Thanks, I "used" the second types until now.
Alcohol or spirit should do that as well, a bit less harmful.
In the same time it takes to remove and clear the holes for one through-hole resistor, you can remove 5-10 SMD ones.
Just use a pair of precision tweezers to hold the part and heat both pads (if you move fast enough you can heat the other side before the 1st one solidifies).
Off topic: I'm being hounded here to place the 1000th post on this thread. Not bad. Some threads about new projects reach 3000 and still no hardware in sight
Being the OP, and having been diverted to lots of other stuff this fall, I finally had some time to catch up on this thread -- and got totally blown away by how well the project has been received. The price for the module is just at the right spot too. Congratulations to the whole Hypex team!! 2012 is sure to be a fine year for you, and I'm pleased to see that you have stayed well clear of any Osborne effect.
So, should I order two power supplies or is one enough for a pair of these puppies? I have a pair of ancient (but well kept and lovingly maintained) Infinity Quantum 3 speakers, 4 Ohms nominally but will probably go down below 3 at some frequencies, and they're very inefficient. I like to play loud at times, so I guess two PS's should be on the order.
Oh, and what is the input sensitivity (Volts, please) for maximum rated output with and without R141 in place?
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@tom4s, I suppose that means you did a good thing starting the thread
One supply will go up to 2x300W. Personally I'd think this is enough in most circumstances but with two 4-ohm speakers you can definitely force the supply into shutdown.
Since gain is (very nearly) 20x, you need 2Vrms for full power. When you drop the input stage gain to 1 you need 9.6V. In that case please drive the input with a symmetrical voltage source because 9.6V on only one input terminal will overdrive it before the amp clips. Unless you're a fan of very efficient loudspeakers I'd say leave R141 in place.
@lotus, the current UcD400oems are indeed the updated version.
One supply will go up to 2x300W. Personally I'd think this is enough in most circumstances but with two 4-ohm speakers you can definitely force the supply into shutdown.
Since gain is (very nearly) 20x, you need 2Vrms for full power. When you drop the input stage gain to 1 you need 9.6V. In that case please drive the input with a symmetrical voltage source because 9.6V on only one input terminal will overdrive it before the amp clips. Unless you're a fan of very efficient loudspeakers I'd say leave R141 in place.
@lotus, the current UcD400oems are indeed the updated version.
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I've connected my DAC directly to the NC400's, with the volume control in the digital domain. It delivers 12 dBu, which is 3.09 V. With R141 removed, I get 12.4 dB gain, which is 4.17x. At 0 DBFS from the DAC, that gives me 3.09 x 4.17 = 12.8853 V, which is 20,75W into 8 ohms. Not all that much, but it is actually more than I ever need. I now that, because I never ever reach 0 DBFS from the DAC....
Which also means that I am operating in the range of the NC400 where distortion is almost unmeasureable.
Which also means that I am operating in the range of the NC400 where distortion is almost unmeasureable.
@Bruno, it is an honour to have started this thread! Thanks for the suggestions. But is there anything to gain with a dual mono configuration, other than maximum power?
@StigErik, you do know that this means that you never ever use the full bit resolution of your DAC? In fact, at low listening levels you would introduce lo-fi "bit crunching" distortion. I now see why you wanted to decrease the Ncore input sensitivity... In your situation I think I would set the DAC at full scale output and use a passive volume control, such as this little unit. or perhaps this one. (Amazing prices for balanced volume controls.)
Thanks for the suggestions. But is there anything to gain with a dual mono configuration, other than maximum power? @StigErik, you do know that this means that you never ever use the full bit resolution of your DAC? In fact, at low listening levels you would introduce lo-fi "bit crunching" distortion. I now see why you wanted to decrease the Ncore input sensitivity... In your situation I think I would set the DAC at full scale output and use a passive volume control, such as this little unit. or perhaps this one. (Amazing prices for balanced volume controls.)
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This is not a problem. Most source signals are 16 bit anyway. With an effective DAC resolution of approx 20 bits (120 dB), that means I can still attenuate 4 bits - that is 24 dB - before I loose any DAC resolution and the signal starts to bury itself into the noise floor. With an analog volume control, you also loose resolution, of the same reason.
The dynamic range of my listening room is no more than 14-15 bits anyway....
Having said that, its a good idea to place the signal in the most linear range of the DAC, that is as far up to 0dBFS as possible.
Hello Tom,
12.9V is roughly 10dB below maximum (low distortion) out voltage. So you may lose that amount from the DAC resolution, which begins at >100dB typically (depending on the DAC type of course, the THD+N figures are of much more interest ).
You'll never reach that dynamic range in a normal listening room. As I "believe", just this type of distortion will remain clearly below the hearing threshold.
Cheers, Timo
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nearly double post, sorry
12.9V is roughly 10dB below maximum (low distortion) out voltage. So you may lose that amount from the DAC resolution, which begins at >100dB typically (depending on the DAC type of course, the THD+N figures are of much more interest
).You'll never reach that dynamic range in a normal listening room. As I "believe", just this type of distortion will remain clearly below the hearing threshold.
Cheers, Timo
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nearly double post, sorry
Ah, yes. Those passive monitor controllers are for audio mixing, video editing, etc. I.e. for intense listening in environments that are not normal listening rooms. In those situations many producers and engineers prefer to attenuate in the analog domain.
If you're concerned about quantizing distortion after a digital volume control, you could always dither the signal before it hits the DAC. Even more fun: oversample before adding frequency shaped dither - most modern DACs can handle 192 kHz, so you can hide dither above the audible spectrum and still get its benefits.
as long as you are scaling the 16 bit input to enter the DAC as 20 bit all is ok. to be frank, I would only worry about truncation with high-end systems, I would bet that most cheap to medium-priced systems aren't good enough to make the difference between 14 and 16 bits discernible. that is not to say that one should throw away bits if attenuation can be solved otherwise.
I would have hoped (selfishly...) that more nCore 400 first adopters would have posted their perspectives on sound quality by now. What are these people doing? Taking vacation or something?!
Stig, thanks for taking the time to post your thoughts and an even bigger shout out to Bruno for taking the time to post on this forum and make the nCore 400 available to the DIY market.
) that more nCore 400 first adopters would have posted their perspectives on sound quality by now. What are these people doing? Taking vacation or something?! Stig, thanks for taking the time to post your thoughts and an even bigger shout out to Bruno for taking the time to post on this forum and make the nCore 400 available to the DIY market.
I agree earflappin.
I an anxious to hear from others about their NCore opinions. Sort of a moot issue for me since I have already placed my order, but it would make me feel a little better about my decision if others were posting with high praise.
My UCD400HG with H x R monoblocks are awfully good and I am hoping the NCore will be an upgrade worth the time and expense.
I an anxious to hear from others about their NCore opinions. Sort of a moot issue for me since I have already placed my order, but it would make me feel a little better about my decision if others were posting with high praise.
My UCD400HG with H x R monoblocks are awfully good and I am hoping the NCore will be an upgrade worth the time and expense.
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