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-   -   nxv300 R2 kit modification. (http://www.diyaudio.com/forums/aussie-amplifiers/237901-nxv300-r2-kit-modification.html)

ze froggy 19th June 2013 06:10 PM

nxv300 R2 kit modification.
 
1 Attachment(s)
hello anthony,
just a little post to show you a modification to simplify
the trim of the idle current. i do this on my 6 modules .
my next modification is to reduce the amp gain to 26db.
in your opinion, should i reduce R24 (33k) or put a pad
on the bal input of the module?
i use four of them with a Minidsp 2X4 bal modul to built a
stereo 2 ways active, powered with 2 SMPS 2x72V 800W.
sound great, very low noise, good dynamics, very happy
with your amp .
thank's from France.
Manu
Attachment 355212

The Saint 19th June 2013 10:53 PM

Hi Manu

To reduce the gain just change R24 to 18k ohm 0805 for 26db gain
Great to hear you like the sound quality of the nxV300 R2 modules.:D

Post some photos of your amplifiers?


Cheers

Anthony

ze froggy 20th June 2013 07:16 PM

hello,
thanks for your reply,
will replace R24 with a 18Kohm, it"s more simply.
what do you think about the idle trim modification?
the first time i try to bias the current, i turn slowly cw
the pot, reading the voltage accros a 10 Ohm in the
PS rail, read 0v, 0v.....0v( middle position),continu to turn
0v, suddenly "over" on the voltmeter(2v range) approx at 3/4
of trim position.very difficult to reach 1v with a very small
debatement of the pot.
do this with 2 modules and read the value for a correct current
(approx 50ma per transistor)=around 105 Ohm.
so decide to transform the bias circuit for more easilly and accurate
setting.
the four modules are assembly on a cooling tunnel with a
thermally controled fan, and a switch off of the PSU over 90degresC.
i"ll post photos soon.
regards
Manu

ze froggy 25th June 2013 07:27 PM

7 Attachment(s)
hello,
some photos :
the modules on the heatsink!


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