I was in need of some transistors to replace the shorted 2SA1169 and 2SC2773 (XM20) outputs in a Yamaha R-1000. I posted a thread at Audiokarma looking for assistance and a very kind forum member messaged me and basically told me he bought out the stock when they were announced to go extinct. He sold me 4 pair, 4 2SA1494 and 4 2SC3858 (MT-200), enough to do two amplifiers. Drop in replacements. Unfortunately I went through them, I repaired two of these R-1000s with shorted outputs. I’m in need of more and instead of going back to ask if he would sell me more, I thought I’d see if I could find a modern replacement that will work with a retrofit.
Below is the NPN I’m trying to replace in the Yamaha.
I’ve looked through parts I have and I believe this may be the closest I have.
Only concerning looking thing to me would be the emitter-base voltage max, 6V vs 5V, which looks like it won’t be an issue in this amp, should be under a volt. Otherwise the replacement is more robust all around. Couldn’t I technically drill and tap a new hole and get this pair to work?
Here is the device that was sent to me and I used in the other two R-1000s.
I’ll keep looking myself, but does anyone know a pair of devices that would be a good go to for these since they’re no longer available?
Dan
Below is the NPN I’m trying to replace in the Yamaha.
I’ve looked through parts I have and I believe this may be the closest I have.
Only concerning looking thing to me would be the emitter-base voltage max, 6V vs 5V, which looks like it won’t be an issue in this amp, should be under a volt. Otherwise the replacement is more robust all around. Couldn’t I technically drill and tap a new hole and get this pair to work?
Here is the device that was sent to me and I used in the other two R-1000s.
I’ll keep looking myself, but does anyone know a pair of devices that would be a good go to for these since they’re no longer available?
Dan
I also have some MJL/NJW 21193/21194 that look promising, the MJL being bigger and closer to the physical size of the originals.
Dan
Dan
What is the supply rail voltage?
5200/1943 pair was common in Japanese units, and MJ series are available from American makers.
Use a cross reference search with rail voltage and amps as the parameter, and go from there, 20 MHz is dinosaur quality, and enough for audio.
5200/1943 pair was common in Japanese units, and MJ series are available from American makers.
Use a cross reference search with rail voltage and amps as the parameter, and go from there, 20 MHz is dinosaur quality, and enough for audio.
Rails are fairly low, according to the schematic a +/- 42.6 Vdc for the output section. This receiver has two sets of rails, the other one is +/- 75 Vdc, but used elsewhere in the receiver.
Dan
maybe this is helpful:
@saabracer23 , is the MT-200 packaging important?
Kind regards,
Drew
- https://www.el-component.com/bipolar-transistors/2sa1169-y
- https://www.el-component.com/bipolar-transistors/2sc2773
@saabracer23 , is the MT-200 packaging important?
Kind regards,
Drew
Currently sold Mosfets/ bipolar will work.
Look for circuits with +/- 50V rails, and go from there.
You can use extension wires to mount them on heat sink, if the package you need is not available.
Look for circuits with +/- 50V rails, and go from there.
You can use extension wires to mount them on heat sink, if the package you need is not available.
Enough said.
Use those, period, unless really unavailable or price is outrageous/impossible.
Saving a few bucks will NOT compensate the possible headaches caused by using very different transistors.
MJL ere very good, very strong, but doubt they work the same in that amplifier; Japanese were justly famous for the highly linear, wide bandwidth transistors they made, not hype but real higher performance.
Quite measurable I might add.
Find Toshiba or Sanken transistors, 5200 / 1943 may work as well (those are Japanese numbers).
Good luck with finding original transistors, you will need it.
Good luck with finding original transistors, you will need it.
MJL2119x is quite a different animal from MJL3281. The latter is a wide bandwidth high linearity type and will usually work where Sanken LAPT types were. Maybe not a “good” as the originals but better than the TTC5200 would. The 5200 was a step BACKWARD, but it was cheap in its day. There are no more REAL MT200 types anymore - Sanken discontinued them, and everybody else’s are copies which range from “maybe ok” to “don’t even try“ bad. On’s version of the 3281 is a bigger die than the C5200 or even the original Toshiba 3281, but other than that is similar. Not exact for sure, but still a >20 MHz fT and flat beta out to 8A.
Oh yeah thank you for the reminder, I have a few dozen each of the 5200/1943. Those would likely be a good match. I don’t think I’d need extension wires, I figure they’d fit in the current position.
Dan
I’m not sure if you read my entire post, but those drop in replacements I was referring to I no longer have. I could reach out to the member to see if he’d be willing to sell me more, but he has very reluctant to sell me four pair is it was. He wants to save them for his future projects, so I figured I would look into the possibility of finding a current device that will work instead of relying on going to eBay for possible counterfeit devices. It’s not necessarily about saving a few bucks and more about finding a good replacement that is current so you can grab them from Mouser, Digikey, etc.
Thank you for that last paragraph, I’ll try to keep it to Japanese devices.
Dan
I have a whole bunch of Onsemi/Fairchild 5200/1943, but I see I can grab Toshiba from Mouser, so I can grab a bunch of those.
Dan
Okay, so find better than the Toshiba 5200/1943? I can certainly grab some MJL3281, I currently have NJW. Yeah, I don’t even want to try what MT200 are out there. So would you recommend the Onsemi 3281 over the Toshiba?
Dan
If you mean eBay, then yes I didn’t try too hard. I try not to make it a habit of buying obsolete devices from eBay. Why chance it if it’s possible to replace an obsolete device with one that will work well that you know with all certainty that it’s authentic. Plus I see many are $12-$15 each. I have two, very possibly 3 of these receivers to do, so if I can get all 3 done for around $50-$60 vs $180 I will. Just like the 2SC2240, sure you can get it from B+D for around $10 each, but why when a KSC1845, a ZTX, or similar can work perfectly fine for a fraction of the cost. Clearly I would buy the originals regardless if they were $10-$12 each if I could get them from Mouser or Digikey.
Dan
Great, that’s great to hear. Is there any reason to not use the NJWs I have already and buy the larger MJL? Are the dies the fairly similar? They seem very close in specs. The MJL would be a bit better at transferring heat to the heatsink, but they have a same power dissipation. In the photos below those are the MJL21193/94. I don’t have true 3281 or 1302 in that size
Thank you,
Dan
I'm not really that of an expert, but I'd say the dies are the same in both cases (MJL vs. NJW).
Best regards!
Best regards!
Thank you, yeah with a bit of research I found that they are indeed likely the exact same device, with the MJL being a bit better at expelling heat due to its larger case.
Dan
That’s what The Big Deal with the MT200 was - getting the heat out of the case. The better job you do there, the more the solution will resemble the original. Biggest you can get nowadays is the TO264.
Sanken is still making some of the same dies they used in the MT200’s - just putting them in the tiny case.
On Semi’s C3281 is about the same size die as Sanken used in their bigger devices. Its bigger than Toshiba’s original C3281 and the stripped down cheapo C5200. 200W vs. 150, 11 nF Cbe vs. 7.
Sanken is still making some of the same dies they used in the MT200’s - just putting them in the tiny case.
On Semi’s C3281 is about the same size die as Sanken used in their bigger devices. Its bigger than Toshiba’s original C3281 and the stripped down cheapo C5200. 200W vs. 150, 11 nF Cbe vs. 7.