Ampro 755 ‘Celebrity’

Additional Info

Ampro 755 – December 1953 Tape & Film Recording, staff test report

THE Ampro “Celebrity,” model 755, and the “Hi-Fi,” model 756 recorders are the first completely electronic-controlled recorders to be placed on the market.
For our report a “Celebrity” model, which has a tape speed of 3¾ inches a second, was picked directly from the production line.
The basic idea behind both models, which are practically identical in appearance, is that the time has arrived for the tape recorder to move into the living room as a piece of furniture, as well as being a utilitarian instrument of value to all the family.
A console speaker is available as an accessory and is built so that the recorder may be placed on top of it, making a very attractive and complete unit.
The case is finished in limed-oak plastic that fits well with any decor. The case is opened by lifting the left side of the nameplate and the top is removable. Microphone, cords, tape reels, etc. fit in a channel at the rear and the cover may be placed on with the seven-inch reels in position.
All controls are in the form of “piano keys” with solenoids doing the work of actuating the mechanism. These eliminate the wear found in mechanical linkage systems and provide rapid, simple operation.
Due to the interlocking of the controls, all changes in tape direction, playback, record, etc. must be operated through the stop position. This is an added safety feature to prevent accidental tape breakage or spillage.
The record key has a safety latch, which must be moved to one side be-fore the key can be depressed. This acts as a preventive of accidental erasure. Both a fast-forward and a fast-rewind are provided.
One of the features that we found useful was the Automatic Selection Locator. It measures tape positions by means of numbers, operating somewhat like a speedometer and once the number has been noted at which a taped selection starts, you can depend upon it to start at that number always, unless the tape is shortened or lengthened.
The Electronic Recording Level Indicator is very easy to use and in addition to providing a check on recording level it also shows when the recorder is warmed up and ready for action. If the two parts of the wedge almost touch on the loudest sounds you are running at a good level. If they overlap, you are overloading the tape.
The speaker, which is enclosed in the recorder cabinet, is a 6 x 9 inch unit and has a good response. In a well on the side of the case, are the jacks for external connections for: a remote control switch, the external speaker, (which may be used for monitoring or additional power amplification), the radio or phono inputs and the microphone input. A cord with jack and alligator clips is provided for making connections to radio or phonograph.
The on-off volume control and the bass-treble tone control, together with the Recording Level Indicator and Selection Indicator form one panel on the left of the machine. In the corresponding spot on the right are the keys controlling the mechanical motions.
In design the unit is very attractive and internally it is well built. A flywheel, individually dynamically balanced has reduced wow and flutter to less than ½ of 1 per cent. The amplifier portion can be separated from the mechanical parts by the removal of four screws, making servicing easy.
The stop and start is very positive and wow free, however, care must be taken that the tape is not loose or breakage may occur. When you press down a key the response is instantaneous. This quick start and stop feature makes it easy to edit tape.
The quality of reproduction compared to standard program requirements is excellent despite the 3¾-inch speed, as the frequency response was fairly linear and of excellent quality on the machine we tested. At the higher frequencies there is a falling off in the linearity of the output. However, taken all in all, this machine accomplishes at 3¾ inch per second speed what many machines are able to do at 7½-inch speed.
The Ampro Model 756, which does have a tape speed of 7½-inches per second, naturally has a much greater range of frequencies falling in the flat response category.
In our preliminary examinations we were a bit concerned about the size of the reel spindles, which fit rather loosely in the reels but actual operation showed that this mattered not at all. There was no difficulty encountered in running the tape nor was there any wobble to the reels when the power was applied.
Mechanically and aesthetically the recorder is excellent. The drive motor is more than adequate for requirements, the temperature rise is normal and the dynamically balanced flywheel assures positive flutter-free operations.
The use of the solenoid controls both eases and speeds operations. The electronic mechanism is also adequate for the job it has to do.
Actually we were quite surprised at the excellence of the tone achieved in playback. In one test we recorded from a radio speaker through the micro- phone, which is about the worst way to make an off-the-air recording, and the results were very pleasing.
Off-the-air recording should be done, of course, by attaching the alligator clips to the radio voice coil leads and then inserting the plug in the phono-jack. Pressing the record key will then tape the program.
We believe that the Ampro is worth consideration if you are planning to purchase a recorder.