2SA1403A replacement output transistor TO3 - Rotel RA-913 integrated amp.

[Hifibythekg]

Hi,

Please can anyone help with some advice?

My Rotel RA-913 integrated amp has 4 2SA1403A TO3 outputs.

One is blown.

Should I:

- Try to buy an original one from a used parts vendor?
- Replace with a new version?
- Replace all 4 transistors with new versions?

And which contemporary model/part do I need to buy?

 

[Hifibythekg]

 

[eizner23]

You can buy a new http://www.ceitron.com/cart/advanced_search_result.php?keywords=2SC1403A&search_in_description=1
Or replace with moderns https://www.mouser.com/Search/Refine?Keyword=MJ15003G
I would put in new beefier moderns the other 3 might be damaged.

 

[Hifibythekg]

For easy reference, some schematics and lists posted above and below..

 

[Hifibythekg]

Hi Eizner.

Thank you so much for such a prompt and helpful reply!
I might buy from RS or Farnell in the UK simply because of shipping costs.

https://uk.rs-online.com/web/p/bipolar-transistors/8624960/
https://uk.farnell.com/on-semiconductor/mj15003g/transistor-npn-140v-to-3/dp/9556460

If cost were no option which MJ model do you think would work best?
Is there much risk of the new models affecting the sound quality negatively?

Thanks again!

 

[Oldsansui441]

Hi Hifibythekg, there is also these that would be suitable. There will be no worry about affecting the sound quality negatively, the fT is very similar to originals.

https://docs.rs-online.com/8489/0900766b8078eaf7.pdf

 

[Hifibythekg]

Hi Oldsansui and Eizner I made an annoyingly silly typo. My sincere apologies.

It's a suitable replacement for a 2SC1403A that I require (please note, C not A).

My apologies to anyone who has scratched their head excessively..
Suggestions continue to be very welcome and thank you.

 

[Oldsansui441]

It's a suitable replacement for a 2SC1403A that I require (please note, C not A).

No worries at all, l think we both figured as much .

 

[Hifibythekg]

 

[dlucy]

replace with moderns https://www.mouser.com/Search/Refine?Keyword=MJ15003G

That is what I would do.

Definitely replace all four so you have the same model number across all four.

 

[Hifibythekg]

Hey Doug, great to hear from you.

I was just about to order four MJ15022G

Is the MJ15003G the better option?

Some comparisons below, but might there be other aspects to consider for this replacement?

2SC1403A:
VCBO 180V
VEBO 6V
Ic 8A max
Pmax 70W
hFE 60 (@VCE = 4V, Ic = 3A)
fT 10MHz (grounded base)*
Cob 130pF

MJ15022:
VCBO 200V
VEBO 5V
Ic 16A max
Pmax 250W
hFE 60 (From graph @Ic = 3A)
fT 4MHz min (grounded ennitter?)
Cob 500pF max

MJ15003:
VCBO 140V
VEBO 5V
Ic 20A max
Pmax 250W
hFE 50 (From graph @Ic = 3A)
fT 2MHz min (grounded ennitter?)
Cob 1000pF max

*Roughly a third for grounded emitter operation.