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Once more Sansui transistor substitutions

thanhky1985 said:
I never use the bass treble or mid knobs on the tone board. because "sound imaging" type players never like that. :biggrin:
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Well, they probably provided it for people tinkering the sound of transistors, so myself I do not need it, but it is there and it enhances the looks of the old amp.
Those people were probably pretty smart, imagining how some techs would approach technology, 50 years later.
 
gslikker said:
Well, they probably provided it for people tinkering the sound of transistors, so myself I do not need it, but it is there and it enhances the looks of the old amp.
Those people were probably pretty smart, imagining how some techs would approach technology, 50 years later.
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yes you are right. i also think technology after 50 will be better. but in the end i still have to admit that there are some things technology + sales + revenue that have made the product quality not the same as 50 years ago. that is why until now audiokama is still active to share with everyone how to hold on to things that are 50 years old. but it also includes people who only hold on to the appearance. some people hold on to both quality and appearance. yes they are just trying to find the original sound of products 50 years ago :biggrin:
 
Thank you for your reply but I got
2SA679 MJ21193G and
2SC1079 MJ21194G.
I know the G means lead free but why the discrepancy? Did I order the wrong ones?
 
Hi all ,

What recommendations do you have for replacements of SanKen Transistors type MT-200 : 2SA1169 & 2SC2773 from the actual market ?
THE ORIGINAL ONES STILL CAN BE FINDED ?
 
CostinB said:
Hi all ,

What recommendations do you have for replacements of SanKen Transistors type MT-200 : 2SA1169 & 2SC2773 from the actual market ?
THE ORIGINAL ONES STILL CAN BE FINDED ?
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That’s a good question and does anyone have seen to buy online “mica” insulation pads or any other thermal material for MT-200 package ?
 
I would like an opinion on these for substitution. Working on a sansui 9090 driver board. Just Want to make sure this is ok before I order. Was having a hard time finding these. And I'm kinda new to this. Just trying to fix someone's hack job on this board...
2sc1628=ksc3503
2sc1720=ztx694b
2sa818=mje350g
2sa849=mje350g
 
2SD118 the list recommends MJ21194G, but the VEB and HFE is a lot lower than 2SD118. Are these two readings inconsequential? As I’ve seen others mentioned as replacements all of which have similar lower readings.
 
Hebridean said:
2SD118 the list recommends MJ21194G, but the VEB and HFE is a lot lower than 2SD118. Are these two readings inconsequential? As I’ve seen others mentioned as replacements all of which have similar lower readings.
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As long as you replace all the output transistors in a channel with new you should be OK - mixing them will give you problems.
 
Nice , this is great news !!!

:bowdown: :bowdown: :bowdown:

The schematic for Sansui 9900Z says +81V , GND , -81V , so 162V will be ok for the upper limit of 180V from the substitute transistors .
 
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I believe I have found near perfect substitutes for the Toshiba dual transistors 2SC3381 and 2SA1349 as used in the Sansui Alpha (α) range, and quite likely elsewhere. I have been interested in finding substitutes for these devices ever since owning an AU-α907MR, as I always look around for substitutes for unobtanium items, for future proofing reasons.

The transistors have an unusual 7 lead package which presents Collector 1,2 Emitter 1,2 and Base 1,2 + a substrate connection i.e. 7 leads in all. There are 10 of these devices used in the above amplifier, six NPN duals, and four PNP duals, they are all used as constant current sources. Because the transistors that make up each device need to be in very close contact, using discrete replacements isn't going to work nearly as well, so I began to search for suitable SMT devices. (The substrate connection is not required).

For a while I couldn't find a device with two transistors in a dual package where all the leads were individually accessible - this is a requirement of the circuit configuration. Eventually I found one, and its opposite PNP complementary device.

Here is the PNP configuration. (kQ30 being the device in question) 2SA1349.

1738179442750.jpeg

And also the NPN configuration. (kQ29 being the device in question) 2SC3381.
1738179617424.jpeg
So here are data sheets for the originals



And the SMD replacements

For 2SA1349 replacement

And for 2SC3381 replacement

If you compare the data sheets they are nearly identical, and the SMT devices are better in some cases - like 'Voltage' & 'Noise Figure' for example.

The above are 'SOT-25-5' devices, meaning they have five connections, the devices are VERY small, so will need to be mounted on a suitable adapter PCB - which looks like this:-

These adapters are 12mm wide and 10mm tall, which should give you an idea of the size of the SMT devices. ;)

1738180335301.png

The markings on the board are for a common emitter dual transistor, not a problem, but it does mean the connections are not labelled correctly for the devices I have chosen. I hope 'Affinity for Artifacts' doesn't mind me pinching his picture of the board, shown on his ebay listing. ;)

The correct connections will read E1 C1 B C2 E2

I am in the process of fabricating some replacements which I will try in my 'α907' at some point. I will very likely fit this in when I next remove the driver modules, which won't be for a while - but I will update here when I have tried them. (There are two per channel in the driver modules, one PNP & one NPN)

Thanks for reading. ;)

@JimEGR
@fojica
@Sui-Yogi
@DB-7
 
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Maybe one thing to think about, the power total for the HN4A51's is spec'd in a confusing manner, they appear to say that you can dissipate 300mW total, but each element should not exceed 200mW (for 400mW total?). In the schematic we'd expect the collector current's to be balanced so I'd look pretty hard at the total package power and derate conservatively based on the temp inside the working unit. The good news is there's an extra 25C of junction temperature available in the modern devices.

As always YMMV
 
Hi - cannot see a recommendation for this but my G3500 has a couple of 2SC1439 on the power board and I'm looking for a replacement.

On a yamaha speaker thread I have seen KSC3503 and KSC2383 suggested.

Anyone found success? Much appreciated.
 
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