New AD1955 DA Build

[redjr]

Hi all,

Well, I've finally done it! I decided to try my hand at putting together a DAC. I decided to go with a relatively inexpensive import that seemed to have decent specifications. I chose this one. This was an interim project while I've been waiting for other amp parts to arrive. I do think it turned out rather nice looking - if I do say so myself.

It took a little while to gather all the correct pieces (case and board) that were compatible since I did not want to deal with much customization of the enclosure - Not to mention some of the required hardware, (stand-offs, screws, etc). Plus, I had my son looking over my shoulder at times, so he could see what DIY'g is all about.

I chose the DIR9001 chip since I wanted all 3 digital inputs (coaxial, Toslink and USB). Phase 2 will be researching and performing mods that will improve the sound.

I decided to chronicle the build so I've included some pictures as I went along. They can be viewed by following this link to Photobucket. I had the resolution set too high on my Lumix and there were far to many images for the forum so just decided to make a folder on Photobucket. Some are non-essential, but others more revealing. Please feel free to critique what you see and offer suggestions. Putting these 'kits' together is not like the days of my Heathkit experiences.! I'm still learning the nuances of the DAC, supporting chips and opamps (that are socket-ed for easy replacement). I'm learning much from this forum and hope to make some improvements.

So, how does it sound? I haven't done any real critical listening so far, but I can tell a difference (audible). The sound seems to be more crisp and has an airy sound to it. I know it's subjective, but so far I'm happy with the sound. I'm listening to it through a USB connection as I write this (near-field speakers) and it sounds great. There seems to be an added and definitive solid punch to the bass too. I haven't hooked it up yet to my vintage rig, so stay tuned.

I'm pleased with how it came together and what the finished product looks like. Like I said, all the parts/modules came from China, and I think the quality of the parts is first-rate. The aluminum enclosure is more than I expected and has impeccable fit-n-finish to it. The face plate is a full 8MM think. I'm happy.

I look forward to hearing from others on what mods can be made to this board to improve the sound ever further.

[redjr]

One a related note... Does anyone know of some Windows software that can monitor the audio out through the USB port and display the sampling rate and bit-depth as a background applet in real-time - for informational purposes? So, far the DAC has played everything I've thrown at it. Fingers crossed.

The more I listen to it, the more I'm impressed with the sound - and that's just with 320kbps MP3 files! In all honesty, the differences are more nuanced than dramatic, but the hardware definitely seems to be up to the task. Since I don't have a high-end system, I know this is all subjective analysis.

[Luke]

nice looking dac and pretty good workmanship. Did you buy all the parts from the same vendor so they work together?

[redjr]

Originally Posted by Luke

nice looking dac and pretty good workmanship. Did you buy all the parts from the same vendor so they work together?

Thanks Luke - Yes, I did. I wanted to avoid the headache of trying to 'mash' the pieces together and a lot of customization to the case in hopes the finish product would be to my standard. As it turned out, I still had to make some minor mods to the PCB (remove RCA jacks). That was no big deal though. I worked with the vendor ('along' on eBay), and got his recommendation on what would work the best together. I'm thinking about doing the same thing with a pre-amp as well. I've been very pleased working with this seller. Too bad the shipping on stuff is kind of expensive.

Without a drill-press, I can't imagine trying to drill a decent hole through a nice piece of 8mm solid aluminum. I was especially taken by the quality of the enclosure. It really is superb. For more aggressive projects where that would be required, I might have to seek out a local machine shop for the honors. Perhaps I'm violating an unspoken DIY oath , but that's just me. I prefer to have my finished projects look as high-quality as possible and sound every bit as good - if not better - than a store bought unit. That particular enclosure is actually quite roomy and could be used for a small amp - depending upon class.

I just got word that my amp enclosure shipped today and should arrive tomorrow. That's my next project. I'm also helping my son put together a small class D amp.

Here are links to the parts/modules I used;

Enclosure - link

DAC Module - link

Tranny - link

[carlmart]

It looks like a very interesting project, at least for me that I'm looking for something with USB & optical inputs too, besides coaxial.

One thing to watch though is which analog IC's come with the DAC, in order to avoid a capacitor at the output.

On the datasheet, Analog implements AD797s, three per channel, for the output. Which I doubt are the ones on this board.

But they are on sockets, so you might look for chips that are low in DC offset and use them there.

[redjr]

I just opened up my case and looked at the opamps. They are Analog Devices - AD275G variety. Not sure what the G designation is for. I don't know if these are good or not and/or suitable to this application. I presume there was some good, audio design reason for selecting them though in the first place. They are socketed so I can try others. At the moment, there would have to be some justifiable and compelling sonic reason for making the kind of tweaks suggested on other threads - especially with my system. If it's just a nuance improvement, other factors in my 'not-so-highend' system will mask the benefits.

Here's a link to the pdf datasheet for them.

[syklab]

Hi,
I also bought the same DAC from the same guy you bought. He is quite ok. Attach is the schem I received from the him. I am planing to replace the 4 PS cap and some of the bypass cap for the op-amp.

https://dl-web.dropbox.com/get/DIYAU...doc?w=7a99fc54

[carlmart]

Can you attach the schematic here instead of somewhere else?

I have to install that Dropbox program to open it, and I don't consider that safe.

[redjr]

Originally Posted by syklab

Hi,
I also bought the same DAC from the same guy you bought. He is quite ok. Attach is the schem I received from the him. I am planing to replace the 4 PS cap and some of the bypass cap for the op-amp.

https://dl-web.dropbox.com/get/DIYAU...doc?w=7a99fc54

I get an error on that dropbox link too.

[redjr]

Originally Posted by syklab

Hi,
I also bought the same DAC from the same guy you bought. He is quite ok. Attach is the schem I received from the him. I am planing to replace the 4 PS cap and some of the bypass cap for the op-amp.

https://dl-web.dropbox.com/get/DIYAU...doc?w=7a99fc54

I've been very happy with using along. I also bought some modules for a building an AB class amp from him as well. There's a bit of a language barrier in emails, but not too bad. That thread is in the Chipamp forum, but has not been updated in awhile. I'm also thinking about getting some modules for a preamp from him as well. In fact, they are already in my eBay basket. The enclosure for my amp only came yesterday. Can't wait to get started on that project! Problem is... my design keeps changing.