Got Cold Feet About OTL Amplifiers?
Are you unsure about using an amplifier with no output transformer? You shouldn't be...

--Franklin Park, 2002

            If you are one of the few who have cold feet about going "Output Transformerless", or "OTL", you might be surprised as to how reliable and prevalent OTL technology really is...

            Do you have a solid-state home stereo? It's OTL. So is the stereo or radio in your car. Do you have a PA amplifier connected to 4 to 8 ohm loads? Chances are your PA amplifier is bypassing its output transformer. OTL is everywhere. OTL technology is reliable and well established.

            Despite the benefits of OTL technology, some people may be reluctant to try an OTL amp despite the benefits because they feel it's nice to isolate the load from the amplifier.  They worry that if the amplifier shorts out--say, from some large DC surge, however unlikely--that it might possibly damage their speakers. Although the odds of a surge of this magnitude occurring is  slim to none, all of Grommes~Precision Electronic's OTL amplifiers come equipped with a variety of protections. For instance, the AXIOM 500-OTL includes built-in fuses and relay board. In the event of a surge, the fuse disconnects the power and the relay board disconnects the speaker loads from the amplifier. Like the entire AXIOM power amplifier series, there is no failure mode that can cause the AXIOM 500-OTL to damage your load.* 

        OTL is a well established, reliable technology.  The only  reason the average PA amplifier needs its output transformer to STEP-UP the amplifier's low voltage output to 70V. Grommes~Precision OTL transformers are built "already stepped- up" with the 70V loads in mind. Therefore, if you know that your load will always be 70V, then you don't need the added cost and weight of an output transformer. It's a reliable and well established technology that can save you money.

      *Our OTL amplifiers provide yet another benefit: extra-low distortion. The Axiom 500-OTL typically exhibits about 0.05%THD @ full power output. And, don't forget, we back each of our manufactured products with our Assurance Pledge: 5 Year Warranty and 30 Day Money Back Guarantee.