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Cambridge DACMagic, anyone? (THREAD II) - Page 39

post #571 of 642
Quote:
Originally Posted by FauDrei View Post

Something like that, yes.

 

...although, I'd rather make it 1x 25-40 VAC.


do the capacitors support that voltage? i'm afraid they'll blow up..and, where can you get 1x24V toroid?? i can only find this one: http://malaysia.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2237822
 

Quote:
Originally Posted by ccbass View Post

Anybody get their DACMagic modified?

 

And what did you do to it?


i had modded dacmagic once..the 4x ne5532 were replaced with 4x LM4562, then the output capacitors were bypassed, big improvement over the stock version in my opinion

 

i have another dacmagic at the moment, and i'm planning to do the same, plus i want to upgrade the psu as well. it think psu will provide even bigger improvement than the previous mod

 


Edited by i_djoel2000 - 5/27/11 at 10:51pm
post #572 of 642
Originally Posted by i_djoel2000 View Post


do the capacitors support that voltage? i'm afraid they'll blow up..and, where can you get 1x24V toroid?? i can only find this one: http://malaysia.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2237822
 


Sorry, my mistake... I've meant 25-40 VA (volt-ampere) as power rating, not 25 V - 40 V AC - this would most certainly blow the internal DacMagic fuse. Of course, you should aim for 12 V AC on secondary.

 

As for modifications, there is a whole thread on DIYaudio on the very topic - mods ranging from swapping PSU and using XLR outputs to complete internal rehaul with external DC PSU.

 

I was very pleased with just output cap bypass, beefier PSU and using XLR outputs. After that I've done the cap swap thing, but, IMO, it does not improve things in a way that can justify the soldering iron hassle or the money some companies ask for the same thing. I also reckon super-regs mod and 8x AD797BRZ on browndog adaptors would substantially improve DacMagic, but, again IMO, not worth the additional money (each AD797BRZ goes for 12-15€) you throw in DacMagic.

post #573 of 642

Any recs on a better PSU?  I'm in the USA, so I'd need a 110V PSU. 

post #574 of 642
Quote:
Originally Posted by ccbass View Post

Any recs on a better PSU?  I'm in the USA, so I'd need a 110V PSU. 

i got mine custom built on ebay

 

custom.cables.uk
 

 

post #575 of 642
Quote:
Originally Posted by FauDrei View Post


Sorry, my mistake... I've meant 25-40 VA (volt-ampere) as power rating, not 25 V - 40 V AC - this would most certainly blow the internal DacMagic fuse. Of course, you should aim for 12 V AC on secondary.

 

As for modifications, there is a whole thread on DIYaudio on the very topic - mods ranging from swapping PSU and using XLR outputs to complete internal rehaul with external DC PSU.

 

I was very pleased with just output cap bypass, beefier PSU and using XLR outputs. After that I've done the cap swap thing, but, IMO, it does not improve things in a way that can justify the soldering iron hassle or the money some companies ask for the same thing. I also reckon super-regs mod and 8x AD797BRZ on browndog adaptors would substantially improve DacMagic, but, again IMO, not worth the additional money (each AD797BRZ goes for 12-15€) you throw in DacMagic.


i see..

 

can you point me to the place you bought your psu at? i can only find dual secondary or center tapped toroid..what are you using?

 

wait, i confused..did you do caps swapping, or bypassing? or you were doing caps swapping, then you settled with just bypassing it? to me, bypassing caps are really worth the hassle smile_phones.gif

 


Edited by i_djoel2000 - 5/28/11 at 2:02pm
post #576 of 642

Well, I already had "Little Pinkie" for my X-Can V2, so it was just plug'n'play for me. biggrin.gif

 

Hmm, perhaps I wasn't clear enough on the bypass thing...

 

On my "first opening" of DacMagic I just quick&dirt bypassed the 6 output caps with 6 pieces of wire (of course, I've checked for DC voltages across them before bypassing). Was very pleased with the audible result (vs. stock) so I left it this way quite long.

 

When "upgraditis tweakius" had biten again I went for "second opening" and replaced analogue PSU caps, caps around WM8740 chips and bypassed them with 100nF Wimas (removed from output) and Vishay 1837 polyprops. Perceived improvement was just noticeable and therefore not worth the trouble (IMO).

 

Was this explanation better?


Edited by FauDrei - 5/29/11 at 12:40pm
post #577 of 642
Quote:
Originally Posted by FauDrei View Post

Well, I already had "Little Pinkie" for my X-Can V2, so it was just plug'n'play for me. biggrin.gif

 

Hmm, perhaps I wasn't clear enough on the bypass thing...

 

On my "first opening" of DacMagic I just quick&dirt bypassed the 6 output caps with 6 pieces of wire (of course, I've checked for DC voltages across them before bypassing). Was very pleased with the audible result (vs. stock) so I left it this way quite long.

 

When "upgraditis tweakius" had biten again I went for "second opening" and replaced analogue PSU caps, caps around WM8740 chips and bypassed them with 100nF Wimas (removed from output) and Vishay 1837 polyprops. Perceived improvement was just noticeable and therefore not worth the trouble (IMO).

 

Was this explanation better?


absolutely, thanks biggrin.gif

 

now i have clear imagination on what to do to my dacmagic, first thing, just let the output caps bypassedbiggrin.gif

 

post #578 of 642

For the output caps, did you fully remove them and bridge the circut with wire?

 

 

post #579 of 642
Originally Posted by ccbass View Post

For the output caps, did you fully remove them and bridge the circut with wire?


You can do that, but it's not necessary - it is enough to "short" the pins of 6 "green" electrolytic output capacitors with a piece of wire. As I said - quick&dirty... wink.gif

 

NOTE!

Before doing that you have to be sure there is less than 15-20 mV DC voltage across each output capacitor you bypass. If you are not sure or do not know what I'm talking about - do not do it.


Edited by FauDrei - 5/30/11 at 12:21am
post #580 of 642
Hello guys , I wonder if anyone has used the musical fidelity X--PSU with their dacmagic?
If any please tell me if it improved the sound and how.

Thanks
post #581 of 642
Quote:
Originally Posted by che15 View Post

Hello guys , I wonder if anyone has used the musical fidelity X--PSU with their dacmagic?
If any please tell me if it improved the sound and how.

Thanks


I center tapped the 24v AC MF V3 PSU to output 12v AC into the dacmagic.  Tighter, beefier and lower bass, better separation and a more organic midrange was the result with my K701 and HD650, it addressed some of the perception of lacking warmth compared to my other digital sources. 

post #582 of 642
Quote:
Originally Posted by FauDrei View Post


You can do that, but it's not necessary - it is enough to "short" the pins of 6 "green" electrolytic output capacitors with a piece of wire. As I said - quick&dirty... wink.gif

 

NOTE!

Before doing that you have to be sure there is less than 15-20 mV DC voltage across each output capacitor you bypass. If you are not sure or do not know what I'm talking about - do not do it.


When the unit is ON, correct?

 

If a cap fails this test, should I skip it and just bypass the others?

 

post #583 of 642

Yes, when checking DC across output caps DacMagic's board has to be on.

 

If there is more than 15 - 20 mV across one cap, I predict there will be similar situation with other caps. I would not bypass any of them in such case.

post #584 of 642
Quote:
Originally Posted by FauDrei View Post

Yes, when checking DC across output caps DacMagic's board has to be on.

 

If there is more than 15 - 20 mV across one cap, I predict there will be similar situation with other caps. I would not bypass any of them in such case.

 

Ah, I'm not familiar with the MDAC's circuts. 

 

Isn't any DC voltage bad though?
 

 

post #585 of 642

On another note, what's the wiring for XLR to RCA cables?

 

I heard that the wiring is different for the DACMagic.  You're supposed to leave the - (NEG) pin floating instead of attaching it to ground?

 

It seems my question was answered....

 

"The OP275 can be bypassed simply by taking your signal from the XLR sockets instead of the RCA sockets.
Pin 1=Gnd, Pin 2= + phase, Pin 3 = - phase.
So take signal from pins 1 and 2 and leave pin 3 alone."

 

So ground and + phase are used, but not the - phase.  Cool!


Edited by ccbass - 6/9/11 at 12:40pm
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