Fantastic $40 WM8740-based board - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 26th February 2013, 02:25 AM   #1
diyAudio Member
 
cogitech's Avatar
 
Join Date: Jan 2011
Location: Kamloops, BC
Default Fantastic $40 WM8740-based board

This isn't really pure DIY, more like BIY plus some tweaks, etc. but...

I just received my $40 WM8740 DAC (ebay item 190685871588) and I have to say it has far exceeded my expectations so far.

I am feeding it with a CM6631A-based USB/SPDIF board that I bought from the same e-bay seller.

Build quality, soldering, etc. are excellent on both.

The DAC board comes with an OP275 opamp in it, but I had ordered both an AD8599 and an OPA2132 because I love to have options!

After some very quick comparisons, I decided to leave the AD8599 in there for a good serious listen. The sound of this WM8740 board with the AD8599 has brought an whole new dimension to my system. Just beautiful!

Anyway, I plan to put the CM6631A board and WM8740 board into a homemade chassis, directly connect them, build the transformer in, mount the USB interface on the chassis, LEDs, switches, etc. as a DIY/BIY project. It is all that I am capable of and it will be a fun, satisfying project.

Anyone like me who cannot quite build a DAC from scratch should have a serious look at some of these Chinese boards.

Last edited by cogitech; 27th February 2013 at 03:17 PM.
  Reply With Quote
Old 26th February 2013, 03:38 AM   #2
diyAudio Member
 
merlin2069er's Avatar
 
Join Date: Sep 2008
Location: Toronto
Blog Entries: 1
Send a message via MSN to merlin2069er
Great, let see what you've done to your dac.
  Reply With Quote
Old 26th February 2013, 03:41 AM   #3
diyAudio Member
 
cogitech's Avatar
 
Join Date: Jan 2011
Location: Kamloops, BC
Will do. Right now it is sitting in a mess of cables, but I hope to start the chassis soon...
  Reply With Quote
Old 26th February 2013, 04:29 AM   #4
diyAudio Member
 
cogitech's Avatar
 
Join Date: Jan 2011
Location: Kamloops, BC
Some listening notes, which will only have meaning if you know what my previous signal chain was.

Old setup:

Ubuntu Linux (kernel 3.2.something) --> Deadbeef (direct hardware with no conversions) --> Tenor TE7022 USB/SPDIF (no 88.2!) --> HotAudio DAC Wow (WM8524) --> Shuguang I-25* --> pair of dual EL70 Planet-10 microTower "Castle".

New Setup:

Linux Mint (Kernel 3.7.6) --> Deadbeef (direct hardware with no conversions) --> CM6631A USB/SPDIF --> WM8740 DAC --> Shuguang I-25* --> pair of dual EL70 Planet-10 microTower "Castle".

The new setup (currently with AD8599 opamp in DAC) is:

- More "real" in general - perhaps more forward or less veiled. I was not unhappy at all with the "realism" of the old setup, but the new setup takes it to a new level, and it seems to get better with added wattage, not worse.

- The sound stage is both wider and narrower -- that which belongs in the centre is really, very much in the centre now, rather than in the left of the right or both... but the stuff that is far off to the right or left is more distinctly placed.

- Dynamic range is better -- bass is fuller/richer and the highs are crisper. Again, more "real".

- Subtle details in the background are much more a part of the experience now. They were just there before. Now they are essential.

- The difference between 16/44.1 and 24/96 (or 88.2) is considerably more apparent now. This varies a lot depending on the recording, of course, but really well produced stuff at high sample rates and res is just mesmerizing. "Gaucho" at 88.2/24 - WOW!

* The Shuguang I-25 is a 25 wpc EL34 PP tube amp. Currently running 4x Psvane EL34 + 2x NOS Sylvania 12AX7 and 2x NOS GE 12BH7 (I added a supplementary 3 amp filament transformer to run 12BH7 in place of 12AU7). I have some EH EL34s for it, but they are noisy as hell and lack the bass of the Psvanes.

Last edited by cogitech; 26th February 2013 at 04:50 AM.
  Reply With Quote
Old 27th February 2013, 04:08 AM   #5
diyAudio Member
 
cogitech's Avatar
 
Join Date: Jan 2011
Location: Kamloops, BC
After work today I decided to integrate this WM8740 DAC board with my new CM6631A USB/SPDIF board.

I began by removing the superfluous components from both boards:

- Removed SPDIF-out RCA interface from USB/SPDIF board
- Removed SPDIF-in RCA interface from DAC board
- Removed USB interface from DAC board
- Removed USB/SPDIF selector switch from DAC board

Then I integrated the two boards:

- Bridged the appropriate pads to permanently select "SPDIF" input on the DAC board (in leu of the removed selector switch)
- Installed leads (green and red) in the DAC board coax SPDIF-in pads
- Connected other end of leads (green and red) to USB/SPDIF board coax SPDIF-out pads
- Used "Mighty Putty" to install/secure the USB/SPDIF board so the USB interface is aligned with the interfaces of the DAC board, ensuring that access to the opamp is maintained

I have ordered a project box that the whole works should fit into. If that fails then I will build a box.

Sorry about the photos, but all I had handy was my BB.
Attached Images
File Type: jpg IMG-20130226-00066.jpg (352.8 KB, 638 views)
File Type: jpg IMG-20130226-00067.jpg (352.6 KB, 606 views)
File Type: jpg IMG-20130226-00068.jpg (372.6 KB, 596 views)
File Type: jpg IMG-20130226-00069.jpg (342.4 KB, 582 views)
File Type: jpg IMG-20130226-00070.jpg (372.3 KB, 572 views)
File Type: jpg IMG-20130226-00071.jpg (962.1 KB, 230 views)

Last edited by cogitech; 27th February 2013 at 04:23 AM.
  Reply With Quote
Old 27th February 2013, 04:10 AM   #6
diyAudio Member
 
cogitech's Avatar
 
Join Date: Jan 2011
Location: Kamloops, BC
Oh, BTW.

Yes. It works. Very, very well.
  Reply With Quote
Old 27th February 2013, 05:50 AM   #7
diyAudio Member
 
cogitech's Avatar
 
Join Date: Jan 2011
Location: Kamloops, BC
The wife and I just did about 40 minutes of opamp rotations. 3 chips; OP275, AD8599 and OPA2134.

For female vocal (Chie Ado) the AD8599 had the edge for "presense" and air.

For slightly more complex (Jack Johnson) to more complex (Dire Straits, Steely Dan) the OPA2134 seems to have the edge for coherance and lack of top end harshness. We can go louder with the OPA than the AD, and the OPA has fuller bass, seemingly. Perhaps that is a slightly rolled off and less harsh top end that we are liking..

The OP275 is surely a smooth, analog sounding opamp. I can see why it was so popular back in the day. However, it sounded "distant" to us. Less real. More like we were listening to a stereo system (a good one, but still...).

This is the first really serious listen we have given to the OPA2134 since getting the new DAC, so it isn't even burned in yet.

Still not sure which opamp we will settle on as the best "all-rounder" but my gut is telling me it'll be the OPA. The AD impresses me, but it seems less refined or less controlled.

If I had to make an analogy. OP275 is like a 72 Vette, AD8599 is like a Ferrari 308 or perhaps a Lamborghini of some sort, and OPA2134 is like a BMW M5.

Which opamp is the Porsche 959?

Last edited by cogitech; 27th February 2013 at 06:03 AM.
  Reply With Quote
Old 27th February 2013, 01:04 PM   #8
diyAudio Member
 
merlin2069er's Avatar
 
Join Date: Sep 2008
Location: Toronto
Blog Entries: 1
Send a message via MSN to merlin2069er
Nice work.

So, about $80 invested into the project so far?
  Reply With Quote
Old 27th February 2013, 02:22 PM   #9
diyAudio Member
 
cogitech's Avatar
 
Join Date: Jan 2011
Location: Kamloops, BC
Thanks!

Yes. About 85 bucks including the opamps.

I suppose I could have bought a complete solution for that kind of money. On the other hand, this "DAC sandwich" provides asynchrous USB, true USB2Audio plug and play with my OS (Linux), an excellent DAC chip, and the option to swap opamps. Not sure if there is a product out there for less money with all these key features (for me).

The enjoyment of "building" it is very important to me as well. I just love getting soldering iron out and tinkering.
  Reply With Quote
Old 27th February 2013, 03:19 PM   #10
diyAudio Member
 
cogitech's Avatar
 
Join Date: Jan 2011
Location: Kamloops, BC
I apologize. I kept writing OPA2134 above, but the opamp in question is actually the OPA2132.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Motional feedback amplifier based on Philips 40 wats amplifier 1970s sanbadgujar Solid State 14 13th October 2013 02:35 PM
MUSE MU-40 - TA2022 based amp TCx Class D 6 4th October 2010 07:25 PM
Does anyone have tried these LM3886 based board ? domtw Chip Amps 4 29th August 2010 09:40 AM
FS: Radio Shack 40-1354a, 40-1197, 40-1242e db6546 Swap Meet 2 26th November 2009 01:11 PM
My LM3886 Board Based On BR100 Schematic gcds Chip Amps 3 8th January 2009 10:08 PM


New To Site? Need Help?

All times are GMT. The time now is 11:53 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2