AudioCircle
Other Stuff => Archived Circles => Hypex Owners Circle => Topic started by: orientalexpress on 28 May 2012, 02:51 pm
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i like Ted ideal :D,bridging with 4-ncor and 2 powersupply or 4-ncor and 4 supply?my speakers need alot powers.. :thumb:
lapsan
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Yea, I will bridge or bi-amp, not sure yet what I will do. Some think I will be better off bi-amping (me) (my speakers are B&W 802D and can be bi-amp/wire) and others bridging with bi-wire (me). Well not just me but that is why I still have not made up my mind. If I have the funds I might do both, bridge four mono blocks. The B&W love power. They love to be bi-wired. So bridged and bi-amped, the Holy Grail!!
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Yea, I will bridge or bi-amp, not sure yet what I will do. Some think I will be better off bi-amping (me) (my speakers are B&W 802D and can be bi-amp/wire) and others bridging with bi-wire (me). Well not just me but that is why I still have not made up my mind. If I have the funds I might do both, bridge four mono blocks. The B&W love power. They love to be bi-wired. So bridged and bi-amped, the Holy Grail!!
Where are you located? Also, what's your system consist of?
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Anybody know how the Ncore modules bridge? Are they reversible (say I have it done, then not solved a problem, could they be unbridged and retrofitted into a stereo config...new back panel or addtl binding post/XLR holes).
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Anybody know how the Ncore modules bridge? Are they reversible (say I have it done, then not solved a problem, could they be unbridged and retrofitted into a stereo config...new back panel or addtl binding post/XLR holes).
No there is no need for it to be "permanent". I haven't seen specific instructions for NCore but Hypex says it is the same as for the UcD series.
So, for a typical balanced connection, bridge tied load (BTL):
* hot(+) signal to amp module A hot(+) input and to amp module B cold(-) input
* cold(-) signal to amp module A cold(-) input and to amp module B hot(+) input
* connect the speaker load between the two positive amp outputs. Typically amp A would be the + side, amp B the - side. They recommend a 47nf cap across the output in that case. Note that NO output grounds (-) are connected.
Here is the wording from the Hypex UcD400 FAQ just for reference. I don't know how the impedance/current protection limitations would specifically apply to the NCore 400/SMPS600. The data sheet does rate them to 580w at 2 ohm loads (for 4 ohms bridged operation, with suitable power supply). I would also be sure the offset is properly adjusted in both.
UcD bridging
Q: I need double the power in an 8Ohm load than a UcD amplifier can produce. Is there some way I can bridge two, for example, UcD400’s?
A: You need to drive one of the modules 180 degrees out of phase by simply swapping the negative and positive input signal wires. Tie the loudspeaker between both positive loudspeaker outputs of the amplifiers and connect a 47n/200V capacitor across the loudspeaker terminals at the amplifiers’ side. This set-up is most applicable for 8 Ohm loads since each amplifier ‘sees’ 4 Ohms with an 8 Ohm load attached. A 4 Ohm load might trigger the current protection leaving you with not nearly as much power as you might have expected.
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Where are you located? Also, what's your system consist of?
Hi Jason. I am located just outside NYC, near Giants Stadium, in Nutley, NJ. I had a chance to hear your Ncore at Dan/letitroll98, Barry/barry-nj, Paul/occam and Martin/mjosef brought them to my house for three hours. Besides Martin, Barry and three members of one of the two audiophile clubs I belong to also came by and heard them. Unfortunately my system was in flux so not quit ideal. Only stock power cabling and no bi-wiring speaker cable for the B&W 802D (they love bi-wiring). No acoustical treatments and my B&W placement was a little off (they are spiked, so not easy to move). Because it was last minute I had to make due. Short version NO NOISE!! Did I say NO NOISE!! But it needs the right setup to be at its best. More in the "listening impressions" ASAP.
My system consists of B&W 802D (first series), PS Audio Perfect Wave Transport, DAC MK II and Bridge. Transport is connected to the DAC by HDMI I2S and Bridge is hard wired by Ethernet. The DAC is true balanced and I use balanced cables to the amp, Nuforce Reference 18 mono blocks. Cables are Synergistic Research Galileo Universal Speaker and Interconnect Cells with Basik cables. Power Conditioning is Synergistic Research Tesla PowerCell 10 SE MK II with Tesla Se Precision power cord. Vibration control is Finite Elemente Cerapuc. My rack is Salamander. Music is CD and High Res downloads. I bi-wire to the B&W 802D.
Holy Grail I: 4 NC1200 as 4 mono blocks bi-amping the B&W. (maybe bridged, 8!) if there was a way to do OEM.
Holy Grail II: 8 NC400 Bridged as 4 mono blocks bi-amping the B&W.
Holy Grail III: 4 NC400 as 4 mono blocks bi-amping the B&W.
Holy Grail IV: 4 NC400 Bridged as 2 mono blocks bi-wiring the bi-amping.
Well first I have to sell my Nuforce Ref 18s. Any takers? I will use the time to research and decide what number to go with (assuming I do not think of another choice).
Thanks for the tour.
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Has anyone actually seen power specs for the bridged Ncores? I have a 3 day old email into Hypex but nothing yet.
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I believe the specs aree 600w/8ohms. 1200W/4ohms. No rating for 2 ohms
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I believe that it is +/-1800W/2ohms and you are right on the 4 and 8 ohms.
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I'd be very leery about running them bridged with a 2ohm load, each amp would only see 1ohm and the Hypex data sheet doesn't rate them for that.
Also, with 2 x SMPS600 power supplies, only 1200W is available.
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I'd be very leery about running them bridged with a 2ohm load, each amp would only see 1ohm and the Hypex data sheet doesn't rate them for that.
Also, with 2 x SMPS600 power supplies, only 1200W is available.
It's just a matter of knowing the impedance of the speakers being used and if the impedance dips to what frequencies that happens at.
If you are looking at an electrostatic for example the low impedance is at higher frequencies where there isn't a lot of energy so the current shouldn't be an issue.
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I'd be very leery about running them bridged with a 2ohm load, each amp would only see 1ohm and the Hypex data sheet doesn't rate them for that.
Also, with 2 x SMPS600 power supplies, only 1200W is available.
Mike, do you mean 1 SMPS600 per chassis (2 modules) ? Is 1 PS per chassis recommended, regardless, or would you do 2?
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Mike, do you mean 1 SMPS600 per chassis (2 modules) ? Is 1 PS per chassis recommended, regardless, or would you do 2?
A single SMPS600 can source ~600 watts for music, so for 1200w you'd need a couple of them.
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Just got the following replies on DIY.
#4254
Juhleren is offline Juhleren Denmark
diyAudio Member
Join Date: Mar 2011
Quote:
Originally Posted by hifial View Post
In bridged mode the NC400 puts out 600w/8ohms-1200w/4ohms and what in 2ohms?
In bridged mode how many power supplies (smps) do you use or can use per bridged modules mono blocks?
If bridged, can the NC400 drive a 2ohm load?
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Al, If you bridge NCORE´s you should theoretically get 2x(what one can do in 4ohm) in 8ohm = 800W/8ohm. (twice the voltage swing and twice the current)
In a 4 ohm load you begin to hit the current limits as you now get twice of what it can do in 2 ohm = 1200W/4ohm.
In a 2 ohm load you are definitely hitting the current limits as each module can deliver 24 A and therefore each "only" swing 24 V into the 1 ohm they "see". That should give you roughly 24*24 = 576 W RMS and 1152 W Peak for the bridged amp.
Under such conditions I would give those amps as much current capacity as they can eat, so minimum a SMPS600 each. You could also consider to feed two NOCRE´s on a SMPS1200 which should save you some money...
This means that you should only benefit power-wise in above 2ohm loads where you get a whopping 1200 W RMS in 4ohm and 800 W RMS in 8 ohm.
Whether there should be any SQ differences has yet to be reported. But if you should try to bridge, then please report your findings
cheers,
waltzingbear is offline waltzingbear United States
diyAudio Member
Join Date: Nov 2005
Location: Portland. Oregon
Quote:
Originally Posted by hifial View Post
I have heard them with the B&W 802D. They are my speakers and a set of Ncore NC400 mono blocks that were loaned to me. I never said they sound strained or clipping when I have had more power and or the Ncore.
didn't mean to imply that. If you really want to know whats going on, measure the voltage being delivered to the speaker with a peak reading meter. The ones I am familiar with are the Fluke189 or 289.
With the ncore and other amps as long as you are within the voltage limits of the amp, you actually have more power for control of the speaker without bridging. The current capability is halved with bridging, and this is the area a lot of speakers "care" about. Doubling of the output impedance also goes along with this, which will double frequency response errors due to output impedance / load interaction. The way I see it, bridging is less power to the speaker, for most of the time.
If a designer was to build symetrical (ie bridging) operation into the design and incorporate the real world current needs of speakers into the design, that might be very interesting as a real (designed) push-pull system has many interesting features.
I have tried bridging independent amps in the past, was never satisfied with the results.
Alan
From Alan's post I have less interest in bridging the Ncore. Current is important to me just as much as watts. Unless someone can give me an over riding benefit, I am not bridging them. Any thoughts?
Al.
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hifial is online now hifial United States
diyAudio Member
Join Date: Feb 2011
Location: New Jersey, USA
Quote:
Originally Posted by Juhleren View Post
Alan I would believe too that bridging wouldn´t be a necessity for most well designed speakers driven with NCORE.
That said, and I suspect that we have been over this before, but bridging should not half the current capabilities of an amp, unless you run into other problems such as stability issues... We probably agree that with bridging each amp only sees one half of the load. But at the same time each amp also only needs to do half the work voltage-wise which means that they have to deliver exactly the same amount of current for the same total output to the speaker.
Effectively this means that where one amp would limit due to current capabilities it still will when bridging (same output potential) and where it would limit due to voltage swing you´ll get twice the potential swing of voltage.
Remember that both amps contributes hence their increased current output only occurs when you also have increased output power. The impedance of the speaker still follows Ohm´s law...
I understand that you don´t like what bridging does in the cases that you have tried it, but have you tried it with NOCRE´s?
That would still be interesting to try as the increased potential voltage swing possible could materialize into audible gains...
cheers,
AH! And the plot thickens. I guess I (we at AC) need to investigate this further. If I buy larger chassis for them and put in single mods and have room to bridge at a later date if I find out it would be worth it might be a way to go.
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Wonder of the SMPS 600 is regulated differently than the SMPS 1200?
Since the NC 400 has up to a +-75 V PS capability sounds like you could use a couple of smps 1200.
BTW the NC1200 has a +-100 V max rating.
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And the plot thickens.
Al.
Juhleren is online now Juhleren Denmark
diyAudio Member
Join Date: Mar 2011
Quote:
Originally Posted by waltzingbear View Post
Maybe I'm missing something here, but we can't have it both ways.
If the amp sees half the load, say 1.7 ohms instead of 3.4 ohms, it will potentially become current starved before the single amp configuration at the same volume level. Its not that the amp is any less capable when bridged, its that it sees half the load value. I'm not concerned with the voltage limiting, until someone measures and says they have peaks exceeding +/- 65V longer than 2 sec, I don't think voltage clipping is an issue.
Current is what I am referring to. The Ncore is rated into 2 ohms, how much below that I do not know. But we already see it sagging at 2 ohms. Current limiting is irrespective of voltage level (until we get to SOA concerns, which are negligible in class D amps)
Hence my comment that a single amp is better at delivering the power to the speaker within its voltage range. Yes, this is less than peak power with bridged amps, but I don't care about peak power, I care about current delivery in the area of concern, during the time it is below the voltage limitations of the single amp.
Does that make my view point clear?
Cheers,
Alan
Yes, you do seem to only look at one amp (one half of the bridge) and not the bridge as a whole (being one amp on the "hot side" and one on the "cold side" of the speaker).
One amp (one side) sees only 1,7R of 3,4R total but also only delivers half the voltage swing (for the same output power and current as a non-bridged amp would).
That means that a bridged amp can deliver as much power and current, but at only half of the voltage swing seen from each "amp" in the bridge.
Together they deliver the same total voltage swing and the same total current as a non-bridged amp would. The bridged config can´t deliver more current, but then it doesn´t have to either.
Lets take a quick n´dirty math example to make my point more clear:
non-bridged:
3.4R x 24A = 81.6V peak (this would in practice result in clipping due to the max 65 to 72V supply limitations, but if we overlook this we would end up with-> 81,6*24 = 1958.4 W peak and 979,2 W RMS both at 3,4R)
Bridged:
only one module:
1.7R x 24A = 40.8 V peak
both modules in the bridge will then deliver: 2 x 40,8V = 81,6 V peak
One module delivers +40.8V and the other -40.8V = total voltage potential on the terminals being the 81,6V
This then provides the 1958,4 W peak and 979,2 W RMS well within the voltage limits of 65 to 72 V per module
In comparison one module with one smps600 should according to the +/-65V "only" be able to deliver 65/3.4R = 19.12A which gives 19,12 x 65 = 1242,6 W peak and 621,3 W RMS @ 3.4R
The bridge is according to the math more powerful in a 3.4R load.
The point at which the bridge is only equally powerful to the non-bridge is in a 65V/24A = 2.7R load.
Hope that helped
cheers,
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I received an email reply from Jan-Peter at Hypex. I asked him, also, whether the briding causes a halving of current??
Ted,
No this is not true. The maximum current in bridging stays exact the same, with two amps you will have double the output voltage and exact the same output current. Please note that you need to use two SMPS600 if you go for bridging.
Regards,
Jan-Peter
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Please note that you need to use two SMPS600 if you go for bridging.
Is he saying that you would need two SMPS600's for each pair of NC400's?
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The Power Supply question is an interesting one...
The SMPS600 specs out as...
ELECTRICAL FEATURES:
- High Line Input Voltage: 180-264 Vac
- Low Line Input Voltage: 90-132 Vac
- Output Voltage: 2x65Vdc
- Max. Output power: 650W
- Max. Output power: 600W @20Hz
- Switching Frequency: 100kHz
and the SMPS1200A700 specs out as...
ELECTRICAL FEATURES:
- High Line Input Voltage: 180-264Vac
- Low Line Input Voltage: 90-132Vac
- Output Voltage: 2x85Vdc
- Max. Output power: 1500W
- Max. Output power: 1200W @20Hz
- Switching Frequency: 100kHz
and the SMPS1200A400 specs out as...
ELECTRICAL FEATURES:
- High Line Input Voltage: 190-250Vac
- Low Line Input Voltage: 95-130Vac
- Output Voltage: 2x64Vdc
- Max. Output power: 1500W
- Max. Output power: 1200W @20Hz
- Switching Frequency: 100kHz
So it would seem as though the SMPS1200A400 has an "Output Voltage" that matches the SMPS600, but the SMPS1200A700 has "High Line Input Voltage" and "Low Line Input Voltage' that match the SMPS600, and both offer double the "Max. Output power". I wonder if one of these power supply modules would work nicely with 2 bridged NCORE amplifier modules(?) Having heard the dead quiet provided by the SMPS600 I'd be a bit affraid of messing with something that really works.
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Is he saying that you would need two SMPS600's for each pair of NC400's?
Yes.
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Is he saying that you would need two SMPS600's for each pair of NC400's?
Yes, one PS per Amp Module to get the full additional power, as the max output of the SMPS600 is 600 watts.
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While many are thinking of the bridged N-cores because they have relatively inefficient speakers and play loud....there are those like myself who are looking for better sound at low wattage levels. My speakers run from 300hz on up and currently are 89db but will soon be 92+ I will never need more than 25 watts. However, I want the best sound possible. The bridged N-Cores may sound better in the first few watts....this is what I am interested in. Many other people have 95db speakers and don't need the extra power but may want better sound too. I am hoping that balanced bridged plain sounds better at all levels of power.
Another thing that may be limiting the grunt capability of the stock N-core may be its tiny power supply caps. What if you could add say a 10,000uf Jensen cap to the rail of each amp right off the output module (assuming the power supply can handle it). The sound would certainly be different and maybe more ballsy. Same with adding some large value poly caps across the rails as well......not to mention larger gauge wire from the power supply to the module. So, we have lots to experiment with but just running them bridged may be a whole nuther level by itself.
Who will be the first to listen to bridged amps?
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You might save yourself some time by reading the owner's manual and spec sheet....
Distortion at low power levels is already so low that it is beneath the noise floor of the measuring equipment.
Hypex has already said that adding any additional caps to the SMPS is a no-no....
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Of course I have read the specs, etc. So silly this kind of talk. What do measurements have to do with tweaking? If you like binding posts then please solder a bunch of them together for your speaker wire....I am sure it won't measure worse. he he.
Please share with me the exact post to read where Bruno said you cannot add power supply capacitance. I would like to read this. Thanks.
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The Ncores may be different, but all the amps I ever tried to bridge back in the 80's and 90's always sounded worse.
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Please share with me the exact post to read where Bruno said you cannot add power supply capacitance. I would like to read this. Thanks.
It's called a data sheet.
"*** The effective power supply storage capacitance of Hypex SMPS is already in excess of 4700uF. Do
not add supplementary capacitance. "
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The Ncores may be different, but all the amps I ever tried to bridge back in the 80's and 90's always sounded worse.
The bridged Spectrons were revelatory. Not even close; they transformed from the decent sounding stereo version.
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Thanks Mike for that info. I see it now in the data sheet. However, there are no large values of caps on the audio board or on the power supply. Maybe this 4700uf is as he says "effective"...meaning done via capacitance multipliers? He does not say the unit will not function if you add them, just he says not to do it. What I am is a possibilities type of guy. I am always pushing the envelope of those that say "no". I just emailed Jan-Peter/Bruno and will see if I can get some more info. Keep questioning, pushing the envelope and keep thinking....this is what makes this game fun....it never ends....no one knows everything and we need all think for ourselves. I am not interested in smoking a power supply or module, believe me....but what are the possibilities?
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The bridged Spectrons were revelatory. Not even close; they transformed from the decent sounding stereo version.
What do you expect from bridged Ncores?
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Dunno, good question. The only reason I am interested is that I have power hungry behemoths as speakers, and the only aspect I've reported with monoblock NCore's is a lack of the sort of dynamics I am used to, which was an area the Spectrons improved when bridged. That's all.. Hoping someone reports back soon.
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Dunno, good question. The only reason I am interested is that I have power hungry behemoths as speakers, and the only aspect I've reported with monoblock NCore's is a lack of the sort of dynamics I am used to, which was an area the Spectrons improved when bridged. That's all.. Hoping someone reports back soon.
I think also that your speakers will benefit.
After the summer I am building the Ncores in a 3 ch front. I have maggies.
Will see what's coming, perhaps Ric Schultz is shining some light in the dark.
Jerry
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Dunno, good question. The only reason I am interested is that I have power hungry behemoths as speakers, and the only aspect I've reported with monoblock NCore's is a lack of the sort of dynamics I am used to, which was an area the Spectrons improved when bridged. That's all.. Hoping someone reports back soon.
In the same boat here, I have bridged spectrons, I managed to run the ncore's into protection yesterday after adding some acoustic panels to my room, atleast they turn off nicely and recover pretty swiftly, no nastyness there.. Restriction of dynamics happens way before running them into protection, well ofcourse not fair comparing them to spectrons which can deliver like 10 times more power.
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In the same boat here, I have bridged spectrons, I managed to run the ncore's into protection yesterday after adding some acoustic panels to my room, atleast they turn off nicely and recover pretty swiftly, no nastyness there.. Restriction of dynamics happens way before running them into protection, well ofcourse not fair comparing them to spectrons which can deliver like 10 times more power.
What speaker/load are you driving and at what kind of levels, room size, etc?
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What speaker/load are you driving and at what kind of levels, room size, etc?
4 ohm load, ~88 dB efficiency, ~17x23 ft room.
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4 ohm load, ~88 dB efficiency, ~17x23 ft room.
Interesting...
My speakers are also a 4ohm load (Vandy 5A's) and even less efficient at 86 or 87 db's. My room is 29x17x8 and opens up into the kitchen and a 2 story entrance foyer. I played music so that it hit over 100 db peaks from 15-17' away and I never heard the amps clip, get hard or glassy.
Is that 4 ohm load a nominal 4 ohms with dips much lower?
Just goes to show...careful system matching is always required.
George
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I haven't tried the N-Core yet but I'm not a fan of bridging based on my limited experience in this area. I have a Coda amp that can be run bridged 2 channel or non-bridged 4 channel mode. I tested it several times in bridged and unbridged mode and, although the bridged mode is much more powerful, I prefer the sound in non-bridged mode, even though I'm only using 2 channels. My monitors are 4 ohms. The non-bridged mode is much cleaner and better sounding, to me at least. I had Phil Bamberg over a few months ago to help dial in my system and ran a blind A/B comparison of bridged versus non-bridged and he picked the non-bridged mode every time.
This was a surprise to me because I had been running the system in bridged for a while (it's way more powerful so I thought it would be naturally superior, better headroom, etc.). Don't know if the same would be true of the N-Core but I'd encourage someone who is considering running these bridged to compare them to a non-bridged N-Core system before assuming bridged is going to sound better. Honestly, I thought it sounded pretty good in bridged mode and I was surprised the non-bridged mode sounded so much better. My system has never sounded better but I'm going to check out the N-Core when I have a chance. Hopefully at Roscoe's place when the demo pair makes its way to Chicago.
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Yes, I think every situation is different with bridging, depending on load characteristics, etc.
I had two BEL 1001 amps that when bridged were an entirely different (good) beast, not at all related to levels/power demands approaching clipping. As a single stereo amp, it was just good, but not great.
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Yes, I think every situation is different with bridging, depending on load characteristics, etc.
I had two BEL 1001 amps that when bridged were an entirely different (good) beast, not at all related to levels/power demands approaching clipping. As a single stereo amp, it was just good, but not great.
+1
I've only a sampling of two (Modwrights and Spectrons) but when bridged they each blossomed, and their stereo counterparts weren't clipping.
George, my issue wasn't clipping, hardness or glassy feel at all. Just dynamics.
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+1
I've only a sampling of two (Modwrights and Spectrons) but when bridged they each blossomed, and their stereo counterparts weren't clipping.
George, my issue wasn't clipping, hardness or glassy feel at all. Just dynamics.
Understood.
Of course, I have the luxury of the having the built in subs and not asking the amps to handle below ~100 hz.
George
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Understood.
Of course, I have the luxury of the having the built in subs and not asking the amps to handle below ~100 hz.
George
Good point, but don't the amps see it anyway, or is the crossover before the amps?
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This may be a naive question. However...
Ted:
Is there any way that you could have a pair of NCores amping the tranmission line section of your Revelations and another pair for the top section? Or would that totally disconbumerate those beautiful crossovers I saw when listening to your system a couple of weeks ago.
In any case, I should have my NCores up and running this coming weekend and will be happy to let you "live" with them for some more time to see if you really need the extra ooomph that bridging would offer.
Regards,
Randy
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When the NC400s are bridged do any specs change besides power? When some amps are bridged the noise floor decreases significantly. That can contribute to a sense of increased dynamics.
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Randy, yes horizontal biamping would be an option, but it doesn't produce any more real voltage to the speaker as a whole (like bridging would, as each amp is still driven full-range i.e before the crossover). If I thought my tweeters were clipping I'd say biamping would help give them more headroom. May be bad logic though... :scratch:
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When the NC400s are bridged do any specs change besides power? When some amps are bridged the noise floor decreases significantly. That can contribute to a sense of increased dynamics.
Bridging can lower the noise floor? My understanding was that a downside of bridging was a somewhat higher noise floor. Of course with the ncore specs, discussion of noise floor may be moot since they could be extremely low in either case.
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my room opens into an L-shaped area about twice the size of the room but hey every room is/sounds different.. Impedance drops to ~2 ohms somewhere but its not that bad. They really have plenty power for most people, its just that I come from bridged spectrons with 10 times more power.. I know how plenty powerreserve sounds :icon_twisted: But it doesnt matter, I'm buying 2 more pairs and am switching to active which in my case will around triple headroom from dropping coils/resistors and halving power draw.
Interesting...
My speakers are also a 4ohm load (Vandy 5A's) and even less efficient at 86 or 87 db's. My room is 29x17x8 and opens up into the kitchen and a 2 story entrance foyer. I played music so that it hit over 100 db peaks from 15-17' away and I never heard the amps clip, get hard or glassy.
Is that 4 ohm load a nominal 4 ohms with dips much lower?
Just goes to show...careful system matching is always required.
George
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Re bridging, and depending on the topology of the amp in question, bridging can reduce power supply noise by summing output noise anomalies. Imagine a +going noise spike on the output of amp 1. All other things being equal (they never are, but bear with me), the same (or similar) +going spike will appear on the output of amp 2. These spikes will represent zero (or a small) voltage difference between + and – sides of the voice coil and thus will not actuate movement in the driver to the extent they are the same voltage spike. Noise reduction results.
Bridging an Ncore should provide this benefit---particularly, I would think, if the two bridged amps are driven from the same supply.
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Btw, I found this note on bridging from a manual for a UcD amp:
(http://www.audiocircle.com/image.php?id=64115)
Because Ncore inputs float, I don't think ground connection is stipulated for unbalanced input.
One other point, Bruno suggests the capacitor probably should be a bit higher for Ncore bridging, like 150nF.
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Ok guys, I have ordered four NC400's and 4 SMPS600's. Uriah Dailey is putting together my bridged mono's. I am waiting to hear from Hypex as to the ship date as I get the information I will post it on a new thread. Also I will ask Uriah to post pictures as the build starts. YAHOOOoooOOooOo :thumb:
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OK they shipped my 4 NC400's and 4 SMPS600's on Monday the 23rd, whew, now they are out and won't be shipping again until 9/3/2012. Case's ordered from Robert. We are moving in the right direction.
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I would agree with prior posters that the Spectron in stereo mode is descent but bridged (mono) mode takes it to a whole new level.
I think the benefit of bridging has to do with cancellation of distortion though and not noise as a prior reviewer explained. Any class D amp I have ever tried already had no hiss even if I put my ear up to the tweeter. But just because they have low levels of noise by no means meant they all sounded good. In contrast I have owned Class A/AB amps that sound phenomenal which however have an audible hiss if you put your ears next to the speaker.
So again, I think its pretty much a distortion cancellation phenomena.
For Spectron when you bridge - one way to think about it is you are cancelling distortion. The other way to think about it is your effectively taking the 500kHz sampling rate and doubling it to 1 Mhz. So what you notice is not only less distortion in midrange but also extended treble.
Mark Levinson in their 53 and did a full 2 MHz - so I would expect this Class D amp does not have any high frequency issues (although I have never heard it). Effectively what they did is bridged 4 amps each switching at 500kHz (and also did so in a syncronized fashion)
So in any case one of the key benefits of bridging the NC400s (if done properly) should be less distortion and better high frequency performance I would expect?
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Dan, if you're referring to me, by noise I meant distortion. Anything emerging from the output terminals of the amp that is not an amplified replication of the input signal is noise, or distortion. That noise may be modulated by the signal, but it's noise all the same.
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I am a comm engineer and for us the terms distortion and noise mean different things, but now I see you are using them in a loose way
So I think then we are on the same page. . .
Anyways, I am curious now to hear what the results are from the bridging!
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Ok guys the bridged mono's are being assembled, I will have pictures either tomorrow or Friday. Uriah is actually putting a board in that has mosfets tied to a switch that will allow stereo, dual parallel or bridged mono. Hoping this covers all options.
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Serengetiplains
Waiting for the explosion.....
Is there any news about the bridging "master"piece
Jerry
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Well I don't know about master piece but it is done and going through the final testing. We decided against the the mosfet board for switching and just made it a straight forward bridged mono. If I need dual parrell or a stereo amp I will just have to rewire. I should have it in the system next week and I will report back and post some pictures.
Guy
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Guy
thanks for the update. When its ready then its ready.
Interested if it not only deliver mass of watts but also is it stable and how about the quality.
Take your time.
Jerry
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Well my bridged monos ship today from Houston to Dallas so they should be here in a couple of days. I have not heard so many good things about an amp (from people who are not fans of class D no less) in a long long time. The guy that built my amps is not a big fan of class D, when he first got all four modules in the chassis he tested each of them to make sure all was well. He did this by going of to a friends who has a balanced pre, a well known Class D designer. He told me their mouths dropped and they could not believe how good the NCOREs sounded. Last night they repeated this process with the amps bridged, using Revel speakers the model just under the top of the line. Both thought the improvement by bridging them was out of this world. My guy told me it was one of the best amps he has every heard, this is from a tube guy. So I asked, well does that put them in the top 5 or top 10? He responded one of the top three amps he has every heard! No I didn't ask what the other two amps were as it didn't matter, he said the highs where the best he ever heard. I can't take it, can't wait till they get here. More to come.
Guy
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Well my bridged monos ship today from Houston to Dallas so they should be her in a couple of days. I have not heard so many good things about an amp (from people who are not fans of class D no less) in a long long time. The guy that built my amps is not a big fan of class D, when he first got all four modules in the chassis he tested each of them to make sure all was well. He did this by going of to a friends, a well known Class D designer. He told me their mouths dropped and they could not believe how good the NCOREs sounded. Last night they repeated this process with the amps bridged, using Revel speakers the model just under the top of the line. Both thought the improvement by bridging them was out of this world. My guy told me it was one of the best amps he has every heard, this is from a tube guy. So I asked, well does that put them in the top 5 or top 10? He responded one of the top three amps he has every heard! No I didn't ask what the other two amps were as it didn't matter, he said the highs where the best he every heard. I can't take it, can't wait till they get here. More to come.
Guy
:D :D :D :D :D :D
Oh Yes, that's we were anxious waiting for...
"Sounds" good looks like an understatement.
Jerry
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Wow!!! : "Both thought the improvement by bridging them was out of this world."
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Well my bridged monos ship today from Houston to Dallas so they should be her in a couple of days. I have not heard so many good things about an amp (from people who are not fans of class D no less) in a long long time. The guy that built my amps is not a big fan of class D, when he first got all four modules in the chassis he tested each of them to make sure all was well. He did this by going of to a friends, a well known Class D designer. He told me their mouths dropped and they could not believe how good the NCOREs sounded. Last night they repeated this process with the amps bridged, using Revel speakers the model just under the top of the line. Both thought the improvement by bridging them was out of this world. My guy told me it was one of the best amps he has every heard, this is from a tube guy. So I asked, well does that put them in the top 5 or top 10? He responded one of the top three amps he has every heard! No I didn't ask what the other two amps were as it didn't matter, he said the highs where the best he every heard. I can't take it, can't wait till they get here. More to come.
Guy
Wow!
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Are you using one or two power supplies per amp module?
Kind of weird how some people who have heard the bridged version have been so positive, while one other was rather negative...
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one power supply for each module, so two for each bridged amp. My guy tried it with rca to balanced with adapters and it was his opinion that using the NCORES with singled ended converted to balanced is missing the boat. All be it, they sounded very good, he said to his ears they sounded much much better when put in a truly balanced system. So I ordered a new balanced Lampizator about two weeks ago. :oops:
Good news is I may have a good deal for someone looking for a single ended 4.5 Lampizator, with remote volume. :o
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Thanks for the answer....
Wonder how they would sound bridged with one smps per two amp modules???? Hmmm, might have to give that a try at some point....
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Any news on the bridged ncore yet? :)
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Hi guys just a short note. The bridged Ncore's got here on Saturday. I have had the amps on since they got here but really have not sat down and listened closely. I can tell that they do a very good job from top to bottom though. I have read so much hype on this amp it will be hard for it to measure up LOL. Right now I am using 9 dollar adapter wires from Guitar center as my balance pre dac has not arrived, if just shipped yesterday (Monday). The Guitar center adapter wires have a plastic RCA connection and a very cheap balanced connection on the other end. For what it is worth the system is dead quite.
When the balanced pre dac arrives I will spend some serious time with the amp's. I would like to think with the Berning ZH270 and the Raven 6550 tube mono blocks that I had very nice amplification to begin with. I can tell already the NCORE's are better, surprisingly there is a lot more information (where did that come from :o ). I have not heard the 200 watt version so I cannot compare to the bridged sound. What I will say much like the bridged Spectrons which where 1800 watts per side into an 8 ohm speaker, the 800 watts of the NCORE like the Spectrons is not ball grabbing, earth moving or room shaking. It is much like a Cadillac, meaning smooth power and lots of head room. I guess one must keep in mind that the difference between 200 and 800 watts is only 6db, and the difference between 200 and 1800 watts is only about 10 db. So IMHO you are not going after BIG power for more decibels, you are doing it for head room, lower distortion etc. More to come when the balanced DAC/PRE arrives in about 10 days :thumb:
Guy
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Hi Guy:
If possible, can you post some pictures? I'd like to see how the power supplies are configured if possible.
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Thanks for the preliminary observations! Very interesting!
I am looking forward to your more detailed review.
Bob
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I can tell already the NCORE's are better, surprisingly there is a lot more information (where did that come from :o ).
Last night I listened to a lot of different familiar cuts, and it is so much easier to hear deeply into the fabric of the music to hear all the minute details- it is like a new, cleaner re-mastering of the recordings. I'm loving it.
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Thanks Guy for the quick update!
Also, are those Spectron3 Mk2 in bridged mode you are comparing to?
Would also be very interested if you could compare the bridged Ncore to bridged Spectron. . .
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Last night I listened to a lot of different familiar cuts, and it is so much easier to hear deeply into the fabric of the music to hear all the minute details- it is like a new, cleaner re-mastering of the recordings. I'm loving it.
No issues with "smear", shallow/narrow soundstage, or with the high end?
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No issues with "smear", shallow/narrow soundstage, or with the high end?
Focus and detail retrieval is as good or better than any I've heard. The only amp with a better soundstage I've heard is the 10 WPC Shindo Cortese.
Those who have heard the NC400 in my system agree on those points. These areas, plus the bass control, are the strong points of the amp, IMO.
The high end is the only area that I think may be problematical for some. Cymbals, etc. are very clean and well defined, with very nice, smooth "tails", but have less subjective weight than other amps. If a speaker has been designed around other amps that have more energy on top, the NC400 may seem recessed on top.
With my RAAL tweeters the highs are very clean, clear and well balanced, but those who like more bite on the top end might not find this aspect to their liking.
Initially my new amp was a bit too forward on the upper mids, but that has subsided pretty notably.
Net, I'm delighted with the sound. It is closer to an "invisible" amp than anything I'd care to pay for. My modded PS Audio GCC-500 (Icepower) amp, which I loved, sounded a bit muffled by comparison, so for me the NC400 is a real step forward at the price point. YMMV.
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I have 9 neo8 panels per line array and love the top end. My builder said it was the best top end he has ever heard. So once again it is all about the match ups. There is no perfect amp, speaker, DAC etc. I don't mind having folks over to hear but you really will not know until you hear it in your system at your home. Some folks love NCORE others not so much.
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jonbee - it wasn't clear - are you doing bridged too?
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Guy - 2 questions:
1) would love to hear how it compares to the Spectron bridged
2) did your builder on the bridged modules do level matching (I think I remember seeing a post where one could adjust output level with a resistor) . The reason I ask is to get optimum cancellation I would expect the levels should be matched between the two.
I see the spec on the NC400 calls out for a +/-.5dB difference in gain. Just from some quick calculations if one amp was at -.5dB and the other was at .5dB this would limit cancellation (just because of levels) to 19dB. Perhaps there are other issues too, do we require phase lock between the two units for optimum cancellation - I don't know. . . anyways thats why I am just wondering if there was anything special your builder did. . .
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2) did your builder on the bridged modules do level matching (I think I remember seeing a post where one could adjust output level with a resistor) . The reason I ask is to get optimum cancellation I would expect the levels should be matched between the two.
I see the spec on the NC400 calls out for a +/-.5dB difference in gain. Just from some quick calculations if one amp was at -.5dB and the other was at .5dB this would limit cancellation (just because of levels) to 19dB. Perhaps there are other issues too, do we require phase lock between the two units for optimum cancellation - I don't know. . . anyways thats why I am just wondering if there was anything special your builder did. . .
FWIW, I've measured about a dozen NC400's, while I didn't record the gain on them, all were really close in gain, way less than .5dB. If I had to guess I'd say they were all within .05dB of each other in regards to gain.
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Dan you make my point, this is why I did not build them :o . Uriah Dailey a well known and respected member of the DIY Community was my builder. Uriah also does a lot of OEM work, this is how he makes his living. I know he tested each unit thoroughly so he wouldn't have any issues down the road. But that is as far as I know, you can get him on the DIY board.
As far as Spectron Vs NCORE goes I think Spectron was on the fore front. John Ulrich was working on digital when he and Arnie owned Infinity speakers. I believe Bruno has taken it to a new lenel, he has really really done a great job with his modules :thumb: .
I have switched a lot of gear to look for some better, I am getting to the point where switching will only get me different. Not saying I have the best but am saying I have some of the very best for my room and my ears, can I hear an amen? :dance:
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Guy,
Thats great to hear that your bridged Ncore sounds so good!
Can you share in what areas do you feel your bridged Ncore excels in? Compared to your bridged Spectron or any other amps?
Also can you tell us what kind of Spectron you have?
Sorry for all the questions but I am planning on upgrading my amps soon and these are both on my list. . . so any feedback would be greatly appreciated!
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jonbee - it wasn't clear - are you doing bridged too?
Sorry, not bridged. Just dual mono, one module per channel.
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Hey Dan, pm me your number if you would like to chat. Quite frankly since I installed my Lampizator a year and a half ago I have quit listening so critically. And what I hear in my house matched with my other gear is not going to be what you hear. My short answer would be the bridged Ncore amps are the most transparent and musical combo (in my set up). Meaning you can find (I am guessing here) a more transparent amp and you can find a more musical amp but one at the expense of the other. The Ncore gives you both, you can find an amp that excels at one or the other better but not both combined, does that make sense? And these amps do sound live like you are at the event :drums:
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More to come when the balanced DAC/PRE arrives in about 10 days :thumb:
Guy
playntheblues
Now that you have had the balanced DAC/PRE for a couple of weeks are you ready to comment?
Bob
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Guy, what did you get?
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Hey guys there has been a delay. Since I use my DAC (LampizatOr) as a pre I needed more gain. Lukasz is mailing me a more powerful DAC board on Monday.
Other than the power the system is sounding wonderful. However I am beginning to realize once again that changing two things at once is not such a good idea. If makes it really hard to pin point what changes are coming from where.
The big changes are...sound stage is much larger and pin point, clarity and musicality. As I get more familiar with the new gear I will share. :D
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Ok guys a little more insight. The bridged NCORE amps are clean clean clean, very transparent, you miss nothing. I love detail so this great for me, but over the years I have grown to like some tube magic, liquidity, body to the music. You all know the age old argument.....Tube lovers think to much transparentce is thin sounding and harsh, while the SS lovers feel to much body is just distorsion.
So for me and my tastes in my room I have combined the Ncores with a balanced LampizatOr Level 4.5. This DAC/Pre has two output tubes ECC 82's and a tube rectifier 5Y3. I have changed the ECC 82's for some Brimmar ECC81 which I feel gives the music body. I also changed the plate resistors at the same time, all according to Lukasz's instructions.
I like this combination of tubes and class D. I am trying not to be over the top with these amps but man are they clean and transparent :o. I have not heard them with a SS. Pre but in my system they are smooth. My last two amps, to give you some perspective were..Berning ZH 270 which was my favorite pre NCORE and before the Berning was Spectron monos maxed out.
I will write more as everything seatles in.
Stay thirsty my Friends 8)
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I hope you have some pictures to post. A picture says more then........ and all that. :D
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Btw, I found this note on bridging from a manual for a UcD amp:
(http://www.audiocircle.com/image.php?id=64115)
Because Ncore inputs float, I don't think ground connection is stipulated for unbalanced input.
One other point, Bruno suggests the capacitor probably should be a bit higher for Ncore bridging, like 150nF.
I have a Y-splitter and wondering if I could quickly try out bridging with my monoblocks?
Is it possible to bridge by instead using the same polarity on both inputs, and invert the outputs instead?
In other words, on Amp1 the red output goes to speaker red and the black output goes to ground,
and on Amp2 the black output goes to speaker black and the red output goes to ground.
High-level its the same concept, but perhaps there are some gotchas related to DC on the lines, or perhaps only the minus outputs can be grounded, etc?
Does anyone know?
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That will work. I built a pair of amps using the configuration you quoted. Sounded very good.
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NVM, I wasnt reading your post fully. You need to build it the way it is in the pic to be safe. Dont cheat it. Besided this isnt to hard to wire up and you can easily return to normal config.
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Appreciate the tip - I will follow the diagram then - thanks!
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Ok - so I bridged my stereo NC400 last night - I used a 150nF cap per recommendation for Ncore
I also have a mono NC400 so I was able to rapidly do an A/B (using only one speaker at a time and connecting the interconnect to amp under test)
Overall my initial impressions were I liked what I heard with bridged - - music was more engaging, partly I think because sounds were more defined.
Going from my Class AB amp to NC400 I had the exact same reaction - I didn't want to go back my Class AB after listening to NC400 mono.
Now after listening to bridged NC400 I did not want to go back to mono - its funny that I thought mono sounded so good until I listed to bridged
With one speaker at a time, I could not test sound stage, imaging, etc - although my guess is those would be improved too
Overall, the jump from my Class AB to mono ncore was the bigger jump, but bridged was definitely better
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Very interesting... are you going to order another set? Keep us posted.
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Are you matching SPL's when making the comparison? It's funny but slightly higher SPL's will give you the false impression of more dynamics or more depth, etc., not to mention placebo affect. I've never tried a bridged ncore but I've tested various amps in bridged mode and they always sound better to me in non bridged mode.
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Are you matching SPL's when making the comparison? It's funny but slightly higher SPL's will give you the false impression of more dynamics or more depth, etc., not to mention placebo affect. I've never tried a bridged ncore but I've tested various amps in bridged mode and they always sound better to me in non bridged mode.
That was my first thought as well. Bridged should give a slightly higher gain, so matching is required to make a comparison.
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I went with the assumption of 6dB of gain difference - although on a 2nd test I reduced this to about 4-5dB.
I did the calibration by ear with music, not properly with a meter and white noise.
I plan on repeating this test more thoroughly when I get a chance.
During my 2nd test, my conclusion was the overall sound is very similar, the tonal balance is identical, the low distortion, low noise, etc also sound substantially the same
In trying to pinpoint the difference I would say the diifference would be in the dynamics. I thought the sounds have a little more pop to them then with single amp. Again, I need to repeat the test a 3rd time with more controls to confirm this for sure.
Just to be clear, bridging is not a whole level difference above - as what the NC1200 amp users are reporting.
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I have done bridging with 2 nc400 and 1 smps1200 per monoblock.
It sounds more dynamic and warmer sound than the standard nc400+smps600 in the test setup.
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Can you say more about your system.
Most specifically, are you using a balanced or single-ended source?
TIA!
Greg in Mississippi
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Can you say more about your system.
Most specifically, are you using a balanced or single-ended source?
TIA!
Greg in Mississippi
Balanced source, is there any other way to do it? ;) I have Burmester cd-player, preamp and speakers.
The first listening was done with an Antelope Zodiac Gold dac/preamp. Also balanced. In a very nicely acoustically treated room.
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Woah! Sounds like a very serious system!
Thanks... I've been a bit cautious about going to bridged on my NC400 until I get a balanced source going, based on some comments from Bruno that I saw in a thread somewhere (maybe this one?). Your experience didn't make me any less cautious... if anything, just a bit more determined to get that balanced DAC project going again.
Of course, the main issue with this for me is that I have no plans for a balanced phono stage!
Greg in Mississippi
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Hello, I'm curious to hear if anyone is bridgng these amps with sucess using a pair of speakers that are known to dip into the 3ohm range?
Personally, I have decided against bridging (at the moment) due to the fact that I know my speakers dip into the 3ohm range (B&W 803di) and according to what I have read about these amps it seems they are already brushing up against the power supply limits into a 4ohm load while bridged.
Are those who are bridging already know their speakers are not dipping below 4ohms?
How likely is bridging with the NCore any better than multi-amping a speaker with the NCore? If anything, it seems from a math standpoint multi-amping has the advantage since one is less likely to run out of power supply steam when considering the wide array of speaker impedances that may be encountered in the real world.
Thanks in advance for your thoughts on this matter.
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Hello, I'm curious to hear if anyone is bridgng these amps with sucess using a pair of speakers that are known to dip into the 3ohm range?
Personally, I have decided against bridging (at the moment) due to the fact that I know my speakers dip into the 3ohm range (B&W 803di) and according to what I have read about these amps it seems they are already brushing up against the power supply limits into a 4ohm load while bridged.
Are those who are bridging already know their speakers are not dipping below 4ohms?
How likely is bridging with the NCore any better than multi-amping a speaker with the NCore? If anything, it seems from a math standpoint multi-amping has the advantage since one is less likely to run out of power supply steam when considering the wide array of speaker impedances that may be encountered in the real world.
Thanks in advance for your thoughts on this matter.
I need to build a couple bridged mono blocs, each with one SMPS1200A400. Thanks for all the data and contributions to this lovely thread.
Re. above quote: minus any reference to PS associated with bridged NC400, its performance specs into any particular loudspeaker are unknown and unknowable. Specs for the bridged mono/one SMPS1200A400 or two SMPS600: 400/800/1200W @ 8/4/2 Ohm, safe to 1 Ohm but no rating. With one SMPS600: 400/800 @ 8/4 Ohm, safe to 2 Ohm but no rating. I presume bridged mono not suitable for single SMPS400, but OK for two SMPS400, unknown specs.
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Specs for the bridged mono/one SMPS1200A400 or two SMPS600: 400/800/1200W @ 8/4/2 Ohm, safe to 1 Ohm but no rating. With one SMPS600: 400/800 @ 8/4 Ohm, safe to 2 Ohm but no rating.
Where do those specs come from? What, in your view, is the limiting factor/parameter for going down below 2 ohm?
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Where do those specs come from? What, in your view, is the limiting factor/parameter for going down below 2 ohm?
Email from Bruno to me provided the following specs for single SMPS600 powering:
- One NC400: 200/400/600W @ 8/4/2 Ohm, safe to 1 Ohm but no power rating
- Two NC400: 200/400W @ 8/4 Ohm, safe to 2 Ohm but no power rating
I'm pretty sure the data sheet echoes the above specs.
Whether modules are bridged or not (see Jan-Peter's comments in this thread), maximum power per module = 600W into the speakers, requiring 600W of power supply current, yielding safe current to 1 Ohm minimum but no power rating.
Take #1 above: doubling the modules (bridged pair) and doubling PS current (1200W) = 2x W across the board and impedance specs stay constant. Ditto 600W PS powering bridged pair NC400 = 2x W across the board and impedance specs stay constant.
So PS current and number of NC400 determines minimum impedance into which NC400 is safe and minimum impedance into which the amp delivers rated power. AFAIK this relationship is linear and unrelated to whether NC400 is single or bridged.
I compared several times and can't seem to tell a difference between mono blocs each powered by SMPS600 and stereo powered by single SMPS1200A400 (about $400 lower cost).
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Email from Bruno to me
Thanks - I am curious, did Bruno actually use the word "safe"?
So PS current and number of NC400 determines minimum impedance into which NC400 is safe and minimum impedance into which the amp delivers rated power. AFAIK this relationship is linear and unrelated to whether NC400 is single or bridged.
I agree with the "minimum impedance into which the amp delivers rated power", as the amps become current-limited. But I am curious about the "safe" part. What does "unsafe" mean? Amp goes in to oscillation? Amp gets damaged?
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Thanks - I am curious, did Bruno actually use the word "safe"?
I agree with the "minimum impedance into which the amp delivers rated power", as the amps become current-limited. But I am curious about the "safe" part. What does "unsafe" mean? Amp goes in to oscillation? Amp gets damaged?
Yes, IIRC Bruno used the word "safe."
It means you are, employing the late James Bongiorno's words to me, "tempting fate." It means to employ a load with less than the rated safe spec is "unsafe" and hence outside the intended use/application of the device. I presume all vital components have similar performance ceiling, meaning any number of immediate major component failures from one to most of the major components might fry. Conversely, if the many failure systems all work perfectly, you might replace only a fuse. That's where "tempting fate" comes in.
The point is, specs like minimum load impedance can be confirmed, and must be confirmed if there is any doubt, and to ignore or exceed the specs is "unsafe" and to be avoided. IOW, spend $X now on more PS or risk spending even more $ on blown amp/speakers later. Like Dirty Harry asked, "Do you feel lucky?"
Professionally and legally and ethically, I presume, if/when any amplifier component burns in use, the OEM can claim such burn proves abuse. IOW, it would be 100% up to the user to prove normal use, and by definition they would fail in legal claim unless there was huge class action with some huge rate of failure.
When Kawasaki released a new liter class Superbike several years ago, a major motor failure soon occurred, which caused Kawasaki to replace a bunch of motors. They didn't wait for the lawsuit because they'd have lost and incurred more damage in reputation. As it turned out, no harm/no foul, all was soon tranquility.
If such amplifier use burnt any loudspeaker component, beware that per professional and legal definition, a burnt loudspeaker component always and only defines abuse, whether or not the speaker company agrees to replace the burnt component, which they generally do not because to do so only promotes further abuse. Usually charging such abuser for their abuse one time is enough to cause the intended behavior change.
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Yes, IIRC Bruno used the word "safe."
Interesting. This is the first time I hear that low load impedances might be "unsafe".
The NC400 data sheet does contain a section with "Absolute Maximum Ratings", with a warning that irreversible damage might occur as a result of exceeding the specified limits. Load impedance is not among those parameters (it is only in the "Recommended Operating Conditions"). The only load-related parameter is Peak Output Current, and the data sheet specifies that it is "Guarded by current limit at 24 A" - clearly the current protection circuitry is there to protect against excessive output current (caused by a load impedance that is too low).
It means you are, employing the late James Bongiorno's words to me, "tempting fate." It means to employ a load with less than the rated safe spec is "unsafe" and hence outside the intended use/application of the device. I presume all vital components have similar performance ceiling, meaning any number of immediate major component failures from one to most of the major components might fry. Conversely, if the many failure systems all work perfectly, you might replace only a fuse. That's where "tempting fate" comes in.
OK, so you don't actually know what the supposed failure mode would be, and what the actual limiting factor is?
The point is, specs like minimum load impedance can be confirmed, and must be confirmed if there is any doubt, and to ignore or exceed the specs is "unsafe" and to be avoided.
See my comment above about "Absolute Maximum Ratings" vs. "Recommended Operating Conditions".
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I think we're going in circles, on the same page, etc.
Anything can fail. Current limit protection comes under the heading "anything."
The sole purpose of the amp's current protection is to protect components from burning as a result of current exceeding a certain threshold, beyond which a component's risk of frying rises exponentially. All these items don't matter except at the margin. In the middle of the curve or below they are irrelevant.
The lower the load impedance the higher is current demand. If you believe current demand and load impedance are universally unrelated I strongly disagree.
When one clearly crosses the line (beyond gray area) re. minimum load impedance, and for whatever reason the amp's "current limit" protection simultaneously fails for any time period no matter how brief (they only must occur at the same time), what is the obvious or implied risk? Burn component and that acrid smell of money flying out one's wallet with which I'm all too familiar.
We're back to "tempting fate."
The less are my personal finances at risk the less interest I have in persons ignoring the advice.
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I think we're going in circles, on the same page, etc.
Quite. Maybe the easiest way to clarify things would be if you could post the actual email you got from Bruno?
Anything can fail. Current limit protection comes under the heading "anything."
Anything can fail - but assuming anything can fail there is nothing that can be considered "safe". Everything can fail as a result of something else failing.
The lower the load impedance the higher is current demand. If you believe current demand and load impedance are universally unrelated I strongly disagree.
Where do you think I have stated that current demand and load impedance are universally unrelated? I specifically stated that peak output current is a load-related parameter.
When one clearly crosses the line (beyond gray area) re. minimum load impedance, and for whatever reason the amp's "current limit" protection simultaneously fails for any time period no matter how brief (they only must occur at the same time), what is the obvious or implied risk? Burn component and that acrid smell of money flying out one's wallet with which I'm all too familiar.
Would Hypex really specify a limit for the load impedance based on "this could cause damage to something, *but only if the protection doesn't work as intended*?
We're back to "tempting fate."
That still doesn't address potential failure modes / limiting factors.
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Yes, IIRC Bruno used the word "safe."
I actually checked with Hypex. They don't see any reason why connecting two modules to the supply would suddenly raise the 'safe' load impedance to 2 ohm either.
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I finally built two bridged mono. I estimate it's one clear step up in performance vs. regular SMPS600 mono or SMPS1200 stereo. Everything that's good about the regular amp is improved, even the bass, if that's possible.
I have earthed all chassis prior to this bridged amp. The only thing that solved fairly bad AC Mains hum in the bridged amp was to lift the chassis earth. Appreciate comments if you have any light to shed on the issue of AC Mains noise, bridged vs. not bridged, chassis earthed vs. not.
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James,
Thanks for the update. Pix would be great!
Did you use one SMPS per channel or one per module?
This may get me off the mark to convert mine to a bridged set!
Greg in Mississippi
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Howdy Greg,
I used one SMPS1200A400 per two NC400, in Siliconray's "RE2507-NC" chassis.
I plan more thorough testing by Tuesday, including direct A-B with regular mono SMPS600.
So far it seems like there's less noise modulating with the music, less grunge, it has more density like the best tube amps (I'm not saying it equals the best tubes in this regard, just more of this effect than regular mono). It sounds calmer, lower stress.
The stock mono is already pretty good in all these aspects, it just seems like the bridged amp is better.
SMPS1200 is the only power supply to use unless cost is no concern. Two 1200s cost slightly less than one 600.
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Keep in mind that when you bridge an amp each channel thinks its driving a load of half of what you put on it. To the bridged amp an 8 ohm load looks like 4. and 2 ohms looks like 1.
Very few amps will like being bridged into a two ohm load because it looks like one ohm.
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Roger, what you posted I have read is the case with stereo amp used as bridged mono. But IIRC Hypex principal Jan-Peter said it's not the case with bridged NC400, but that may apply only when bridged PS current is doubled vs. stereo.
My 93 dB AudioKinesis Zephrin 46 speakers are unique in that each channel comprises two 16 Ohm separate loudspeaker loads: a "Main/On Axis" section and "Late Ceiling Splash" section. The two sections can wire parallel (8 Ohm) or series (32 Ohm). Bridged NC400 makes 100W @ 32 Ohm, so I'm anxious to audition it both ways.
I shall also audition bridged NC400 powering the 16 Ohm "Main/On Axis" section, with my receiver powering the 16 Ohm LCS section.
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Roger, what you posted I have read is the case with stereo amp used as bridged mono. But IIRC Hypex principal Jan-Peter said it's not the case with bridged NC400, but that may apply only when bridged PS current is doubled vs. stereo.
My 93 dB AudioKinesis Zephrin 46 speakers are unique in that each channel comprises two 16 Ohm separate loudspeaker loads: a "Main/On Axis" section and "Late Ceiling Splash" section. The two sections can wire parallel (8 Ohm) or series (32 Ohm). Bridged NC400 makes 100W @ 32 Ohm, so I'm anxious to audition it both ways.
I shall also audition bridged NC400 powering the 16 Ohm "Main/On Axis" section, with my receiver powering the 16 Ohm LCS section.
I use the term bridged to mean that one channel is driven 180 degrees out of phase and the load is connected between the hots. Does he do something different?
The supply current is doubled.
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But IIRC Hypex principal Jan-Peter said it's not the case with bridged NC400, but that may apply only when bridged PS current is doubled vs. stereo.
In view of the previous exchange in this thread, can you share with us Jan-Peters exact words?
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The only thing that solved fairly bad AC Mains hum in the bridged amp was to lift the chassis earth.
Do you have a schematic of your earthing scheme?
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In view of the previous exchange in this thread, can you share with us Jan-Peters exact words?
I'll search his posts here and quote him if I find it.
Again, the speaker can be wired parallel for flat 8 Ohm above the bass range, 6 Ohm minimum, worst case moderate phase angle. 8 Ohm = 93 dB per 1W input (2.83V). 32 Ohm = 87 dB per 1/4W input (2.83V).
I presume SMPS1200A400 powering Bridged NC400 = 100W @ 32 Ohm. IIRC someone I trust stated NC400 does not change distortion spectra into different impedance loads, but I personally checked and same as every SS amp I know of, it's distortion spectra degrades (albeit not a lot) as load impedance decreases. This of course implies the opposite, being more pleasing distortion spectra as load impedance rises (up to a point I suppose, that point being unknown to me...there are certainly very few speakers with high load impedance to test this).
Supposing Bridged NC400 had reasonable to more than reasonable magnitude of head room powering the 32 Ohm load described above. Does anyone know why performance might improve powering the 8 Ohm load?
It's a completely different animal, but just for reference, I auditioned over long period my analog chip amp powering both the 8 Ohm and 32 Ohm loads (into these loads the amp makes 100W and 25W, respectively). Powering the 32 Ohm load it was immediately obvious that treble quality improved, with a large portion of that shimmering magic of the best SE tubes. But after time, overall I preferred the 8 Ohm load for its power advantage. It just sounded more "grounded." As usual, still no free performance lunch.
It appears Bridged NC400 has good power reserve into 32 Ohms, with better perceived distortion spectra vs. typical 8 Ohm load. A 100W amp with a 1200W power supply...the proverbial iron fist in a velvet glove.
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Roger, what you posted I have read is the case with stereo amp used as bridged mono. But IIRC Hypex principal Jan-Peter said it's not the case with bridged NC400, but that may apply only when bridged PS current is doubled vs. stereo.
My 93 dB AudioKinesis Zephrin 46 speakers are unique in that each channel comprises two 16 Ohm separate loudspeaker loads: a "Main/On Axis" section and "Late Ceiling Splash" section. The two sections can wire parallel (8 Ohm) or series (32 Ohm). Bridged NC400 makes 100W @ 32 Ohm, so I'm anxious to audition it both ways.
I shall also audition bridged NC400 powering the 16 Ohm "Main/On Axis" section, with my receiver powering the 16 Ohm LCS section.
If your only load option was 32 ohms then bridging would make sense.
Again, if bridging is hooking up the load between the hots you will get the same power using just one channel as you will using two, so why use two. One channel is 100 watts at 8 ohms, isn't it? :scratch:
From Hypex website (technology ucd)
Reasons for choosing full bridge:
dot_or Voltage swing. At the current state of MOSFET technology, diode recovery problems become prohibitive for devices of VBRDSS>150V. If more than, say 50Vrms of output swing is required, either current-steering diodes must be added, or a full-bridge configuration selected. We are aware of people building class D amplifiers using 200V MOSFETs without using current-steering diodes, but these designs have serious EMI and efficiency problems because of this.
dot_or DC operation. In non-audio applications where DC output voltages and currents are required, bus runaway (pumping) pretty much rules out half-bridge designs.
Not reasons for choosing full bridge:
dot_or Pumping (in an audio application). The storage capacitance needed to produce a suitable DC supply is already sufficient to render pumping effects pretty much a non-issue. Much is made of the pumping problem by people who have full bridge amplifiers to sell.
Reasons for choosing half bridge
dot_or Economy. For up to a few hundred watts, half bridge power stages are the lowest cost solution, and are also the most compact. Otherwise put: for the vast majority of applications, half-bridge amplifiers are the default choice.
Not reasons for choosing half bridge:
dot_or “Better performance or sound quality”. Given equal care in design, there is no difference in attainable performance in full-bridge or half-bridge amplifiers. No sonic differences have been found caused by the power stage arrangement.
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It's not my amp. It belongs to a client. Actually, one NC400 makes 200W @ 8 Ohm.
Again, I presume, all things being equal, distortion spectra improves with increasing load impedance, which If this is correct, might justify Bridged 100W @ 32 Ohm over single NC400 @ 8 Ohm (latter makes twice the power).
I'm wiring the series load right now while my mountain bike patch dries.
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I made, well, a lot of NC400 single mono/SMPS600 and stereo/SMPS1200. For reasons relating to cost and performance above the bass range, some time ago I "downgraded" from single NC400 to my old standby analog chip amps.
Brand new, no hours, Bridged NC400 making 100W into this 32 Ohm load is a revelation. It simply blows away mono NC400, not even close. It's a completely different animal. Of course YMMV, depending on the load, room, personal taste, ad infinitum.
I am not at all looking forward to downgrading from Bridged NC400 to the analog chips now.
It should take only a few minutes to switch to 8 Ohm load to directly compare. Considering with peaks above 100 dB there was no audible distortion into 32 Ohm load (100W), I predict worse performance (less pleasing distortion spectra) into 8 Ohm, but we'll see.
Remember that the higher the load impedance the better is loudspeaker audible performance, and vice versa. This is because the higher the load impedance the smaller is the ratio of the wire's contribution to the entire load (wire + speaker).
Wire is effective 9AWG, about 12' total.
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It should take only a few minutes to switch to 8 Ohm load to directly compare.
That is still much longer than human auditory short-term memory, so it won't be a "direct" comparison.
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What? I can remember years later......you simply do not trust yourself nor your experience.
If you have a reliable constant reference then you can easily discern differences.....even day to day.
Some years ago I put on the first Stereophile test disc after not hearing it for several years......different systems in each case. Clearly did not sound as good as before......yes, I remembered. So, I tweaked the speakers and there it was......much better sound. You can remember! You can hear! You can discern differences! Yes, it does not take a "Golden Eared One". Anyone can do it......but you have to actually listen with an open mind to a very tweaky system.
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Humor me for a moment.
Do you hear differences between components/speakers in their ability to accurately portray pitch?
Forgive me for stating what might be obvious, but harmonic overtone structures determine differences between a flute (closest to sine wave, few harmonics) and violin (sawtooth waveform, all multiples of the fundamental and high in level). These are direct mathematical relationships of which we speak.
The higher is pitch sensitivity in the entire chain (from the instrument to the ears and everything in between) the more easily is pitch perceived. The more is pitch perceived the greater is the illusion maintained and the lower is the listener's stress level (less brain activity required for a given magnitude of illusion).
Can you tell if one instrument is more closely tuned to pitch than another? Presume one guitar is tuned for John Williams (guitarist, not the schlock movie score composer), the other by a not so great 12 year old guitarist. These are extreme examples only to make the point.
Would you necessarily need only a brief time period between hearing the two guitars to know one is tuned closer to proper pitch?
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Do you hear differences between components/speakers in their ability to accurately portray pitch?
None of my speakers or systems distort pitch in any way - they reproduce pitch accurately. They might not reproduce amplitude relations between harmonics totally accurately, but they do not distort pitch.
Would you necessarily need only a brief time period between hearing the two guitars to know one is tuned closer to proper pitch?
No, because an error in guitar tunings are reflected in incorrect pitch relationships that are audible without reference to any other sound, because a guitar tuning is not an absolute thing, it is a relation between the strings of the guitar, so you reference the pitch of each string against the pitch of the other strings, not against something you have to retain in your memory. A change in *colour* (in terms of frequency response or distortion) isn't referenced to anything except you recollection, so is harder to detect after a delay.
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None of my speakers or systems distort pitch in any way - they reproduce pitch accurately. They might not reproduce amplitude relations between harmonics totally accurately, but they do not distort pitch.
No, because an error in guitar tunings are reflected in incorrect pitch relationships that are audible without reference to any other sound, because a guitar tuning is not an absolute thing, it is a relation between the strings of the guitar, so you reference the pitch of each string against the pitch of the other strings, not against something you have to retain in your memory. A change in *colour* (in terms of frequency response or distortion) isn't referenced to anything except you recollection, so is harder to detect after a delay.
Pitch is referenced to the fundamental apart from the harmonics. The notes on the music staff reference the fundamental and are oblivious to harmonics. But harmonics are direct mathematical multiples of the fundamental. So this begs the obvious question: in audio, exactly how can harmonic distortion be compartmentalized separately from the fundamental? I doubt the two are separate from each other. If the two are intertwined (how can they not be?), then HD and pitch are interrelated.
Toole knows a few things about this. He posits one of the benefits of improved reverberant field is improved pitch sensitivity. The ear gets a "second look" at the pitch (Geddes says ideally 10-20ms later), thus solidifying the first on-axis impression. IMO this "second look" at the pitch also lowers stress and increases the illusion of live music. Over the past 1.5 years I've had the luxury of turning on-off the reverberant field section of my loudspeaker.(which comprises two separate full range speakers per ch).
Perhaps one could envision the orchestra and chorus of Beethoven's 9th or a huge Wagner piece and imagine all these instruments playing inter related pitches, and imagine that there is more to pitch portrayal than is commonly believed to be the case.
Regarding the two guitars, I asked if time passing would affect one's ability to judge which guitar was more properly tuned vs. the other, or meant to if I did not.
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I asked:
Do you hear differences between components/speakers in their ability to accurately portray pitch?
Followed by:
None of my speakers or systems distort pitch in any way - they reproduce pitch accurately.
If I was hard pressed to state whether your reply is closer to "yes" or "no," I'd have to guess "no."
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Regarding the two guitars, I asked if time passing would affect one's ability to judge which guitar was more properly tuned vs. the other, or meant to if I did not.
And i answered, or meant to, that the tuning of one guitar string is referenced relative to the other strings. You don't compare the tuning against a remembered acoustic picture, you listen for harmonic intervals. When comparing two reproduction systems you don't have that reference, and are forced to rely on auditive memory.
Anyway, that has nothing to do with bridging.
You are claiming and suggesting a bunch of things that contradicts what Hypex (the designers and manufacturers of the modules) are saying. I think I prefer to believe Bruno and the Hypex technical people, as they ought to be the ones who know their own modules.
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I made, well, a lot of NC400 single mono/SMPS600 and stereo/SMPS1200. For reasons relating to cost and performance above the bass range, some time ago I "downgraded" from single NC400 to my old standby analog chip amps.
James,
I'm wondering how much of the difference is the SMPS600 versus the SMPS1200. Do you have experience with single or dual NC400s with each of these SMPS's and whether you heard any differences?
TIA!
Greg in Mississippi
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Bump.
Just curious if anyone else out there has heard a bridged nc400 mono block lately and compared it to standard version.
I have yet to listen to a nc400 amp but hope to someday, so just wondering if bridging is worth it for these amps.
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I have yet to listen to a nc400 amp but hope to someday, so just wondering if bridging is worth it for these amps.
Bridging is worth looking at if you need more power and have speakers with an impedance that doesn't drop too low, but otherwise it doesn't make any sense.
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Bridging is worth looking at if you need more power and have speakers with an impedance that doesn't drop too low, but otherwise it doesn't make any sense.
Thanks for the reply.
I have some speakers coming that are a 3 way design with 87db sensitivity and 4ohm nominal.
Do you think they could benefit from a bridged nc400 mono pair? I do like to play loud at times.
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I have some speakers coming that are a 3 way design with 87db sensitivity and 4ohm nominal.
Do you think they could benefit from a bridged nc400 mono pair? I do like to play loud at times.
87 dB/1W means 113 dB/400W. That is pretty darn loud.... So no, I don't think you need bridging.
My Isobariks have a sensitivity of 86 dB, and we have our own house, so I can enjoy really loud levels if I want to - and I have never yet reached full volume on the volume control.
4 ohm nominal could mean too low at the lowest impedance points.