Sansui Au919 Parts
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noveltone
Active Member
Transistors
Welcome to AK! I have an AU-919 and I needed to replace those transistors, the drivers and outputs. You can check with Woodang.net, who has some stock of the 2SA1116 or 2SC2607, but not a full set at my last check. Hopefully he has what you need.
Since those transistors are no longer made and replacements are likely to be counterfeit, what many people here do (including me) is buy a reliable substitute. I used On-Semiconductor brand parts, like many here. With them, the amp sounds just like before and seems to be working reliably. They can be purchased at Mouser or Digikey.
Here's what I used, based on recommendations of much more experienced users:
Subs for 2SA1116/2SC2607: On-Semi MJ21193 and MJ21194
Subs for 2SD382/2SB537: On-Semi MJE15030 and MJE15031
Subs for 2SA939: Try Mouser and search for part number KSA939. They're made by Fairchild and seem to work well as replacements for the 2SA series.
The above worked for my AU-919, and if you choose to use those subs I wish you luck with your project.
Collin
Welcome to AK! I have an AU-919 and I needed to replace those transistors, the drivers and outputs. You can check with Woodang.net, who has some stock of the 2SA1116 or 2SC2607, but not a full set at my last check. Hopefully he has what you need.
Since those transistors are no longer made and replacements are likely to be counterfeit, what many people here do (including me) is buy a reliable substitute. I used On-Semiconductor brand parts, like many here. With them, the amp sounds just like before and seems to be working reliably. They can be purchased at Mouser or Digikey.
Here's what I used, based on recommendations of much more experienced users:
Subs for 2SA1116/2SC2607: On-Semi MJ21193 and MJ21194
Subs for 2SD382/2SB537: On-Semi MJE15030 and MJE15031
Subs for 2SA939: Try Mouser and search for part number KSA939. They're made by Fairchild and seem to work well as replacements for the 2SA series.
The above worked for my AU-919, and if you choose to use those subs I wish you luck with your project.
Collin
noveltone
Active Member
transistors
Nikomi021,
It sounds like your amp is working now, but you'd like to restore it with original parts. Is that right?
One thought I had was that the original output trans. I had differ from the 2SA1116/2SC2607. I had NMA1012 and another odd one, apparently special parts produced for Sansui by Sanken, the maker of the 2SA1116/2SC2607 parts. It seems like many parts having about the same specs will work here without affecting the sonics too much.
Even in the US it is difficult, if not impossible to find original Sansui-era transistors. This is based on the observations and experiences of others here. I certainly don't know a great deal about this, but the little I've picked up looking around on this site and elsewhere tells me it's better to go with legitimate new parts rather than old, likely fake parts if you can even find them. I've read a few accounts of fake transistors even damaging peoples' equipment.
Will Digikey et al ship to your location?
Collin
Nikomi021,
It sounds like your amp is working now, but you'd like to restore it with original parts. Is that right?
One thought I had was that the original output trans. I had differ from the 2SA1116/2SC2607. I had NMA1012 and another odd one, apparently special parts produced for Sansui by Sanken, the maker of the 2SA1116/2SC2607 parts. It seems like many parts having about the same specs will work here without affecting the sonics too much.
Even in the US it is difficult, if not impossible to find original Sansui-era transistors. This is based on the observations and experiences of others here. I certainly don't know a great deal about this, but the little I've picked up looking around on this site and elsewhere tells me it's better to go with legitimate new parts rather than old, likely fake parts if you can even find them. I've read a few accounts of fake transistors even damaging peoples' equipment.
Will Digikey et al ship to your location?
Collin
Stene
The Introducer
Au-919
The original Power Transistors for AU-919 are NMA1012 and NMC1012 and as you said special made for Sansui by Sanken. See pic for an eventually reason for 2SA1116/2SC2607
I have a 919 here with non-original outputs in it. Part of what makes the 919 desirable were the high-speed output transistors, the original NMA1012's and NMC1020's, which are no longer manufactured or available. The 2SA1116 and 2SC2607 would make great substitutes, but they also were discontinued years ago. I just emailed Sten at Woodang, and although he has a few of the 2SC2607's, he has only one 2SA1116.
For these reasons, I'm going to replace the original TO-3 style transistors with Toshiba 2SA1962 and 2SC5242 TO-3P(N) style devices. The base and emitter fit nicely into the holes in a TO-3 socket, but the collector is a problem. I plan on soldering a small uninsulated ring terminal to the collector lead, and putting the mounting screw through it when the device is mounted.
Mica insulators are also tough to find for these transistors for some reason, so I'm using Bergquist K10 Sil-Pads. I'll likely post a pic of the finished product...it'll be kind of a kluge to use the TO-3P(N) transistors where the TO-3's are supposed to go, but I think it's the only way to preserve the sound of the amp.
For these reasons, I'm going to replace the original TO-3 style transistors with Toshiba 2SA1962 and 2SC5242 TO-3P(N) style devices. The base and emitter fit nicely into the holes in a TO-3 socket, but the collector is a problem. I plan on soldering a small uninsulated ring terminal to the collector lead, and putting the mounting screw through it when the device is mounted.
Mica insulators are also tough to find for these transistors for some reason, so I'm using Bergquist K10 Sil-Pads. I'll likely post a pic of the finished product...it'll be kind of a kluge to use the TO-3P(N) transistors where the TO-3's are supposed to go, but I think it's the only way to preserve the sound of the amp.
noveltone
Active Member
This is extremely interesting. EW, thanks for you insight here. Although I recall many people using the On-semi transistors with moderate success (including myself recently) I am very curious how the Toshibas will affect the sound.
Does the transistor's "speed" refer to the graph of collector current vs. bandwidth product?
Sansui promoted the AU-919 as having a fast "rise time." Are the output transistors a critical part of this? The driver transitors? The reason I'm asking is that I recently replaced the driver transistors with On-Semi's that EW said were slower than the originals. I listed these above in post #2. Using this slow driver, would it make any difference to replace the slower On-semi output with the Toshibas?
Interesting.....I'm really looking forward to seeing a pic of this. I hope all this discussion helps you, Nikomi.
Thanks,
Collin
Does the transistor's "speed" refer to the graph of collector current vs. bandwidth product?
Sansui promoted the AU-919 as having a fast "rise time." Are the output transistors a critical part of this? The driver transitors? The reason I'm asking is that I recently replaced the driver transistors with On-Semi's that EW said were slower than the originals. I listed these above in post #2. Using this slow driver, would it make any difference to replace the slower On-semi output with the Toshibas?
Interesting.....I'm really looking forward to seeing a pic of this. I hope all this discussion helps you, Nikomi.
Thanks,
Collin
Yep. Many manufacturers don't give you a graph, but simply list a typical or minimum 'ft' specification. The On-Semi MJ21193 and 94 outputs are rated at about 4MHz, whereas the original devices were about 20 to 30MHz. The Toshiba transistors I mention in my previous post are spec'd to have a typical ft of 30MHz.
Both. 'Weak link in the chain' concept.
Sure will.
Fast TO-220 drivers and fast plastic TO-3P power transistor are fairly easy to come by...fast TO-3 power transistors are extinct. The swap to the plastic TO-3P(N) transistors will not be aesthetically pleasing once done, but should preserve the specifications of the amp and help it sound as it is supposed to.
The schematic shows plain-ol 2SC2238 and 2SA968, which are only rated at 160V. But both of these transistors are available in an 'A' variant, rated at 180V, and also a 'B' variant, rated at 200V. I'd think the big Sansui's ought to at least use the 'A' variant.
So I'd go with the Panasonic 2SA2140P and 2SC5993P. These are 180V, 1.5A insulated plastic cases, so no mica insulator is needed for mounting...just grease.
Many Sansui amps cannot use these plastic tab devices because Sansui makes the collector connection through the metal tab instead of the center collector lead.
So I'd go with the Panasonic 2SA2140P and 2SC5993P. These are 180V, 1.5A insulated plastic cases, so no mica insulator is needed for mounting...just grease.
Many Sansui amps cannot use these plastic tab devices because Sansui makes the collector connection through the metal tab instead of the center collector lead.
nikomi021
New Member
Yes, there is a lot of options! Does anybody knows what is the different from original output and substitutes? In my AU919, there is MOSPEC MJ15003,MJ15004 at both channels at output, one channel has original drivers trans. and other channel has MJE15030, MJE15031 and instead 2SA939 there is BF470......Amplifier sounds great, and I can`t hear the difference.I don`t know how sounds ORIGINAL amp. but I think that this amplifier has GREAT construction, and it is the reason why everybody tells that it sounds good! I started my project with disassembling all switches and polishing contacts, every contact was resold and 85 capacitors replaced from NICHICON to PANASONIC FC. Output relays was replaced.Because I`m perfectionist, I need original parts.......
Nicowico
Active Member
What about the Sansui X1? For stability reasons it's adviced to replace the original 2SA1068/2SC2493 for the MJ21193/MJ21194, but what is the difference soundwise? And what are the specs of the 2SA1068/2SC2493?
ghamilton
Super Member
919 Output Transisters...
I am looking for a bottom line to all of this.:tears: I would like to know what pwr output transisters are the closest to the originals that mount properly.:scratch2: All mine are the originals. :yes:But they will probably in the future need to be replaced.:sigh: It would be nice to have the best setting on the shelf for that day. :yes:So which is it guys? :scratch2:Can you agree on which is the best? :scratch2:I would like to order them asap.:yes:
Thanks
I am looking for a bottom line to all of this.:tears: I would like to know what pwr output transisters are the closest to the originals that mount properly.:scratch2: All mine are the originals. :yes:But they will probably in the future need to be replaced.:sigh: It would be nice to have the best setting on the shelf for that day. :yes:So which is it guys? :scratch2:Can you agree on which is the best? :scratch2:I would like to order them asap.:yes:
Thanks
The original AU-X1 output transistors are Sanken LAPTs (high frequency multi-emitter Linear Amplitude Power Transistor). Sanken still produces LAPTs but not on a TO-3 package, only on epoxy packages.
Old specs for the 2SA1068/2SC2493:
TO-3 package 100W, 150V, 10A, 60MHz, HFEmin=30
The closest current Sanken devices are the 2SA1186 and 2SC2837 complementary pair in TO-3P package 100W, 150V, 10A, 60MHz, HFEmin=50. If you want the part that is electrically compatible as the original, these are the ones you would probably use. Probably because the TO-3P package is less efficient is dissipating heat which means bigger heatsink is required compared to a TO-3 metal package. The TO-3P package can be modified to fit in a TO-3 footprint by bending the B and E leads 2mm from the body and utilize the original TO-3 B & E holes. The TO-3P hole has to be mounted near on the TO-3 collector hole that is farther away from the B&E leads. A wire has to be used to connect the TO-3P collector. Remember to add insulation on the B & E where it goes through the heatsink to minimize the possibility of shorts. There are higher rating (125W-130W) TO-3P Sanken LAPT devices but with lower ft of 35-50MHz.
The advantage of the LAPT transistor aside from the higher ft is the HFE linearity vs Ic. Here's the ON MJ21193/94 datasheet for comparison. Check amplifier design books regarding this advantage.
Bottom line, you can't buy the original TO-3 anymore. You can only have it physically the same but not electrically the same and vice versa.
Old specs for the 2SA1068/2SC2493:
TO-3 package 100W, 150V, 10A, 60MHz, HFEmin=30
The closest current Sanken devices are the 2SA1186 and 2SC2837 complementary pair in TO-3P package 100W, 150V, 10A, 60MHz, HFEmin=50. If you want the part that is electrically compatible as the original, these are the ones you would probably use. Probably because the TO-3P package is less efficient is dissipating heat which means bigger heatsink is required compared to a TO-3 metal package. The TO-3P package can be modified to fit in a TO-3 footprint by bending the B and E leads 2mm from the body and utilize the original TO-3 B & E holes. The TO-3P hole has to be mounted near on the TO-3 collector hole that is farther away from the B&E leads. A wire has to be used to connect the TO-3P collector. Remember to add insulation on the B & E where it goes through the heatsink to minimize the possibility of shorts. There are higher rating (125W-130W) TO-3P Sanken LAPT devices but with lower ft of 35-50MHz.
The advantage of the LAPT transistor aside from the higher ft is the HFE linearity vs Ic. Here's the ON MJ21193/94 datasheet for comparison. Check amplifier design books regarding this advantage.
Bottom line, you can't buy the original TO-3 anymore. You can only have it physically the same but not electrically the same and vice versa.
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About the only choice.
Only if you blow it up....otherwise there's no reason why they can't go another 30 years.
Quit worrying about it, and enjoy your amp.
2SC2493 - Vceo=150V, Ic=10A, Pc=100W, Hfe=60, ft=70MHz
2SA1068 - Vceo=150V, Ic=10A, Pc=100W, Hfe=60, ft=50MHz
The MJ21193 and 94 are orders of magnitude slower than the original devices (they are rated at 4MHz). Couldn't tell you what this does to the sound, but it certainly is a hellova long way off from what Sansui wanted in that amp. I'm sure it does nasty things to open loop gain.
The 2SC2071 and 2SA939 are rated at 250V, and the B649 and D669 at only 160V. If you do not NEED the high voltage capability, I'd use the 160V-rated Sanyo 2SA1209 and 2SC2911, or going up in voltage, the 200V Sanyo 2SA1380 and 2SC3502. If you really need a rating of 250V or more, then the Sanyo 2SA1353 and 2SC3417 would do well.
Why all the Sanyo's? Seems high-voltage, wide-bandwidth TO-126 transistors are getting tough to find, and Sanyo just happens to have a lot of good ones.
