Picked up a NAD 2150 recently. Sounded good, seller said it was all original. Brought it home and opened it up, and looks like 2 of the Sanken Transistors were swapped out with Toshiba (and a messy soldering job).
This goes a bit beyond my knowledge... anyone have experience? I suppose I'm just looking for thoughts in general. How does this effect the sound?
Thanks.
This goes a bit beyond my knowledge... anyone have experience? I suppose I'm just looking for thoughts in general. How does this effect the sound?
Thanks.
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If the specs match, it is okay, Toshiba is good quality, unless you can tell which brand of speaker wire is being used.
Then the senior members will tell you their opinion.
Messy soldering, cut tracks, flux residue...not well done.
Clean off flux residues after reworking the soldering, it is corrosive, I use iso propyl alcohol and an old tooth brush.
Check for proper heat sink mounting on the old and new transistors, the compound or pad may not be well done either.
Check for DC, bias and other parameters.
Sanken was taken over by Sanyo, which then went to OnSemi...so the best chance of the original device is Toshiba and OnSemi, plenty of fakes available, but that has been discussed on this forum.
Then the senior members will tell you their opinion.
Messy soldering, cut tracks, flux residue...not well done.
Clean off flux residues after reworking the soldering, it is corrosive, I use iso propyl alcohol and an old tooth brush.
Check for proper heat sink mounting on the old and new transistors, the compound or pad may not be well done either.
Check for DC, bias and other parameters.
Sanken was taken over by Sanyo, which then went to OnSemi...so the best chance of the original device is Toshiba and OnSemi, plenty of fakes available, but that has been discussed on this forum.
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The 2SA1389 (green colored )has a lower wattage and FR, not by a lot but its not a first choice replacement although the working voltage is the same.
The two Sanken are actually marked by Sanken as complimentary .
A 2SA1493 is a better replacement for a 2SA1215.
The complimentary for the 2SA1493 is the 2SC3857.
If they are available I would replace both those Toshiba BJT,s with the actual complimentary ones above--especially the 2SA1389.
The two Sanken are actually marked by Sanken as complimentary .
A 2SA1493 is a better replacement for a 2SA1215.
The complimentary for the 2SA1493 is the 2SC3857.
If they are available I would replace both those Toshiba BJT,s with the actual complimentary ones above--especially the 2SA1389.
Those Toshibas aren’t even a complementary pair. The proper mate for C2565 is A1095. They have a super high fT, and not a spectacularly high SOA. Really nice for small-ish amps (50 W or less) but I’d look for something stronger and more comparable to the Sanken’s.
American MJ series, and similar European series transistors might also be substitutes.
15030/31 are mentioned on AudioKarma, and there are similar threads here on diyaudio as well.
15030/31 are mentioned on AudioKarma, and there are similar threads here on diyaudio as well.
Or, you could just fit a set of the same Sankens as it already has - they're still available in USA, albeit at $5-6 each - from a Sanken authorised distributor.
Discontinued and dwindling. Might still be able to get from Profusion but forget it from Digikey. They have a handful of mismatched types on hand. Don’t buy ISC (and NTE is likely coming from ISC now instead of Sanken unless it’s old stock) substitute something else first. If you are more concerned with maintaining Sanken performance, use their latest TO3-P’s, whatever type it happens to be today. If you are more concerned with SOA, use MJL3281/1302. They have higher capacitance, but a full 200 watts and pretty good beta droop performance.
I was just gonna say, why should i not just buy the original pair? Is it fear of being counterfeit or non-functional?
2SA1215 + 2SC2921 Audio High Power Transistors By SANKEN | eBay
2SA1215 + 2SC2921 Audio High Power Transistors By SANKEN | eBay
Do not buy Sanken transistors, or any premium power transistors for that matter, from eBay - You will get fake parts which will blow up and cause more damage to your amp.
That applies to pretty nearly part out there.
Stick to known sellers.
Sankens are rare, and the price is like a used car, buyer and seller expectation must match. But here you have no way of taking a test drive...
If somebody offers you a Big Mac for $10, or 10 cents, become very alert, because the price is $5 at McDonalds.
And if you have substitutes in regular package, use those, my Sansui manuals have different - bat wing and regular - transistor illustrations for Europe and USA markets of the same model.
The regular ones are easier to find, and still in production or at least much more larger stocks exist, at reasonable prices.
Stick to known sellers.
Sankens are rare, and the price is like a used car, buyer and seller expectation must match. But here you have no way of taking a test drive...
If somebody offers you a Big Mac for $10, or 10 cents, become very alert, because the price is $5 at McDonalds.
And if you have substitutes in regular package, use those, my Sansui manuals have different - bat wing and regular - transistor illustrations for Europe and USA markets of the same model.
The regular ones are easier to find, and still in production or at least much more larger stocks exist, at reasonable prices.
US listings on Ebay can be a different matter as there are, or perhaps were local repairers, who may have small stocks of genuine parts that are no longer needed so they offer them at fair, not cheap prices. These are the traders you hope to be dealing with but how can you tell them apart from opportunists who buy super cheap copies and outright fakes only to resell at inflated prices?
As a matter of interest, I have received genuine parts from one of the traders; "Small parts-big difference", shown on your linked Ebay page. If you want assurances though, shop with local traders where you can get your money back without having to prove and pay expensive return airmail charges if their products turn out to be fake.
As a matter of interest, I have received genuine parts from one of the traders; "Small parts-big difference", shown on your linked Ebay page. If you want assurances though, shop with local traders where you can get your money back without having to prove and pay expensive return airmail charges if their products turn out to be fake.
After Covid, there may be a lot of estate sales in the USA of parts and equipment, and the seller most likely has no idea of the value, the owner having passed on, incapacitated, or just wanting to retire quickly.
The market will get murkier.
In cameras, at least there were auctions of camera collections with catalogs and so on, and the value of the total was high enough for auction houses to take the trouble.
Here, I would not expect the average value to be that high, for a technician's equipment and stock.
2SA5200 are about $ 1.5 to $ 3.5 here, so this discussion is about $10 or so worth of parts, plus shipping...
The market will get murkier.
In cameras, at least there were auctions of camera collections with catalogs and so on, and the value of the total was high enough for auction houses to take the trouble.
Here, I would not expect the average value to be that high, for a technician's equipment and stock.
2SA5200 are about $ 1.5 to $ 3.5 here, so this discussion is about $10 or so worth of parts, plus shipping...
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