Thanks cab, I checked out some 12 pin terminal blocks online just after posting and I do think that would be a good option.
Space is a bit tight in my enclosure so I'm going to go a different route though as I just dropped by the local Radio Shack and found some small metal butt connectors that will let me Y each of the wires together to connect to the SMPS600 wires (after cutting off one of the unneeded molex connectors). I'll crimp them with a bit of solder inside and then apply heat and then some heat shrink insulation. Should make for a solid connection.
Fun stuff.
Space is a bit tight in my enclosure so I'm going to go a different route though as I just dropped by the local Radio Shack and found some small metal butt connectors that will let me Y each of the wires together to connect to the SMPS600 wires (after cutting off one of the unneeded molex connectors). I'll crimp them with a bit of solder inside and then apply heat and then some heat shrink insulation. Should make for a solid connection.
Fun stuff.
If I understand you, you're saying keep both molex connectors on the SMPS600 cable and connect the wires from the two NC400's into the pin side of one of those connectors.
The wires are 20 gauge and even a single wire won't fit into that side of the molex connector. The pins that the molex connects to on the NC400 and SMPS600 are smaller than 20 gauge.
So I think the only way to do this, whether splicing each wire in a Y as I plan to do or using a terminal block, is to remove one of the two molex connectors on the cable that comes with the SMPS600.
The wires are 20 gauge and even a single wire won't fit into that side of the molex connector. The pins that the molex connects to on the NC400 and SMPS600 are smaller than 20 gauge.
So I think the only way to do this, whether splicing each wire in a Y as I plan to do or using a terminal block, is to remove one of the two molex connectors on the cable that comes with the SMPS600.
Homemade Y-cable for one SMPS600 & adding heat sinking
When I made a Y-cable, I cut supplied cable in two, and used heat shrink after soldering the wire-splices - using heat shrink gave me more confidence to avoid shorts, but IMO making this Y took too much time to complete -wish Hypex had made a factory Y cable available.
BTW, I have two stereo sets of Ncore amp modules. Did not hear much SQ difference, if any, between powering a stereo pair with two SMPS600 (individual SMPS for each ncore amp module), and another ncore pair powered by only one SMPS600 with my homemade Y-connector cable.
IMO, SMPS600 aluminum heatsink (the one close to the big electrolytic filter caps) gets uncomforably hot after about half an hour or so, especially when one SMPS600 powers two ncore modules using the homemade Y-adapter - even when ncores are idle = not playing music.
Having a SMPS600 heat sink get hot & located immediately next to electrolytic caps is not very good, long term, I believe ...
Not sure it's a good idea, but I got the SMPS600 heat sink to run much cooler by placing 3 pieces of 1" wide x 1/8 thick aluminum bar stock on top of the heat sink. This add-on heat aluminum sinking is just thick enough to be in in contact with the enclosure/case top which is also made of aluminum, but maybe there's potential electrical isolation/noise issues? As far as I can tell, the Ncores still seem to work OK with this heat-sinked SMPS600 -- and so far there's no perceived hissing, noise, etc.
When I made a Y-cable, I cut supplied cable in two, and used heat shrink after soldering the wire-splices - using heat shrink gave me more confidence to avoid shorts, but IMO making this Y took too much time to complete -wish Hypex had made a factory Y cable available.
BTW, I have two stereo sets of Ncore amp modules. Did not hear much SQ difference, if any, between powering a stereo pair with two SMPS600 (individual SMPS for each ncore amp module), and another ncore pair powered by only one SMPS600 with my homemade Y-connector cable.
IMO, SMPS600 aluminum heatsink (the one close to the big electrolytic filter caps) gets uncomforably hot after about half an hour or so, especially when one SMPS600 powers two ncore modules using the homemade Y-adapter - even when ncores are idle = not playing music.
Having a SMPS600 heat sink get hot & located immediately next to electrolytic caps is not very good, long term, I believe ...
Not sure it's a good idea, but I got the SMPS600 heat sink to run much cooler by placing 3 pieces of 1" wide x 1/8 thick aluminum bar stock on top of the heat sink. This add-on heat aluminum sinking is just thick enough to be in in contact with the enclosure/case top which is also made of aluminum, but maybe there's potential electrical isolation/noise issues? As far as I can tell, the Ncores still seem to work OK with this heat-sinked SMPS600 -- and so far there's no perceived hissing, noise, etc.
Bill,
Thanks a lot for the info. I knew there should be no sound quality difference just because another NC400 pulls power off the same line and Bruno has confirmed this, but it's good to hear your results nonetheless.
I hadn't thought about the possible higher running temperature of the SMPS600 though -- that warning is much appreciated. I just now ordered a 3.5" x 1.1" aluminum heatsink (about 1 inch tall with fins) to fit the top of that existing flat heatsink on the SMPS600.
Thanks a lot for the info. I knew there should be no sound quality difference just because another NC400 pulls power off the same line and Bruno has confirmed this, but it's good to hear your results nonetheless.
I hadn't thought about the possible higher running temperature of the SMPS600 though -- that warning is much appreciated. I just now ordered a 3.5" x 1.1" aluminum heatsink (about 1 inch tall with fins) to fit the top of that existing flat heatsink on the SMPS600.
I also did my Y-cable by splitting the cable.
In my boxes I had one normal cable and then another cable with only one side, so I split the normal one and then soldered all the small cable into Y's and applied heat shrinked pipes.
Keep in mind though that many of the cables are the same, so you don't need to do this for all of them but you can combine the cables by color.
In my boxes I had one normal cable and then another cable with only one side, so I split the normal one and then soldered all the small cable into Y's and applied heat shrinked pipes.
Keep in mind though that many of the cables are the same, so you don't need to do this for all of them but you can combine the cables by color.
Read this on another site:
"+1 on the Acoustic Imagery ATSAH NC amps, I have had a preview set for a few months as well and as good as the NC400's are, these are a considerable step up.....
I've measured both and the NC1200 based amps don't measure quite as well in nearly all regards except for power. Given my speakers, the difference in power is pretty much a moot point but I know of 5 others who have heard both in the same systems and to a person they all found the ASTAH NC's (1200's) subjectively better."
They are talking about a commercial 1200 ncore product. Curious if anyone has any ideas on why it should sound substantially better than the 400, which has better specs???
"+1 on the Acoustic Imagery ATSAH NC amps, I have had a preview set for a few months as well and as good as the NC400's are, these are a considerable step up.....
I've measured both and the NC1200 based amps don't measure quite as well in nearly all regards except for power. Given my speakers, the difference in power is pretty much a moot point but I know of 5 others who have heard both in the same systems and to a person they all found the ASTAH NC's (1200's) subjectively better."
They are talking about a commercial 1200 ncore product. Curious if anyone has any ideas on why it should sound substantially better than the 400, which has better specs???
I'll stick with my DIY ncore amps, and save big bucks.
Bruno Putzeys was quoted: "It's always a dilemma whether an amp should be tuned for things like subjective bass control, sweet mids or not. --- But it's tough to resist the occasional sonic touch-up. I can emulate the sound of pretty much any amp out there if I wanted. But so far I'm resisting."
Bruno Putzeys was quoted: "It's always a dilemma whether an amp should be tuned for things like subjective bass control, sweet mids or not. --- But it's tough to resist the occasional sonic touch-up. I can emulate the sound of pretty much any amp out there if I wanted. But so far I'm resisting."
Thanks to OllBoll for pointing out that the wires can be combined when making a Y cable for a stereo build, that did save some time.
Here's a shot of the custom cable I needed to make installed in case it helps anyone else doing this later.
Sounds amazing, BTW!
Here's a shot of the custom cable I needed to make installed in case it helps anyone else doing this later.
Sounds amazing, BTW!
Attachments
I definitely know too little about the test conditions let alone the actual builds being compared to make an educated guess, but I´d guess that the two amps had different power supplies. If the NC1200 based amp had one dedicated PS per channel and the nc400 instead shared one smps600, that could be an obvious factor.
Also, the ASTAH implementation of the nc1200 boards could be slightly tweaked away from standard to the vendors liking and "house sound"-interpretation of better sound.
If it was possible to test the nc1200 against a bridged nc400 based amp, it could be interesting if the tables turned indicating the sheer tab power/potential voltage swing to be responsible...
quite a few people complaining about heat issues made me look at output transistor type on my UCD180s. at one side there's a 14NF12FP. datasheet lists Ron as 0.14 ohm. a while back while I was working for an automotive company I was curious about the FETs that were driving a 100A motor. I looked them up (don't remember the part code) and they were 1 mohm Ron devices. Farnell has some parts with Ron less than that.
would a lower Ron device bring some benefits, heat-wise?
would a lower Ron device bring some benefits, heat-wise?
The other thing to consider is that the quote comes from a noob/shill on A/C. Take that FWIW.
This was my comment. I have a Prism DScope III that was used for measurements, along with a nearly non inductive load bank capable of absorbing up to 4kW. My line voltage is generally between 120 and 122V and the shop has a several 20A circuits. I use a laptop on battery power when testing to prevent any PS noise from the computer from affecting the result. I also insert a Prism ds-LPF low pass filter between the amps and the DScope, this is an AES-17 filter designed for use when testing class D amps.
The ATSAH NC amps use the Hypex SMPS1200 PS, one per mono block. The NC400's use the Hypex SMPS600 supplies, again one per mono block, nothing shared. Looking at the data sheets from Hypex it's pretty clear the NC1200 OEM modules measure a little worse in terms of THD but of course they have much more power. I did not do extensive measurements but what I did run agree with the data sheets. The FFT plot of both amplifiers is superb but since the NC1200 based ATASH amps have slightly more THD (per their data sheet spec), the 2nd harmonic is a little higher on the FFT plot, but still very low.
It is my understanding the John @ Acoustic Imagery does not tweak the modules for a house sound.
My NC400's are assembled as prescribed in the data sheets, tightly twisted wiring and such. The measurements for both amps that I have taken match the specs in the Hypex data sheets. The NC400 actually manages a little bit more power than the spec, I consistently see about 240W into an 8R load. I've tested at least a dozen NC400's and they are all very close to the same.
In my system the ATSAH NC (NC1200 based) amps are subjectively superior to the NC400's. The offer greater resolution of low level information, somewhat larger sound stage/image and are subjectively warmer/fuller/richer. The highs also have a bit more open sound to them.
I run both fully balanced from a Krell KCT preamp, main speakers are GedLee Abbey's, so an easy load. Had I not had the opportunity to be a tester for the AI amps, I'd still be really happy with the NC400's.
HTH, mike
I have wondered the same thing myself but not enough to try and build a new PS for the NC400's, which I know some have done. The specs are not very different and low order harmonic distortion is is generally considered benign and in both amps the upper harmonics are buried in the noise floor at least 120dB down. (1W of output).
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