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Old 13th October 2006, 02:33 AM   #1
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Default Integrated gainclone, NOSDAC and DAR

Fasteddy,
Aftyer having read some of the forums over at SLIMP3, the general consensus seemed to be that the best bang for the buck in terms of mods was upgrading the power supply. I did not chnage any of the caps on the main board or even the caps on the elpac board. I only replaced the standard walwart with a higher grade Elpac 5v. The housed the elpac SMPS inside thye case alongside the gainclone toroids. All feed of the same AC socket. The sound over the stock is a little more improved, better control a little more base, nothing crazy though. I will post photos' if you want. I seem to remebber buying it from Mouser:
http://www.mouser.com/search/Product...ply&Mpcn=68001

Danon,
Thanks for the compliment and remebering the DIY paradise unit i built earlier in the year. To be quie honest i am not entirely thrilled with the sound quality of teh LM3875 yet. The sound of the gainclone NOSDAc combination is definitly cleaner with less coloration than the Charlize / Bel canto that i was running before (some may call that sound analytical i call it honest). However I am having issues with volume (doesn't play that load- not enough gain) and the sound still strikes me as being very closed in.
I think the closed in issue probably can just be put down to break in time. I am going to build a buffer (again from Peter) in the hope that it will help. What perturbs me more, and perhaps you or someone else can shed more light on this is the issue of volume... there aint much of it. All the voltages check out; 35 on the rails and a balanced 12mV across the speaker posts. I suspect it has something to do with the output of the DAC something i hope the buffer will help with. After the buffer is in i will be in more of a position to draw a comparison between the LM3875 and the T-amp.
I will definitley post my results
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Old 13th October 2006, 02:38 AM   #2
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an image of the mounted toroids
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Old 13th October 2006, 02:39 AM   #3
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mounted NOSDAc
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Old 13th October 2006, 02:41 AM   #4
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1" thick aluminum heatsinks. All were taped to recieve screws for bolted connections
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Old 13th October 2006, 02:44 AM   #5
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almost complete (missing buffer). The DAR is located to the right
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Old 13th October 2006, 02:46 AM   #6
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final product exterior
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Old 13th October 2006, 02:47 AM   #7
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and finally the rear... only speaker binding posts here
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Old 13th October 2006, 05:13 AM   #8
danon is offline danon  Germany
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n_k - thanks for continuing the discussion in a separate thread and your frank remarks.

A propos volume level: I can only report the anecdotal evidence I've come across. If memory serves, the current host of popular non-os dacs such as the nixon dackit, diyparadise's monica, audiosector's dac all have passive output stages. Many, besides yourself, have observed that their output may be insufficient to optimally drive an amp directly. So much for anecdotal corroboration.

I suppose the thing to do is to seek out some intermediary line stage, buffer, preamp etc, to provide gain. I haven't investigated here. Offhand maybe the kookaburra preamp from twisted pear audio, rolled with AD8620 opamps ...?

Alternative possibility: a dac with an active output stage. Perhaps something along the lines of the dac-ah: I believe its output stage is sufficient even to drive headphones.

Aside - before your gainclone clone is superceded (usurped?) by anything else, might I suggest - if not yet done - rolling its input caps? In the longish "Charlize, my thoughts" thread I reported my cursory observations with a handful of different caps. In short, after marvelling at your work with the gcc, I thought it would be a pity not to explore some simple but (very) effective optimization of the diyparadise amp. Even more so should a comparison to the gc be upstream.
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Old 13th October 2006, 08:17 AM   #9
Nuuk is offline Nuuk  United Kingdom
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Quote:
Alternative possibility: a dac with an active output stage.
Adding a Burson Audio buffer to either my DacKit or Charlize made one of the biggest improvements to the system that I have experienced!

As stated, the outputs of these NOSDacs are passive so I would always recommend an active stage between them and the power amp, preferably with some gain.

Of course, a lot depends on the speakers used but I find even with efficient speakers, a NOS DAC, no gain stage, typical power amp, does not have enough oomph.
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Old 13th October 2006, 03:14 PM   #10
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Danon, thanks for the great response
1. Well i can certainly add to the anecdotal experience... NOSDAC + LM3875 = not enough oomph, gain what ever. I will build the buffer in the next few weeks and report back. I am hopeful. Funny i was just reading the lengthy Russ White "twisted pair" posts las tnight
2. I recall your feedback re inpout caps and charlize. Thanks fro reminding me. I am definitley going to pursue that. To avoid having to read the 10,000+ posts under Charlize my thoughts would you mind recapping your observations. Either post here or ping me directly. Thanks for the encouragment and kind words.

Nuuk,
Would you mind telling more about the Burston audio buffer and Charlize
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