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Old 12th December 2010, 10:37 AM   #1
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Default which amp is this?

nice pcb layout anybody know this amp pls explain and watts,v.
what are the transistors used.
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Old 12th December 2010, 07:40 PM   #2
djk is offline djk
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A quasi-comp all N-channel Hexfet design. It has a bias transistor on the heatsink, so it's probably class AB. The 63V caps suggest it should run at about 57V or so, maybe 300W/4R.
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Old 13th December 2010, 09:29 AM   #3
ontoaba is offline ontoaba  Indonesia
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Not a good pcb, an electrolyt may explode. Not good design, it has huge drop voltages that means it lost much power rating and getting very hot. 14dBgain for high open loop gain will affect in high damping factor, it will not satisfy your ear for long time listening.

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Old 13th December 2010, 07:14 PM   #4
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hi nazirdigi

this is quasi nmos350 workin on +-70 vols.this is nmos200 pcb modified by me.
forgot to raise the caps voltages.you can find the schematic and pcb on quasis site.
Nmos350 / 500 - Quasi's DIY Audio Site

regards

ravs


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Old 14th December 2010, 02:21 AM   #5
quasi is offline quasi  Australia
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Yup, looks like a hot-ed up Nmos200. Nice work Ravs.

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Old 14th December 2010, 06:28 AM   #6
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hi quasi,

no see long time whats going on

ravs


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Old 14th December 2010, 01:36 PM   #7
djk is offline djk
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http://sites.google.com/site/quasisd...attredirects=0

T7 would benefit from a resistor in the range of 330R in series with the base. This resistor prevents the voltage reference (D1, D2) from collapsing when T7 saturates during a negative clip, improving the recovery time (see any Pass amplifier schematic with a similar front-end).

I would also consider using gate zeners if driving a 2R load.
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Old 15th December 2010, 04:49 AM   #8
quasi is offline quasi  Australia
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Quote:
Originally Posted by ravslanka View Post
hi quasi,

no see long time whats going on

ravs


be a vegeterian....
Hi Ravs
My life is so busy man and I have little time for DIY. Even so I recently helped a friend build a set of AOS transmission line speakers (very nice) and I have begun to build an Nmos350 Mk2.5 (not yet published) as well as some other small electronics projects (non-audio).

I am also trying to landscape our garden, raise 2 sons, keep a happy wife and a hectic job.

How's life with you man?

Cheers
Q
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Old 18th December 2010, 01:02 AM   #9
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hai ravslanka can u upload the working pcb layout and the changes .what are the voltage do u use and the transistor.
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