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I assembled a short tutorial about 45-RPM records that might be of interest to some of you. Eventually, we will place this, and other tutorials, on the Diamond Cut website.
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45-RPM Record Restoration
RCA Victor developed the 45-RPM record between the years of 1939 and 1949. Introduced on March 31st in 1949 as the “New System”, it was designed to be a replacement for the bulky 78-RPM record. It was touted to be 1/10th the weight of its 12 inch counterpart and having a playtime of up to 5.3 minutes per side. It featured a lightweight record design and small 7-inch diameter with improved fidelity in terms of noise levels and frequency response. The so called “quality zone of recording” is improved with the 45 form factor over 78’s because the ratio of tangential velocity from the outermost groove to the innermost groove is 2:1 less. This feature produces a more consistent response and distortion* characteristic over the playing range of the recording. These records were designed to be played on a special turntable having a large rotating spindle that could change a record in only one revolution. The records were made of vinyl plastic for low noise and durability and included a “Shoulder Construction” which consisted of a bump on the edge and center of the record preventing recording surfaces from contacting one another when stacked, thereby reducing the deleterious effects of poor handling. These records were designed to be played with a 1.0 mil sapphire stylus which tracked at only 5 grams and used a new recording equalization curve called the “New Orthophonic Recording Characteristic” which was later to become the industry standard RIAA curve. As an added element of marketing interest, these records were color coded as follows:
Children’s: Yellow
Classical: Red
Country & Western: Green
International: Sky Blue
Popular: Black
Popular Classical: Midnight Blue
Rhythm & Blues: Orange or Cerise
Despite the fact that 45-RPM records were marketed as having low distortion compared to their 78-RPM predecessors, many people associate 45-RPM records as having high levels of distortion and the following reasons may help explain this phenomenon:
1. They are often played on the wrong type of turntable
2. They were very low cost
3. Some very early recordings were dubs of their 78 RPM counterparts
4. They were often mishandled
5. They were often played on standard turntables having the wrong tracking angle and stylus.
6. They were often intentionally over-modulated (especially in the 1960’s and 1970’s) so that cheap record players would sound louder and the rock would sound grungier.
Since these records were optimized to be played on special 45-RPM record players, their performance is somewhat impaired when played with the relatively long (and incorrectly positioned) tone arm associated with a standard turntable. The optimum method of playback would be the use of a tangentially tracking turntable or a modified old 45-RPM record player. However, most of us are relegated to playing these records on a large disc LP turntable. This results in more distortion than these records were designed to produce because of the error in the tracking angle. Also, the early records were designed to be played with 1.0 mil conical styli, whereas today’s styli for turntables are typically 0.7 mils and elliptical in shape.
The process of restoring these recordings is not dissimilar to that of other mechanical record recordings. The difference is in the turntable mismatch to the record and the distortion encountered. To minimize the distortion when using a standard turntable, consider using a heavier tracking force during the transfer process. This will reduce the distortion. Rather than using the standard Diamond Cut CNF, consider using the Diamond Cut Auto CNF, which will be more effective in noise and distortion reduction on 45’s. Also, to reduce the distortion after the initial restoration process, consider applying the dynamics processors de-esser function to further decrease distortion.
*Note: The Intermodulation Distortion design limit for the 45 RPM record development team was set to be no greater than 10 %.
keywords: 45 RPM Record, 45 RPM History, RCA Victor 45, Victor 45's, 45's, 45 RPM Record History
I assembled a short tutorial about 45-RPM records that might be of interest to some of you. Eventually, we will place this, and other tutorials, on the Diamond Cut website.
---------------------------------------
45-RPM Record Restoration
RCA Victor developed the 45-RPM record between the years of 1939 and 1949. Introduced on March 31st in 1949 as the “New System”, it was designed to be a replacement for the bulky 78-RPM record. It was touted to be 1/10th the weight of its 12 inch counterpart and having a playtime of up to 5.3 minutes per side. It featured a lightweight record design and small 7-inch diameter with improved fidelity in terms of noise levels and frequency response. The so called “quality zone of recording” is improved with the 45 form factor over 78’s because the ratio of tangential velocity from the outermost groove to the innermost groove is 2:1 less. This feature produces a more consistent response and distortion* characteristic over the playing range of the recording. These records were designed to be played on a special turntable having a large rotating spindle that could change a record in only one revolution. The records were made of vinyl plastic for low noise and durability and included a “Shoulder Construction” which consisted of a bump on the edge and center of the record preventing recording surfaces from contacting one another when stacked, thereby reducing the deleterious effects of poor handling. These records were designed to be played with a 1.0 mil sapphire stylus which tracked at only 5 grams and used a new recording equalization curve called the “New Orthophonic Recording Characteristic” which was later to become the industry standard RIAA curve. As an added element of marketing interest, these records were color coded as follows:
Children’s: Yellow
Classical: Red
Country & Western: Green
International: Sky Blue
Popular: Black
Popular Classical: Midnight Blue
Rhythm & Blues: Orange or Cerise
Despite the fact that 45-RPM records were marketed as having low distortion compared to their 78-RPM predecessors, many people associate 45-RPM records as having high levels of distortion and the following reasons may help explain this phenomenon:
1. They are often played on the wrong type of turntable
2. They were very low cost
3. Some very early recordings were dubs of their 78 RPM counterparts
4. They were often mishandled
5. They were often played on standard turntables having the wrong tracking angle and stylus.
6. They were often intentionally over-modulated (especially in the 1960’s and 1970’s) so that cheap record players would sound louder and the rock would sound grungier.
Since these records were optimized to be played on special 45-RPM record players, their performance is somewhat impaired when played with the relatively long (and incorrectly positioned) tone arm associated with a standard turntable. The optimum method of playback would be the use of a tangentially tracking turntable or a modified old 45-RPM record player. However, most of us are relegated to playing these records on a large disc LP turntable. This results in more distortion than these records were designed to produce because of the error in the tracking angle. Also, the early records were designed to be played with 1.0 mil conical styli, whereas today’s styli for turntables are typically 0.7 mils and elliptical in shape.
The process of restoring these recordings is not dissimilar to that of other mechanical record recordings. The difference is in the turntable mismatch to the record and the distortion encountered. To minimize the distortion when using a standard turntable, consider using a heavier tracking force during the transfer process. This will reduce the distortion. Rather than using the standard Diamond Cut CNF, consider using the Diamond Cut Auto CNF, which will be more effective in noise and distortion reduction on 45’s. Also, to reduce the distortion after the initial restoration process, consider applying the dynamics processors de-esser function to further decrease distortion.
*Note: The Intermodulation Distortion design limit for the 45 RPM record development team was set to be no greater than 10 %.
keywords: 45 RPM Record, 45 RPM History, RCA Victor 45, Victor 45's, 45's, 45 RPM Record History
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