Andre,
It's not for computer I am testing in my main system. I can use the balance control there. But I want to find and fix the source of the problem. That is my experiment. To see if I can do this, with little help of course.
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Andre,
It's not for computer I am testing in my main system. I can use the balance control there. But I want to find and fix the source of the problem. That is my experiment. To see if I can do this, with little help of course.
Leo's yer manQuote:
Originally Posted by Bodran
http://theartofsound.net/forum/showthread.php?t=315
Quote:
Originally Posted by Bodran
It could be caused by a few things, example incorrect or drifted value resistor in the output stage, fb resistor etc, one channel of the dac chip output maybe faulty or maybe loaded down too much.
Also check the soldering especially around the dac chip
Is the input voltage to the left and right channel op-amp the same? (inverted and non inverted input not the supply)
The voltage regs feeds both channels so if one was faulty it would affect both channels
dismantled all the previous mods and installed for another time some new some old twek nothing changed.
if can help anyone where is the led i measure 3,4-3,5v with the optical input and 1,3-1,35v when there is the jump on coax input.
:scratch: but nothing.
thanks
Did you select the jumper/link in the socket for co-ax input?
hi leo,
where is the supply input socket(+5 -12 +12 etc etc) there is also the socket for the choice of input.
correct?
. . . like this(over view) 3 points.
one side coax and one side optical: correct?
when i jump the 2 legs for the optical input i find about 3-3,5v where is the led, when i jump the coax 1,2-1,25v in the same place.
today the last famous words of my lampucera have been: bzzz tick tock bzzzz and after the SILENCE.
i think once and for all dead.
thanks for support and sorry.
Hi Leo,Quote:
Originally Posted by leo
Thanks for taking the time to help here.
Problem solved. You are gonna love this ……..….. it was the crappy pin connector on the cable from the board to the RCA, specifically the half on the cable.
Your suggestions stimulated me to action, so I looked up the datasheet to identify the input pins and off I went. This is how I measured the op amp input and output voltages. Please tell me if method is valid.
I used the stereophile test disc on track 20 repeating at constant volume. Measuring AC voltage from each individual pin to AG at the output RCA, all four inputs, pins 2, 3, 5 & 6, were equal at .057v and output pin 1 was .335v while pin 7 was .331v. Is 4mv difference significant?
So it’s not the dac or the op amp lets check the output at the RCA, there is a big difference l versus r which after all is the problem. Now where is it? I separated the halves of connector J6 and measured l & r outputs to AG and they were equal. Bingo problem isolated. So I pulled the pins from the other half and gave them an extra crimp and now all is well.
Coming back to the supplied power supply if my measured -16.4v is correct then somehow they make the -12v higher than the +12v, even though both are 12v regulators (7812 & 7912). Is that possible? Then -5v is derived by a drop across R23. Does that leaves -12v remaining or is there something else dropping it back to -12v?
Regards,
Hi Alan,
The -16.4V is incorrect. I think that is the same voltage you would have before the 7912 reg..
Check the soldering of the 7912 regs centre pin (ground)..
Thanks BarryQuote:
Originally Posted by audio1st
The transformer datasheet confirms that 16.39v is the secondary no load voltage. My mistake was that the pin out of 7912 is different to 7812. For 7912 the center pin is the input. When I measure the correct pins the voltage is fine.
Regards,
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.
To big pdf.
At last:)
Too low quality. :)
New pdf.
Hi everybody. I have a CS4397 dac with the following mods: All electrolytics replaced with oscons at the digital section. Bypass the analog stage by removing C27,28,30,31 and connecting two scr mkp caps directly from the cs4397 (AOUTR-, AOUTL-) to the output RCAs. It was working great for weeks, but suddenly the following problem appeared: I get strong noise (like an impulse signal) when changing to the next track of a cd. During a track's playback everything is ok. Changing to the next track gives a strong noise, and the woofer gets displaced out to its limits, like dc is passing to the speakers for a very short period of time, which does not make much sense since i have dc blocking capacitors at the outputs.
While this noise is heard, i measure the chip's output dc falling from 2.5V to approx 2.0V dc and then it gets back to normal 2.5V. This is when measuring directly the output pins (AOUTR- for example). When i measure AFTER the dc blocking capacitors that i have added, the voltage is 0V dc (as expected) but when the noise happens the analog voltmeter indicates a negative voltage, like a negative impulse signal. Check the following video to see what i mean. I measure the voltage on my rca outputs (= after the dc blocking capacitor) and the needle is on 0V. I press the "next track" button and the needle moves to negative voltage for a while.
http://www.youtube.com/watch?v=Be4j2biZPgU
I measure the voltage on C3 and it remains stable when the noise happens. I measure on C25 and the voltage drops when i change track. If i change tracks many times continuously (pressing the next track button 2-3 times per second) the voltage drops more each time i change the track (like something sucks much current instantly) and when i stop changing tracks the voltage gets back to normal. I increased the C25 to 150uF and the voltage drop is quite smaller but the noise is still quite strong and the woofers pop out to their Xmax
I re soldered most of the connections (input rca, power supplies etc) with no improvement. The same happens when i connect the dac to my computer and play a sound file. At the beginning and the end of the file the "tsak" noise happens and the woofers stick out. It seems like when the spdif is initiated or stopped the noise is heard.
Any ideas what could be wrong?
and this is when measuring directly the chip's output: The voltage is stable at 2.5V (needle stays at the right corner, maximum of the scale). I press the play button on the cd and 3 impulse noises happen, and the voltage drops down to 2V for three times, and then the track starts playing.
http://www.youtube.com/watch?v=5FeucajR6is
Hi all. Lots of good info on modifying this dac!
I was wondering if there are any recommendations for a replacement power supply for this dac, preferably diy?
Hi DIY-ers, happy to post, that the sound of my mini DAC is improved further (see #417 ). The foil GE-s were replaced to 0.33 uF Mundorf Silver/Oil. It makes the total project pricier, but the song of mini’s turns to another league! I have very good results using Russian military silver mica KSZG caps right now: 100 nF/500 V. I found them very close (or better) to Mundorfs at lesser price! There is question showed up about the values of C25, C16. I replaced Yageo at C25 to Blackgates (2x10 uF) and left C16 (OsCon 150 uF). There was a nice, clear sound, and! deeper bass. But, during long listening I found the sound tiresome (if it is the correct word for). Lampizator’s advice was chosen; I put 100 uF OsCon at C25. I know, the value is much higher than the factory recommendation. The sound is very relaxing, nice, there is a bit less bass but easy to listen for 2-3 hours. It is not slowed down, as was mentioned earlier. Did you find similar results?
Hi from a newcomer. :)
I hope that someone will give me a helping hand. After soldering a new C8 capacitor I noticed that there is no voltage on the soldering pads. The voltage should be the same as on pin 26 on CS4397 chip, right ?
Hi, I am experienced using Mundorf Silver/Oil and KSG capacitors further. I think, despite of high respect of Mundorf S/O, they colors the sound a lot, KCG-s do as well, maybe not that much. There is a very important capacitor, namely C9 (DC blocking capacitor) just in SERIES in the signal path. I got some Russian military SSG-3 (CCГ-3) 126 nF/350 V Silver Mica’s from Vilnius. Because of their size, I made a new rout to receiver chip via a BNC terminal installed (do not forget there is a 75 ohm between signal to ground just before silver mica). I put 0,252 nF CCГ-3 silver Mica’s (C9). The result is surprisingly good (stunning). I highly recommend trying this tweak. János (to get CCГ-3, search on US e-bay)
Any comments on whether this DAC really needs an output stage LPF to eliminate 400Khz noise that some people refer to?
anyone news about the plopping as described above? I do have the same problem when connected via toslink to my Ac Ryan mediaplayer.
Is there somethink we can change? looks like the dac is having problems to lock on the signal the mediaplayer provides.
please help!
hi janos can you explain a bit clearer what you did with the silver mica on c9????I think I would like to give it a go but cannot understand what you have done...alanQuote:
Originally Posted by janos_904
Nice to see the modding is still going quite strong for these dacs, I've not used mine for a while (its currently on loan) so may have a bash at another
Just a note to the new members, can you please pop into the welcome section of the forum to keep the site owners happy :)
I can't remember all the part numbers for the dac but I presume C9 is for the SPDIF input coupling
I recently did a passive mod to this dac. Not bad.
Agree, not bad for a cheapie
Hi 'AndersN', 'Ekke', 'yiannis', 'fandersen', 'BlackNight', 'kput', 'hansr', 'belgiangenius' and 'janos_904',
Welcome to AOS :)
Could you please pop into the Welcome area and introduce yourself to our community by supplying your proper first name, basic geographical location, system details and music tastes, as this is the requirement for all new members joining AOS.
Cheers! :cool:
Marco.
After successfully building one of these DACs -- thanks Leo, et al -- I ended up at diyaudio to learn about bypassing the opamp with transformers. The diyAudio thread is very long but full of info on implementing transformers. I ended up installing Jensen JT-11p-1 transformers but there are lots of options. IMO, a worthwhile upgrade.
Hi 'fandersen',
Please see my post above and pop into the Welcome area and introduce yourself before posting any further on the main forum. You are joining a community here, not simply an information resource to use at your leisure.
This also applies to other new members who've posted here and haven't yet introduced themselves properly. I would ask that you observe the required protocol.
Thank you :)
Marco.
Yup, I did (based on your earlier post). I apologize for not doing this at the start but I think we all start by lurking a bit and then get wrapped up in the wealth of knowledge on the forum. I'm still very much a newbie in diy audio but learning quickly and hoping to one day contribute more than just my enthusiasm for this hobby.Quote:
Originally Posted by Marco
Do you have any pics of these mods? Welcome by the way.Quote:
Originally Posted by fandersen
Rob.
I used an old CD player to house the DAC as I wasn't concerned about cramming everything into a small box. The CD player also had a decent power transformer that had an 8v output that I ran through a TREAD power regulator to give me a nice clean 5v for the DAC. Since I was bypassing the output stage I didn't have to worry about the 12v.Quote:
Originally Posted by Puffin
Initially I ran the DAC with an opamp, hence the mods that are still on the board for the output. The transforms are connected to the C27, C28, C30, and C31 connections. The input and output filters are based on Jensen recommendations for these transformers.
Hmm.... the images didn't make it on the last post :scratch:
Thanks for the pics. Might try it meself.Quote:
Originally Posted by fandersen
Rob.
Hi, Sorry for my post to be unclear. So, I made an a new spdif input for the DAC. The signal path is the following: BNC (RCA) inlet, Silver Mica in series, and the output leg of the capacitor soldered by a fine silver wire (or by copper) directly to the CS8416 Receiver chip signal input leg. I will make a photo, how it is looks like. After a test period and some advices, I decided to use 10 nF Silver Mica capacitor insteed. (0.01uF 350V 0.3% tol. Russian millitary SILVER-MICA capacitor). It makes a great job, the signal shape is not affected, I recommend it highly. Cheers, JánosQuote:
Originally Posted by kput
Dear Leo, I recommend to re-play with this small board. First of all, please design separated (dedicated) 5V, and 3,3 V power supplies, using low noise power regulators. At the receiver chip in the 3,3 V line advicable to use Os-Con very low ESR polimer capacitors (SEP, SEPC). And the DAC rocks :-). May be you are the only one, who could compare this one to Buffalo. But just after the modds listed above. Cheers, János
Hi János ,
I have another one of these dac boards so will start modding it soon. I may even try the Paul Hynes regs with it :lolsign:
Hi, here goes a photo to help to isolate power lines. It was taken from a polish diy forum. My polish is poor, but the label is may be not correct :-)! On the picture the labeled line goes directly to the Vref leg of the DAC chip. I disconnected it by a sharp blade, and soldered a new 5 V power inlet, according to the green arrow. Be careful, not to cut deep and wide, because of the ground is close. The +5 V analog of the DAC goes at the under-side of the board. It is good to separate too. Now, we can install and connect separated 5 V supply for DAC chip. Don't forget: the receiver still needs 5 V (3.3 V fits too, or not enough?), because to choose one of the spdif input (optical or coax).
Hi, I have to correct my last post. So, both the DAC's analog power (number 28) and voltage reference (number 22) pins are connected by the very same via. That is the worst case for an a voltage out DAC. I guess, the only way to provide a nice VOLTAGE REFERENCE to the DAC is: simply lift up the reference pin, and connect it to our voltage reference source directly. The song of Cs4397 benefits a lot by dedicated (separated) voltage reference.
I have given every major power point to each chip its own, LT317 regulated power supply...thats 6 independent battery powered feeds. I have used silver mica on c9....the sound was at first harsh...I walked away for a few hours , started to sound shockingly good.....eventually I had to recharge my tripath amp batteries, I did not touch the dac board, but when I turned back on...NOTHING.....
1)all the pins on the chips that need voltage are getting what they require
2)have continuity from the digital input and analogue out puts
3)have signal entering the reciever chip
4)have 2.5v dc on the analogue outputs but no AC
5)cannot understand the transistor near c21. I suspect this as it has something to do with the mute function...On the circuit diagram it shows one pin of the transistor connected to pin15(dac), one pion connected to pin 14 of the reciever chip and one pin connected to ground...I cannot find any of my pins on that transistor connected to ground
can any one help...as it was initially working it must be just some stupid mistake I have madehttp://www.lampizator.eu/LAMPIZATOR/...ampizator.html