Has anyone tried the LT6234 low noise op amp in this type application?
http://cds.linear.com/docs/Datasheet/623345fc.pdf
It as around $4 in single quantities. Digikey has it but Mouser does not list it.
http://cds.linear.com/docs/Datasheet/623345fc.pdf
It as around $4 in single quantities. Digikey has it but Mouser does not list it.
I bought the 2 x OPA627 at e-bay. $7.50 incl. shipping
1PCS Dual to Mono OPA627AU replace OPA2604 NE5532 TL072 | eBay
It will take a month or so, but at least I will have time to get used to the new sound of NE5532, and then when I change it to the OPA627 I can hear the difference.
1PCS Dual to Mono OPA627AU replace OPA2604 NE5532 TL072 | eBay
It will take a month or so, but at least I will have time to get used to the new sound of NE5532, and then when I change it to the OPA627 I can hear the difference.
Sadly I don't know how to correctly design it...but I guess you can try with a series resistor of 12 kOhm and a 470 pF shunt cap.
But probably a buffer after the filter is needed.
Maybe would be better to add a proper LPF filter to the dac...
I just got finished simulating the LPF on mine, -3dB at 90KHz which is ok for 92KHz bw, but I'd like to roll of starting around40KHz.
The recommended filter in the manual won't be difficult to patch in and should sound better as the -3dB point is around 49.2Khz.
At least it simulates better.
It's probably so but I'm not able to design it...without opamps... but the opamp filter is already on the datsheet
Anyone with more expertise is willing to do it for trasnformers?
Working on upgrade - in the BOM R24 &R34 are listed as 1KOhm and in the photo R34 is shown as 2.2K.
Hi Bob,
if I remember correctly you bought the AK4396 version, right?
For AK4396 those resistors (R24 to R34) are specced in BOM as 2.4K (2.2K if PRPs from PCX).
1K resistors are for AK4393.
If I am not wrong I think that is the HDAM discrete circuit, though in this case with the CFP mod.
I think it could be tried on the AK4396, probably eliminating the 100uF capacitor, which I think it's a must in the Marantz they made it for.
Another problem is the input filter, which involves inductors.
It should be marked C37, and is a 1 uF cap.
It doesn't appear on the "upgrade BOM" because Dario didn't see a need to replace it -- thus no change from the stock cap provided with the 2496-mini-DAC kit.
It is listed in Dario's "full BOM" as a 1 uF capacitor, 50V, any manufacturer, standard elco capacitor. My kit came with a dinky teapo 10/00 (?) cap, rated for 105 degrees C. Most of the photos posted on this thread show a larger cap, but it's up to you.
I hope that helps !