OTL Asylum

OTL, Output Transformerless Amplifier User Group.

Use this form to submit comments directly to the Asylum moderators for this forum. We're particularly interested in truly outstanding posts that might be added to our FAQs.
You may also use this form to provide feedback or to call attention to messages that may be in violation of our content rules.

You must login to use this feature.

Inmate Login

By default, logging in will set a session cookie that disappears when you close your browser. Clicking on the 'Remember my Moniker & Password' below will cause a permanent 'Login Cookie' to be set.

Moniker/Username: The Name that you picked or by default, your email. Forgot Moniker?	Examples "Rapper", "Bob W", "joe@aol.com".
Password:	Forgot Password?
	Remember my Moniker & Password ( What's this?)

If you don't have an Asylum Account, you can create one by clicking Here.

Our privacy policy can be reviewed by clicking Here.

Inmate Comments

From:
Your Email:
Subject:

Message Comments

Original Message

RE: There were a number of OTL circuits that showed up after the war.

Posted by cpotl on November 8, 2012 at 15:49:14:
I found a website giving some history of the circlotron. This also has Cecil Hall as the first (patent filed June 1951, according to him). The splendidly named Alpha M. Wiggins, sometimes said to be the inventor, filed a patent later, in March 1954. Between those two is what sounds like the first OTL circlotron, by Tapio K�ykk� (patent September 1952). But that was for an 800 Ohm speaker, so I suppose it hardly counts as OTL in the spirit that it is meant these days.

I didn't manage to track down the actual articles for OTL amplifiers prior to Futterman's 1953 patent and Dickie and Macovski's, and then Futterman's, 1954 Audio magazine articles. These were all for low-impedance speakers (16 ohm, typically), and so genuine OTL in the modern sense. Of course these were all totem-pole, not circlotron. I suspect that earlier OTL articles, such as Brociner and Shirley (Audio Engineering, June 1952), which I couldn't locate, were for high-impedance speakers.

Chris