Who knows the Nikko Alpha II ?

ginetto61 · 19th October 2009, 02:33 PM

Dear Friends,
I have this Nikko Alpha II power amp, with one channel not functioning
I have to replace a 2SD381 and a 2SB536 in the driver stage of the not functioning channel.

The working channel sounded good in a brief preliminar test.

I have two question:
1) are there other couples good for replacing the difficult to find 2SD381 and 2SB536 ?

2) any opinion on the overall sound quality of this amp ?

If it is not against the rule I will be attaching the service manual of the amp,
or at least the schematic, tomorrow.
Thanks to everyone and kind regards,

gino

Pure_Brew · 19th October 2009, 07:04 PM

I used to own one of these over 10years ago and I wish I never sold it. Perhaps it's been too long and hard to really compare for listening now, but I owned some modest Boston Acoustics VR30 towers then, and the sound of the VR aluminum tweeters were always a bit too bright for me. When I used this amp with them, it actually smoothed things out a bit and made everything sound much more sweet and listenable. I always loved the dual-mono sweep meter design too

ginetto61 · 19th October 2009, 09:41 PM

Thank you very much for your kind and helpful reply.
So the unit's sound is basically good.

Personally I like its dual mono construction and from the working channel I hear a powerful clean sound.
I wil try to restore by myself.
And in case I will pass it to a technician.

Thanks again and regards,

gino

Pure_Brew · 19th October 2009, 10:13 PM

np, just keep in mind that some older transistors that are available as new could be fakes/bad copies. I've seen some alpha II's, like 3-4 of them on ebay over the past couple weeks that might be good for parts, although right now there are none.

ginetto61 · 20th October 2009, 04:45 PM

Quote:

Originally Posted by Pure_Brew

np, just keep in mind that some older transistors that are available as new could be fakes/bad copies.
I've seen some alpha II's, like 3-4 of them on ebay over the past couple weeks that might be good for parts, although right now there are none.

Thank you very much again for your kind and very much helpful reply
I would prefer to replace all of them with newer parts. They are 4 + 4 in total.
Not many. The person who tried to repair the faulty channel used non pin compatible chips !
As I said the good channel sings quite well. Clean, powerful in the bass and transparent enough for me.
Thanks againd and kind regards,
gino

19th October 2009, 02:33 PM	#1
ginetto61 diyAudio Member Join Date: Sep 2009 Location: Near Milan	Who knows the Nikko Alpha II ? Dear Friends, I have this Nikko Alpha II power amp, with one channel not functioning I have to replace a 2SD381 and a 2SB536 in the driver stage of the not functioning channel. The working channel sounded good in a brief preliminar test. I have two question: 1) are there other couples good for replacing the difficult to find 2SD381 and 2SB536 ? 2) any opinion on the overall sound quality of this amp ? If it is not against the rule I will be attaching the service manual of the amp, or at least the schematic, tomorrow. Thanks to everyone and kind regards, gino

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19th October 2009, 07:04 PM	#2
Pure_Brew diyAudio Member Join Date: Oct 2009	I used to own one of these over 10years ago and I wish I never sold it. Perhaps it's been too long and hard to really compare for listening now, but I owned some modest Boston Acoustics VR30 towers then, and the sound of the VR aluminum tweeters were always a bit too bright for me. When I used this amp with them, it actually smoothed things out a bit and made everything sound much more sweet and listenable. I always loved the dual-mono sweep meter design too

19th October 2009, 09:41 PM	#3
ginetto61 diyAudio Member Join Date: Sep 2009 Location: Near Milan	Thank you very much for your kind and helpful reply. So the unit's sound is basically good. Personally I like its dual mono construction and from the working channel I hear a powerful clean sound. I wil try to restore by myself. And in case I will pass it to a technician. Thanks again and regards, gino

19th October 2009, 10:13 PM	#4
Pure_Brew diyAudio Member Join Date: Oct 2009	np, just keep in mind that some older transistors that are available as new could be fakes/bad copies. I've seen some alpha II's, like 3-4 of them on ebay over the past couple weeks that might be good for parts, although right now there are none.

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