TGM11 - no GNFB - inspired by Steven Dunlap 'KRILL'

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[...]I do not know enough engineering to know either way[...]
Some understatement in this sentence, I would say ;)


[...]You can check the posts back through the years. It makes interesting figures.

That Krill interested me, and I found a thread which is a good read, and not too long....
DIYHiFi.org • View topic - The Steve Dunlap Krill amp

Late Charlie Hansen was quite positive about it there, but what did HE now anyway...apart cranking out some of the absolutely finest amplifiers. He is missed, sorely.
 
The issue was that there was very little bias on the spreader and it was hard to understand it could generate bias in the non active driver.

There are other regimes to ensue all outputs remain on (viz allison outputs) but in practice there seem little reduction odd order harmonics. Further my later work with the active CCS diamond buffer I took from Andrea Ciuffoli's block showed high levels of odd harmonics at all levels, and since it sounded very good in critical listening tests I came to the conclusion it really was not the goal for best sound.

I admire Hansen and his Ayre models reflected his physics training. A deep thinker. I wish I had stronger math so I could manipulate some of the poor models.

HD
 
Steve didn't find it easy dealing with people on the forum and vice versa. It can be a rough place and Steve was in a bad place from a health perspective. He's not been active for a long time. People objected to some of his claims about his amplifier, especially saying it was 'non switching' at the output. This was later clarified by another forum member 'andyc' who sadly left the forum for similar reasons (difficulty interacting with people) but who was very talented. The amplifier is really a Class AB output but there are signals and circumstances where it does not switch (current always flows). REGARDLESS there were many good reports of good sound from his amplifier. I am FULLY persuaded that his amp works (I know of at least one person in private correspondence who built it and said it was good); it is worthy of proper attention in the DIY community. I have adopted it's output stage for my TGM11.

The non-switching mode is a form of cross-conduction. This is a parasitic mode that is usually to be avoided at all costs if you want a reliable amplifier not one that blows up. So, plenty of reasons to be scornful. However, exploiting this mode is what Steve's amp does. I rather like the rebel approach that Steve took and admire his work. I also respect the work from those who were critical such as Edmond who has considerable experience and talent himself. So, I suggest you folk dive in with your soldering irons and find out for yourselves!
 
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Hi

It's easy to see how the output stage is biased, beginning with the current sources trying to pull both sides ON as hard as possible and the bias regulator in between taming it down.

The odd part is how the signal is coupled in. It seems a little "loose" to me.
 
Hi,

Just had a thought. What if I did the circuit as I described in my first post but used 3 diodes and at a resistor at the emitter to make it into an AB amplifier and use it in a bridge configuration ( 2amplifiers) with a bipolar cap in between, since it will be impossible to match the bias.Then build a simple one transistor phase splitter to create the out of phase signal. Do you think it would sound good?

Oon
 
Hi,

Just had a thought. What if I did the circuit as I described in my first post but used 3 diodes and at a resistor at the emitter to make it into an AB amplifier and use it in a bridge configuration ( 2amplifiers) with a bipolar cap in between, since it will be impossible to match the bias.Then build a simple one transistor phase splitter to create the out of phase signal. Do you think it would sound good?

Oon
Sorry. Accidentally replied to wrong thread. Moderator can you delete it.
 
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