ebay:Weiliang Dual X2 AK4399 DAC with LCD

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Each opamp has a ripple suppression at least 60 dB.. 78/79 stabilizers have 60 dB.. that provides 120 dB which is more than enough..

Try LT1363, there's no better opamp for this purpose..
Hi Vulejov sorry if I sound stupid but I'm still new to this DIY electronics.
Why do you need feedback on op amps.
I have read with tubes the feedback is to stop humming but they sound better with no feedback.
Lampizator site.
 

Attachments

  • Sparko-103.jpg
    Sparko-103.jpg
    237.6 KB · Views: 557
What lampizator?
It's a site on the Internet.
He sells tube dac kits and explains in detail how they work.
He also shows lots of mods to cd players.
He also shows how to upgrade cheap chineese tube amps.
It's a good site to check out just search Lampizator.
My project started out as the behringer dac project about two years ago.
That's why I have gone for tube output because I had the parts already.
 
Your filter still have capacitor in the opamps feedback, and that terribly spoils performance..
The filter is an active filter, hence the capacitor in the feedback loop. Advantages of my filter:
* -40 dB/decade roll-off instead of -20dB/decade
* constant group delay in the pass-band

Hi Vulejov sorry if I sound stupid but I'm still new to this DIY electronics.
Why do you need feedback on op amps.
I have read with tubes the feedback is to stop humming but they sound better with no feedback.
Lampizator site.
Not a stupid question at all Dave. You can think of an ideal op-amp as a single component: an amplifier which amplifies the voltage across its both inputs with infinitely high gain. This way it can be used in a lot of ways, just as, for example, a capacitor can be used in various ways. To use the opamp as a buffer or amplifier, you must set the gain using feedback, with resistors, so that part of the output is fed back to the input. You can also include passive components in the feedback loop, the amount of feedback then depends on frequency of the signal, and so does gain. The opamp then becomes an active filter.
The real max gain an opamp can deliver is called open loop gain.
 
lomonosoff: fake, if you want AD797 than buy BRZ (highest version)...btw, what happened to your discrete OPA you bought from china? does it sound bad or what?

Nino: any chance you could make -3db version :D? my current version is still too loud compared to my other DAC, what should I do than with those 2 pairs of Wima 0.1/100v? these aren't in version 1 just in v.2

finally big Elnas arrived, so changed them instead of original 6800uf BC, top of that I changed aluminum 220uf/25v next to analog regs. to 1000uf/25V Nichicon KA as mentioned in schematics.
Harshness and background noise is gone but it's still bright and cold, like typical Pioneer sound, I hate that, tried also new OPA627BP which arrived in the meantime but sound with these is somewhat boring lacking crisp and dynamics even if harshness is gone, I will give it a last chance with AD797BRZ next week and will see if it make any sense continue...

In the meantime all the upgrade I did on my 2xWM8741 burned in together with AD823 and I can honestly say I never heard such a pleasant and relaxing sound which doesn't lack anything other than wider soundstage, especially vocals are stunning, like listening singer front of you, amazing :sing:
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.