Opening the new DacMagic???? - Page 6

Glenn2 · 24th April 2010, 07:18 PM

Yes the analogue circuit is identical even in terms of part labels.
The actual values of the capacitors and resistors are different though, as is necessitated by the 192kHz upsampling vs the 384kHz of the 740C.

What Ianmac has planned doesn't make a whole lot of sense to me though, unless I'm missing something. So the phono stage (with RIAA eq) is to be fed into an analogue low-pass filter with balanced inputs? Is the FM source balanced too?

The analogue stage as it is has no gain to speak of too.

Another thing, the SMD components are small and hard to get to.

What you are proposing is something I personally wouldn't attempt even if I thought it was a good idea.

But in the true spirit of DIY, don't let me put you off!

Glenn

Ianmac · 24th April 2010, 09:01 PM

Apologies If I have not made myself clear

I am looking for the same functionality from my DAcmagic as one gets from cyrus DACXP or a Benchmark Pre.
The ability to process Spdif and Toslink inputs plus two analog inputs from my FM tuner and Phono amp
I need balanced outputs to drive my Hypex mono amps and a gain/attenuation facility to accomodate the differences in level from all input sources.
The analoge inputs will be unbalanced and need to be electronically converted to balanced. Three crosspoints (dual for balanced) will be needed to allow selection of DAC output or tuner or phono. This could possibly go in between the DAC output and balanced output stage.
Looking at the comments on power supply issues it seemed logical to me to address these at the same time thus my looking for a complete diagram so I get a full picture of the Dacmagic.
Like your avatar hope its real 625 pal

Ianmac

Glenn2 · 24th April 2010, 11:01 PM

OK, I don't really see how it can be done with this circuit, at least to good effect, but happy to be proved wrong!
The circuit takes two pairs of balanced signals (there's a dual differential DAC per channel) to produce one. So each pair of balanced signals is processed by a differential op-amp circuit.
DAC L+ & DAC L- ==> DAC L+
DAC L- & DAC L+ ==> DAC L-
DAC R+ & DAC R- ==> DAC R+
DAC R- & DAC R+ ==> DAC R-
I don't see where/how you can bring in your FM/phono signals.

EC8010 · 25th April 2010, 08:52 AM

I'll slap myself over the wrist for going off-topic later, but as there's been a comment about test cards, here's another.

Glenn2 · 25th April 2010, 02:04 PM

Carole Hersee, then and now:

Mihaylov · 3rd May 2010, 07:26 PM

I think that it is the best way to output the signal from XLR.
03.05.jpg 03.05_.jpg

http://www.lynxstudio.com/nav/getFil...&t=productfile

White Mike · 27th May 2010, 02:49 AM

Quote:

Originally Posted by Glenn2

Quoting from the first page...

...guess what's in the box on top?

That is a very tidy solution! I like it.

How does the Zapfilter sound with the DM?

2betton2 · 8th September 2010, 08:24 PM

Could someone dump for me his dacmagic eprom?
You can't get this part in service because Cambridge don't sell it separately (only complete main PCB) and it is one component which you don't buy in ordinary shop (24lc256 of course, but not programed).
In my dacmagic power supply (stabs on main board) has broke down (probably the reason was voltage surge) and burned few components. I have changed it, but eprom is dead (dacs probably work and receiver too). I don't know if DSP is broken, but without EEPRON I couldn't test it.
This is simple to do and wouldn't take much time. EPROM is easy to remove (socket) and if you want, you can make the programmer by yourself (JDM and serial port in computer). No one of my friends is dacmagic owner and on polish DIY forum I didn't receive any answer. This DIY community is a very famous one, and I hope to find someone to help me. Thank you in advance.

Fatmangolf · 16th October 2010, 05:47 PM

Thanks for sharing this information, I just opened my DACMagic to bypass the caps. You helped me to get an immediate improvement

and saved me a lot of experimentation.

I couldn't get the service manual from the link given. Does anyone have a copy they can send me, please?

Fatmangolf · 16th October 2010, 07:54 PM

Has anyone replaced the 10uF NP caps (not the PS filter caps) between the 2 DACs and the filters? I assume this will improve the clarity, but there is limited space so what did you use for this? And is it worth it?

BTW Ian Mac, your postings on VE inspired me to do a lot of beneficial work on a CA 540P and then rebuild a 640P.

Thank you very much!

16th October 2010, 05:47 PM	#59
Fatmangolf diyAudio Member Join Date: Oct 2010	Grateful new arrival seeks service manual Thanks for sharing this information, I just opened my DACMagic to bypass the caps. You helped me to get an immediate improvement and saved me a lot of experimentation. I couldn't get the service manual from the link given. Does anyone have a copy they can send me, please?

16th October 2010, 07:54 PM	#60
Fatmangolf diyAudio Member Join Date: Oct 2010	The other coupling caps in DACMagic Has anyone replaced the 10uF NP caps (not the PS filter caps) between the 2 DACs and the filters? I assume this will improve the clarity, but there is limited space so what did you use for this? And is it worth it? BTW Ian Mac, your postings on VE inspired me to do a lot of beneficial work on a CA 540P and then rebuild a 640P. Thank you very much!

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24th April 2010, 07:18 PM	#51
Glenn2 diyAudio Member Join Date: Oct 2006 Location: London, UK	Yes the analogue circuit is identical even in terms of part labels. The actual values of the capacitors and resistors are different though, as is necessitated by the 192kHz upsampling vs the 384kHz of the 740C. What Ianmac has planned doesn't make a whole lot of sense to me though, unless I'm missing something. So the phono stage (with RIAA eq) is to be fed into an analogue low-pass filter with balanced inputs? Is the FM source balanced too? The analogue stage as it is has no gain to speak of too. Another thing, the SMD components are small and hard to get to. What you are proposing is something I personally wouldn't attempt even if I thought it was a good idea. But in the true spirit of DIY, don't let me put you off! Glenn

24th April 2010, 09:01 PM	#52
Ianmac diyAudio Member Join Date: Jul 2007 Location: Ayrshire	Apologies If I have not made myself clear I am looking for the same functionality from my DAcmagic as one gets from cyrus DACXP or a Benchmark Pre. The ability to process Spdif and Toslink inputs plus two analog inputs from my FM tuner and Phono amp I need balanced outputs to drive my Hypex mono amps and a gain/attenuation facility to accomodate the differences in level from all input sources. The analoge inputs will be unbalanced and need to be electronically converted to balanced. Three crosspoints (dual for balanced) will be needed to allow selection of DAC output or tuner or phono. This could possibly go in between the DAC output and balanced output stage. Looking at the comments on power supply issues it seemed logical to me to address these at the same time thus my looking for a complete diagram so I get a full picture of the Dacmagic. Like your avatar hope its real 625 pal Ianmac

24th April 2010, 11:01 PM	#53
Glenn2 diyAudio Member Join Date: Oct 2006 Location: London, UK	OK, I don't really see how it can be done with this circuit, at least to good effect, but happy to be proved wrong! The circuit takes two pairs of balanced signals (there's a dual differential DAC per channel) to produce one. So each pair of balanced signals is processed by a differential op-amp circuit. DAC L+ & DAC L- ==> DAC L+ DAC L- & DAC L+ ==> DAC L- DAC R+ & DAC R- ==> DAC R+ DAC R- & DAC R+ ==> DAC R- I don't see where/how you can bring in your FM/phono signals.

25th April 2010, 02:04 PM	#55
Glenn2 diyAudio Member Join Date: Oct 2006 Location: London, UK	Carole Hersee, then and now:

3rd May 2010, 07:26 PM	#56
Mihaylov diyAudio Member Join Date: Jul 2009 Location: Moscow	I think that it is the best way to output the signal from XLR. 03.05.jpg 03.05_.jpg http://www.lynxstudio.com/nav/getFil...&t=productfile

8th September 2010, 08:24 PM	#58
2betton2 diyAudio Member Join Date: Dec 2009 Location: Krakow - Poland	Could someone dump for me his dacmagic eprom? You can't get this part in service because Cambridge don't sell it separately (only complete main PCB) and it is one component which you don't buy in ordinary shop (24lc256 of course, but not programed). In my dacmagic power supply (stabs on main board) has broke down (probably the reason was voltage surge) and burned few components. I have changed it, but eprom is dead (dacs probably work and receiver too). I don't know if DSP is broken, but without EEPRON I couldn't test it. This is simple to do and wouldn't take much time. EPROM is easy to remove (socket) and if you want, you can make the programmer by yourself (JDM and serial port in computer). No one of my friends is dacmagic owner and on polish DIY forum I didn't receive any answer. This DIY community is a very famous one, and I hope to find someone to help me. Thank you in advance.

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