Shure 66D User Guide

DATA SHEET No. 162

DATE:

SUBJECT:

September 1940

MODEL 66D PIEZOELECTRIC STETHOPHONE

GENERAL:

zoelectric crystal converts the vibrations transmitted through the flesh into corresponding electrical impulses for amplified reproduction or recording. The instrument responds with uniform efficiency to the entire frequency range covered by heart sounds, murmurs, rales, etc. Model 66D replaces the earlier Model 65A Stethophone.

The new Stethophone is highly sensitive to the vibrations produced by body sounds but is extremely insensitive to air-borne or acoustic sounds. It is therefore possible to use the instrument in close proximity to loud speakers

without acoustic feed back, and to successfully

amplify extremely faint body sounds in the presence of external noises. This has not been possible heretofore with electrical Stethoscope devices which acoustically pickup body sounds from an air chamber.

In operation the Stethophone is simply ap-

plied to the body with moderate pressure in much the same way as the conventional Stethoscope would be used. A suitable high gain amplifier and reproducing or recording equipment must be supplied by the purchaser.

APPLICATIONS :

ment has extended to fields which are far beyond the possibilities of the ordinary Stethoscope. Heart and chest sounds can be observed with much greater clearness than with a Stethoscope. Extremely faint noises can be heard clearly with the Stethophone which would be difficult or impossible to detect with the ordinary Stethoscope.

A 66D Stethophone, in conjunction with a

suitable amplifier with one or more sets of headphones, constitutes the simplest complete equipment for auscultation. The sounds can be heard by several persons simultaneously by simply providing a sufficient number of headphones. This feature is particularly useful in teaching auscultation to medical students.

By feeding the output of the amplifier to one or more suitable loud speakers, body sounds can be demonstrated to a large group without the necessity for individual headphones. If desired, the demonstration can be made at a point

remote from the patient.

The Stethophone Can be strapped to the chest of a surgical patient during an operation and the condition of the patient’s heart can be observed continuously throughout the course of

the operation. The observation may be made at a distance from the patient by suitably extending the connecting cord thus causing a minimum of

interference with those actually engaged in the

surgery.

COPYRIQHT 1940 SHURE BROTHERS. CHICAGO (OVER)

Model 66D Stethophone is primarily designed for pickup or heartbeats and chest sounds. A pie-

The usefulness of the Stethophone in conjunction with the proper amplifying and reproducing equip-

Auscultation

Clinical Demonstrations

Surgery

By means of a cathode ray oscillograph or

other suitable device, the electrical wave forms which correspond to the body sounds may be observed visually. In this way it may be possible to observe abnormalities which might not be apparent from auscultation.

By means of a suitable recorder, recording galvanometer, or oscillograph, permanent records of heart sounds can be made which are analogous to the Well known electrocardiograph records.

With the aid of the Stethophone, recordings can be made or heart end body sounds by any of the well known sound recording methods. "Instantaneous" phonograph discs are especially

Convenient for this purpose. Such sound records offer convenient means for demonstrating abnor-

mal heart sounds to students.

Many other applications of the Stethophone will undoubtedly occur to those in the medical profession.

CONNECTIONS:

indicating and recording devices are shown in Fig. A. Many other arrangements are of course possible.

The Stethophone should be connected to the grid circuit of the first tube across a resistance of 5 megohms, as shown in Fig. B.

The output level Of the Stethophone depends upon individual conditions but good results should be obtained with high-gain amplifiers designed for crystal microphone operation.

A 7-foot cable is supplied attached to the Model 66D. If necessary, added cable may be attached for extension purposes to a maximum of 25 feet total length. High quality, low-capacity cable should be used. It is essential that the leakage resistance of the cable be high so that

it will not appreciably reduce the effective shunt resistance across the Stethophone. Heartbeat sounds are of relatively low frequency and

leakage resistance will reduce the low frequency

response.

When splicing in extra lengths of cable,

the respective coded conductors should be sol-

Model 66D Piezoelectric Stethophone

Visual Observation

Graphic Records

Sound Recording

Suggested block diagrams of the 66P Stethophone, associated amplifier and various reproducing,

PRINTED IN U. S. A.

No. No. 162

DATA SHEET

dered together and carefully insulated with a good grade of rubber tape. A wrap or fine wire or a piece of metal braid sleeving soldered to the shield of the cables should be used to cover the

joint of the cable to complete the shielding. Connector fittings are suitable for jointing cables if they provide complete metallic shielding or the conductor.

OPERATION:

to come in contact with hard, sharp objects. It should not be operated at temperatures exceeding

Voltage Sensitivity:

Recommended Load

Impedance:

Diameter. . . . . . . .

Thickness . . . . . . .

Finish. . . . . . . . .

Net Weight (less cord).

Shipping Weight . . . .

Code Word List Price Guarantee:

one year from date of shipment from the factory, provided all instructions are complied with fully.

License Notice:

Although the crystal unit Of the Stethophone is not extremely del-

icate, It should not be allowed

SPECIFICATIONS

The output level depends upon individual conditions. The output voltage for an average heartbeat Is of the order of 5 to 10 millivolts r.m.s.

5 megohms

MODEL, 66D

(See Fig. C)

1-5/16"

15/16"

Chrome Plated

3 oz.

3/4 lbs.

.......

Every Shure Stethophone is guaranteed to be free from electrical end mechanical defects for a period of

Shure Crystal Devices are licensed under patents of the Brush Development Company. Shure patents pending.

RUTEF

$35.00

125° F. or permanent damage to the crystal may result.

FREQUENCY RESPONSE:

Stethophone has been designed to reproduce these sounds faithfully and accurately. The response to frequencies above 1,500 cycles is low, thus lessening pickup of undesirable high-frequency sounds. The response is down 10 db at 2000 cycles and down 25 db at 8000 cycles. By suitable design of the amplifier, the transmitted frequency range may be adjusted to accentuate either normal heart sounds, or murmurs, in any desired manner.

Heart and chest sounds are made up of frequecies below approximately 1,500 cycles and the 66D

FIG. A

FORM NO. 1621243¼C