AVCC 2.1 - module update

[Russ White]

Hi folks,

While I was laying out the Buffalo III-SE PCB - I decided it was about time to refresh the AVCC module. So I designed PCB version 2.1 of that module.

A couple of key improvements:

- We started using the same improved error amp we are using for the Trident - it is the dual version.
- There is better local feedback around at the shunt element by adding degeneration. This promotes better stability and RF rejection.
- There is compensation added to the feeback loop to give the circuit a much improved phase margine. It is as a result very stable and rejects EMI better.

The result is a module that does a better job at regulating - and truly does sound better than the previous version. I don't say that lightly.

This updated module can be operated at slightly higher input voltage like the new Tridents can.

This mean that input voltage up to 6V should be just fine.

I also improved some aspects of the layout making better use of top and bottom planes. It is thermally and electically a better solution.

It is a much more robust drop in replacment for B-II and B-III.

It will be available soon. We are getting them made now.

Here is a picture of one Brian built up by hand for testing.

Cheers!
Russ

[thomaspf]

and truly does sound better than the previous version. I don't say that lightly

That is a strong statement. Does this improvement also manifest itself in any measurement on the actual audio outputs?

Cheers

Thomas

[Russ White]

Originally Posted by thomaspf

That is a strong statement. Does this improvement also manifest itself in any measurement on the actual audio outputs?

Cheers

Thomas

I wish I could answer that. I simply don't have access to gear with which I could measure that at the moment.

I would be very glad to see results from any of our users who does.

One note though is that these changes are exactly the same kind I made to the Trident. Those changes did have positive measurable effects on the regs themselves (wider phase margine and lower noise and output impedance in the critical band), but alas those tests where not done by me, but by a user, and I am not sure he has shared those yet.

For now - I can only offer my subjective opinion. They sound better.

Cheers!
Russ

[thomaspf]

I suppose the best thing that could happen to all of us is to get you a Dscope III or something similar ...

Cheers

Thomas

[Russ White]

I certainly wouldn't turn one down.

[Russ White]

What I can say is that simulation at least backs up the assertions, but I would never say that simulation is infallible proof.

[Erlend Sæterdal]

Originally Posted by Russ White

I wish I could answer that. I simply don't have access to gear with which I could measure that at the moment.


For now - I can only offer my subjective opinion. They sound better.

Cheers!
Russ

In what way ? What is better sound for you ?

[MartinC700]

Russ,

Any timeframe on when the new module will be available?

Cheers

[Russ White]

Originally Posted by MartinC700

Russ,

Any timeframe on when the new module will be available?

Cheers

They are being made now. They will also be what we ship with the Buffalo III-SE.

[Russ White]

Originally Posted by Erlend Sæterdal

In what way ? What is better sound for you ?

I hate it when people ask me questions like this.

Because while I know what I like - it is hard to find the right adjectives to describe why.

I spent quite a lot fo time the last few weeks listening to the new BUF-III SE - so keep in mind this comment will be based on that setup with Legato 3.1 driving various headphones.

Since you force me (just kidding) I will say that what I like better is what I would call a sense of control and precision. Also the background is crystal clear and clean. No noise is present accept that which was recorded.

I would say that the AVCC module is *the* single most important regulator on the Buffalo.

I am not as eloquent as others, so I hope some other folks will write better reviews.

Cheers!
Russ