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Nikko Alpha 440 Output Transistor Subs Question

cemerson

cemerson

Active Member
I have an Alpha 440 with a blown channel that was going to be pitched. I hated to see it recycled for the 30 pounds of aluminum in it. I took it because it's in perfect shape,other than the blown channel and FREE. I've been searching thru the posts and just want to verify that the Sanken 2SA1215 / 2SC2921 are the best substitutes for the original Toshiba 2SC2565A / 2SA1095A Outputs? I'd prefer to stick as close as possible to the MT-200 form. Any suggestions or other comments would be appreciated.

Thanks, Chris
 
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Yes, buy them before they run out as they are end of life. I don't think there's any other MT-200 case outputs anymore.
 
Thanks everyone. I found a set of the 1216/2922, so we’ll see how these work out. I got them thru B&D Ent. I hope that’s not a bad move. I see them all over the auction site, but wanted to purchase them from someone that would at least appear to guarantee them. This unit has other issues that caused the output transistors to blow in the first place so I’ll have to take care of these isssues first. Time will tell.

Chris
 
Cool.... haven’t heard of B & D selling fake Sankens so all should be good..

Hope all pans out well...

A few years back I worked on one of these where shocking repairs collapsed it... all output transistors were different... a lot of random MT100 devices...
Replaced driver transistors and a few resistors, and a matching output stage saw it to rights...

Do post on how it goes...
 
SVI2004A said:
Cool.... haven’t heard of B & D selling fake Sankens so all should be good..

Hope all pans out well...

A few years back I worked on one of these where shocking repairs collapsed it... all output transistors were different... a lot of random MT100 devices...
Replaced driver transistors and a few resistors, and a matching output stage saw it to rights...

Do post on how it goes...
Click to expand...
Thanks, I’ll report back how it goes once I get the other parts, so far, it appears to be a couple fried resistors, a blown transistor and any number of other things. On a side note, I’ve been to Fremantle, Perth many years ago... great country, very friendly warm people there. Loved my short stay!

Thanks, Chris
 
Retrofit 2SC5200/2SA1943 TO3PL parts and be done with it and never look back. I did this for Pioneer SX-880, SA-9500 II, etc. Replacing with those parts gives one a whole new level of confidence.
 
I'm sure all are fine transistors. Two screws holding them down seems better to me. There are many amps with the power transistors held by a single screw, so I'm sure it is fine too.
 
redk9258 said:
I'm sure all are fine transistors. Two screws holding them down seems better to me. There are many amps with the power transistors held by a single screw, so I'm sure it is fine too.
Click to expand...
I agree. I saw a post on here or DIY Audio where a guy used the 2SC5200/2SA1943 on an Alpha 450 and they worked great, but he had to tap & drill new holes in the heat sinks to accommodate the single screw. I was trying to avoid that, not that I wouldn't have done that if it was my only option. He did a really nice job, but if I can avoid that, so much the better.

Thanks, Chris
 
I think there is a pioneer SX-1980 thread where someone (maybe echowars or markthefixer) made bars with holes which matched up to the mounting holes to retain the output transistors. Could be done on one of these (Alpha 450) also....would eliminate tapping and drilling, and done right can look pretty good.
here's a picture:
index.php
 
Last edited:
sregor said:
I think there is a pioneer SX-1980 thread where someone (maybe echowars or markthefixer) made bars with holes which matched up to the mounting holes to retain the output transistors. Could be done on one of these (Alpha 450) also....would eliminate tapping and drilling, and done right can look pretty good.
here's a picture:
index.php
Click to expand...
I agree, that does look nice and I could imagine echowars coming up with something like that. I'll keep this in mind if the 2SA1216/2SC2922 units I ordered don't work out.

Thanks for passing along that ingenious suggestion, Chris
 
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