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NCC 200 build

337alant

337alant

Negatively Biased
Pretty neat work there Alan.
But separate box for trafos?
Not seen it done that way before.

Conventional bodging wisdom:-

1. Trafo should be close to rectifier/caps
2. Not a good idea to run raw ac down external umbilical
 
I am just trying to get the magnetic field away from the amp boards.
Have to put the Cap6 near the amp board to keep impedance low.
 
That is a really excellent build standard Alan, well done chap, and those cases are just superb, if you don't mind me asking what UK £'s are the landed cost each?? I see you have the 10mm front panel ;) really nice approach with the traffo's in a sperate case, however I would have placed the schottky's in the same case so that DC is travelling along the umbilical cord, the res caps are better served next to the speaker binding posts as you have done.
Hope you will posting the listening results, of couse you bloody will, and damn great they will sound too. Alan did you have any of the Evox-Rifa 2.2uF 100V CMK Polycarbonate caps I offered out here, I have 2x NCC200 based amps and they both have these caps as the AC Coupling caps, and bloddy excellent they are indeed, if you want a pair PM me your postal address and I will send them off to you.
Paul
 
Nice work!

How did you get solder to take to those binding posts?

I got some of those on ebay and I couldnt solder them for s***. I even left the sodering iron stuck in the end to try and get some heat in there, it was a nigthmare!
 
How did you get solder to take to those binding posts.
Click to expand...
My father left me a big old soldering iron, must be 100w and like a poker for a coal fire, that sorted them out:D

Pulse studio thanks for your comments, obviously I will be tinkering with them once I have run them as standard for a while and got to know the sound better, that way I can better assess the changes when I make them.
I can only find a receipt for 2 x pesante diss 03 cases and I paid 245 euros in February delivered, so they are not cheap but they are nice.
.
 
Can someone explain please what is the difference between having raw ac at low(ish) voltage and raw ac at 240v going into your power amp? and why an ac umbilcal is not recommended? I ask because my planned build will be exactly what alant has done unless it's a real big no-no.
 
The connections from the transformer to the rectifiers have a lowish AC voltage, but a big, and very peaky current flow, as current only flows through the rectifiers during the brief period that peak of AC voltage is bigger than stored voltage on the capacitor.

There are two worries with this current. Long connections add extra resistance (and inductance), but that will be much less than the resistance and inductance of the transformer secondary unless you go mad with lead length. Much more worrying is interference - you now have a long lead length radiating high current pulses.

The current in the primary side of the transformer is much lower, by the same factor as the voltage step down, so is rarely a problem.
 
Thanks, I'll go for a 'standard' monoblock construction instead, especially since my kit will be quite closely packed together.
 
Very nice work iamjohnwayne, I wouldn't worry too much about putting the transformers in a separate case, I built a A260z in two half-width naim boxes a few years back and they work perfectly.

260_2.jpg


260.jpg
 
Amp up and running sounding excellent, major family crisis today so sorry cant give opinioin on sound, may get time to listen properly tomorrow.
Many Thanks to Les W and Zener for the calls and support today (fast response team)
Alan
 
Alan,
it looks like you have some room in the Amp Box, have you considered adding a
couple of power block accelerators.
 
337alant said:
I am just trying to get the magnetic field away from the amp boards.
Have to put the Cap6 near the amp board to keep impedance low.
Click to expand...

Nice work!

I would recommend splitting the cap6 and keeping the first one or two capacitors near the transformer, and leave the final capacitor near the NCC200. This way you get the best of both words (but you will not be able to take full advantage of the CAP6 PCB).

You can use the cap6 PCB with only two capacitor near the transfo, and have larger capacitors (Kendeil?) near the NCC200.

BTW, what was your motivation to use heatsinks on the transfo case? Is it getting hot? I would assume that the NCC200 are better candidates for heatsinks.

Teddy
 
what was your motivation to use heatsinks on the transfo case
Click to expand...
None, they don’t get hot and the heat sink are unnecessary this was a cock up by me with my eagerness to build my first amplifier.:mad:
the BIG mistake was buying the amplifier case before I new the dimensions of the NCC 200 and cap6 boards and transformers, so let that be a lessons learned to other first time bodgers.
I originally bought 2 of those 3U cases with the heat sinks to build 2 power amps, only to find all the bits won't fit in the cases and 2U height cases would have been adequate anyway. I may change this case in the future.

I am reluctant to mess with the Avondale boards at the moment they are so meticulously well made, as they are they still sound brill so I am going to leave them as they are for now, but I know that in the future I will start to experiment with ways of improving the layout.

couple of power block accelerators
Click to expand...
Mark what are these and what are the benefits?


Alan
 
Oh well, but from the pics the bigger case looks deep enough to fit the ncc200 boards vertically like you can mount one on each heatsink as the design intended.
 
From Alan: "Mark what are these and what are the benefits?"

They're an add-on box of wizardry Alan designed to equalise the capacitive effects of the main bank. Operation is based on a number of well tried principles which must remain confidential. The effect is to speed up transient delivery and stop the flow when required. The music takes on a sense of reality I find.

I've been working on some new experiments and in fact there is a new one well into development to match the Cap6 & which should be available this back end.
 
First listening
I had 2 x Rotel 960 power amps and they presented a nice sound and image but when the tracks got complex they became a bit aggressive and muddled.
The NCC200 produced a bigger bolder image, awesome control of the bass lines and drum in fact every instrument is so easy to pick out and when the track get complex they stay in control.
Dynamics are just effortless and voice is so so natural, these amps really are classy. They Rock:D:D:D:D:D
Thanks LesW I am very, very pleased

AlanT
 
337alant said:
First listening
I had 2 x Rotel 960 power amps and they presented a nice sound and image but when the tracks got complex they became a bit aggressive and muddled.
The NCC200 produced a bigger bolder image, awesome control of the bass lines and drum in fact every instrument is so easy to pick out and when the track get complex they stay in control.
Dynamics are just effortless and voice is so so natural, these amps really are classy. They Rock:D:D:D:D:D
Thanks LesW I am very, very pleased

AlanT
Click to expand...

Your listening results seem to chime exactly with my own experience with my NCC200 build, see post# 58 & 60 here:

http://www.pinkfishmedia.net/forum/showthread.php?t=45711&page=4

Yes they are truly classy amps and great VFM for the DIY'er.
Paul
 
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