Newbie Help - Ncore build

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Julf

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Re: Newbie Help - Ncore build
« Reply #260 on: 1 Nov 2014, 12:22 pm »
Even better! Makes for a good design with these units given they want the internal cable spiraled

Twisted, not spiraled. Small but important difference. :)

zenpmd

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Re: Newbie Help - Ncore build
« Reply #261 on: 1 Nov 2014, 12:48 pm »
True! :)

I am in disbelief why not everyone is using these Speakeron. Looks great

Speedskater

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Re: Newbie Help - Ncore build
« Reply #262 on: 1 Nov 2014, 12:50 pm »
Twisted, not spiraled. Small but important difference. :)
What would that difference be?

twisted
twist (twist)
Verb: twist·ed, twist·ing, twists
1. To entwine (two or more threads) so as to produce a single strand.
2. To coil (for example, vines or rope) about something.
3. a. To impart a coiling or spiral shape to.
3. b. To assume a spiral shape.
4. a. To turn or open by turning.
4. b. To break by turning: twist off a dead branch.
5. To wrench or sprain.
6. To distort the intended meaning of.
7. To move in a winding course.
8. To rotate or revolve.

spiraled
spi·ral (spi'rel)
Noun
1. The two-dimensional path formed by a point moving around a fixed center at an increasing or decreasing distance.
2. a. A three-dimensional curve moving about a central axis; helix.
2. b. Something having the form of such a curve.
3. A continuously accelerating increase or decrease.

Adjective
1. Of or resembling a spiral.
2. Coiling in a constantly changing plane; helical.

Verb: spi·raled spi·ralled, spi·ral·ing spi·ral·ling, spi·rals.
1. To take a spiral form or course.
2. To rise or fall with steady acceleration.

Etymology:  Greek speira, coil.
spi'ral·ly
Adverb




Julf

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Re: Newbie Help - Ncore build
« Reply #263 on: 1 Nov 2014, 01:15 pm »
What would that difference be?

In this specific case, the difference between

Quote
twisted
twist (twist)
Verb: twist·ed, twist·ing, twists
1. To entwine (two or more threads) so as to produce a single strand.

spiraled
spi·ral (spi'rel)
2. a. A three-dimensional curve moving about a central axis; helix.

What you want is two cables tightly twisted together, without any space between them, and with the result pretty much forming a straight line. What you don't want is two separate, individual spirals around a central axis.



Julf

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Re: Newbie Help - Ncore build
« Reply #264 on: 1 Nov 2014, 01:16 pm »
I am in disbelief why not everyone is using these Speakeron. Looks great

They smell of pro audio, a definite no-no for audiophiles :)

It is like asking why everyone keeps using the horrible, unbalanced RCA plugs instead of balanced connections.

barrows

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Re: Newbie Help - Ncore build
« Reply #265 on: 1 Nov 2014, 02:11 pm »
Neutrik Speakon connectors rely on the spring force of the contacts to keep the connectiopn tight.  When new I suspect that the spring force will be adequate to make a good connection and keep micro arcing to a minimum.  But after many dis-connect/re-connect cycles the spring force will diminish, and the connection will suffer.
A traditional speaker binding post will always allow a tight connection with a spade connector, and the contacts themselves can be easily cleaned as well-these are real world advantages to the traditional spade and binding post connection.  The newer binding post designs from WBT are really excellent, good materials, easy to to tighten firmly by hand, and your choice of contact plating.

jtwrace

Re: Newbie Help - Ncore build
« Reply #266 on: 1 Nov 2014, 02:16 pm »
The only thing that I can say about that is that they (speakOn) are rated for > 5,000 mating cycles. 

Julf

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Re: Newbie Help - Ncore build
« Reply #267 on: 1 Nov 2014, 04:01 pm »
after many dis-connect/re-connect cycles the spring force will diminish, and the connection will suffer

How often do you unplug and re-plug your speaker cables? Speakons are designed for PA and studio applications, where cables are re-plugged almost daily, and despite that they keep working, year in, year out.

clpetersen

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Re: Newbie Help - Ncore build
« Reply #268 on: 7 Nov 2014, 07:02 pm »
In this specific case, the difference between

What you want is two cables tightly twisted together, without any space between them, and with the result pretty much forming a straight line. What you don't want is two separate, individual spirals around a central axis.

Yes (twisted). Basically, think of it this way: for a two wire circuit (AC or DC), at any instant, one wire (say the left) is carrying the outward current and other one (say the right wire) is carrying the (equal) return current, excepting the time when capacitors are charging (storing charge/current). Each loop of the twist emits a small magnetic field (think of a single turn of a simple solenoid or transformer). But the neighboring loop is in the opposite sense - the right/left wires become left/right  due to the twist, so the neighboring field has the opposite 'polarity'. These fields will tend to cancel and the equivalent frequency for say a 1 cm twist pitch is about 30GHz, a little outside normal audio.

So, twists are very good at rejecting common mode magnetic pick-up and reducing emissions. Spirals won't due this; as stated, twist (criss-cross) each wire around the other.
See the attached picture.


Selarom

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Re: Newbie Help - Ncore build
« Reply #269 on: 8 Nov 2014, 06:13 pm »
Yes (twisted). Basically, think of it this way: for a two wire circuit (AC or DC), at any instant, one wire (say the left) is carrying the outward current and other one (say the right wire) is carrying the (equal) return current, excepting the time when capacitors are charging (storing charge/current). Each loop of the twist emits a small magnetic field (think of a single turn of a simple solenoid or transformer). But the neighboring loop is in the opposite sense - the right/left wires become left/right  due to the twist, so the neighboring field has the opposite 'polarity'. These fields will tend to cancel and the equivalent frequency for say a 1 cm twist pitch is about 30GHz, a little outside normal audio.

So, twists are very good at rejecting common mode magnetic pick-up and reducing emissions. Spirals won't due this; as stated, twist (criss-cross) each wire around the other.
See the attached picture.


Great post!

Thank you for this

clpetersen

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Re: Newbie Help - Ncore build
« Reply #270 on: 14 Nov 2014, 02:25 pm »
Down to the wire - options and decisions

OK - here is where things stand, need to order to have parts on hand for a holiday-time build.
1) Ghent Audio just listed a very nice pair of mono blocks for the NC400 and SMPS600 combo (and others) - on ebay - $365 per pair
2) Aluminati is making stereo cases (milled from solid aluminum) - ~$1250 for the case
3) Siliconray and Ghent have cases that could work for stereo pairs, with some simple drilling for mounting required

So:
1) Stereo case or mono blocks? I think a stereo module could be assembled for $1200 or so, all in.  Monoblocks (using Ghent) would approach $1800. With mono blocks I would (like most) locate each block near the speaker and use a longer run of balanced XLR cable. 

2) If stereo, use one SMPS 1200A400 vs. one or two SMPS600 for the power supplies?  I see a lot of people have used the 1200A400.

In all cases I will add:
a) some sort of line fuse, like a 5x20mm standard fuse.
b) a trigger mode ('remote operation') using a simple 1W 9-12VDC supply and a simple relay (to be closed by the external trigger signal)

occamsrazor

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Re: Newbie Help - Ncore build
« Reply #271 on: 14 Nov 2014, 02:49 pm »
I am debating the same possibilities. Monoblock does seem to be a nice way to go, especially if you need long runs to the speakers, but by going stereo you do save some money and avoid duplication on the power supply and case. It's a tough one...
I'd be very interested in how to enable the trigger mode.

barrows

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Re: Newbie Help - Ncore build
« Reply #272 on: 14 Nov 2014, 04:39 pm »
I prefer a stereo case for simplicity, the amp is still dual mono though, with two SMPS 600s.  The SMPS 600 is designed specifically for the NC-400, so I see no good reason to use something else, and full dual mono keeps me from getting paranoid about whether or not things could be better.  In my system, only 2.5 meter speaker cable is required with the stereo amp, so there is little to be gained by mono blocks and the hassle of an additional power cable.  By properly spacing inside the case there is plenty of separation between modules to make cross talk a non-issue. 
Save money on chassis and go with a stereo amp build, and then spend some money on good fuses.  BTW, the SMPS 600s have fuses built in, so you do not have to add any line fuses of your own, but most report thta upgrading these fuses will have benefits, so consider trying some aftermarket fuses.

clpetersen

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Re: Newbie Help - Ncore build
« Reply #273 on: 14 Nov 2014, 06:24 pm »
I am debating the same possibilities. Monoblock does seem to be a nice way to go, especially if you need long runs to the speakers, but by going stereo you do save some money and avoid duplication on the power supply and case. It's a tough one...
I'd be very interested in how to enable the trigger mode.

Trigger Mode: to put the SMPS supply into standby, the standby pin needs to have a voltage supplied to it, if no voltage the amp is powered on - normal operation. I don't have the specs in front of me, but I believe the standby signal is between 5 and 12VDC. Standard 12V trigger outputs (from say a pre-amp) are 12V when the device is on, 0V when off. So, you need to invert this.

To do this, get a very small  1 Watt (or less), 9 to 12VDC power supply (about $2- from someone like Mouser or Digikey) and a simple mechanical relay, also about $2.
The relay would be run 'normally closed'  -  contacts closed to supply the mains voltage (typ. 110 VAC) to turn on the 1W supply. The supply would then energize the standby pin, putting the SMPS into standby mode. As a bonus, this same voltage could be used to turn on an LED to indicate standby mode.  When the pre-amp is on, the 12V trigger signal would be applied to the relay coil, opening the contacts, de-energizing the 1W supply and bringing the SMPS into normal mode. The LED would also turn off.  You could use the DC signal voltage supplied from the SMPS to turn on a different (say green or blue) LED to indicate the system is powered.

Don't forget series resistors for the LED's.

Then your standby consumption is 1W, but more importantly, the SMPS and NC400 are not active ('idle') when not needed.

Hope this helps.

clpetersen

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Re: Newbie Help - Ncore build
« Reply #274 on: 14 Nov 2014, 06:27 pm »
Thank you for the reply. I missed that the SMPS600 has on board fuses. So this would simplify things.

Which case did you select?


barrows

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Re: Newbie Help - Ncore build
« Reply #275 on: 14 Nov 2014, 07:45 pm »
I work with Jesus at Sonore, and so I was able to use one of his custom cases for my build.  These are not really available for most folks though.
BTW, I would not go to the bother of hooking up the standby feature as the amps sound way better when kept powered, and at idle they use only a handful of watts anyway.  Instead, consider putting a switch on the Nampon wires: this will allow you to mute the amp output (handy for turning on other components which might have a DC spike) without shutting it down.

zenpmd

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Re: Newbie Help - Ncore build
« Reply #276 on: 12 Mar 2015, 02:28 pm »
For my fresh build, I'm thinking of using Van Damme cable internally, as I have some lying around and I trust it. It is, however, quite thin, 0.75mm, as shown below. Is that ok?


mikeeastman

Re: Newbie Help - Ncore build
« Reply #277 on: 12 Mar 2015, 04:36 pm »
If you are talking about the output wire to speaker post, I used a similar size wire, but my amp only powers the mids and highs of my efficient speakers. If your is driving full speakers I would think you will need bigger wire or twist several strands together, I'm sure someone that knows a lot more than me will chime in.

zenpmd

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Re: Newbie Help - Ncore build
« Reply #278 on: 30 Mar 2015, 12:36 pm »
Thanks Mike. Does anyone else have a view on whether that thickness speaker wire is ok?