If we are comparing with a properly designed SMPS, there are not really any advantages of using a linear PSU - and lots of disadvantages.
That would have been my opinion. But then again, I don't think power cables sound different either ;-)
Hi Julf,
I guess what is hard to assimilate is that the SMPS1200 just provides more of a good thing for nothing. I can't see any real drawback (5W, really?). Both have super low EMI according to Hypex so I have no idea what the different diodes bring, if anything.
Hypex is (perhaps rightly) tight lipped about the power supply + NC400 derating vs duty cycle, so we're just left guessing.
I like from chamber music to Brazilian hardcore heavy metal, so low peak/ave support at full juice is a must but I can see this not being a must have for a lot of users.
I guess what is hard to assimilate is that the SMPS1200 just provides more of a good thing for nothing. I can't see any real drawback (5W, really?). Both have super low EMI according to Hypex so I have no idea what the different diodes bring, if anything.
Hypex is (perhaps rightly) tight lipped about the power supply + NC400 derating vs duty cycle, so we're just left guessing.
I like from chamber music to Brazilian hardcore heavy metal, so low peak/ave support at full juice is a must but I can see this not being a must have for a lot of users.
Dear Rajapruk:
I'm contemplating doing a stereo NC400 build with SMPS1200A400 myself. Have not bought any parts yet and Hypex does not give detailed specs on their connection cable Cable set SMPS1200
Can you please elaborate on your custom cabling? Did you purchase two of those cable sets and cut off some connectors and simply make a "y" to feed both NC400s?
I updated the AC wiring to a twisted quad of 16awg- the quad will have a lower loop area than the pair of 18awg, and that's enough improvement to justify the effort IMO. Even in amps as quiet as these, every little stray field you can suppress without harming something else, is a good thing.
In the end, I upgrade my AC wiring to AWG14 - twisted pair.
Left the DC wires as it is.
Signal wire to Mogami 2534.
Dead thread I suppose- guess most everything's been covered. Not much to add, when the NCore are so good- I'm thinking about selling off just about every other amp I own to get more NCore for biamps- I've not heard resolution like this in my rig with this level of power behind it. UCD for years was great but this is a significant (and not cheap) upgrade over those.
need some help with transformer coupling
I have been wanting to try transformer coupling the input of the NC-400 for awhile, and am finally getting around to it.
I bought some affordable transformers to experiment with first, before going to Jense/Lundhall etc. These are Edcor units with 3 pin inputs and outputs (they are center tapped).
Ncore amp is wired XLR only, according to hypex recs, source is also wired the same way: pin 2 hot, pin 3 minus, and pin 3 to chassis and G.
1st attempt: source + to tranny +, source - to tranny -, source ground unconnected, output the same except with the center tap connected to XLR pin 1 on amp input (isolated grouind connection). Result: Hum
2nd attempt: same as above, but with Sheild (pin 1) connection bypassing the transformer. Result hum (I do get music as well)
Seems to me that at least the 2nd attempt should work fine? The amp is totally hum free with normal (no transformer) XLR cabling.
Any ideas? Should I connect sheild (G, pin 1) to the center tap of the transfomrer on the input and output?
I have been wanting to try transformer coupling the input of the NC-400 for awhile, and am finally getting around to it.
I bought some affordable transformers to experiment with first, before going to Jense/Lundhall etc. These are Edcor units with 3 pin inputs and outputs (they are center tapped).
Ncore amp is wired XLR only, according to hypex recs, source is also wired the same way: pin 2 hot, pin 3 minus, and pin 3 to chassis and G.
1st attempt: source + to tranny +, source - to tranny -, source ground unconnected, output the same except with the center tap connected to XLR pin 1 on amp input (isolated grouind connection). Result: Hum
2nd attempt: same as above, but with Sheild (pin 1) connection bypassing the transformer. Result hum (I do get music as well)
Seems to me that at least the 2nd attempt should work fine? The amp is totally hum free with normal (no transformer) XLR cabling.
Any ideas? Should I connect sheild (G, pin 1) to the center tap of the transfomrer on the input and output?
Schematic for the way you're implementing, and what trafo model you're using, would help a lot. I connect mine with primary +/- connected to RCA outputs from source, and the secondary to +/- XLR inputs, with the inter-winding shields connected to output ground. Dead silent and sounds great.
Why not try connecting source ground to the center tap on the primary?
Why not try connecting source ground to the center tap on the primary?
its simple...
Transformers are Edcor PCW 150/150. They are simple 1:1 with a single primary and secondary, and have a pin for center tap on both coils.
I am hooking up balanced to balanced. And there is no pin for the interwinding sheild, or to ground any other part of the transformer.
I just tried connecting the sheild (AKA pin 1) on both primary and secondary to the center taps, and the same hum ensues.
Very strange indeed, as I have now tried every possible wiring configuration and all result in hum. I do get music... Still cannot possibly understand why no 2 above did not run hum free, when the amp works fine with that same wiring without the transformer.
Maybe I just need to put them in a sheilded enclosure...
Transformers are Edcor PCW 150/150. They are simple 1:1 with a single primary and secondary, and have a pin for center tap on both coils.
I am hooking up balanced to balanced. And there is no pin for the interwinding sheild, or to ground any other part of the transformer.
I just tried connecting the sheild (AKA pin 1) on both primary and secondary to the center taps, and the same hum ensues.
Very strange indeed, as I have now tried every possible wiring configuration and all result in hum. I do get music... Still cannot possibly understand why no 2 above did not run hum free, when the amp works fine with that same wiring without the transformer.
Maybe I just need to put them in a sheilded enclosure...
You shouldn't connect anything to the centre taps, and the whole point of transformers is the isolation, so don't connect ground/shield either. Just non-inverting and inverting outputs of source to ends of primary winding, and non-inverting and inverting inputs of nc400 to end pins of secondary winding. If you still get hum, it is picking it up magnetically.
hmmm
Thanks Julf, I'll give it a shot, But: last time I tried to run the NC amp without the input of the module connected to source G, I got hum (no transformers, just floating the G from the source).
My amp build is wired per Hypex: nAmpon to chassis (through switch), shield from module to chassis, and pin 1 XLR to chassis. Everytime I tried to make the amp work without the XLR pin 1 connecting to source G, there was hum. It all gets back to my curiosity about the "sheild" wire from the NC modules, in my experience this thing has to be connected to source G. One would think that a true differential input stage would be OK with this left floating (just connected to chassis, with no path from chassis to source G).
Juhleren: Mostly curiosity. I have a suspicion that the NC-400 is sensitive to RF on the input, so the transformer is one way of reducing that, plus, if I get a little more warmth/body to the sound (even if the cause is added distortion) that would not be a bad thing in my system. I know some folks have a disdain for adding a signal transformer, but I have heard plenty of transformer coupled high end components, and never felt their was a lack of resolution there (Rowland, PS Audio DS DAC, etc). Oh there is no DC, my source is cap coupled.
Thanks Julf, I'll give it a shot, But: last time I tried to run the NC amp without the input of the module connected to source G, I got hum (no transformers, just floating the G from the source).
My amp build is wired per Hypex: nAmpon to chassis (through switch), shield from module to chassis, and pin 1 XLR to chassis. Everytime I tried to make the amp work without the XLR pin 1 connecting to source G, there was hum. It all gets back to my curiosity about the "sheild" wire from the NC modules, in my experience this thing has to be connected to source G. One would think that a true differential input stage would be OK with this left floating (just connected to chassis, with no path from chassis to source G).
Juhleren: Mostly curiosity. I have a suspicion that the NC-400 is sensitive to RF on the input, so the transformer is one way of reducing that, plus, if I get a little more warmth/body to the sound (even if the cause is added distortion) that would not be a bad thing in my system. I know some folks have a disdain for adding a signal transformer, but I have heard plenty of transformer coupled high end components, and never felt their was a lack of resolution there (Rowland, PS Audio DS DAC, etc). Oh there is no DC, my source is cap coupled.
And that has been my experience - the input works just fine without a connection to source ground (as long as the source has balanced output).
A transformer doesn't really reduce RF on the input - a shunt capacitor would be better.
Thanks...
Julf. Quick question: are all your NC amps and source both connected to AC ground, and hence, pin 1 referenced to AC ground through chassis?
It is odd to me that as soon as I break the connection from NC-400 module sheild wire to the source ground, I get hum and you do not. My source has true balanced output.
Julf. Quick question: are all your NC amps and source both connected to AC ground, and hence, pin 1 referenced to AC ground through chassis?
It is odd to me that as soon as I break the connection from NC-400 module sheild wire to the source ground, I get hum and you do not. My source has true balanced output.
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