Audio Systems: Cd questions, harbor freight tools, scratch removers

Question
First off,thanks for your help in the past.We communicated back and forth on my system,I know you get alot of questions but I had the Dynaco Stereo 70,was having a problem with breaking up on loud musical passages.The problem was the voltage bias settings were way off! I bought a $4 multimeter from Harbor freight tools,both channels should read 1.56 volts when the amp is warmed up after about 20 minutes,at startup they usually read higher ,but they were at 1.77! they now read about 1.66 and then the proper measurements after the unit is thouroughly warmed up.Thus though I am no electronic genuis it is obvious that 1.the amp cannot sound its best if the tubes are not getting the proper voltage 2.this will shorten the tubes life.Anyway the amp sounds much better,gone is the distortion of loud and complex passages,It sounds just great.Anyway the reason I wrote you is that I asked 2 other people on this site these questions and got no reply! 1.What is SACD ,I read it usually uses just 2 channel stereo but promises better resolution than a standard CD? 2. Do you know of any commercial CD scratch removers that are effective at removing minor to moderate scratches.I have 2 CDs that skip for about 10 seconds on a certain track.Another skips for aboyut 25,So I know that probably can't be fixed.I made sure there were no fingerprints on these Cds and cleaned them thouroughly wiping from the center of the disc outwood like they suggest.Any suggestions?

Answer
Dear Peter,

Good to hear from you.

In reverse order:

Any commercial scratch remover should do the job. Try any Best Buy or Circuit City. Hi-fi stores also carry product. Keep in mind, however, that even a scratch patch can't restore lost data, which could happen if the scratch penetrated the aluminum substrate on the disc and compromised the digital encoding.

SACD means "super audio compact disc". It is a multichannel audio standard designed to play back music in multichannel (some would say "surround sound") format, generally the 5.1 standard used by the first generation of A/V applications. SACD discs are becoming more common, although the format has not taken off the way its proponents expected. SACD requires a specialized playback player and a 5.1 speaker array. Dedicated SACD players are expensive. However, there are a number of DVD players which also play SACD discs that are relatively inexpensive; i.e., less than $200.

SACD competes with a format called "DVD-A" or DVD Audio, pretty much designed to do the same thing, reproduce music in multichannel format. The formats are not compatible. DVD players that can play back SACD sometimes also play back DVD-A.

I own some SACD discs, but I haven't installed a SACD-capable player in my A/V room yet to test the format.

Kindest regards,

Kevin