PeteM said:
Wow that's mighty quick deliveryOnly here you mention something to the contrary 3 DAYS AGO
Sorry you comment here smells funny
I dont like the sound of what you're implying Pete? do I have any reason to lie?
delivery time is the only good thing about it, I ordered it on the 3rd and it arrived the morning of the 5th, not bad from hong kong, still not impressed and no I havent tried it on the battery supply, I had to use the supplied 12v AC adapted to fit a UK socket. I suppose I can try it with a battery but it will cost 1/3 of the price of the DAC, will the performance increase justify the cost? I'm willing to wager no.
Hi Matt
I never used it with the delivered PSU, and I did not recommend it.
Even Mr. Wu is recommending using another PSU eg. Batteries.
Dont forget: I was talking about a nice module to use for DIY.
My recommendation to you: take a 12VAC tranny followed by a bridge or diode rectifier, some 1000uF or more cap followed by a LM7812 followed by some 1uF or more as PSU.
Afterwards, I will be very interested in your comment.
Regards
Franz
P.S.
Actually I am messing around with a humming audio stage
I never used it with the delivered PSU, and I did not recommend it.
Even Mr. Wu is recommending using another PSU eg. Batteries.
Dont forget: I was talking about a nice module to use for DIY.
My recommendation to you: take a 12VAC tranny followed by a bridge or diode rectifier, some 1000uF or more cap followed by a LM7812 followed by some 1uF or more as PSU.
Afterwards, I will be very interested in your comment.
Regards
Franz
P.S.
Actually I am messing around with a humming audio stage
Attachments
matt J said:
I wonder if you are expecting too much from such a cheap DAC given that you are running a pretty good cd player already. I looked at it as a way of making my 15 year old Pioneer cd player sound ok for a small outlay. It has done that well. From what I understand, power supply is critical to make these dacs sound good, so maybe you will notice a difference running it from a battery.
Franz G said:
Hi Franz,
Thanks for the DIY tips, unfortunately all the above is like a foreign language to me
I'm supposed to be learning electronics, just havent got round to starting yet.
as for the comment about the CDP, the CD67 was only an entry ish level CDP when I bought it about 7-8 years ago, its hardly a great player, its also supposed to respond well to mods bu tI got told I'd gain even more from the addition of an external DAC thats why I tried this one.
Its probably a good base for you modders, but straight out of the box its pretty average.
oszillating opamp?
Hello Everybody
After first positive feedbacks in here about this little DAC I thought I’ll give it a try.
It arrived (in Switzerland) two days after ordering.
First listening impression were very positive, my “Noxon” (network audio player / Terratec) sounded much better with this green little box than through its original analogue outputs.
Anyway, I turned the volume a little over normal listening levels without any digital input signal, just to see whether this DAC really operates quiet or there may be any noise or hiss.
Then, the disaster happened: Both the ribbon tweeters went up in smoke. As you can imagine I really feel more than fooled.
The problem seems to be an oscillating opamp. The multimeter shows around 4 volts AC from analogue output to ground, on both left and right channel. I don’t have an oscilloscope so that’s all I can say right now.
What’s next: I think I’ll try to reverse engineer the DAC or at least its output stage, hopefully this will bring some more insights.
I wonder if other people’s DACs have similar problems or work flawless.
Regards
Mario
Hello Everybody
After first positive feedbacks in here about this little DAC I thought I’ll give it a try.
It arrived (in Switzerland) two days after ordering.
First listening impression were very positive, my “Noxon” (network audio player / Terratec) sounded much better with this green little box than through its original analogue outputs.
Anyway, I turned the volume a little over normal listening levels without any digital input signal, just to see whether this DAC really operates quiet or there may be any noise or hiss.
Then, the disaster happened: Both the ribbon tweeters went up in smoke. As you can imagine I really feel more than fooled.
The problem seems to be an oscillating opamp. The multimeter shows around 4 volts AC from analogue output to ground, on both left and right channel. I don’t have an oscilloscope so that’s all I can say right now.
What’s next: I think I’ll try to reverse engineer the DAC or at least its output stage, hopefully this will bring some more insights.
I wonder if other people’s DACs have similar problems or work flawless.
Regards
Mario
Stripboard and HT.
Hi Franz,
Stripboard with copper can't hold up much voltage. My very beautiful AM transmitter with sub.min. tubes died that way. If you use a board without copper it will be fine. So my guess is that the stripboard is the culpit.
Also I used a selenrectifier, guess what happend when the RF amp tube shorted out...
Got rid of that hum?
Best regards,
Magnus
Hi Franz,
Stripboard with copper can't hold up much voltage. My very beautiful AM transmitter with sub.min. tubes died that way. If you use a board without copper it will be fine. So my guess is that the stripboard is the culpit.
Also I used a selenrectifier, guess what happend when the RF amp tube shorted out...
Got rid of that hum?
Best regards,
Magnus
Uuuups!
I noted some hiss, when no player is connected. But even when some oscillation occurs, it was your poweramp clipping and delivering DC to the tweeters. So your audio chain is some kind of dangerous for the speakers, isn't it?
What power supply did you use for the DAC?
As I dont have an original DAC in the box right now, I cannot measure with my scope. But I will ask a friend who bought one of this boxes.
Yes, I think the same. Thats why I changed the setup.
No, I did not have time for more investigation. Maybe next weekend. It must be some oscillation, even when I disconnect the DAC completely and test just one channel.
Kind regards
Franz
Yes, now I did get rid of it
The reason was some oscillation. I removed the filter caps C1 and C2 I inserted according to the last schematic in John Broskies blog 75 (Balanced DAC & Filtered Broskie Cathode Follower).
John Broskies Blog 75
Actually I am driving the DAC without filtering. It sounds great but I still miss some dynamics and I have the impression, to have some lowpass "filter" somewhere in the circuit.
Franz
It took a while to get my AC-voltage problem fixed - but it’s finally done.
Removing the four small SMD Caps in the output stage located on the bottom side of the board solved the problem.
I’ve e-mailed Eddie Wu about this issue. He told me it was the first time something like that happened and my purchase wouldn’t be charged.
Yesterday I’ve added an external output stage (a simple op amp based differential amplifier, +/- 12V supply). Although I first intended to keep everything inside the tiny little box I thought it might be better to redesign the analog section to get rid of the coupling capacitors. Well, first listening impressions confirmed that it’s been a worthwhile modification.
I'll do some serious listening tests next days ...
Regards, Mario
Removing the four small SMD Caps in the output stage located on the bottom side of the board solved the problem.
I’ve e-mailed Eddie Wu about this issue. He told me it was the first time something like that happened and my purchase wouldn’t be charged.
Yesterday I’ve added an external output stage (a simple op amp based differential amplifier, +/- 12V supply). Although I first intended to keep everything inside the tiny little box I thought it might be better to redesign the analog section to get rid of the coupling capacitors. Well, first listening impressions confirmed that it’s been a worthwhile modification.
I'll do some serious listening tests next days ...
Regards, Mario
Attachments
Hi Mario
Very good news! We should compare our two breadboards in a listening test, as we don't live to far from together!
My broskie cathode follower version is working now perfectly!
I made a silly mistake and inverted the right channel, resulting in some cancellation effects.
Here I attach the corrected view.
Franz
/Edit: I used for the picture the same filename as in post #15, replacing the wrong picture.
Very good news! We should compare our two breadboards in a listening test, as we don't live to far from together!
My broskie cathode follower version is working now perfectly!
I made a silly mistake and inverted the right channel, resulting in some cancellation effects.
Here I attach the corrected view.
Franz
/Edit: I used for the picture the same filename as in post #15, replacing the wrong picture.
Attachments
Turning sow's ears into silk purses is always a commendable endeavour but the following passage is pure nonsense:
As for myself, i don't believe an external spdif dac built with complete desregard towards jitter, layout or component quality stands a chance against any moderately good cd player.
If you really like to test a CS4397 why not bulid the dac from scratch without the ridiculous confines imposed by the $59 retail?
What is $59 retail+shipping+customs extortion worth in component cost? $10?
PS i have an original dac-in-the-box somewhere. Yes, it sounds worse than any cd player i've ever owned but it is a product of real engineering - well developed circuit and decent components. It even has some resale value.
Franz G said:
As for myself, i don't believe an external spdif dac built with complete desregard towards jitter, layout or component quality stands a chance against any moderately good cd player.
If you really like to test a CS4397 why not bulid the dac from scratch without the ridiculous confines imposed by the $59 retail?
What is $59 retail+shipping+customs extortion worth in component cost? $10?
PS i have an original dac-in-the-box somewhere. Yes, it sounds worse than any cd player i've ever owned but it is a product of real engineering - well developed circuit and decent components. It even has some resale value.
As spartacus mentioned: fun, educational and a challenge, at least for myself
What do you mean with a "massive power supply"? A tranny, a rectifier, a choke and an electrolytic cap? What is massive?
I dont understand your point of view. Every part for my tube buffer comes out of my hobby box, I just bought this chinese DAC and 6 caps.
BTW: you are invited to visit me and to try to destroy my tweeters with a source signal.
Regards
Franz
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.