by Record-changer »
Tue Jan 12, 2010 7:12 am
More on this:
We have to realize that records of each speed were made in multiple sizes. There is no one size that goes with a given record speed.
Most record changers made before the late 1960s have size intermix, This was done because many record albums contained records of more than one size. I have two albums that have several 12" records and one 10" record, and another album with two 12" records and a 7" record. This also allowed a greater choice of records to put in the stack.
Some record changers even have speed intermix. I own two of these. You can mix 12" and 10" 33 records with 7" 45s. The one in my avatar can do this, but the 45s must be last.
There were several methods used to sense record size:
- Feel the first record on the turntable - no intermix, but has automatic single play
- Feel the record as it falls from the stack - random size intermix, no auto single play
- Both of the previous methods - random mix of 12" and 10" records, but 7" records used separately, no auto single play of 12" records
- Feel the unplayed stack - arranged intermix (larger records must be before smaller records), no auto single play
- Lower the record from the stack slightly, then feel it - random intermix, no auto single play
These were not the only methods, but they are in the majority.
Automatic single play was not usually provided before the late 1960s. Most designs that took intermixed record sizes could not do automatic single play. Then, with the advent of component systems, more people wanted automatic play of a single record.
Many companies started making changers with size controls instead of automatic indexing, so the changers could also play single records with the short spindle. Examples include most of the Miracord changers made after 1961, the BSR changers made after 1967, and the Dual changers after 1964. These changers sacrificed the ability to mix record sizes in favor of automatic single play.
In the late 1960s and early 1970s, changer manufacturers started linking the record size to the speed control. This, of course, meant that many older records could not be played automatically. These changers also didn't know what to do with 45 rpm classical albums and disco singles. Note that some of the earliest 3-speed changers also linked speed to record size on the speed knob.
Garrard was the first to do this after the intermix period, in 1967. The SL-95 and SL-75 took the following size-speed combinations: 12" 33, 10"33, 7" 33, 7" 45, 12" 78. These can not be intermixed. Note that 10" 78 was left out, even though there are more 10" 78 records than 12" 78 records. They also made the changer so it would not change anything except a 12" small hole record or a 7" large hole record. STUPID!
In 1969, Garrard changed the AT series so it also used the speed control for size. The choices were: 12" 33, 7" 33, 7" 45, and 10" 78.
In the mid 1970s, most changer manufactures cheaped out, and made changers that took only 12" 33 and 7" 45. The public stopped buying them, because they had records of other speed-size combinations. Only Collaro kept making changers with automatic arranged-intermix index to the end.
There are a few changers that can take intermixed sizes and also index a single record:
- Dual 1003, 1004, 1005, and 1006, and the Luxor RT series, used feeler wheels to sense the size of only the top record on the turntable. They could play standard and odd sized records mixed in any order.
- Dual 1008 and 1011 used a drop feeler to sense the dropping records during changer play. But a second feeler sensed the size of a single record only when the single play spindle was installed.
- Miracord 16, 160, 161, and 191 had an automatic arranged index that worked like the Collaro (large records must be first), but also had a single play record size switch.
- Many of the Philips AG series had a special control for the size of a single record.
- Glaser-Steers 3000 and 4000 would index a single record if you put the tip of the raised overarm over the rim of the record. But it repeated the record forever until you put the overarm down over the spindle or selected STOP.
Also, some record changers sense the size automatically, but do not allow size intermix:
- The PE 2000 series does this, feeling the first record in the turntable again and again.
- Philips made a changer that used the arm tip to feel record size (like Collaro), but it feels the records on the turntable, rather than the records on the spindle.