NAD 3120 - Newer output transistors?

[dedero]

Hey there,
I'm actually planning the recap of this little amp but the one I bought it seems it was repaired at least once and the ouput transistors were replaced for different equivalent ones, it has only 1 original RCA transistor, therefore I would like to use the closest possible to the original ones..

- Is it worth to buy used ones original RCA on ebay or there is a big risk of getting counterfeit ones?
- In case it worth to buy newer ones, I checked on Mouser and Digikey and they don't have the original ones because they are not manufactured anymore (MJ2955 and 2N3055) but they have the newer versions of them MJ2955G and 2N3055G from onsemi, do you guys have a clue whether this newer versions can be used without altering anything in the circuit?, I checked the datasheet between the original ones and this "G" versions and they don't differ in basically anything..

Thank you!

 

[pwauk12]

use the new ones, most anything offered as "original" is either pulled from another unit or a fake, especially on EB

 

[pwauk12]

I should also add if the originals test ok (have you tested Hfe?) and/or work, I would be inclined to leave them be.

 

[dedero]

I should also add if the originals test ok (have you tested Hfe?) and/or work, I would be inclined to leave them be.

thanks!, the thing is that there is only one original in there.. and there are some resistors which also have been replaced and they are a bit burned, and still the amp works with no issues..

Do you think the "G" kind of transistors can be used instead of the originals?. Thanks

 

[pwauk12]

yes

 

[redk9258]

I believe the G version is lead free but not 100% sure.

 

[mbz]

Do you think the "G" kind of transistors can be used instead of the originals?.

Vaguely recall that base and emitter resistors should be added if you change from OEM outputs.
Hopefully someone that knows for sure will chime in.

 

[Brian1970]

New onsemi 2N3055G/MJ2955G's will work way better than the original RCA ones (or any brand of old ones). The old ones had a very low fT and new ones are much higher which makes them perform better. The G versions are just lead free. You won't have any problems using them. They're just a little more expensive but the non-G's aren't being made anymore so not much choice. You don't need to change emitter resistors unless the ones you have are out of spec.

 

[mbz]

You don't need to change emitter resistors unless the ones you have are out of spec.

The NAD3120 output stage does not include emitter or base resistors.