ebay:Weiliang Dual X2 AK4399 DAC with LCD

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#364
lomonosoff: I don't know if X9 is worth +$300 but I might be wrong, never heard about M-audio speakers but if I understood well these are bit noisy due to internal amplifier and of course made for studio sound so all depended on if you like this kind of sound, I already bought this DAC so I'll be doing comparison once it arrives and finally decide which one to keep
 
#368
Serge, I was noticing that the less noise, the more that details
would come through, just by passive line filters alone, so I can imagine that the new regs are a huge upgrade.
I started out just looking for a more rich and solid tone or timbre with my mods, then discovered that clean power makes a big difference as well, but have only done minimal work in that area.
I would be interested in what gains can be had to the 8805 power supply chain...
I think that there is potential for interference with any of the components, but none of them are in contact with other traces or wires either, am sure that would be a problem.
I did partition off, with a steel panel, a section of my enclosure for the transformers, and use soft rubber feet, made a difference. Now just the leads go to the boards, separate from each other.
 
#371
#372
Has anyone tried to change the output resistor to something a bit lower than the 100 ohm that shows on the schematic?
I had some caddock film resistors in 12 ohm that sounded pretty good in another dac from the same designer.
Just a thought anyways, didn't mean to breakup the regulator banter...🙂
 
#374
IMG_0674.JPG
 
#375
phase said:
Has anyone tried to change the output resistor to something a bit lower than the 100 ohm that shows on the schematic?
I had some caddock film resistors in 12 ohm that sounded pretty good in another dac from the same designer.
Just a thought anyways, didn't mean to breakup the regulator banter...🙂
Click to expand...
Hi phase
I think the betterment in SQ was probably due to the better audio resistor you used.

But why not remove the resistor? For example the LME49710 has short circuit protection on-chip, so no resistor is needed; I don't know why it's used anyway, it's also not used in the single op-amp example in the datasheet.

Regards,
Nino
 
#376
Yeah, could do the straight wire I suppose, just had two extra decent resistors, so it seemed a logical application I suppose, and the lower out put impedance hadn't been addressed here, so I thought I'd mention it.
Pretty good benefit per dollar if you stick with a wire wound...
 
#379
Hi Sunsun22
The capacitor is part of the active filter system, together with the resistors and opamp itself. When using 510pF, the filters' cut-off frequency becomes 96 kHz instead of 109 kHz with 390pF. Also with 510pF, the signals' transfer function goes up slightly at the cut-off frequency, it's not entirely flat.

I think you can better use 390pF, because the pass-band is flatter with that value.
 
#380
latest update, I made some additional upgrade with Caps as below, analog supply part has now all caps as per schematics with Nichicon KA version, top of that I change those BC aluminum esr caps with ultra low Nippon Chemicon version, I couldn't hear any audible difference, but last week I upgraded analog part with HDAM modules as visible on the picture, hard to describe it properly but it's amazing, more dynamics, more punchy bass, no harshness at all, absolutely happy man 😀

An externally hosted image should be here but it was not working when we last tested it.

free picture upload
 
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