A NOS 192/24 DAC with the PCM1794 (and WaveIO USB input)

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#5,642
kartick said:
I am using Cinemags with my 4 board stack and loading the configuration with 10k resistors at present. Will i hear a difference in the sound quality if I use it with the prescribed 15K resistors?
Click to expand...

Since there were no suggestions, I said what the heck and arranged 2 15k loading resistors from Kiwame and put it in place of the 10k ones. I am really really amazed with the kind of bass authority I am feeling in the music now. It feels weighty, has more body to the overall sound and gives a very natural and easy flowing character to the music. I am now going to arrange the Vishay Naked Z-foil resistors to go in as the Ra/Rb & Cinemag loading resistors and expect stellar changes after that. Inputs are welcome.
 
#5,643
Kartick,

Could you describe the difference you experience between 10k load and 15k load of your Cinemag. (You seem to have more bass, what about the treble ?)

Beside the load on the Cinemag itself what is the input load of your preamp ? The 10k or 15k is supposed to be the parrallel load of the two.
 
#5,644
dddac said:
Simon, I do not have an issue with ringing sound, but it may depend on the loading as well. so try to load the Sowters with a resistor at secondary.
I have real value for this, so you might want to try if this makes a differente with 5k 10k or so.
Click to expand...


Thanks Doede not sure if it's a ringing sound but for sure some high frequencies are ringing or distorted which is not right.

My pre amp input impedance I believe is approx 34K ohms
 
#5,648
Lobotom1 said:
Kartick,

Could you describe the difference you experience between 10k load and 15k load of your Cinemag. (You seem to have more bass, what about the treble ?)

Beside the load on the Cinemag itself what is the input load of your preamp ? The 10k or 15k is supposed to be the parrallel load of the two.
Click to expand...

Hey, so I laid emphasis on the bass in my initial impression because there is where I felt the biggest jump. Although, the highs are very buttery and smooth. I have never felt any dearth of extension on the top end. Overall, the sound has reached a new high as far as my build is concerned.

My pre-amp is a DHT 4P1L based and has a 470K ohms input impedance. So I am sure that is no concern.

I am going to invest in the Vishay Z foils for the DAC's Ra/Rb & Cinemag loading resistors to experiment further. Hope it is gonna give a further improvement. As these resistors are nowhere cheap. I am gonna place the order in a day or two, so folks any last suggestions??
 
#5,649
Any Last Suggestions??

Kartick,

Dwjames and I tested Wima FKP 3 film caps across the Cinemag outputs and found that 150pf brings musical detail into proper focus.

The Wima FKP 3 is a high quality Polypropylene (PP) Film and Foil Capacitor, but is a very inexpensive tweak to try.
 
#5,650
carlsor said:
Kartick,

Dwjames and I tested Wima FKP 3 film caps across the Cinemag outputs and found that 150pf brings musical detail into proper focus.

The Wima FKP 3 is a high quality Polypropylene (PP) Film and Foil Capacitor, but is a very inexpensive tweak to try.
Click to expand...

Oh that is great. But can you explain the rationale as to why this cap is needed in the first place? What does it do electronically to bring the music in proper focus? Cinemags anyways block all DC so I am guessing that is not the use of these caps. Do these act as again the harmonic noise blocking/filtering caps?

Also, how exactly are these to be connected, if you could elaborate via a simple diagram or some simple method.

Thanks.
 
#5,653
Kartick,

The rationale is that it sounds better to me. Now for the technical.
If you feed the DDDAC with PCM square wave signal you will see a square wave on a scope coming from the IV load resistors. Coming out of the Cinemags you see something very different from a square wave, but it sounds good anyway. The 10K/15K Cinemag load resistors and the WIMA cap compensate in some way for less the perfect characteristics of a transformer trying to pass a signal that our ears tell us is the most musical. I have also achieved this result with a TVC volume control a few years ago.

The WIMA cap can be installed across the 10K/15K Cinemag load resistor or from the center signal pin on the RCA output jack to ground.

Please report your results from this WIMA Cinemag tweak. The SQ change is small, but for James and me it's real and desirable.
 
#5,654
carlsor said:
Kartick,

The rationale is that it sounds better to me. Now for the technical.
If you feed the DDDAC with PCM square wave signal you will see a square wave on a scope coming from the IV load resistors. Coming out of the Cinemags you see something very different from a square wave, but it sounds good anyway. The 10K/15K Cinemag load resistors and the WIMA cap compensate in some way for less the perfect characteristics of a transformer trying to pass a signal that our ears tell us is the most musical. I have also achieved this result with a TVC volume control a few years ago.

The WIMA cap can be installed across the 10K/15K Cinemag load resistor or from the center signal pin on the RCA output jack to ground.

Please report your results from this WIMA Cinemag tweak. The SQ change is small, but for James and me it's real and desirable.
Click to expand...

Thanks, I will have to see if I can arrange these WIMA caps from somewhere local. Interested to find out the kind of improvements it brings in.
 
#5,655
Hi guys,
about 8 years ago I started diy building an audiovalve RKV with PCL805. The project didn't continue for a long time. But one year ago I finished the profect and am very happy with the probably smallest RKV out there. My problem. I am looking for an audio source worthy feeding my RKV. Doing research since I finished the RKV I dreamed about the DDDAC, but completing it (400€?) is about twice as much as my RKV.

From time to time I read about some experimental DDDACs like one with Rasperry PI or some reclocking boards. Is there happening into this direction?

My question: Is there a cheaper way for running the DDDAC module properly without the original WaveIO and Mainboard? I don't fear DIY, aslong as I don't have to invent things and just need to mainly copy electronics.

I am really not having a good overview of the current relevant DACs. So maybe you can help 🙂 What are currently the best alternatives for the DDDAC, especially when you are looking for a good bang for the buck.

Thx

Cheers
gimpy
 
#5,658
All quiet on the DDDAC front

Hello,
I have been busy ripping my cd collection for a week now using dbpoweramp cd ripper. When finished i have to get an ethernet cable from the router to where i wanna put the Aurender.
Then ask the shop to try one at home to see if it is as good as some people say and then just buy one. I wish diy audio would be that easy all the time.
So once you start using devices such as Aurender where to get your music?
Greetings, Eduard
 
#5,660
dddac said:
Hey Gimpy,

if you can bring right justified 24 bit data to the dac-board and you can do DIY on the power supply, Inputs and Rload section, that will work...
Click to expand...

Hi Doede (If I am right),
thank you very much for your reply. My initial post might have sounded a bit arrogant and disrespectful. I am very well aware of the effort you and the community as put into the dddac an how complex the topic is.

My idea was building/diying around the dddac original module as far as it is useful. I know, I need a proper source like the WaveIO and I would not diy this. Just maybe combine the dddac with another proven Source.

Well I could use a battery for the start and find out if my ears can hear the difference at all. I think the Motherboard and later the power supply might be diyable for me. Are the PCB-Layouts available?

Maybe someone has time, to tell me (noob) what the key challanges of the dddac development where and which components are the most quality related.

Cheers
gimpy
 
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