choosing a choke

[bottleheader]

Hi folks,
It is recommended to replace the first 270 ohm resistor with the Triad C-7X which is 90mA.
Would the Lundahl LL2743 at 90mA and 50H inductance work (well?) in the Crack?
Thanks

 

[bottleheader]

@Paul Birkeland I'd be grateful for your insight on the LL2743 in this circuit

 

[Paul Joppa]

The choke usually goes in the power supply, where it reduces the (already-inaudible) hum. It is not in the signal path.

Yes it will work, in the sense that it will reduce the hum even more than a 10H choke would.

 

[bottleheader]

Thanks @Paul Joppa So there would likely be no audible benefit to the LL2743 over the Triad C-7X?

 

[2wo]

The DCR of the CX-7 is a good match for the resistor it replaces

 

[Doc B]

DCR of the C7-X is 270 ohms, same as the resistor it replaces. So B+ will not change. Looks like the LL2743 wired in series would have a DCR of 400 ohms. So you will potentially (yes a bad joke) be seeing about 9-10V less B+ assuming around 75mA current. Probably not enough difference to worry about. Fitting it may be more of a challenge as it is a bit bigger than the C7-X. Potential for audible benefit (less PS ripple) could probably be modeled in SPICE before you spend the coin. It is roughly 10X as expensive as the C7-X. If you get 10X better performance from the LL2743 it would certainly be worth sharing your result here.

 

[bottleheader]

Thanks Doc!

 

[Paul Birkeland]

You could certainly use that Lundahl and just wire the halves in parallel, but you'll end up about back where the C-7X is, and the C-7X is like $15.

 

[Thermioniclife]

The c7x worked fine for me in my crack, albeit in the second 270 node of the power supply.