Missing sound of instruments/voice/ on CD tracks

Problem solved. What a DA I am. Thanks for the input guys. It was a interconnect error.

Thats a very odd problem. I would first start with Onhwy61's recommendation. Assuming the problem persists, I can only guess, but a couple of things come to mind. If you made copies of these CD's, you may have some settings wrong. I know you can make CD's for karaoke. From what I understand, to remove the vocal tracks, by alternating phase between the 2 channels. If this is the case, even if there is no vocals, it can probably mess up anything in the same frequency range. From some of the instruments you list, I think its a possibility that this may be the case.

Also, while talking about phase, check your speaker cables very carefully. If you wire the speakers out of phase with each other, it will cause all kinds of problems. You won't hurt anything, but, for example, the vocals may seem like they are comming from one of the side walls instead of between the speakers.

The only other thing I can think of is a possible gain issue. Sometimes too much gain or not enough gain can cause all sorts of problems. Kind of like if you buy a high output MC phono cart and a standard MC phono stage when you should have got a MM phono preamp. Too much gain and things sound very bad and sometimes disappear. Given you have a lot of tube equipment, you can very well have a bad tube. It wouldn't hurt to check your bias either.

Beyond that, I can't think of anything else other than to make sure you read all the other posts because and I am likely wrong on this one.

Sargentfriday,

If its not too much trouble, can you explain what kind of interconnect error it was? I don't know why, but I did post with some possible fixes but it looks that Audiogon never posted them for some reason. Looks like I was wrong but the problem was very odd and I'm just very curious as to what the problem was.

>I'm missing sound of some instruments or voice when playing CD's. Even duplicate CD's, when played, I'm missing some digital information or not having it picked up some where. For instance, the lead guitar part in a song may be totally missing or on other artists' recordings barely audible. It can be voice, horn, reed, string, etc., but it's always the same instrument even when played on another copy of the same CD.

>Maybe the laser in the CD is dirty? HELP. Thanks

No. That will get you static and perhaps rhythmic clicks as it fails to correct errors but can't remove individual frequencies let alone instruments.

The plausible explanations are that you're getting acoustic cancellation between multiple sources or are missing output from one or more drivers.

Polarity could be getting flipped in one place but not another. Maybe you have one channel out of phase with the other and are getting diffuse + quiet center images. Some amplifiers have the output terminals as mirror images of each other, some don't (makes it easy to use a dual banana plug for bridged operation). Maybe you have the connections reversed on one of the cable runs headed to one speaker and are getting cancellation in frequencies around the cross-over frequency. Maybe some one screwed up replacing a driver or at the factory and got the cross-over connections backwards inside (it's happened to review samples).

Perhaps you aren't getting enough gain from one tube so a set of drivers is quieter in one speaker. Maybe 12AU7/12AT7/12AX7 tubes have been substitute for one with more gain (same size, same pinouts, each one just has progressively more gain with mu of 20, 60, 100). Maybe a solder joint has broken in a cathode resistor bypass so you're getting local feedback in a tube which wasn't intended so there's less gain.

You need to measure (make a test CD, or hook a computer up to the stereo) and see what's going on.

Feed test tones > 200 Hz to each side separately and measure with your SPL meter. They should be about the same. Play them in stereo. They should be 3-6dB louder. Measure the output at the amplifier terminals with a DVM. For a given input level it should be about the same at all four outputs.