NCD questions

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wtfaidh

Member
Joined 2004
Next step in NCD. Now it's waiting for the softstart/filter combo's. After that it'll be all aboud designing a proper case...
 

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novec

novec

Member
Joined 2005
Clock sync and DC filter/soft start uni

On the old ZAPs, I remember you recommended using a syncronised clock when running more than two amps in one case. Does that apply to the NCD too, when I'm running four modules in one case? They're well separated, with 4-pole cap bank and 10mm aluminium walls all around.

Another thing: When will the DC filter/soft start unit be available? Like wtfaidh, that's one of the missing pieces of my NCD puzzle
 
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wtfaidh

Member
Joined 2004
Physical layout DC/Filter softstart combo

Hi Lars,

Could you give us/me an update of the global physical layout and wiring of the softstart/dc filter.

I've ordered two combo's but if there is anything between the UPS and the NCD module it might be much more convenient to buy separate modules!!!!!

Especially to keep wires as short as possible....

Regards, Eric.
 
L

Lars Clausen

Member
Joined 2003
newclassd.com
Another thing: When will the DC filter/soft start unit be available? Like wtfaidh, that's one of the missing pieces of my NCD puzzle
Click to expand...

In about 10 days time.

On the old ZAPs, I remember you recommended using a syncronised clock when running more than two amps in one case.
Click to expand...

It is no longer so critical, however i have no experience about what clock syncronization does to the sound. Yet ;)

Could you give us/me an update of the global physical layout and wiring of the softstart/dc filter.
Click to expand...

You can see the soft start module here : http://www.newclassd.com/index.php?page=80

All the best from

Lars C
 
M

marmatsouris

Member
Joined 2005
Lars Clausen said:


In about 10 days time.



It is no longer so critical, however i have no experience about what clock syncronization does to the sound. Yet ;)



You can see the soft start module here : http://www.newclassd.com/index.php?page=80

All the best from

Lars C
Click to expand...

Hi Lars,

I am also waiting the combo to include in my amp project which is about ready. I am also waiting the second p/s for a true dual mono design.

I have posted the long-awaited photos.

Thanks also to Richard (from Hexatech) for the nice cabinet.

I will post my sonic experience soon. Needless to say that i have tried it against the Lc Audio's 700XE but you just have to wait a bit longer for my final verdict. I HAD to mention this in order to get your attention......

Bye for now,

Nikos


:bigeyes:
 
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marmatsouris

Member
Joined 2005
Hello Eric, and Lars,

many thanks for your comments.

It took me a while to (almost) finish the amp but believe me it is worth the effort as i wanted the amp to look as good as it sounds. ( i still need to upgrade it with a second power supply and the LM 4562 ic).

I believe this is the best design ever offered by Lars (up till now as we never know what future holds us from this clever designer...).

Compared to the LC Audio 700XE module in a "better" implemented amplifer (two 650VA transformers by the same maker as mine, 2x18,000mF Gold Tune Nichicon caps per channel bypassed by Jensen foil caps, VDH wiring, power maxed at 350watts per channel etc), the NCD1 was much better in the soundstaging, better resolution, faster (i believe the "slowness" of the 700Xe based amp was caused by too much capacitance at the p/s section), and more controlled bass but not as extended as the higher powered amp.
The above observations are not final because the NCD1 modules have only been broken-in for 30 hours...
Next is the fitting of the second p/s and the change of the LT chip.

The ultimate test will be the comparison of my Audia Flight 100 amp with the NCD1.

Stay tuned, as "i will be back" with more listening impressions...

Regards to all,

Nikos
 
E

edge540

Member
Joined 2005
marmatsouris said:
(two 650VA transformers by the same maker as mine, 2x18,000mF Gold Tune Nichicon caps per channel bypassed by Jensen foil caps, VDH wiring, power maxed at 350watts per channel etc), the NCD1 was faster (i believe the "slowness" of the 700Xe based amp was caused by too much capacitance at the p/s section
Click to expand...

I think to bypass the 15000µF with some pio: 1.5µF+.68µF+0.1µF for example.
I want to improve micro dynamics, but you say that too much capacitance slows the amps. Could you tell me more about it?
 
M

marmatsouris

Member
Joined 2005
edge540 said:


I think to bypass the 15000µF with some pio: 1.5µF+.68µF+0.1µF for example.
I want to improve micro dynamics, but you say that too much capacitance slows the amps. Could you tell me more about it?
Click to expand...


Hello Edge540,

I have seen this "over-capacitance" effect not only on the 700XE module but also with the 2.3SE one before that. If you raise the total capacitance beyond a certain point ( and that point depends on the kind of loudspeaker used ), the sound becomes "heavier" and "slower" in dynamic expression. I have seen this happen with "ordinary" sensitivity loudspeakers aroung 87-90 dbs but also with hybrid ESL+woofer speakers with impedancies much lower than normal ones. I have not tried thsi with higher sensitivity loudspeakers, so i cannot comment on that.
I believe that more than 30,000mF per channel will slow things down (it has in my experience anyway) but do not take my words for granted and please experiment as every amp/loudspeaker combination can "react" differently.

I have not tried the second p/s yet ( which will double the capacitance of my amp as it is now) and as soon as i install it i will let you know of my findings.

With regards to your by-passing idea, i believe thatyou are on the safe side. Please also try to mix&match different "sounding" bypass caps like MKps with Paper-in-oil or polysterin ones to "find" the right timber for you listening tastes.

My latest "absolute capacitor" is the Duelund foil ones....One word, perfect.

Regards,

Nikos
 
M

marmatsouris

Member
Joined 2005
Pboden said:
Your amp look great. I have order the same chassis from Hexatech, and as soon as it arrives, my NCD modules will be installed.
I am looking for some transformers. Yours look nice, so where did you get them?

Roger
Click to expand...


Hi Roger,

There is a local guy that all his life has been producing transformers to the local industry....He runs a little shop that does wholesale buy you can also buy retail from him. Thre is no web page of some sort to see his products as this is aone-man-show kind of business.
I have asked him (politely) to put the transformers in the metalic caps and pour as much resin as possible. there is no ringing, humming, singing bla bla bla of the transformers. I never expected the core material to be from a meteor landed form outspace or the wiring to be 10Ns of extra pure copper mined from Down Under.
Simple 500Va transformer with extra 15Volts for the 6-wire Power supply module, and that's it.

Regards,

Nikos
 
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