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Old 31st January 2013, 04:28 AM   #21
evette is offline evette  Canada
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Sir Could you please tell me if your have any pcb,s for sale on any of your amps, Thanks Evette
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Old 31st January 2013, 06:07 AM   #22
Bonsai is offline Bonsai  Taiwan
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Hello Evette - coming in the next few weeks for sx-Amp, nx-Amp, protection boards and PSU board. e-Amp will follow later in Q2
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Old 31st January 2013, 06:18 AM   #23
Bonsai is offline Bonsai  Taiwan
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Quote:
Originally Posted by Samuel Jayaraj View Post
Bonsai, is the BC847 (SMD) in thermal contact with one of the Output devices or is it mounted to be in contact with the Heatsink? Due to unavailability of non-inductive power resistors and wanting to couple the nx-amp with a different protection circuit, I would like to make my own PCB (single sided, preferably). Hence, the question about thermal compensation scheme. Thanks.
Samuel, you can make the boards single sided. The sense transistor (BC847C) must be placed very close to the collector lead of one of the output devices. If its placed on the bottom side between the PCB and the heatsink (assuming you use the same construction as I do), that should work ok. I did not couple the sense transistor to the output transistor with thermal grease - you can also do that but I find it not necesary.
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Old 31st January 2013, 02:39 PM   #24
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Could you tell me what`s the bias value on the startup and after how many minutes is stabilized?
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Old 31st January 2013, 02:43 PM   #25
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Thanks for the information. I'll see what method I can come up with.
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Old 31st January 2013, 02:48 PM   #26
evette is offline evette  Canada
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Thank You Sir,,I can,t wait. Regards Evette
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Old 31st January 2013, 09:36 PM   #27
Bonsai is offline Bonsai  Taiwan
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Quote:
Originally Posted by bogdan_borko View Post
Could you tell me what`s the bias value on the startup and after how many minutes is stabilized?
Bogdan, it's set to 300mA about 1 minute after start up( 125mA per pair plus 50mA for the front end) and it goes to c 350mA after the heatsinks get hot driving a 8 ohm load.

With no music, the bias setting is very stable after switch on.


Note in this design, the drivers and the power devices are on the same Heatsinks and the drivers are fullpack TO-220. This is the same construction technique used on the e-Amp.
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Old 3rd February 2013, 05:03 AM   #28
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Are the distortion figures in Your amps measured, or just simulated? I though it was measured, but You mention about simulation at page 6.
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Old 3rd February 2013, 01:58 PM   #29
Bonsai is offline Bonsai  Taiwan
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Wojtek, the are the simulated results. The measurements will go up when I get a new sound card or access to an AP again.
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Old 12th May 2013, 04:00 PM   #30
fab is offline fab  Canada
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Originally Posted by Bonsai View Post
Hello Evette - coming in the next few weeks for sx-Amp, nx-Amp, protection boards and PSU board. e-Amp will follow later in Q2
Hi Bonsai

Any update on the availability of the NX amp pcb or board?

Thanks
Fab
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