Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

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: Slew rate, TIM hogwwash

Posted by gusser on July 7, 2017 at 07:09:21:
Yes I know all about M. Otala and his papers. He had an agenda obviously to promote his name. His technical findings are true and accurate. But that doesn't mean they show a PRACTICAL problem. TIM is a classic text book exercise when it comes to audio amplifiers.
Now when Elon Musk populates Mars and in a few ten thousands years when our bodies adjust to the thinner atmosphere, Perhaps TIM will be a legitimate factor for audio amplifiers on Mars where sound can travel faster!
TIM is not necessarily about slew rate. It was promoted as an attack against feedback. The old Einstein time paradox where you can't experience something before it happens. And it's and a serious problem in some areas of electronics design. But not for audio. The path delay of a typical audio amplifier is too short to have any detrimental effect on an audio signal coming from a natural source.
I have no doubt there are a plethora of papers online about the horrors of TIM. But do these papers have traceable credibility? Hint, Stereophile is not an accredited reference!
As for MEANINGFUL measurements, don't use a square wave generator like Mr. Otala did. Take a modern digital waveform snap shot of a musical session. Measure the fastest rise time. Multiply by 5 using the classic engineering 5x bandwidth rule. Then see what the required rise time of the total amplifier circuit is. Now in fairness perhaps some early solid state gear with slow power transistors did fall short, But no amplifier designed past 1980 transistor technology should have a TIM problem.