Mini review: Class-D Designs NX200 vs Hypex - Page 4 - diyAudio
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Old 7th April 2009, 10:04 AM   #31
Havoc08 is offline Havoc08  Denmark
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ahh that justifies the price .

I'll take further comments to the appropriate thread, thx for the link.
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Old 14th April 2009, 09:40 AM   #32
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Quote:
Originally posted by sharpi31
Been made redundant. Two modules ordered :-)

I'm looking forward to starting a new project on Monday, rather than another week of working my **** off.
Hi,

Did you get your amplifiers okay and how is the building going? Hopefully, you have got them up and running by now. How do they sound? Please let us all know your opinion.
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Old 14th April 2009, 10:34 AM   #33
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No sign of the modules yet, although I've been emailed to say that they will be with me this week.
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Old 14th April 2009, 11:19 AM   #34
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Quote:
Originally posted by sharpi31
No sign of the modules yet, although I've been emailed to say that they will be with me this week.
That's not very good then. What date did you actually order them?
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Old 14th April 2009, 11:22 AM   #35
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modules ordered 02.04.09
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Old 15th April 2009, 02:03 PM   #36
flight1 is offline flight1  United Kingdom
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Default NX200 5 channel Power amp

Hi all

Just half way through building a 5 channel power amp to plug into my HTPC sound card pre amps which is the Asus Xonar HDAV 1.3 Deluxe (very good sound quality highly recommend).

I am using the NX200 modules so will post when completed and i will let you know how it competes to the Hypex udc180's as i have a friend which has a two channel power amp to be able to do a comparison. I was going to use Udc180's but one's budget is restrictive.

Cheers all
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Old 15th April 2009, 02:41 PM   #37
Havoc08 is offline Havoc08  Denmark
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Nice.. It'll be interesteing to hear both of your reviews
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Old 30th April 2009, 08:57 AM   #38
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Quote:
Originally posted by sharpi31
modules ordered 02.04.09
hi,

Have you received your modules yet and how is it going? very interested to hear your results.
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Old 30th April 2009, 09:34 AM   #39
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The modules arrived a while ago - I'm waiting for a new aluminium enclosure and other parts to arrive.

The modules arrived without paperwork so I asked Class-D for some info - worth noting for anyone who wants to use these amps:

The mosfets should be insulated from the heatsink
The trimmer adjusts bias current - around 60mA is optimal, 30-100mA normal range
C6 is an input coupling capacitor - looks ceramic so worth bypassing
Input impedance is around 12Kohm

My enclosure, connectors and other bits should arrive by the end of the week. I've also ordered two 100uF 100V Rubycon ZLH caps to replace the Samwha PSU caps on each board. I'm also keen to replace the 47uF feedback cap with 2x30uF MKV film cap. If I can ensure I have enough access to swap caps after building the amp, I'll test the amp boards 'as supplied' before making the cap upgrades. If the case is too tight, I'll change caps before assembling the amp. While this isn't ideal, I think anyone looking at using these modules would upgrade the caps.
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Old 30th April 2009, 11:15 AM   #40
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[QUOTE]Originally posted by sharpi31
[B]The modules arrived a while ago

Glad to hear that you have at last got your modules Mine also arrived without any information or wiring diagram so had to phone them to e-mail it to me. Incidentally, they said the the best way of adjusting the bias was using an oscilloscope and signal generator and set up for a minimum crossover distortion.
Also said that, as I haven't got an oscilloscope adjusting the bias to 30 milliamps was recommended. So take your pick.

Please class-d if you read this, make it a policy to put the instructions/wiring diagram automatically in with the order before dispatch. It would save a lot of hassle and frustration for your customers and much more businesslike.

Please do a test and review before modifying these boards if at all possible. I can imagine if you don't do this and you get inferior results class-d will say it's because you have adversely affected a good product. On the other hand, with good results then it's all to do with your modifications and we get no definitive answers.
A before and after review would make very interesting reading.

Wouldn't have the technical knowledge to know if replacing the capacitors as you suggest is worthwhile sonically or not. So would be interested to know the reason why you are replacing them.
Also, Isn't the input capacitor there to protect against dc voltages on the input causing damage?
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