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Old 26th November 2012, 08:41 PM   #21
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Yes it is bulk of it is discrete except the servo which is an opamp (simply because it is hard to achieve the kind of DC performance you need without an opamp).

We might decide to produce it as a kit after I have a chance to test a couple of part changes. It is probably a couple months off at least before I even build another prototype. The decision to produce it will depend on a number of factors.
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Last edited by Russ White; 27th November 2012 at 02:05 PM.
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Old 26th November 2012, 09:15 PM   #22
4est is offline 4est  United States
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Ah, looking for a taste of the dark side eh Barrows?
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Old 26th November 2012, 09:34 PM   #23
RollE2k is offline RollE2k  Sweden
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Russ: Will the PCB be same size as Legato and IVY?
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Old 26th November 2012, 10:14 PM   #24
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I am very interested in this Counterpoint III. It will be a unique product on the market. Why solve your own problems when Russ can solve them for you?
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Old 26th November 2012, 10:34 PM   #25
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Default Hahahaha...

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Ah, looking for a taste of the dark side eh Barrows?
Perhaps, I have been doing some research , also I am about to be testing another nCore amplifier amp build here, and these amps seem to be very finicky about RF at their inputs. I know that technically the filter stages of my current Legato 2 should be removing RF from the output, but testing with my previous nCore build (for someone else) indicated that something bad was getting to the outputs, as the nCores had some very low level (ear to tweeter) rough static-y sounds coming through, which were not present with a different DAC (Opus/IVY III) at the input, or with the input open. A highly textured noise floor has always bothered me, no matter how low in level. I prefer to hear just a nice, smooth, even, white noise hiss indicative of the thermal noise of electronic components.

Also, as mentioned, I have heard some very, very good sounding DACs which coupled their outputs through Lundahls. I know everbody says this (lol), but my set up is pretty dam resolving at this point, if transformers did obscure detail at all, I would be able to note it pretty easily here, so it might be a fun experiment to try them. As Russ mentioned, it might be better to transformer couple the input of the amp (I suspect he means in terms of impedances), but this nCore build is not technically for me at this point, and I would have to add transformers externally on any of my other amps, adding complexity and connections, which I hate!

I'll probably just try no connection to pin 1 at first, unless Santa brings me a couple of $140 Lundahls!
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Old 26th November 2012, 11:52 PM   #26
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Quote:
Originally Posted by RollE2k View Post
Russ: Will the PCB be same size as Legato and IVY?
yes
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Old 27th November 2012, 12:40 AM   #27
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Default Russ...

Now that you have spilled the beans on the forthcoming Counterpoint 3, perhaps you will start an announcement thread on it for discussion? I am assuming this will be a feedback bipolar circuit with low input impedance to suit the ESS 9018, I would like to hear what other people think of it conceptually vs the IVYIII.
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Old 27th November 2012, 01:27 AM   #28
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Quote:
Originally Posted by barrows View Post
Now that you have spilled the beans on the forthcoming Counterpoint 3, perhaps you will start an announcement thread on it for discussion? I am assuming this will be a feedback bipolar circuit with low input impedance to suit the ESS 9018, I would like to hear what other people think of it conceptually vs the IVYIII.
I will start an announcement thread when and if I think its ready for prime time.

It's far more like Legato than IVY-III. In fact it has almost nothing in common with IVY-III except that it converts current to voltage.

It has no global feedback - just a servo that sets the cascode current to get the common mode voltage to 0V.

It is also right now just an experiment.
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Last edited by Russ White; 27th November 2012 at 01:10 PM.
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Old 27th November 2012, 01:32 AM   #29
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Here is a sneak peek of the last proto. Be warned though, it is going to look quite a bit different with the new parts.
Attached Images
File Type: jpg cp3.jpg (621.6 KB, 253 views)
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Last edited by Russ White; 27th November 2012 at 01:35 AM.
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Old 27th November 2012, 02:50 AM   #30
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Default Sweet, Russ...

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Originally Posted by Russ White View Post
I will start an announcement thread when I think its ready for prime time.

It's far more like Legato than IVY-III. In fact it has almost nothing in common with IVY-III except that it converts current to voltage.

It has no global feedback - just a servo that sets the cascode current to get the common mode voltage to 0V.
Now you have my attention! Relatively simple circuit with no global feedback, but with a servo. Too bad I just purchased a L3 kit... One can never have too many output stages to try though , thanks for creating another interesting option.
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