KLUDGE@AGCB1.LARC.NASA.GOV (12/19/90)
Two comments: On 78's being abrasive: Most 78's are made of unplasticized vinyl, with a filler material for strength. There are a few which were actually made of shellac and a few made of modern vinyl, but most are of a PVC material which forms small ball-like grains which need a substrate to cling to. Carbon black and chalk were the most common filler materials, but there were many others. Often you'll find records made of a heavily filled material for strength, with a coating of a lightly-filled material around it, for lower noise. In any event, the filler is indeed abrasive and it will run your stylus down. And if course if you use a microgroove stylus to play wide-groove records, you'll ruin your stylus, record, and sense of hearing all at the same time. By the way, many solvents can be wicked up into the unplasticized material causing the grains to expand. When they contract due to evaporation you'll get microcracking problems, with an increased noise rate. So be very careful cleaning them and don't soak them in anything, even water. On Audax: The Audax drivers are decent. You get what you pay for. Parts Express also has many of the Phillips components which are also worth a good look. This isn't extreme high-end stuff, but you can build surprisingly good speakers with them if you are careful. In fact, I am rebuilding a 1950's pair of Wharfdales with Phillips and EV drivers this weekend, to surprise a friend for Christmas. --scott
bill@uunet.UU.NET (Bill Vermillion) (12/20/90)
In article <8461@uwm.edu> KLUDGE@AGCB1.LARC.NASA.GOV writes: >Two comments: > >On 78's being abrasive: > Most 78's are made of unplasticized vinyl, with a filler material for >strength. There are a few which were actually made of shellac and a few >made of modern vinyl, but most are of a PVC material which forms small >ball-like grains which need a substrate to cling to. Carbon black and >chalk were the most common filler materials, but there were many others. >Often you'll find records made of a heavily filled material for strength, >with a coating of a lightly-filled material around it, for lower noise. >In any event, the filler is indeed abrasive and it will run your stylus >down. And if course if you use a microgroove stylus to play wide-groove >records, you'll ruin your stylus, record, and sense of hearing all at the >same time. By the way, many solvents can be wicked up into the unplasticized >material causing the grains to expand. When they contract due to evaporation >you'll get microcracking problems, with an increased noise rate. So be very >careful cleaning them and don't soak them in anything, even water. There were more than a FEW 78's made of shellac. That was the principle ingredient for quite a while. In World War II the Japanese caputured Sumatra (I beleive that's right - from memory now), and cut off most of the supplies. The depression era of the '30s effectively shut down the record industry. There were 2 or 3 records that sold a million copies in 1927-1929. Then the record industry fell on hard times with just a few thousand of each being pressed. People stayed home an listened to that new invention - radio. It wasn't until World War II with the patriotic song "There's a Star Spangled Banner Waving Somewhere" that there was a record that sold a million copies. About 13 years between them. To get a new record during the war years you had to turn in an old one so that it could be reground to make newer disks. THe low production rate of the 30's couple with the turn in a disk to buy a new one leaves us with the result that there are fewer records from that era available. I have many from after the war. And many from the accoustic era, but the 30's is a period that didn't get a lot of its music recorded for history, and what did get recorded often vanished. The abrasive disks were from the accoustic playback era, from the tunr of the century until the 30's. Most of the vinyl 78's were special product, and not many were in the consumer market place. (The execption was the HI-FI microgroove 78's of Emory Cook). The record companies serviced the radio stations with vinyl promo copies. They cost more, but they didn't wear as fast, and were more durable. This was not universal. During the war years and after, Columbia records used to make laminiated 78's. They were break resistant. They had a carboard middle, which kept the breakage down somewhat, while increasing the noise level a bit. The problem with those is that you could not punch out the label and reprocess the rest as the rest had fiber filler. So if you look at the history of the 78, they go from the turn of the century until the late 50'- and early 60's. Only the biggest hits made it to 78 by 1960. Record companies started servicing the radion station swith 45's in the summer of 1954, 5 year after the 45 introduction. Capitol shipped every station a heavy black rubber disk , about 1/4" thick, and with a recess in the middle so the 45 could fit in it. The outer edge was grooved so you could back-cue it. I still have one of those somewhere in my house of junk. I remeber working at the college station, and one Saturday afternoon - while the CE was out making measurements, I sat playing records and soldering cables, and that afternoon wired in an RCA 45 phono unit to our >ANCIENT< audio console and played the first 45's on the air there. (The console was about a 1935-38 Western Electric - I want to say the model number was a 7B) Really OLD! Things like that got me hooked on audio. -- Bill Vermillion - UUCP: uunet!tarpit!bilver!bill : bill@bilver.UUCP