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: SEE URL Para 2

Posted by cpotl on January 22, 2019 at 09:12:22:
"I'm not sure what to call this"

Well, I think one calls it an output transformer. Namely, an impedance-matching transformer between the output tubes and the loudspeaker. To quote from Graaf's own description of the GM 100:

"The GM 1OO circuit derives from the OTL configuration and uses a new type of interfacing between the output tubes and the loudspeakers. This system adds to the OTL configuration a transmission line transformer which shifts the tubes impedance from 36 / 72 ohm to 4 / 8 ohm."

It has a smaller primary/secondary turns ratio than a conventional output transformer, but the purpose is the same; impedance matching.