Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Other Topics => Topic started by: zendragon63 on September 16, 2010, 11:46:33 am

Title: That PP Tube Amp sound
Post by: zendragon63 on September 16, 2010, 11:46:33 am
A recent post by bruno on Class A push pull

http://www.el34world.com/Forum/index.php?PHPSESSID=8c8fd7f20cd9c986bbbdb00dbf338f46&topic=10066.0

and a PRR's comment .... why the heck do you care? Class A does not sound better to the ear, no matter how much bumph they put in the ads. got me curious as to why so many of us dig that Class AB overdriven sound. Leo's classic 5F6A and so many that followed. I ran accross an short article in Electronic Engineering Times that summarizes what I did not know about 'duty-cycle modulation'--that, when overdriven, truly seperates the sound phenom delivered by PP tubes.

 http://www.trueaudio.com/at_eetjlm.htm

There were another couple of reminders that I needed; it is a pretty short read and IMHO has a few good points for us technologically-challenged folks to consider while we are hacking away. Thanks for making me 'think'. Regards

dennis
Title: Re: That PP Tube Amp sound
Post by: simonallaway on September 16, 2010, 12:42:44 pm
Wow, that was very interesting. I'm not strong on the definition of 'duty cycle' though. I see this:

http://www.answers.com/topic/duty-cycle

...but still don't get it.

Say a wave is square, is it referring to the ratio between the width of the pulses on each of the top and bottom of the wave?
Title: Re: That PP Tube Amp sound
Post by: stingray_65 on September 16, 2010, 12:50:14 pm
GOOD READ!

That article has tied together a lot of things I've read bits and pieces of.

I'll bet a dollar to a donut that this link will find it's way into Chips mountain of useful data and someone will be directed there to clarify some confusion  :icon_biggrin:

Thanks for the link!
Ray

Simon,

waves are classified by their shape. (in general) and usually fall into a few groups. sine, saw or triangular and square. There may be others.

A square wave on an oscilloscope has a flat top and a very fast rise in its slope.