Download Print this page

RCA D 22-1 Instructions And Information

Microphone howl
Hide thumbs

Advertisement

Quick Links

S. O. 765244
Subject:
MICROPHONE HOWL
MODEL D 22-1
INSTRUCTIONS AND INFORMATION
The high level of sound energy within the cabinet of the D 22-1 may
occasionally cause acoustic regeneration or a sustained howl.
condition occurs only during record reproduction and is due to vibrating
elements in the 6L7 of the audio expander stage.
Improvements have recently been effected in the manner of supporting the
6L7 elements so that the tendency to howl is eliminated.
instruments and tubes of the 6L7 type received lately should, therefore,
be free from "howling" tendencies.
The "howl" produced by the origina1 type of 6L7 is usually at a
frequency of about 2000 cycles.
type will be at a frequency of approximately 400 cycles.
The improved 6L7 is being shipped in the first detector socket of the
D 22-1 receiver chassis as well as in the expander stage so that they
may be interchanged if "howl" occurs.
Camden, New Jersey.
INSTALLATION
AND
SERVICE DIVISION
RCA Manufacturing Company, Inc
NATIONAL OFFICE
Camden, N. J.
Any "howl" experienced with the later
W.J. Zaun
Installation and Service
Date Nov. 12, 1935
Number 3.156-B
Classification
Instructions
and
Activities
This
D 22-1

Advertisement

loading

  Related Manuals for RCA D 22-1

No related manuals

  Summary of Contents for RCA D 22-1

  • Page 1 NATIONAL OFFICE Camden, N. J. INSTRUCTIONS AND INFORMATION The high level of sound energy within the cabinet of the D 22-1 may occasionally cause acoustic regeneration or a sustained howl. This condition occurs only during record reproduction and is due to vibrating elements in the 6L7 of the audio expander stage.
  • Page 2: Installation

    Its price is comparable to that of an automobile, which on delivery receives a complete check with slight adjustments. We consider that such procedure should be accorded the D 22-1. Intensive tests are now being conducted in Camden to obviate troubles so far reported.
  • Page 3 SERVICE DIVISION Model Classification D 22-1 Part Number 11481 Instructions RCA Manufacturing Company, Inc Information NATIONAL OFFICE Camden, N. J. INSTRUCTIONS AND INFORMATION Trouble may be experienced with the D22-1 pickup head due to instability of the armature centering adjustment. Improvements have been made in recent production to minimize this condition by decreasing the diameter of the centering spring and making a more substantial attachment of the same spring to the pickup armature.
  • Page 4 INSTALLATION Subject: Date November 18, 1935 Number 7.6B Reduction of “Wows” SERVICE DIVISION Classification MODEL D 22-1 Rejecting RCA Manufacturing Company, Inc Inspection. NATIONAL OFFICE Camden, N. J. INSTRUCTIONS AND INFORMATION "Wows" may originate in the worm or worm gear of the motor clue to unevenness of either part or manufacturing variations.
  • Page 5 S. O. 765244 There are, of course, other factors contributing to “wows” such as spindle eccentricity, turntable wobble, vertically and record groove eccentricity with respect to the spindle. Many times, rotating the turntable 180° with reference to its original position on the spindle will help decrease the amount of vertical turntable wobble.