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RADIO BROADCAST ADVERTISER
Introducing
Two Revolutionary Audio Transformers
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TWO years ago Silver-Marshall startled the radio world by introducing the largest and heaviest audio amplifying transformer ever seen! Tested, condemned, ridiculed, and praised, within 6 months the then famous 220 Transformer had become the largest-selling high-grade A.F. transformer ever produced. Since then it has been specified for more circuits than any competitive type.
With S-M 220 Transformers firmly established in public favor, SilverMarshall, Inc., now introduces two totally new types of audio transformers so far superior to present standards as to justify the term "revolutionary"!
Below are curves proving that the new S-M 255 and 256 audio transformers give far greater amplification and a better frequency characteristic than three pairs of much more expensive standard transformers. And they are cheaper and smaller than the inferior but more expensive types.
Not content with this practical revolution of the A. F. amplifier field, S-M engineers went a step further. The impossible was accomplished, and a second type of transformer, also new in principle, was created, possessing better than the theoretically unattainable flat characteristic right down to 32 cycles; of standard bulk, practical freedom from hysteretic distortion, almost twice average amplification, and at less than average prices! These remarkable units are S-M 225 and 226, for first and second stage, respectively.
At the R. M. A. Trade Show, S-M engineers will demonstrate a comparison amplifier in which any standard type of audio transformers can be compared against the new S-M's. This test audibly proves the statements above — and the curves below. You can hear it at any time you are in Chicago.
These Curves Prove Absolute S-M Audio Superiority!
Curves A, B, and C are of highly regarded types of $8.00 and $10.00 standard A. F. transformers. Curve D is of one S-M 255 and one 256, costing $6.00 each. Curve E is of one S-M 225 and one 226, priced at $9.00 each. This curve does not show the freedom from hysteretic distortion which only the new S-M transformers afford.
NOTE: Amplification figures are from detector plate to power tube grid circuit and amplification of power tube is not included. For general purposes the amplification fig' ures at the left may be multiplied by the M» of the power tube to be used to find the overall gain of a two-stage amplifier (for example, for 171 or 250 output tube, multiply by 3.8 approximately; for 112 or 210 output tube multiply by 8 approximately).
100 200 3C0 400 500
Frcquencv In Cycles.
SILVER -MARSHALL, Inc.
838 W. Jackson Blvd., CHICAGO, U. S. A.
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