Author Topic: the best of the best  (Read 23094 times)

Offline omodo

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Re: the best of the best
« Reply #40 on: January 05, 2011, 07:31:37 PM »
Do you know how the value of the output capacitor in the dac impacts on the sound?  Is there a minimum value/max value that can be used?    I ask because I notice you are using 0.47uF cap in that position  while I am using 2.2uF.     I understand our circuits/output stages will differ!

http://en.wikipedia.org/wiki/High-pass_filter


tuyen

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Re: the best of the best
« Reply #41 on: January 05, 2011, 10:58:02 PM »
Cheers heaps omodo!

Oh yes I semi-recall learning that at uni!  Pity I dropped out of electrical engineering half way and did computer programming.  :(   The knowledge would of been kind of useful to me nowdays!!  ah well..


Fc = 1 / (2*PI*R*C)

So  if I was to use a 0.25uF cap..  (and resistance of kdac is 3000ohm)

Fc = 1 / (2*3.14*3000*(0.25/1000000))  = 212hz       .. meaning it is acting as a high pass filter with a cutoff of ~212hz.  


And when I was using the 2.2uF caps that came with the dac

Fc = 1 / (2*3.14*3000*(2.2/1000000)) = 24hz    .. so with this cap in place, the cutoff freq is ~24hz.


I am running the dac now with 0.25uF dearborn cap ( I thought wat the hell.. Ill try it.. no harm as there is no DC coming through to harm the speakers).   Little to no bass response at all!   It's rolling off really early..  eeep!

Am I on the right track?

So my next question is, what if we run say 10uF caps where the Fc = ~5hz.  What happens to the sound then.   I dont have any big around that value to try!
« Last Edit: January 05, 2011, 11:01:28 PM by tuyen »

Offline omodo

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Re: the best of the best
« Reply #42 on: January 05, 2011, 11:30:04 PM »
on the right track, but the resistance of the filter is the load being driven by your dac, so your preamp or poweramp input impedance..

100k and 0.25uF = 6.4Hz
50k and 0.25uF = 12.7Hz

50k and 2.2uF = 1.4Hz

note that the cutoff freq/corner freq (Fc) is the point where the power is halved (or -3dB down), but the rolloff of a 1st order filter starts nearly a decade above the Fc, so based on this a good rule of thumb is to size the cap for a Fc 10 times lower than the lowest freq that you want to pass...




« Last Edit: January 10, 2011, 08:45:05 PM by omodo »

tuyen

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Re: the best of the best
« Reply #43 on: January 06, 2011, 02:23:58 PM »
Cheers again omodo!

I see.. my active xo has an input impedance of 50kohm  so  with the 0.25uF cap...  i'll be looking at rolloff around 130hz.. which seems about right with what I was hearing..   

I think I'll stick to the 2-3uF range :)

Still don't understand the problems associatied when using a output coupling cap with a really high value (ie. 10-50uF).   Any harm? in trying?  Will the treble start rolling off?

Offline Erik van Voorst

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Re: the best of the best
« Reply #44 on: January 07, 2011, 08:12:44 PM »
Both your experiences in your mentioned applications are the same as the results I read everywhere... ;)
However in my situation I did not come across a shoot-out yet...but we will see.
With the Duelunds......Pio Cast is the only material for high voltages (630 V)!

First impressions.....

They both are definitely playing in the same league....although the AN Silver has been burned in....and the Duelund straight out of the box.
The AN has the better hand in treble and gives the low slightly more definition...the Duelund power is in voices, more realistic and warm.
All seems a bit more balanced but also less exciting with the Duelund.
First I will have to play with the Duelund in for a few days so I can compare the differences in a burned-in comparison.
Again it is definitely a character-thing we are discussing here...almost a luxuriuos problem... ;D

Offline Erik van Voorst

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Re: the best of the best
« Reply #45 on: January 13, 2011, 11:00:51 PM »
The Duelunds were more..uhh.."emotional"...."captive"..... so i did choose them over the AN Silver 0.47 uF

We did build them in yesterdayevening... 8)

tuyen

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Re: the best of the best
« Reply #46 on: April 30, 2011, 06:06:34 PM »
Hi Erik! :)

Are they CAST Ag or CAST Cu  ??

Now that they are run in I'm sure.. how do you find them?! :)

Offline Erik van Voorst

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Re: the best of the best
« Reply #47 on: April 30, 2011, 06:18:07 PM »
I find them emotionally involving.....!!!!!

At a certain stage I do not pay attention any longer on better highs-mids-bass but I want to get ..uhhh....more drawn into the music by a new/better item that I implement in a component.

I know this sounds pretty vague but that how it is (for me) lately...

I am most certainly not poor but the silver version is out of my league so things out of my league I have no intrest in........meaning..... to try them out in my system...

BTW I find the copper Duellunds already on the edge of "affordable" (for me).... ;D

I also liked the Silver Audionotes....in the end I chose the more involving ones....

I do not share the silver versus copper opinion I find both have there own merites and I use them as such.....lets say as "seasoning"...to speak in cookery terms... ;D

tuyen

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Re: the best of the best
« Reply #48 on: April 30, 2011, 06:30:55 PM »
Understood!  I am on same boat as you now re silver vs copper.  Seasoning it is ! :)

The emotional connection to the music is something hard to measure, but matters so much for us diy tweaker guys doesn't it!

I notice you are friends with Doede!?  What do you think of his dac creation? How does it compare to your 'audionote 6' ? :)


« Last Edit: April 30, 2011, 06:32:31 PM by tuyen »

Offline Erik van Voorst

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Re: the best of the best
« Reply #49 on: May 01, 2011, 01:48:38 AM »
We only had a small shoot out years ago at my place when he was visiting me, that was  before my last serious modifications on the AudioNote Dac-3......

What I still can remember was that Doede was also at that time in the development stage with his dac.

Anyway to give some sort of an answer I can still remember as clear as day that with a voice and single instrument his tiny Dac (at that stage in that year) blew my Audionote away.....only when the complex music was played it started to get a bit too rough....

Would you believe that as a result of that I was seriously thinking of using both Dac's in my own system ...depending on the music played... ;D
« Last Edit: May 01, 2011, 01:52:08 AM by Erik van Voorst »