Emitter resistors, single piece?

[VMat]

Hello,

I've been working on an old Technics "New Class A" amp (SU-Z65) with a dead left channel. Already asked for help in another thread, about small-signal BJT replacements (thanks, guys!).

Now I'm wondering about the emitter resistors, I would bet this doesn't matter much, but decided to ask, just in case.

When I got the amp years ago, it had already been serviced (and only now I'm finding the guy did some stupid "changes", but that's another story). The right channel has a single ceramic emitter resistor in the output stage, with three terminals. Each "half" is 0.22ohms x 3W - this configuration matches the schematics in the service manual. The left channel had a couple of wirewound resistors, I just replaced them with two separate ceramic resistors (0.22ohms x 4W) back then.

Should I try to replace the two resistors with a single one? Do you know if it it's important to keep a single resistor there, to keep the temperature closer between the two halves, or something else?

Thanks,

 

[jitter]

The same type of three-legged resistors are in my Marantz PM-40SE, however, the PM-80SE has single resistors.
Based on this, I think that keeping single resistors in is fine. I don't think that the exact matching or thermal coupling of these low value resistors is terribly important (otherwise you'd probably find them in all amps).

 

[VMat]

The same type of three-legged resistors are in my Marantz PM-40SE, however, the PM-80SE has single resistors.
Based on this, I think that keeping single resistors in is fine. I don't think that the exact matching or thermal coupling of these low value resistors is terribly important (otherwise you'd probably find them in all amps).

Yeah, that makes sense. It makes me curious why they would pick the single resistor, which I'd guess is more expensive than two separate ones. But you're right, they should be in all amps if they were so critical. I didn't think of that.

Thanks!

 

[jitter]

The dual resistor might be a little more expensive to make, but my guess is that less handling offsets this in larger production volumes because if you need to count, store and mount only half the components, time will be saved. And time is money.