[TimJo]

Quote:

Originally Posted by pabbi1 /img/forum/go_quote.gif So, certainly TimJo has new phones

Just plugged them in for the first time.

Too soon to say much, other than they sound really nice, but very different compared to the CTH and DT 880 combo I've grown to love. I'm beginning to think that my ears may have gotten used to a more colored sound, and now I am hearing a truer representation of what is sitting in the record's groove.

The amp is fantastic sounding (albeit only minutes into burn-in) and there is no shortage of bass extension with the 404LE's, so I am happy.

Thanks Alex for giving us an affordable, high end amp. I doubt I'd be listening to stats right now without your generosity to the head-fiers. Thanks!!!

 

[XXII]

Quote:

Originally Posted by runeight /img/forum/go_quote.gif I still need: XXII bidoux acmemr bidoux, I know you are working on this.

Hi Alex,

I've sent you a pm regarding this.

 

[runeight]

Yes, got it now.

 

[luvdunhill]

Thinking more about a measurement jig... would a capacitive divider work? Say a 3pF capacitor with a 3000pF capacitor for the bottom of the attenuator. Perhaps add a voltage buffer... Result, dead 'scope? Dead amp? Dead people? Or.... ghetto wide frequency 1000:1 probe?

 

[Beefy]

Its alive! And making sweet, sweet music

Very early impressions are that it exceeds even the lofty expectations raised by Pabbi, headphoneaddict and others. Certainly superior to my previous t-amp SRD7-SB combo. Dead silent noise floor at normal listening volumes.

Mounting everything in the case will commence this week, as will the FPE order.

 

[luvdunhill]

 

[les_garten]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif Its alive! And making sweet, sweet music Very early impressions are that it exceeds even the lofty expectations raised by Pabbi, headphoneaddict and others. Certainly superior to my previous t-amp SRD7-SB combo. Dead silent noise floor at normal listening volumes. Mounting everything in the case will commence this week, as will the FPE order.

Nice! What Vol control is that?

 

[Beefy]

I'll let the person behind the volume control speak up if they so choose.

Suffice to say, it is freaking fantastic. Well, once it is wired up correctly anyway....

 

[digger945]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif Its alive! And making sweet, sweet music

Quote:

...it exceeds even the lofty expectations...

Quote:

Certainly superior...

Quote:

Dead silent noise floor...

I'de say he's got the bug.

Very nice, as usual, Beefy.

 

[luvdunhill]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif I'll let the person behind the volume control speak up if they so choose. Suffice to say, it is freaking fantastic. Well, once it is wired up correctly anyway....

Documentation has never been my strong suit

Haven't I hi-jacked this thread enough? I guess this is one of those things boiling in kitchen so to speak. Looks like magic, but it's functionally a balanced 192-step attenuator (down to -95.5dB) in the mode that Beefy has configured it in.

I'm not sure what Beefy spent on it, but I know he has the current record for cheapest build (not including power supply and random 0805 resistors that might have went flying in the process).

 

[Beefy]

I'll hijack it then

Its a balanced PGA2320 volume control, with rotary encoder. Usable rotation is much better than a pot, without having to turn way too many times to get volume. Encoder has a push switch shaft for mute.

Cost outlay was very low - well under $50. But the PGA chips were obtained at a significant discount.

 

[runeight]

Well gents, I don't mind a little hijacking. How about some more information.

 

[Beefy]

Considering mine is only the second functional unit, I think it is a long way from prime time

 

[luvdunhill]

It's that pesky mod that hangs around here that I worry about

In this case, the devil is in the software, but the rest is fair game.

The datasheet is here:

http://focus.ti.com/lit/ds/symlink/pga2320.pdf

and the microcontroller I'm using:

http://www.atmel.com/dyn/resources/p...ts/doc8006.pdf

My layout is here:

Pretty straightforward and I tried to follow all the layout guidelines from the datasheet and what not. Trying to find time to work on developing the "companion" board in the next few weeks.

Here is what it looks like in it's intended deployment:

 

[dBel84]

way too tangential, shouldn't be allowed I tell you.

Marc, have you got a thread dedicated to this? I would like to read more about it. Looks fantastic. Great work too Beefy , looking very neat ..dB