I built up another one of these simple little DAC's so that I can do a comparison of two different D-A chips to see if I could discern any audible differences.Of course the quality of the power supplies and the analog output stages play a large roll but I'm curious to see if I can hear any differences between equally spec'd chips from two different companies.Namely the Cirrus CS4398 and AKM AK4396 both are 24bit/192 k Delta-Sigma differential voltage output devices.Other than the addition of a 16/48k non async USB input on the Cirrus board the two are near identical thus making it an apples to apples comparison.Both very similar PC board layouts,the same power supply scheme,and use the same Cirrus CS8416 digital input reciever.
As with the original AKM board I used Panasonic FC series electrolytics for local decoupling ,and Panny stacked film's for supply bypassing.
Aswell a BNC connector is used to assure proper 75 ohm termination impedance and a pulse transformer provides galvanic isolation from my PC's soundcard.The main filter caps in the second board are UCC's vs Nchicon's in the first.
As the pics show I used another though slightly larger version of the cute little Hammond cases.After I'm finished with the comparo I will use the extra chassis space to beef up the main filter capacitance with the addition of an auxillary PC board with 4x 3900uf.
Outta curiosity whats something like this run you?
Roughly $60-70 per completed chassis not including the external transformer.
The transformer was a freebie but you would be looking at $20-25 ish from places like Digi Key and Mouser.A suitable transformer is also available from the Asian ebay vendors for these PC boards or kits.
Forgot to mention the all important opamp used in both is an LME49720.
Nice work, Fred.
Thanks gents ,and yes Rich same opamp aas IVY III and Leg also known as the LM4562.And yes I have compred the little AKM to the Buf III ,this little vid depicts the outcome nicely. :cheesygrin:
The finished product with RCA and BNC connectorss installed.For neatness sake I epoxied the pulse transformer directly to the body of the BNC con.
That is a neat little package Fred. I like the pulse attachment.
Thanks Rich,I wish I could wedge the Buf III into one of these cases.