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Nikko Alpha II

jeffe

jeffe

AK Subscriber
Subscriber
translations please!

I got this and a Gamma I tuner so my Beta II pre amp would have company...

anyway, after unpackeing (broke a sweat!, great job by an ebay seller!) I let the two run for about an hour unloaded and noticed the amps left channel was warmer then the right channel. I have the manual and it has several adjustments listed that look to be easy to perform BUT, just for my clarifiacation, I have mid point voltage adjustment and idling current adjustment. What translates to DC bias? And, should I make these adjustment in any particular order?

BTW, the manual also says I need to attach dummy loads to the L & R speaker terminals. While making previous adjustments on my gear I have not had any loads attached. Is this proceedure particular to Nikko?

Thanks in advance!
 
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Idling current = bias

Check offset and adjust, then check and set bias, and go back and check offset before closing up.

Bias may take a good 30 min to an hour to stabilize, FYI.

Once offset is confirmed to be OK, you can connect your speakers as the load, but it will make little difference in the final adjustment.
 
Thanks!

I'm heading off to the garage! Been working way too much lately to enjoy our hobby lately but last weeks NS-1000M tweeter replacement and 1st time listening to my Yamaha "dream" system, the B-2/C-2a/T-2 and CD-1 and newly repaired but slightly roung NS-1000M's got me excited again and damn the dirty house!, I'm going to tweek some gear and enjoy some more music tonight and tomorrow!

FBD!

Love my Nikko's! The Gamma I is one of my favorite tuners! Got a NA-850 inbound to go with my NT-850 tuner too! The Gamma/Alpha/Beta are all the silver variety.


5/13
cool house, warm, humid garage! She started sweating and I thought I'd wait! and have another beer.... Got to it this AM. The right channel was right on at 19mV while the left (which was noticably warmer) was at 37mV. The midpiont voltages were both in spec. After adjustment the bias voltages are both at 19mV and the midpoint voltage is 11mV R and 13mV left within the 0+/- 20mV spec. Here they are. The amp and tuner look pretty darn good, the pre is not quite as nice and needs a selector knob.
 

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I really like the Alpha II's! If you can believe it, I had 3 Alpha II's powering my HT system at one time with a Marantz 5.1 pre/tuner! I scrapped the setup since I couldn't get rid of a low level hum that was irritating...
 
ugh!

was your home theater TV source cable? Improperly installed cable (the rule, not the exception?) can cause havoc in an HT system. I hope you isolated the cable tv from your system before you scrapped the idea. Man, that would have been a sonically and visually impressive system! Older homes with ungrounded outlets are yet more possible sources of your hum. I've seen grounded plugs installed... without any grounds attached, and they don't play nicely with our gear or our ears!
 
jeffe said:
was your home theater TV source cable? Improperly installed cable (the rule, not the exception?) can cause havoc in an HT system. I hope you isolated the cable tv from your system before you scrapped the idea. Man, that would have been a sonically and visually impressive system! Older homes with ungrounded outlets are yet more possible sources of your hum. I've seen grounded plugs installed... without any grounds attached, and they don't play nicely with our gear or our ears!
Click to expand...

It was a new house at the time, built in 1997... It could have been a zillion different things that was causing it. I tried some AC filters with no luck. It was a shame because I spent a few bucks and waited for months for 2 Alpha II's to show up on ebay to add to the Alpha II I already had. Another draw back was the huge, bright meters were a distraction during movies! I was covering them up with towels while movies were playing. I sold off the entire system and bought a Denon 7.1 HT receiver, and to be honest, it was the best move I ever made in terms of HT. I missed the integration of the old 70's audio equipment with modern HT equipment but what I gained was more power per channel, dead quiet at idle (no hum), and reliability! Oh, I miss the rack handles though! :yes:
 
SebTheSoundM said:
Can someone tell wath is the WPC of the NIKKO Alpha II ???
i got one for 100$ in perfect condition
Click to expand...

I believe it's rated as 120 wpc in 8 Ohms. I've got the silver version. It's a great sounding amp, but you' d better use it with 8 ohm speakers.

All the best
 
Nice setup Jeffe! I have the same in silver also. Black is more common. Everybody who sees those VUs on the amp wants to buy it.
 
Can a Nikko Alpha II owner please do me a favor, either open up or look through you heat sink screen and tell me what order, left to right, the 4 Transistors on the back are in.
It seems out of order judging by the schematic, but I want to be sure.
Thanks
Zack
 
EchoWars said:
Idling current = bias

Check offset and adjust, then check and set bias, and go back and check offset before closing up.

Bias may take a good 30 min to an hour to stabilize, FYI.

Once offset is confirmed to be OK, you can connect your speakers as the load, but it will make little difference in the final adjustment.
Click to expand...
I have Nikko Alpha Two. The amp had got hot a burn. I had open and replaced all the visible damage parts. I connect up back everything But the relay didn't click I bypass the protection board and there was DC offset present. I tried adjusting the pots but same problem. Any heads up or Idea what may be the problem?
 
EchoWars is on hiatus from AudioKarma.

Maybe someone else will point you in the right direction.

Sounds like an issue with the power supply board to me.
 
BigElCat said:
EchoWars is on hiatus from AudioKarma.

Maybe someone else will point you in the right direction.

Sounds like an issue with the power supply board to me.
Click to expand...
ok I will check the the voltage
But do you know the voltage that suppose to be present?
Thank You
 
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