Hypex Ncore

[mr_push_pull]

I do not plan to add an indicator neither as the ncore itself glows in red when on. I will just let a small fence somewhere near the front panel.

you could easily come up with a mirror system that directs the light towards the front panel

 

[ChrisPa]

I do not plan to add an indicator neither as the ncore itself glows in red when on. I will just let a small fence somewhere near the front panel.

you could easily come up with a mirror system that directs the light towards the front panel

or .... a light pipe

....dan?

 

[dan1502]

I was just wondering how bright the light from the NC400 is and whether just using a light pipe might be a good option but I still prefer blue. I'm now struggling finding another part!

 

[Mark Verhoeven]

Is there something against the idea of making the gain switchable by fitting a good quality selector switch with different value resistors wired in place of R141? The power amp I am using at this moment has the possibility to choose between 3 gain settings and this is VERY helpful while I am driving it directly from my DAC and I use digital volume control. (I always choose a gain setting where I can "open" my digital volume control almost completely)

Thanks in advance,

Mark.

 

[ChrisPa]

If I remember correctly, r141 is part of the control loop - sticking it out on the end of a big wire is really duff idea

if you really want a switchable attenuator make it an external divider before the input.

 

[roscoeiii]

Won't an external divider prior to the input degrade the sound. I found this comment posted in another forum:

"this is simply attenuating a signal using a resistor in SERIES forming a voltage divider with the load resistor. This, naturally, adds noise to the signal and degrades the sound; so is not recommended unless you can find a "perfect" resistor."

 

[mr_push_pull]

If I remember correctly, r141 is part of the control loop - sticking it out on the end of a big wire is really duff idea

yeah, I was thinking just that. with an amp with such low distortion and noise levels I would not mess with stuff like that.
which gets me thinking... maybe one of the reasons Bruno went for a discrete opamp was to avoid the upgraditis (like with the UCD)?

 

[ChrisPa]

Won't an external divider prior to the input degrade the sound. I found this comment posted in another forum:

"this is simply attenuating a signal using a resistor in SERIES forming a voltage divider with the load resistor. This, naturally, adds noise to the signal and degrades the sound; so is not recommended unless you can find a "perfect" resistor."

Ah! those pesky resistors. If we could get rid of them we could have straight wire with gain!

(they're worse than opamps, you know)

 

[OllBoll]

A dedicated switcher I think Bruno said would mess upp paths and some other stuff too much, but how about a small switcher like the one on the backside of old IDE hard drives to switch master/slave? While it wasn't that hard to remove R141 a simple jumper would have been nice so it's easier to reverse in the future if one would want to =)

 

[mr_push_pull]

you guys have no idea how happy I am my DAC has internal volume

 

[ChrisPa]

A dedicated switcher I think Bruno said would mess upp paths and some other stuff too much, but how about a small switcher like the one on the backside of old IDE hard drives to switch master/slave? While it wasn't that hard to remove R141 a simple jumper would have been nice so it's easier to reverse in the future if one would want to =)

One of the key reasons why the nCore performs just as well as it does is becasue of detailed circuit layout - which is true of any high performance electronics.
And a major contributing factor to this is the use of surface mount and small conductor lengths

Bruno has already commented in an earlier post about the adverse effects of even using leaded components (including R141).
If I remember correctly the parasistic inductance of leaded components and their associated 3d layout starts becoming significant.

So why on earth does anyone want to throw away the detailed performance ingredients simply because they want to tweak the analogue gain. It would have been better if Bruno had said the gain was fixed (for some magical snake oil reason, or the particular sound of the resistor and value chosen for r141)

- if you want to change the gain as a one-off, fixed change, then change r141
- if you want variable or switched gain, then do it upstream of the amp

 

[guyv]

Clearly in the case of active speakers the question is about low-to-mid frequency distortion products arising from low-frequency signals. The thing that mainly amazes me is that it implies that at least the lower than -70dB distortion products of UcD are still audible at low frequencies (where the ear is much less sensitive and linear) through a woofer that is nowhere as linear. OTOH StigErik's woofer setup will have unusually low distortion and his room is well controlled.

Perhaps I'm just not being consistent enough. If I didn't accept that midband and HF distortion figures down to -90dB and better matter, I wouldn't be doing what I do. So all I might need to accept is that the same thing might very well hold true at low frequencies too.

...

At the link below Monte Kay makes the case that non-linear distortion is most audible at low frequencies.
Theatre woofer

While it is widely accepted in the industry that non linear distortion at low frequency is not particularly audible I am convinced that it is audible. In fact I believe that non linear distortion is the most audible at low frequency. One look at the equal loudness curves of human hearing should convince anyone that non linear distortion is least audible above about 3 KHz and most audible below 3 KHz. Above about 10 KHz it should be completely inaudible because the 2nd harmonic is exceeding the human hearing range. At 20 Hz the human ear will hear an equal level 40 Hz tone as 20 dB louder based on a 90 dB reference level. This means the 40 Hz harmonic must be 20 dB below the 20 Hz fundamental just to sound as if it is the same level or 100% 2nd harmonic distortion.

It's very difficult to achieve low distortion at frequencies in the 20 Hz range. Consequently I wonder how test were conducted to produce the widely held belief that distortion is inaudible at low frequency? Since most woofers produce at least 10% distortion at 20 Hz which sounds like 100% distortion at the 2nd and far higher at the 3rd, they have no clean reference to determine if induced distortion is audible. The test platform is starting with too much distortion to begin with for anyone to assess that an induced distortion is or is not audible.

 

[mr_push_pull]

on another note, after a long and difficult battle I decided to give up and instead go for the SiliconRay enclosure. it's cheaper than the most basic HiFi2000 enclosure that can accommodate the NCORE and also eliminates all the headache that goes with using a 1U enclosure. I just realized that the input/output caps needed for a SMPS which is powerful enough for the NCORE simply don't come in lower that 35 mm assortments (which does not render enough clearance when adding the PCB thickness and solder protrusions). all this was basically helping me procrastinate
the only downside is that I'll need to resort to the local CNC shops again. the same shops that did a butcher job one another nice case I had.

 

[dan1502]

On the subject of cases again. Is it necessary or advisable to have any vent holes and if so, where is it best to position them? I presume away from high voltage areas that could be poked at by someone stupid with a paper clip or such like!

Mr Push Pull, I ended up increasing the size of my cases a bit just to give a bit more room for manouvre. They'll still be pretty compact though.

 

[roscoeiii]

- if you want to change the gain as a one-off, fixed change, then change r141

This to me seems to be the best solution in terms of sound quality.

IIRC earlier there was some discussion of what resistor values would lead to which amounts of gain.

If a system has sufficient gain, is there any sound quality downside to decreasing the amp's gain via R141 replacement?

 

[mr_push_pull]

On the subject of cases again. Is it necessary or advisable to have any vent holes and if so, where is it best to position them? I presume away from high voltage areas that could be poked at by someone stupid with a paper clip or such like!

Mr Push Pull, I ended up increasing the size of my cases a bit just to give a bit more room for manouvre. They'll still be pretty compact though.

cooling needs depend on application. for instance my UCD implementation has the worst cooling imaginable and I've used it for some 6 years with no issues. if you plan on using all the available power you'd better make sure no corners are cut.
what case is that?

 

[dan1502]

It's just a case design I'm hoping will be viable to have made. I am just awaiting a final quote and will then need to give the design a final check before going ahead.

 

[Omholt]

I'm looking at PRAL-22307 as earlier mentioned:
Chassis case item
The price is NT$3300/pc(TWD) or EUR87.

I asked thlaudio if they could make "line holes" on the sides like some of the others have (for instance PRAL-30277C right above). Some cooling would be good, right?
Here's the answer I got:

We ship the chassis case as it stated on the web. Custom design need minimum order of 10 pieces & up, but in you case we will try to make same case with side opening when we have refill the case.

If someone else is interested in this, I would recommend contacting thlaudio soon.
thlaudio web site pages

These cases should definetly be a step above Modushop's. Was told from from one who has ordered some of their High grade chassises that they looked very nice indeed.

 

[robbbby]

It's March, the month of the next ncore batch! Hope everything is on schedule, I really need an amp badly, just not the same using this AVR.

 

[Erlend Sæterdal]

I hope to. It will use the cabinet an supply I use for LC. Audio The End XP. Solid State AB Non fedback.

Non feedback is ****.