to an Audio Interphase SUT which in turn is hooked up to the MM
section of the pre. As for options re set up,there are none. This is where I believe my problem lies.I hear all the detail and all the 'hi-fi' stuff, but it is not as lush and fleshed out as on a cheap FM tuner that I use for background music in the system. It seems as if there may be a better connection between tuner and pre than the vinyl set up and pre to my ear. Even though all the better wires are on the vinyl set up.

Also, I have a cheap 1oo dollar Panasonic DVD player I sometimes use for a CD or two, and it too seems to have a fuller, more direct sound. Not better, not by a long shot, just a livelier more robust sound it would seem.
It's as though the phono signal has gone through the ringer one too many times and come out a little bleached,a little tired.
You just feel like your only getting 50% of the signal instead of the full 100%
like the tuner and DVD seem to put out.
Arm set up is good too. I have the RS A1 Labs arm which plops down anywhere.
I've had it for five years and I've got it dialed in pretty well.