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-   -   Huygens MCD 1202 - Class D amp finally arrived (http://www.diyaudio.com/forums/class-d/121831-huygens-mcd-1202-class-d-amp-finally-arrived.html)

TheDealer 22nd April 2008 10:19 PM

Huygens MCD 1202 - Class D amp finally arrived
 
2 Attachment(s)
This very gentle guy called Adam Comack from spain developed with his Partner Fumac (member here) a brand new design of Class D amp.
Called MHz Class D or MCD. Finally the amp arrived well to me.

Detailed review follows after warm up and long listening:

TheDealer 23rd April 2008 08:34 PM

Hi Fumac, if you read this thread, please could you explain me the
technical datas for the MCD 1202 in your homepage eden-audio.com ?

I am little bit confused about this:
Type MCD-1002 MCD-1202 MCD-1802 Name 4 input integrated stereo class-D amplifier Voltage AC :115/230 V 50/60Hz Output 4ohm ,THD<0.5% 100Wx2 120Wx2 180Wx2 power 8ohm ,THD<0.5% 50Wx2 70Wx2 100wx2 THD @ 1k Typical @ 7k Typical @ 15k(50k bandwidth) @1W 0.005% 0.007% 0.008% @8W 0.008% 0.015% 0.02% @Half power 0.02% 0.04% 0.04% Frequency response 5Hz~30K +0/-0.05db 1Hz~80KHz +0/-3dB (All load all power).

Are these technical datas for three models ?


-----------------------

Thats beside my review which will follow soon.

fumac 23rd April 2008 09:13 PM

hello TheDealer

this is the datasheet of MCD1x02 AMPs

http://www.class-d.net/mcd-1x02.pdf

this is the modules datasheet that inside the MCD1x02 AMPs
http://www.class-d.net/MCD-255%20datasheet(test%20version%201.1).pdf

because my english is not so good,
so perhaps some mistakes ,
if something wrong please tell me

best rg
fumac

Pabo 24th April 2008 09:47 AM

Fumac

The residual amplitude tells me that you have fairly high attenuation in the output filter. This means that your filter resonance frequency is much lower than your switching frequency and that your small signal bandwidth is much greater than your large signal bandwidth. What happens when you apply a high amplitude 1kHz square wave and have inductive load or no load at all? Is it still stable?

fumac 24th April 2008 10:41 AM

Quote:

Originally posted by Pabo
Fumac

The residual amplitude tells me that you have fairly high attenuation in the output filter. This means that your filter resonance frequency is much lower than your switching frequency and that your small signal bandwidth is much greater than your large signal bandwidth. What happens when you apply a high amplitude 1kHz square wave and have inductive load or no load at all? Is it still stable?

hi Pabo
nice to meet you
we have a filter for class-d at 150k+0/-3db, pwm is 1mhz, about 6 times
one other class-d amp is 50k +0/-3db, pwm is about 400k, 8 times

so , you can get , our filter is not "much lower than pwm signal" than the others :)

because our pwm frequency is much higher than audio . so we can get very low residual amplitude
here is a picture for know about it :

http://www.class-d.net/tech/picture/...1mhz%20emi.jpg


http://www.class-d.net/tech/picture/...0frreqresp.jpg

more information here:
http://www.class-d.net/tech/

you can get the 200hz ~20khz square wave 60v output (6ohm 150Wrms)
at next data sheet at page 7

mcd-255 data sheet

it is very good at running at high power output.

if you need , i will take pictures for new test at low power and high power frequency respond.

rg
fumac

Pabo 24th April 2008 11:10 AM

fumac

Thank you for your reply!

What does the square wave response look like without load?

peranders 24th April 2008 11:25 AM

Patrik, I know you know a lot about this so I'll ask a newbie question:
1 Is it important to have a good beahviour without a load?

2 Can you predict something when you see the low load behaviour?

fumac 24th April 2008 11:34 AM

2 Attachment(s)
Quote:

Originally posted by Pabo
fumac
Thank you for your reply!
What does the square wave response look like without load?

ok
show you a picture, that you can get the diffrent at with and without loading


if we dont connet load , the square wave will be ring.
this depend on the output filter. class-d will be ring without load.

you can see, from open load to 4ohm, the respond at 1k is no diffrent, and at the 20k, is +/-2db,
from top to button
unload, 8ohms, 4ohms

fumac 24th April 2008 11:41 AM

Quote:

Originally posted by peranders
Patrik, I know you know a lot about this so I'll ask a newbie question:
1 Is it important to have a good beahviour without a load?

2 Can you predict something when you see the low load behaviour?


hi peranders
nice to see you again

perhpas we dont use an amp without load, but we can test it without load then we can get more infomation of the respond at diffrent load
testing is not just test the nomal Conditions, to test it at special Conditions, then to know more about it . will help us make it better.
rg
fumac

Pabo 24th April 2008 11:46 AM

fumac

Your datasheet states that the frequency response is +0dB/-3dB 1Hz to 100kHz all loads and all powers? The graph you just showed says different?

peranders

At the filter resonance frequency (40kHz or more) a 15 subwoofer will act as open load. If the amplifier goes into subharmonic oscillation and sets on fire when going into severe clipping it is not considered to be a robust design.

It is very difficult to do a class d design that is good at everything. I know this for a fact.


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