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Old 17th March 2012, 12:18 AM   #1
tvrgeek is offline tvrgeek  United States
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Default Nak 420

Anyone know the history of the Nak 420? Who designed it, anything about the topology? Anything about it's reputation?
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Old 17th March 2012, 08:14 AM   #2
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he he he ... i can tell you the history

that is a classic NAK with the classic mistakes sweet sounding amplifier with some cooling issues and obviously not a party animal still distortion figures are pretty low and generally is a nice class AB amp

Mistake is that due to size requirements that filter capacitors are placed horizontally with he well known end of life issue but the worst from all is that the choice of capacitors for the rest of the circuit is horrible and expect them all to be very dead .

If you also have the matching preamp no questions asked all the capacitors inside are dead as we speak and need to be replaced

As about the amp NaK had stability and power issues and bad feedback from costumers that expected a NAk to be a party animal and eventually blow the speakers

Nak Had to add a protection circuit to the amp afterwards

as about the preamp i will say that it was too complicated to sound clean .... stage by stage well designed though

Kind regards
sakis
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Old 17th March 2012, 09:42 AM   #3
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The protection circuit makes 'farting' sounds when driving speakers that dip lower than 8Ω.

Not a very robust piece.
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Old 18th March 2012, 06:57 PM   #4
tvrgeek is offline tvrgeek  United States
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Much thanks. Good thing Mr. Pass stepped in there to fix things up. I will spend my money elsewhere. Pa5, Acrus, Adcom 535 or more Rotels.
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