Definitely recommend anyone new to the thread to read through Bruno's early posts--informative philosophically (design constraints) and extremely clear language.
The NC400 really isn't that much smaller than the NC1200. In a rectangular enclosure it requires 88x88mm of space. The NC1200 module requires 79x120mm. I like 'em packed in tightly.
An externally hosted image should be here but it was not working when we last tested it.
A small question about nAMPON (it has been a long time 
) :
I even get cracking noises in case of bad connection.
Am I missing something?
Or is it no errors for 2 seconds only for the first time?
EDIT: the flowchart presented page 7 of the datasheet seems to answer my question: looks like the timer used for the 2 sec test is only reset when in case of an error...
Subsidiary question (probably already answered 10x times, and I probably also read those responses at that time, sorry) : does this mute functionality reduce power consumption in any way?
What is the advantage compared to eg shorting the input?
) :In my tests the signal goes on as soon as nAMPON connected to a ground. No delay, no relay noise, no nothing that would indicate any kind of test or advanced logic.nc400 datasheet said:
I even get cracking noises in case of bad connection.
Am I missing something?
Or is it no errors for 2 seconds only for the first time?
EDIT: the flowchart presented page 7 of the datasheet seems to answer my question: looks like the timer used for the 2 sec test is only reset when in case of an error...
Subsidiary question (probably already answered 10x times, and I probably also read those responses at that time, sorry) : does this mute functionality reduce power consumption in any way?
What is the advantage compared to eg shorting the input?
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Wow!
That was long thread! Finally caught up with the last 300 pages or so...
I have a question regarding NC500 datasheet, is the Typical SNR of 135db with the Hypex default LM4562 based buffer in place?
Acoustic Imagery rates the SNR of it's Atash500 monos at 128, and they supposedly using all standard Hypex parts and provide case work only. Boggit's specs don't have SNR rating to confirm.
I would assume yes based on the fact that nc1200 datasheets shows SNR values for buffered and unbuffered boards and NC500's does not.. And NC400 as I have learned from here, already has the buffer integrated.
Any of you guys know for sure?
Also, I was very interested in bavmike's own discrete buffer with 140db SNR! But no more updates on that front...
Getting pretty interested in this ncore technology! These numbers of noise floor and distortion were dreams just a couple of years ago!
That was long thread! Finally caught up with the last 300 pages or so...
I have a question regarding NC500 datasheet, is the Typical SNR of 135db with the Hypex default LM4562 based buffer in place?
Acoustic Imagery rates the SNR of it's Atash500 monos at 128, and they supposedly using all standard Hypex parts and provide case work only. Boggit's specs don't have SNR rating to confirm.
I would assume yes based on the fact that nc1200 datasheets shows SNR values for buffered and unbuffered boards and NC500's does not.. And NC400 as I have learned from here, already has the buffer integrated.
Any of you guys know for sure?
Also, I was very interested in bavmike's own discrete buffer with 140db SNR! But no more updates on that front...
Getting pretty interested in this ncore technology! These numbers of noise floor and distortion were dreams just a couple of years ago!
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Yes it's awesome technology. And you can't go wrong with any Ncore based amp you choose.
Thanks @waltzingbear
If so, it makes sense then. Adding the buffer board would slightly lower the total system SNR vs just the ncore module. Still, 128 db SNR is very impressive.
@bavmike - Still working on your discrete class A buffer? I'm sure many are interested in finding out how is that development coming along.
If so, it makes sense then. Adding the buffer board would slightly lower the total system SNR vs just the ncore module. Still, 128 db SNR is very impressive.
@bavmike - Still working on your discrete class A buffer? I'm sure many are interested in finding out how is that development coming along.
My findings related to the UCD400HG are that this excellent module can be significantly improved with just component changes.
I was doing that gradually and each particular change made a really nice, easily audible improvement.
Here is a list of what I have done so far:
- Input caps removed (of course);
- LM4562 replaced with LM49722 (OPA1612 is waiting to be tested). LM4562 nowdays is of ordinary quality. There are better opamps around;
- Stock smd resistors around the opamp replaced with SUSUMU smd resistors (you would be surprised with this, totally unexpected improvement);
- Output filter capacitors replaced with WIMA MKP2 (one above and the other below, although mines are with magnetic leads);
- Decoupling capacitors replaced with PANASONIC FC 100V and 63V rated (yes, FC is easily audibly better than the stock HYPEX AUDIO 220uF/100V capacitor).
Next I will concentrate on the SMPS400 module. The fuse is already replaced with better one. The another one smps is waiting to be implemented for the dual mono approach.
Baki
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Only the music I am very familiar with and listening to it very often.
Measuring only the output DC offset
Maybe slightly different bandwidth because the input capacitors are removed.
These mods will not be measurable by normal standards, and Julf knows that
Big part of DIY fun is doing mods and hear the difference; the more expensive the mod the better the sound
I do believe however that Baka's mods might make sense.
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And nothing wrong with that - my only concern is that while you clearly perceive an improvement, it is possible that what you perceive as an improvement might, in an objective sense, be a degradation - for example by adding "pleasant" distortion or frequency response.
I understand your point but pleasant distortion shouldn't be the case related to the changes I have done.
As for the opamp the important issue here is an input bias current that should be relatively low. That narrows the possible choices. According to the datasheet LM49722 is a "directly interchangeable with LME49720, LM4562
and LME49860 for similar operating voltages". Specs are almost the same but the later one sounds audibly better. It is at least more transaparent and well suited for that position.
All smd resistor around the opamp are the magnetic ones. The same goes for the couple of Vishay MELF resistors used there. Susumu resistors are at least non magnetic and the end result was a perceivable cleaner sound. These resistors are, for example, used in SE editon of DEXA Technologies Discrete Audio Op-Amp. I am sourcing my experience from these opamps having them both in standard and se edition.
Changing the ordinary polyester capacitor for the polypropylene one in the output filter does produce less grain, better speed, dynamics and resolution. That should be of no surprise. Wima is particulary good beeing also very compact - radial leads with 5mm spacing.
And yes, there were/are/will be a plenty of changes that were/are/will be discarded as well.
These are all mostly standard upgrades aplicable elsewhere.
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I agree - the distortion was just an example of something that can be perceived as an improvement despite being a backward step from an objective point of view. Nevertheless, it does illustrate the problem of relying purely on subjective evaluation.
So assuming your mods do make an audible difference, all we know is that you consider the difference to be an improvement that you describe as a "more transparent", "cleaner" sound with "less grain, better speed, dynamics and resolution". But what does that mean in objective terms? Would somebody else perceive the differences the same way? One man's "less grain" is another man's "dull".
When making an improvement, I prefer to understand the actual physical effect the improvement has, and how that affects the sound.
It is certainly in 0402 format.
RR0510R-49R9-D - SUSUMU - Chipwiderstand, Oberflächenmontage, Dünnschicht, Baureihe RR, 49.9 ohm, 62.5 mW, ± 0.5%, 25 V | Farnell element14 Deutschland
I have ordered them indirectly. This should be the link for the one of that kind. Please explore Farnell.de further.
Search also this forum for SUSUMU.
Susumu offer a range of thin film resistors. The RR series aren't "non-magnetic". They aren't even particularly precise (0.5%, 25ppm). You probably replaced a better resistor with a poorer one. MELF is a package. Vishay offer thin film MELF resistors. Do you know the series of the resistor you replaced?
http://www.susumu.co.jp/english/product/category.html?cid=5
http://www.susumu.co.jp/english/product/category.html?cid=5
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