View Full Version : NCC 200 build


337alant
19-07-08, 07:57 AM
Ok this is my bodge up
I am building 2 amps using NCC 200
I have the first amp and power supply built and waiting for switch on
Would appreciate a call from Les or Zener (01429 236072)
see pics
http://i259.photobucket.com/albums/hh290/337alant/ncc2001.jpg
http://i259.photobucket.com/albums/hh290/337alant/ncc2002.jpg
http://i259.photobucket.com/albums/hh290/337alant/ncc2003.jpg
http://i259.photobucket.com/albums/hh290/337alant/amppowersupply.jpg

Alan

morksbeanbag
19-07-08, 08:01 AM
Are they the modushop cases?

If so, what did you think of their build quality?

cromodora
19-07-08, 08:24 AM
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

337alant
19-07-08, 09:10 AM
Yes they are Modu / HIFI2000 and are excellent quality

337alant
19-07-08, 09:14 AM
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.

Pulse Studio
19-07-08, 09:21 AM
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

mikesnowdon
19-07-08, 10:05 AM
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!

337alant
19-07-08, 10:46 AM
How did you get solder to take to those binding posts.
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.
.

iamjohnwayne
19-07-08, 11:04 AM
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.

PigletsDad
19-07-08, 11:43 AM
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.

iamjohnwayne
19-07-08, 11:52 AM
Thanks, I'll go for a 'standard' monoblock construction instead, especially since my kit will be quite closely packed together.

Basil
19-07-08, 12:26 PM
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.

http://hometown.aol.co.uk/Glimour%20P%20S/260_2.jpg

http://hometown.aol.co.uk/Glimour%20P%20S/260.jpg

337alant
19-07-08, 03:15 PM
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

markf
19-07-08, 11:11 PM
Alan,
it looks like you have some room in the Amp Box, have you considered adding a
couple of power block accelerators.

teddy_pardo
19-07-08, 11:57 PM
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.

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

337alant
20-07-08, 03:20 AM
what was your motivation to use heatsinks on the transfo case
None, they donít 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 Mark what are these and what are the benefits?


Alan

cromodora
20-07-08, 03:44 AM
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.

LesW
20-07-08, 03:58 AM
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.

337alant
20-07-08, 07:14 AM
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

Pulse Studio
20-07-08, 08:39 AM
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

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

markf
20-07-08, 04:09 PM
"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."

Good news then for the DIYers
Any idea of the footprint required for this module ,perhaps anybody starting an amp build could leave some room for the accelerators. (a rough estimate would do or even a picture of the M2 internal would help)

337alant
23-07-08, 07:17 AM
These amps are amazing they just keep sounding better every day, guess thats the burn in period?:D

Paul yes I remember your build very nice indeed;)

What’s the optimal Bias setting IYO.
I initially set them to 38ma as per LesW advice after an hours warm up adjusted them again to 38ma then left them over night switched on but no music through them.
Next day checked it again and it had risen to 41ma so adjusted them back again to 38ma, then played music all day to get them hot, amazingly nothing gets hot just warm they are so stable.
Disconnected everything and checked the Bias again after the amp had had a good thrashing and the Bias was up to 42-43ma so I left them for half an hour then it settled down to 40ish so I decided to set it to 36ma to compensate for when the are being driven hard.

Am I being paranoid about this bias setting, and does it affect the sound quality?

Alan

Pulse Studio
23-07-08, 09:12 AM
Hi Alan
Thank you :)
I have done more or less exactly the same and set my bias to 36-37mA on all my NCC200's boards, I did experience a little increase to around 41mA after a 2 hour burn in, so I reduced the initial setting to be 36-37mA after just 20 minutes from cold start, this should be performed with no signal and no load connected, I really don' believe that a couple of mA's over bias is going to cause any harm IMHO, but MC, PD, LW or Jim would be better qualified to answer this, calling all qualified bodgers ;)
Paul

martin clark
23-07-08, 09:24 AM
3mA is neither here nor there.

Start to worry only if you hit 100mA and it starts climbing quickly ;)

337alant
23-07-08, 09:41 AM
Thanks Paul and Martin, I will just sit back and enjoy now.
http://i259.photobucket.com/albums/hh290/337alant/NCC200inst.jpg