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2503-Litz Output Transformer
Quantity: 1+3+ 5+ 7+ 9+ 13+ 17+ 
Price for each:$38.50$37.70$36.90$36.10$35.30$33.70$32.10
Your savings:- 2%4%6%8%12%17%
Number of Products in stock: 35

Click to enlarge

Click to enlarge

The 2503-L is a custom made audio output transformer. The 2503-L has been designed to replicate the transformers found in the vintage API recording consoles from the 1970's. In the console, this transformer was mainly used to balance the output signal on the 325 cards which were post fader, booster amplifiers. The 2503 was also used as the balancing output transformer in nearly all of the 500 series modules like the 550, 550a, 550b and more.

The Litz wire version of the 2503 has occasionally been referred to as the "preferred" sounding version of this popular quadfilar transformer. Litz wire is a type of cable made up of multiple strands of wires electrically insulated from one another and twisted together in a prescribed pattern. It has been said that winding with Litz wire produces a more uniform high frequency response but we have also noticed the bottom end seems to be a little "bigger" and "deeper".

The 2503-L can easily be distinguished by the red keeper lamination and the sexy black bobbin.

The vintage 2503 is probably most renowned for it's part in the unique sonic character of the coveted API 312 card. The 312 was originally designed as a "plug-in" mic preamplifier, booster amplifier or line amplifier. With the combination of the 2622 input transformer, the 2520 discrete operational amplifier and the 2503 output transformer, you have one of thee most sought after microphone preamplifiers ever designed. The circuit is ever so simple and the components far from perfect. The inherent phase shift and distortion, are what make it all sound so special.

The 2503-L has flying leads and can be mounted directly to a PCB
The physical layout matches its vintage predecessor, the EA2503 and also the popular CMOQ-2 series of transformers

Additional information:

PDF specs

  This product is proudly manufactured in the USA

This product was added to our catalog on Saturday March 14, 2015.
Classic Audio Products, Inc.
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Classic Audio Products, Inc. is not affiliated with API. Customers and fans should not refer to Classic Audio Products, Inc. as "Classic API." API is a registered trademark of Automated Processes Incorporated. Classic Audio Products, Inc. has no affiliation with Automated Processes Incorporated.
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