Ha ha. Well I hear Apple is already working on the iPhones 3 generations ahead when they release a new iPhone. The awesome thing about the Nord's is they are a gift that can keep on giving for years to come. That can't be said for 99% of other amps on the market 🙂
Shouldn't be hard with the LM4562. It is unity gain stable. Just alter the feedback resistors, ensuring the LM4562 sees the same load.
One with a gain stage section that looks like this is a great example:
Lots and lots of little thingy majiggies. Must be good!
I love the way you keep tossing out this pic of the volume control section of the PD2. Even though you are no longer distributing them?
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No but neither does a pic showing lots of thingy majiggies offer any insight as to its performance. Given this is a DIYaudio forum I think readers might be much more interested in hearing more about something you have built.
Your other favourite pic. Any more?
PS: I have zero interest in the PD2. My Casablanca IV with Xtreme D3 DACs suits me just fine.
PS: I have zero interest in the PD2. My Casablanca IV with Xtreme D3 DACs suits me just fine.
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Rev C boards arrived with Si994s. Finally!
Sounds good, its 2am here, so can't put much volume. All i can say, that i want to listen to these first so they get burned in to my ear (if you will), and then try the browndog LME49990s and then again these, and i'll know which is better for me. The LME49990 is already so good, so no immediate wow effect, but lets see when i can crank up the volume. The sound staging seems a bit different. There is more center energy, which means more slam.
Overall: No problems, sounds really good (for the people who misunderstand things easily).
Sounds good, its 2am here, so can't put much volume. All i can say, that i want to listen to these first so they get burned in to my ear (if you will), and then try the browndog LME49990s and then again these, and i'll know which is better for me. The LME49990 is already so good, so no immediate wow effect, but lets see when i can crank up the volume. The sound staging seems a bit different. There is more center energy, which means more slam.
Overall: No problems, sounds really good (for the people who misunderstand things easily).
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Indeed. This "basic" schematic of the input buffer is provided in the NC500 data sheet (the minor revisions for Rev C suggested by Richard can be found herein, but don't affect the gain - or noise for that matter) but the evaluation tool factsheet makes it even easier by stating the change explicitly. Potentially R10 and R12 could also be removed and jumpered for lower noise but this requires a little more evaluation to make sure the LM4562 isn't overloaded by the amp stage. (Use the LTspice model I provided.)
BTW just because the LM4562 works well at unity gain doesn't mean all other op amps will.
Bavmike, input buffers aren't hard. Here's a pic of a balanced to single-ended unity gain input buffer I did for an amp I am working on - it uses the equivalent of twelve LM4562 (3 x quad packages). Just for fun. No need for me to post scale-less measurement pics here and further clutter Boggit's thread. You've done that enough already. Suffice to say its noise doesn't rise above the noise floor of the measurement device.
BTW just because the LM4562 works well at unity gain doesn't mean all other op amps will.
Bavmike, input buffers aren't hard. Here's a pic of a balanced to single-ended unity gain input buffer I did for an amp I am working on - it uses the equivalent of twelve LM4562 (3 x quad packages). Just for fun. No need for me to post scale-less measurement pics here and further clutter Boggit's thread. You've done that enough already. Suffice to say its noise doesn't rise above the noise floor of the measurement device.
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Since human ear cannot hear so low distortion, I think there are also and other thinks that count.
i.e. drive, speed, harmonics ....
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That might be, but it doesn't in any way contradict what I wrote.
What do those terms mean in the context of a signal?
Harmonics are generated by non-linear distortion, and emphasized or de-emphasized by linear distortion (uneven frequency response), but what is "drive" or "speed" and how does one affect them (unless we are talking about the subjective perceptions created, once again, by uneven frequency response and possibly some non-linear distortion)?
If I knew how to affect them, I would be Mark Levinson or The One And Only. 🙂
Since I am not, I am of the theory of 'synergy'. 🙂
AKA put them all together in your room and listen to them.
Buy one and find out. Sebby did. I built the Nord Rev C boards back in the fall. They sounded great. Here's the measurements.
Now what have you built to contribute to this thread? Any measurement results? Even a picture would be better than nothing.
A question. This curve corresponds to the output buffer or the output buffer connected to a NC500?