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Old 19th November 2006, 02:49 PM   #31
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Old 19th November 2006, 02:59 PM   #32
Kooka is offline Kooka  Italy
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Got it!
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Old 23rd November 2006, 09:17 AM   #33
Kooka is offline Kooka  Italy
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Hi Neil, maybe I missed it, what is the current value of te Elpac psu?
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Old 23rd November 2006, 10:08 AM   #34
Kooka is offline Kooka  Italy
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Well, I don't know if the word "current" in english is correct: I mean if the value is 2A as the original poor power supply unit.
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Old 4th December 2006, 12:00 AM   #35
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I just finished updating my blog with additional photos and essay on this unit. You are welcome to visit at:
http://web.mac.com/noteldov

Click on audio projects on the home page.

Cheers
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Old 9th February 2007, 01:23 AM   #36
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Neil,

First of all, great job! I'm sure many others thought about a solution like yours, but you executed it! Wow! I looked at those enclosures you used but they looked a little pricey for me!

Anyway...I was curious with regards to the buffer you added. I'm trying to figure out why you needed the buffer, or the extra 'oomph.' The output voltage of Peter Daniels' NOS dac I believe is about 2V, so it has plenty as the input sensitivity of these gainclones are about 0.6V RMS. Most of my colleagues have told me that even if you match up the DAC and amplifier perfectly, you still ought to have about 8-12 dB of headroom. So that looks like the answer here.

I'm currently finishing up my gainclone amp using Peter's boards. Per his recommendation I'm also using a pair of Plitron 400VA transformers. In addition, I've added a pair of Lundahl input transformers for 6dB stepdown switching. I'm also finishing up Peter's NOS dac + HagUSB in one enclosure. I have a transformer coupled tube preamp using Magnequest transformers that should sound pretty good here.

All very, very cool and inspiring.

Thanks for the bandwidth,

Anand.
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Old 9th February 2007, 03:27 PM   #37
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Anand,
My transformers may have been slightly undersized (a pair of 120VAC) which in my ear / mind appeared to truncate some of the sound.
It was purely on a whim that i decided to add the buffer. I think it made a difference, subtle but definitely there.
I had made no allowance for a pre-amp and i believe the buffer fills that role.
Regardless, it sounds like your setup is going to be pretty ideal. I would be interested to hear what you think of the tube pre with the gainclone.

Thanks for the words.
Neil
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Old 9th February 2007, 04:04 PM   #38
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Quote:
Originally posted by nycavsr2000
Anyway...I was curious with regards to the buffer you added. I'm trying to figure out why you needed the buffer, or the extra 'oomph.' The output voltage of Peter Daniels' NOS dac I believe is about 2V, so it has plenty as the input sensitivity of these gainclones are about 0.6V RMS. Most of my colleagues have told me that even if you match up the DAC and amplifier perfectly, you still ought to have about 8-12 dB of headroom. So that looks like the answer here.
The buffer does not add any gain. It is a stage that provides impedance matching. The output of the DAC is based on passive I/V and as such its output impedance is rather high at 2k7 ohm. Adding a buffer directly after the DAC, lowers the output impedance of that stage to 6ohm, which translates in better impedance match to the next stage and is expressed in more dynamic and dimentional sound.
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Old 10th February 2007, 04:41 PM   #39
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Peter,

Thanks for the explanataion. I overlooked/didn't know what the output impedance of your NOS dac which you say is 2700 ohms. So indeed you would want an amp/preamp whose input impedance is at least 10 times or about 30K to prevent high frequency rolloff and limited dynamics. I was about to ask you what the output impedance of your dac was, but you beat me to it!

Thanks,
Anand.
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Old 21st September 2007, 07:36 PM   #40
fmedhus is offline fmedhus  Norway
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Love the work you've done here, Neil

I want to make a new chassis to my squeezbox with dac. Also want the possibility to connect external source to the dac.

Any tips for what I can use. Not on a very high budget
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