AMP9 Basic feedback

[vtaylor]

Salut

1. The output diodes are a pain dans les fesses to solder and it's easy to create a solder bridge to one of the Tripath pins as I did. Also the diode orientation needs to be checked with a meter as the markings are practically invisible and don't give the orientation anyway.
2. Not mentioned in the instructions: you need a jumper on the first pins to wake-up the Tripath chip. You also need a switch (or touch the pins with a screwdriver, for example) on the mute pins to activate the DC-offset nulling routine.
3. A 12V tranny (so about 16V DC) is not really enough to drive Maggies - even actively.

Sounds OK (first impressions) but I need more power - there's nasty clipping when I turn the volume up.

EDIT: I had some residual noise that completely disappeared when I connected ALL the earths to the common chassis point - power supply and input.

@+

Vernon

[MikeHunt79]

If you want more power the easiest way would be to have an input voltage of 25V.

Also, is it possible to have the DC-offset nulling routine performed automatically every time the amp is powered up?

[MikeHunt79]

If you want more power the easiest way would be to have an input voltage of 25V.

Also, is it possible to have the DC-offset nulling routine performed automatically every time the amp is powered up?

[chris4916]

Bonjour,

Well, first time, soldering diodes is a bit challenging. Then, once you understand how to do it, it's quite easy. I was at the beginning reluctant with CMS but I've to admit it's faster and not so difficult.

What is this "DC-offset nulling routine" ? I though it was handled at power-on stage but reading your comment, I might be wrong.

16V doesn't provide a lot of power, especially using 8ohms drivers but why not just trying up to 24 or 27V? In any case, with 16V, you will not get a lot of power. It's not due to AMP9 design. I mean AMP9 is maybe what will give you the best ratio with such "small" transfo.

I'm very happy with my AMP9-B with 27V SMPS (400VA [8D] )

Christian

EDIT: OK, I just read previous topic related to DC-nulling... I'll give a try. [:I]

[vtaylor]

Salut

Yeah - I realise more volts (and amps) = more power. It was just some feedback for anyone with a big 12V transformer in their bits box (like me). Someone somewhere in the forums also reckons that 12V is sweeter.

Anyway, 'just' up to 24-26V means shelling out at least 60€ for a 300-400VA transformer, or not much less for an ebay SMPS of unknown performance; and the models above 250W have a fan - something I've been eliminating from my PC audio player.

@+

Vernon

P.S. There are delay power-up circuits for the mute in the forum.

[MikeHunt79]

quote:Originally posted by vtaylor

There are delay power-up circuits for the mute in the forum.

Thanks, I'lll do some digging. :)