DIY Burr Brown PCM1798 / 2007 based USB DAC

[Audiodoc]

Here is my new DAC. Sounds warm yet detailed. Haven't added the tube buffer as yet. After the Wolfson & Burr Brown Sound Sabre Comes Next!

 

[iaudio]

Audiodoc, I am sure as with your all builds, this one is also gonna reside in a beautiful enclosure. Aural and aesthetic pleasure without compromise! Once the Sabre based DAC is done, you can give an impression of these phyla of DACs.
So, will you be adding a tube buffer now? Or happy with the sound as it is, since you mentioned it is already warm sounding?

 

[Audiodoc]

Although I have the tube to try out I feel the typical warm burr brown sound doesn't need much mellowing down (though I will experiment). Now the enclosure is something that I cant buy off the shelf as of now may have to DIY it.

 

[gopib]

Your 2012 seems to be roaring ahead with builds...!!! Nice one:clapping:..will watch your impressions...need to do one of this too...

 

[santhosh]

Impressive as always Audiodoc:clapping: Tell us more about the kit - from where, how much etc?

 

[Audiodoc]

5.5K with tube from some anitadavid on ebay. You can upgrade to pin compatible PCM1794. 2707 is controlling the USB input and NE5532 / other opamp (which check in the evening) in the i/v stage (upgrades with better ones possible). It has digital outputs SPDIF as well as optical which can be toggled with the onboard switch. Will upgrade to a spdif input module lated as my XPS laptop does output digital which is better than USB bandwidth wise.
So lots of tinkering can be done.

 

[cha_indian]

Hi Audiodoc, I have PCM1798 DAC which is quite similar to what you got....I would to add here that when i changed to 'better' opamps than stock ones, it did not change sound signature at all. In fact for amplication, the stock NE5532 sound is better than anything else.

 

[Audiodoc]

Then I believe the best and first upgrade that I should do will be to replace the output (DC blocking) bipolar electrolytic capacitors (green ones) by polypropylenes. Like the Axon ones on my B1.

 

[cha_indian]

I suggest you first burn in the stock setup for atleast 2 weeks 24/7 and listen to your favourite songs. Then move to mod it....

 

[happy_carrera811]

Well sorry for being slightly off topic audiodoc, where can i find norge 2060 or 1000 in chandigarh ? Well you have really nice setup i must say. Why this forum does not have any private message or visitor message options ?

 

[omishra]

Why this forum does not have any private message or visitor message options ?

It is there. If you left click on user ID at the left side of any member's post then you get drop down menu which has option (second from top) to send private message.

 

[kaushik]

ross from rossmartin audio said this pcm 1798 has some distortion at the hifreq region
PCM1798 cant be swapped with PCM 1794 due to some capacitor correction difference. how u got the kit in 5.5k..all the places it is 120USD +

(FYI rossmartin audio does some ready dac with PCM 1794,custom configs USB/opamp selection at 230USD mark )

 

[sudhishkv]

Some pics...

USB DAC Assembly instructions

 

[Audiodoc]

won a bid on ebay! Ross Martin ones have good reviews but cost almost double the price.

http://www.head-fi.org/t/539614/ros...-dac-199-single-dac-399-dual-dac-with-headamp

 

[sudhishkv]

A noob question...

If you compare your dac and the dac below, whats the difference in audio quality? GrubDAC Overview

 

[Audiodoc]

The latter one is based on the PCM2707, WM8524 (wolfsons 8524 is much lower end than the 8740 in my E7, currently the 8741 is the leader which has been superseded by 8742) combination while mine has thr PCM2707, burr Brown1798 followed by the i/v and tube buffer stages and is definitely great value for money. Cant compare the audio as I believe in A/B blind testing only.

Just to add I could not hear any problems within the higher frequencies and it definitely sounds better than the FiiO E7 DAC Amp which is based on the Wolfson 8740. Compare the features here by numbers the one you have pointed out is way behind:

http://www.wolfsonmicro.com/products/dacs/WM8524/

http://www.wolfsonmicro.com/products/dacs/WM8740/

http://www.wolfsonmicro.com/products/dacs/WM8741/

http://www.wolfsonmicro.com/products/dacs/WM8742/

http://www.stereo.net.au/forums/sho...e-to-spend-to-beat-Oppo-BDP83-for-CD-playback

 

[kaushik]

Ross Martin do pack some serious stuff inside :
TIs DIX 9211 receiver chip,USB via TE7022 chip that does 24/96 via USB.and 24/192 via spdif...

Here is your board in 88USd no bidding needed =4.5K INR approx
TUBE USB DAC [TUBE USB DAC] - US$88.00 : headfishop.com

 

[Audiodoc]

Man add the $20 to $40 ($30 in my case) shipping cost and pray it does not land with customs otherwise they will add 13% to the bill. Mine (5500) is all inclusive with the tube.

 

[kaushik]

Man add the $20 to $40 ($30 in my case) shipping cost and pray it does not land with customs otherwise they will add 13% to the bill. Mine (5500) is all inclusive with the tube.

i just added link for forum mates ,agree that you might have done 5.5k.

But if i order that will come here in 500Rs shipping , moreover the customs like me ) actually broker will clear it ,else they will feel too lazy to take duty ,thanks to china guys), but i dont have plans to do that as i live with the USB that PCM2707 does pretty poor job here , so my fav will be good USB(24/96) i/f >reference DIY Dac

 

[Audiodoc]

Hardly have any 24/96 stuff to listen to. My Hifiman HM601 does that job for me.