Nikko Aplha 650 needs help.

[Vinylcalle]

Yeah,it's "just" 650 in BTL mode and about 330 into 8 ohms and 340 into 4 ohms.

Of course thats alot of power no doubt.

It just seems like about every Nikko amplifier delivered just about the same power into 4 ohms as into 8 ohms.

So Nikko doesn´t seem to be the choice if you are thinking about using speakers with low impedance.

Whats the size of the main caps?

 

[Rob41]

True

I wouldn't call my speakers low impedance at 6 ohms, but the Alpha 650 performs with an effortless authority. Most of my amplifiers are in the 250 to 600 watt per channel range into 8 ohms. Some will almost double the output (3db increase) into 4 ohms and others like the Alpha 650 will not. With the amount of power on tap I find that all of my amps are very effective at driving my speakers to levels I require. I suppose there are less efficient, harder to drive speakers out there that would require more than this amp can dish out.

I'm sure one size doesn't fit all. This is one of the finest sounding amplifiers I have ever owned. I kind of went out on a limb spending more than $400 for this amp considering it was stuck in protection mode. Fortunately, I was able to repair it. I didn't even need to use DeOxit on the level pots and considering it is in near pristine condition, it must have been well cared for.

I forget what the main caps are rated at but they are about 2 1/2 inches in diameter and about 5 1/2 inches tall.You can see them between the dual toroidal transformers in the photo:

 

[Rob41]

information

Just wanted to add that there is another Nikko Alpha 650 on ebay right now. It is stuck in protect mode like mine was. Who knows if this one will be as easy to fix as mine was. After listening to my now repaired 650, I wish I had the cash to get this one.

Edit: Dammit! Even though I was going to pass it up, I just couldn't stop myself. So now I've got a second Alpha 650. Guess I'll have to build my bi-amped speaker project.

 

[bmrtoyo]

Alright, It's all better now. A transistor and a diode on the protection board were bad and it now works perfectly. I was expecting this amp to sound good and it does. It is definitely one of the better sounding amps I've heard for sure. So $4 dollars worth of parts and it's music to my ears.

Here are a couple pics of it in my current system:

niice!!

 

[Glen B]

Of course thats alot of power no doubt.

It just seems like about every Nikko amplifier delivered just about the same power into 4 ohms as into 8 ohms.

So Nikko doesn´t seem to be the choice if you are thinking about using speakers with low impedance.

Whats the size of the main caps?

I used to run an Alpha 2000 (virtually the same in design and specs as the Alpha VI and Alpha 650) with a couple of different 4 ohm speakers and it worked and sounded just fine. One of those speakers was my PSB Stratus Gold i's, which drop to 2.7 ohms in the midbass region, and present a fairly difficult phase angle. The Alpha 2000 never balked at driving the PSBs at high levels. I put the Alpha 2000 up against other solid state amps that were supposed to be "high current" designs and the Nikko amp sounded more effortless.

 

[damacman]

information

Just wanted to add that there is another Nikko Alpha 650 on ebay right now. It is stuck in protect mode like mine was. Who knows if this one will be as easy to fix as mine was. After listening to my now repaired 650, I wish I had the cash to get this one.

Edit: Dammit! Even though I was going to pass it up, I just couldn't stop myself. So now I've got a second Alpha 650. Guess I'll have to build my bi-amped speaker project.

You still have these?