Author Topic: discrete dac mock up  (Read 24666 times)

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Offline yeo

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Re: discrete dac mock up
« Reply #60 on: February 03, 2012, 07:13:59 PM »

as a pre regulator, it's fine.

yeo

Offline kkerwin

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Re: discrete dac mock up
« Reply #61 on: February 04, 2012, 04:33:41 PM »
hi all,
i replaced the inductor with 180r. i have 26vac in and measure 16vdc on the entrance to the dac board.not sure in voltage should be higher or not, but with the dac board not connected, the voltage reads more in the 21vdc range.???
  i maybe have a little less gain, but no reason to care.  with the sd card reader on pause, and the amp on ful volume, there is no hum.  the soundstage is back, in force.  the tone, everything is in place, even my complaints about in phase, out of phase, are much more minor.  not sure why that is, but i will take it!
anyway, for now, i am back to listening.

thanks
k

Offline kp93300

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Re: discrete dac mock up
« Reply #62 on: February 05, 2012, 12:46:23 AM »
Hi

2 groups came to audition the dac.
The first group came last night and  I let the set warm up 1/2 hr before auditioning.
They were impressed described the sound as analogue, non digital type  . Bass is deep and taut with a space around the musicians and a deep wide sound stage. One person described it more a better Monica  with ability to play high resolution files. I was still playing with 16 /44.1 with qls 5500.

The second group came rather unexpectedly  and I have no time to warm up my system. They  left just now and complained of lack of energy , bass. Lack of high frequency extension.  After a few tracks , we switched over to  Monica and another dac from China.  WE all preferred the monica.

When they left, i switch back  to discrete dac. What a difference  after warm up. I thought the bass is the best of the three. The high freq information are present but not highlighted.

 It should be noted that the other 2 dacs are played without the need for a pre.

Yeo, can you posted some picture of the place to  insert a Wenzel shunt ?

 I rip a disc with EAC, the soft distortion before the music comes on is still heard. The tape hiss is also audible with soft passages. Maybe this is associated with the high gain of 6.6 in the pre. ??


thanks
 kp93300

Offline yeo

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Re: discrete dac mock up
« Reply #63 on: February 05, 2012, 01:38:10 AM »
hi kevin

i made a mistake. current draw of dac is about 100ma for 2 channels. sorry.

this explains without the dac you get 21v, with the dac hooked up, you get 16vdc. 16vdc is okay though i prefer a bit higher on the b1 buffer. some folks prefer 18v though.

from your description, looks like you really like the sound!   :)

hi kp

yeah, the regulators all take a while to warm up. yes, warm up does make a big difference here.

i'll send you some pics later. i still don't get the distortion thing.

i'm going to experiment with some gain stages. i'll let you know how that goes.

yeo

Offline CKL

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Re: discrete dac mock up
« Reply #64 on: February 06, 2012, 05:37:52 AM »
Hi Yeo,

I want to use LL1660 as the output transformer. Where should I tap the signal?

Thx

Offline yeo

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Re: discrete dac mock up
« Reply #65 on: February 06, 2012, 07:20:09 AM »
hi ck

sorry to go off track.

from what i understand, you don't have enough gain. using the ll1660 isn't going to help much i believe.

if you want to tap the signal, it's best to connect after the buffer. or where you tap the analog signal right now.

yeo

Offline kkerwin

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Re: discrete dac mock up
« Reply #66 on: February 06, 2012, 08:25:08 PM »
hi yeo,
yes, the sound is really good, very clear.  the setup is very silent all the way to full volume. no hum at all.
k

Offline kp93300

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Re: discrete dac mock up
« Reply #67 on: February 09, 2012, 05:38:54 PM »
I want to give the feedback from another hi ender who came to audition. He is seasoned and has been to my house on numerous occasions.
His comments   "too much echo, nasal sounding mid  and the front to back soundstage  is too much   The female vocal is detached from the rear music. "He thinks it is due to bad positioning of my speaker ! However, since his last visit , I have no significant change in the rest of the set up with the exception of the discrete dac and the AD 815 pre.

I told him the so called echo are due to reverberation of sound in the studio. I played some piano and sound very natural. The decay is fantastic . The decay and harmonic texture  of a triangle is very real. Female vocal is very real  to my ears. I could hear the breath intake and Harry belafonte sound throaty, powerful and rich . This is what i have been aiming for --better appreciation of the atmosphere of the recording studio. The audience clapping  in Harry belafonte  Live in carnegie convey a real sense of being there.

I take his comments and have been thinking why he made such comments.

I think this illustrate the problem of evaluating hifi as one man? meat is another person? poison. We hear and perceive differently and prefer different types of sound.


I want to hear comments from other users of discrete dac.

thanks

kp93300



Offline CKL

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Re: discrete dac mock up
« Reply #68 on: February 09, 2012, 05:50:12 PM »
When I first compared the discrete DAC with my optimized Monica3, I felt Monica3 gives more bass & treble. I prefered Monica3 more.

After more burn in, I can hear the discrete DAC plays piano better. I can hear the piano is more live & each string is more bouncing.

Its major advantage is playing the 96k and 192k files. With the Monica3, I don't feel 96k and 192k wins too much with 44k. With the discrete DAC, it is easy to hear the advantages of 96k and 192k over 44k. I don't know why.

I suppose the BGs needed more time to burn in. BTW, if the discrete DAC is powered on all the time, do I need to play 30 minutes music to warm up?

Offline kp93300

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Re: discrete dac mock up
« Reply #69 on: February 09, 2012, 06:50:12 PM »
Hi CKL,
I agree with your assessment  -- I quote  --(When I first compared the discrete DAC with my optimized Monica3, I felt Monica3 gives more bass & treble. I prefered Monica3 more.)

Are these sounds a reflection of the BG  at the output ?

I have not used BG at the output  of Monica 3 and 2 for quite a while already.

You using an output transformer ?

kp93300

Offline CKL

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Re: discrete dac mock up
« Reply #70 on: February 09, 2012, 06:55:37 PM »
Hi KP,

My optimized Monica3 had bypassed the BG NP output to LL1660 output transformer. I think the discrete DAC is using BG NP output so I mean the new discrete DAC needed more time to burn in, right?

Offline CKL

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Re: discrete dac mock up
« Reply #71 on: February 09, 2012, 07:04:55 PM »
I have an idea that Monica3 is not a true 96k DAC so the extra information is truncated. The discrete DAC is a true HD DAC so I can hear the improvement when playing 96k & 192k.

Offline yeo

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Re: discrete dac mock up
« Reply #72 on: February 09, 2012, 08:25:52 PM »
hi guys

if you want to play higher sampled music on monica, remember to use a software like audacity to convert it down to 16 bits first.

the tda1545 is only good for 16 bits though it could play with higher sampled music, all the way till 382khz if i'm not mistaken.

you also have to check whether your software supports high rez. many don't!

regarding run in... not only the black gates caps need running in, the power supply has a few rubycon zl caps. these caps sound horrible at first too.

hi kp

regarding your visitor's comments, this is why it's vital to listen to a whole range of music and get listeners of various music background.

someone who plays musical instrument is even better!

for example, i don't care about soundstage nor imaging. i often mixed up left and right (ck knows this very well. sorry!) but i care about tone and i care about coherency.

if tonal balance and coherency is off, i run!

a friend who reviews equipment on a part time basis is very good with rhythm. first impression of the discrete dac is that he was surprised he could follow the rhythm much easier on the discrete dac compared to other dacs.

now perhaps there's something i did in the dac! i know what it is, but i'm not saying anything. ha ha!

yeo

Offline kp93300

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Re: discrete dac mock up
« Reply #73 on: February 09, 2012, 09:03:46 PM »
Hi
I agree with the timing and coherency comments.
I will play some music and  get my children to comment as they play piano and has better ears than me!
regards
kp93300

Offline kp93300

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Re: some observations and questions
« Reply #74 on: February 19, 2012, 06:43:12 AM »
I have a hum problem that i have never been able to solve.
It was much lower than my initial encounter before the power supply mod. I tried LM 317 reg, cap multiplier and the hum is still the same.
It is audible with my ear about 6 in from the mid. However,  intermitently it is audible from my listerning chair.
I also noted that this is volume related and the hum is aggravated by touching the BG output caps of one side only.
Is this oscillation ?

.Yeo, what have you in mind when you place the  out point in the pcb ?

There is an empty hole next to the 4k7 resistor . What is this for ?
regards

kp93300
kp93300
.