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Old 20th December 2005, 12:27 PM   #551
reMC is offline reMC  Netherlands
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Hi Peter,

Why didn't you take the plastic of the caps in the 5-channel Patek?
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Old 21st December 2005, 01:13 PM   #552
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Hi Peter. Just wondering if it would be possible to buy one (1) of this small green WIMA cap (3.3nF) that you use for the digital filter. I cannot find one and I'm building your DAC. I did my own PCB using your schematic and posted PCB images (thanks for sharing).

Let me know, all the others parts are already ordered.

Merry Christmas.

Bye...
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Old 21st December 2005, 02:42 PM   #553
rdf is offline rdf  Canada
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Quote:
Originally posted by Peter Daniel
While in stereo setups with a single transformer you could still use two separate boards, on more than one occasion I had reports of humming supply so I always recommend using a single rectifier board.
Hi Peter,

Have you experimented with using the copper bar as the star ground? I plan on building the premium kit around a 1000 VA Plitron when back in town after xmas and am working through the pluses and minuses of various options.
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Old 22nd December 2005, 02:16 AM   #554
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Quote:
Originally posted by reMC
Why didn't you take the plastic of the caps in the 5-channel Patek?
Maybe because I don't find it makes that much difference, beasides, customer knows what he's actually getting.


Quote:
Originally posted by Algar_emi
Hi Peter. Just wondering if it would be possible to buy one (1) of this small green WIMA cap (3.3nF) that you use for the digital filter. I cannot find one and I'm building your DAC. I did my own PCB using your schematic and posted PCB images (thanks for sharing).
I also can't get those Wima caps. I'm using Panasonics from DK, best grade polypropylene.


Quote:
Originally posted by rdf
Have you experimented with using the copper bar as the star ground? I plan on building the premium kit around a 1000 VA Plitron when back in town after xmas and am working through the pluses and minuses of various options.
I never tried that. Quality of ground return wires is imporatant though.
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Old 22nd December 2005, 05:17 AM   #555
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Quote:
Originally posted by rdf
Have you experimented with using the copper bar as the star ground?
Hi rdf,

I use a copper buss for my p2p gainclones that works very well, but in the BrianGT (shown in the picture) it didn't quite work as I have some hum. I forgot that the power and signal earths are connected on the amp pcb. I eventually removed the buss and did the earths as in instructions and guess what, it fixed the problem. (BTW: I didn't connect chassis ground.)

http://www.briangt.com/gallery/nigc-...T_GC_2_800x600

I guess with a little more effort I could have gotten the copper buss to work but why bother and the results at the moment are excellent.

regards
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Old 22nd December 2005, 10:19 AM   #556
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Quote:
Originally posted by Greg Erskine


Hi rdf,
I use a copper buss for my p2p gainclones that works very well, but in the BrianGT (shown in the picture) it didn't quite work as I have some hum. I forgot that the power and signal earths are connected on the amp pcb. I eventually removed the buss and did the earths as in instructions and guess what, it fixed the problem. (BTW: I didn't connect chassis ground.)

regards

Greg,

Nice looking layout, and nice separation from the signal path to the noisy stuff! Those look like the lower power LM3875 chips rather than the LM4780s, but your amount of heatsinking seems light. Is that an aluminum angle bolted to the rear chassis panel you are using to essentially heatsink the chips into the chassis? How warm are your chips running?

Robert
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Old 22nd December 2005, 01:40 PM   #557
rdf is offline rdf  Canada
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Quote:
Originally posted by Greg Erskine

I use a copper buss for my p2p gainclones that works very well,
Thanks Greg. Were the amps which worked well single transformer? My torroid is a 1000 VA from a dead Zen project so the amp will use ony one. I also have some 2" x 1/4" copper flat stock sitting around, my thought was to use a physical layout similar to the Peter's Patek but mount the single rectifier board on the bar's end opposite the amps and use the flat stock as heat sink and ground return.
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Old 22nd December 2005, 07:02 PM   #558
karma is offline karma  Canada
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Quote:
Originally posted by Peter Daniel
I received it today. Will sent the package on Monday.
Thanks.

received it today. one word wow

thank you.
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Old 23rd December 2005, 03:09 AM   #559
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Quote:
Originally posted by karma



received it today. one word wow

thank you.
There are 4 screws holding the whole chassis together. The wooden piece that I included, should be used to separate the channels from from front and rear panels (by tapping with a hammer). I don't have access to my email account presently, so if you have any questions, I can answer them here (directly from Cancun )
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Old 23rd December 2005, 03:14 AM   #560
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Quote:
Originally posted by wdavis009
One thing that surprised me is there is much less gain than I expected, given how many people use it with a passive preamp. I am using a Allen Wright modified Sony CDP, passive preamp and Vandersteen 3a Sig's. With the volume pots at full volume I am just barely achieving my normal listening level. Any suggestions on what the best solution would be (short of recommending an active preamp or different speakers, of course)?
With a source having 2V output and 93dB speakers, the gain is enough for any normal listening levels.

You could increse it further by lowering the impedance of 680R resistor ( -IN to ground), but I can't say how well it will work.

A simple preamp implemented around OPA627 or AD815 might be a better solution, especially with chip amps, that work actually better with active line stages.
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