what Is the purpose of the bottom of pcb chip
what Is the purpose of coupling electrolytic caps between dac L+ L- R+ R- and OPA - could they be bypassed without any think to worry
Printable View
what Is the purpose of the bottom of pcb chip
what Is the purpose of coupling electrolytic caps between dac L+ L- R+ R- and OPA - could they be bypassed without any think to worry
I present for your perusal, and probable amusement :lol: my 1rst DIY audio project: The one, The only............... 2xUGLY-2xDAC.
Go here to :stalks:
http://s713.photobucket.com/albums/w.../2xUGLY-2xDAC/
This thread and the Lampizator's site were my primary inspirations. Initial plan was just to get one working as delivered. SQ was better than anything I ever had, but it quit working in short order. Leo's comment about having trouble w/the stock RCA digital in jack reminded of another post about 75ohm BNC jacks & proper cable (I used RG/6u) being superior for digital signals. Implementation promptly brought the DAC back to life, and what's this? It sounds better!
You guys know how it goes now, the story begins to tell itself. Mod-itis has set in. Ok, I need to get the LM4562 optimized, and get that DC offset squared away, but first I'll poke a Lampucera in there to compare to the opamp version, and this, and that, and then something else...... but then I got spooked by how easy it is to mess this thing up. If you look closely at the tube DAC, you'll see where I had to go the CS4397 leg directly for one of the inputs to the 6n6p, yep lifted a track when removing C27. Man, that thing is like a hair. My cd playback was already so much better than anything I was used to, I was able to allow myself to divert to some long put off speaker projects.
Well, enough speaker projects are done that my attention is drifting back to the 2xUGLY-2xDAC. Think I'll start back w/some of the more fundamental stuff like getting some correct components in to fix the DC offset and enhance the digital lock in for the receiver chip.
My electronics expertise barely extends beyond being able to solder, but w/access to resources like The Art of Sound, I can do much more than I would have even considered otherwise. Thanks guys, not only am I having a ball with this thing, my system sounds better that I ever thought it would.
Questions, comments, jokes (funny ones) are very welcome.
Here's to you, boys! :cool:
Very nice!
One question though, what's the light dimmer for?
This all goes way over my head Mace, but one of the photo captions says "Yes, that's a household lighting dimmer. I didn't have an assortment of resistors to trim heater voltage, but had the dimmer laying around being useless."
Interesting project, Mazeppa.
Excellent stuff!
Most of my stuff starts off just bolted to a wooden chopping board often looking well ugly but allows easy modding
Quote:
Originally Posted by mace
Tube filament and heater are supplied by individual xformers. Optimal heater voltage for 6n6p is 6.3v. My 115v/6.3v heater xformer yielded 7.6v in circuit as household supply is slightly over 120v. Lighting dimmer was placed in series w/the high side xformer winding to provide adjustment to desired 6.3v.Quote:
Originally Posted by Alex_UK
BTW: In comparing the opamp DAC to the tuber, one large difference I noticed was greater bass output from the tubed DAC. While shopping e-bay for some different 6n6p's for spares and trials for SQ differences, included in a pitch for his (a fella in Ukraine) wares, it was noted that 6n6p tubes accentuate bass frequencies. Hmmmmmm.
Leo, you mentioned trying the Lampucera, I believe. Could this (reported bass freq. enhancement) be the source of the coloration you noted?
BTWII: The tube DAC is much preferred so far, but I strongly suspect I've yet to hear the LM4562 at its best.
Hi, I found Lukasz Fikusz's pages approx 4 months ago. There are many interesting stuff over there, and I decided to give a try to "Lampucera 1.0" project (because of the cheapest one :-)). After a while,, I bought a mini DAC board only, and upgraded the smd parts. The sound of the DAC is good, but the balanced version is even better, smooth, lovely, dynamic, analog like! I steal the signal from L-, L+, R-, R+ points, followed by GE 330 nF/850 V capacitors. The signal goes to a (DIY :-) Balanced Bride of Son of Zen preamp . Important, that the power source is an 6 V SLB (Sealed Lead) battery with special stab circuit giving regulated 5 Volts. On the picture the black labels shows one board made to my friend; the red substitutions are my one DAC. I also think to replace/add tantal caps to Wima-s and maybe to try the lamped version. János
Here's mine unmodified board..
http://ekke.kapsi.fi/temp/CS4397/cs4397_tn.jpg
http://ekke.kapsi.fi/temp/CS4397/cs4397_bottom_tn.jpg
Bigger versions here: Top (1.9MB) & bottom (1.5MB)
Now I just need to figure out what to do with it.. There seems to be some changes to 1. post like led and R28 & R29 and some additional components between CS-chips..
LeoQuote:
Originally Posted by leo
would you please explain
1) PLL values coming with dacs are wrong BUT some say that they are right for 32 - 44.1 KHz and the new values are right for 96 Khz mode ?
2) OPA filter values R8,R9,R14,R17 to 30k and C32,C33,C34,C35 to 150pf are correct for all OPA types Incl LM4562
3) R28 and R29 should be missing means that they have to be removed - why ?
4) C3, C18, C11 can be left alone (Just pulling pins high) - removed ? c18 Is 100/16 between c3 and c11
5) C12, C8, C13, C10, C14(C41) bypass with MKP 0.1uF - add a new cap or first remove smd cap ?
regards
Hey. Remove all r´s and c´s in the analog section and r23,c1,c4,d2. and cd4053 below, (neg. supply) and add 8 2.2K resistors. LM4562 opamp. ~2mv dc at output. Look at the PDF. Plays wonderfull. Anders.