Any advantage to replacing PS resistors with chokes?

[Tubejack]

I was curious if anyone say an advantage to replacing either one or both of the 270R PS resistors in the CRCR with a choke, e.g., Hammond 155H - 270R @50MA.  I am also planning to install the Speedball. C4S.

[Grainger49]

This is interesting, Bottleheads often replaced one of the power supply resistors with a choke in the FP 2.  The Paramour upgrade used a power supply choke.  The Paramount uses a choke in the heater supply.

It seems that with fully shunt regulated circuits there is no advantage (Paramount and Eros).  But it would be interesting to see if someone tries it in Crack.

[Paul Birkeland]

In a highly modified Crack that I have here, I did indeed use a choke in the power supply (Triad C7X).  The Hammond 155H won't work so well, as the Crack draws more than 50ma. 

I would suspect that a single Hammond 157L or 158L would do in place of the two 270 ohm resistors.  Just double up the power supply caps after the choke.  (I haven't tried this, so don't be too shocked if it might be nosier than it should be)

[Grainger49]

Paul,

Are you suggesting a CLC (doubled) filter or an LC (doubled) filter?  I think I remember that the stock filter is CRCRC.

[Paul Birkeland]

CLC.  Just LC would have tremendous voltage drop.

[BNAL]

Was just reading this post, because I'm thinking of replace the first 270R resistor with a Triad choke and before doing so I wanted to review previous posts and see if there was anything on the subject. I already have 1 choke installed in a CRCLC configuration. Since I have a second choke I thought what the help why not use it. From what I gather from the previous posts If I install the second choke in a CLCLC configuration I should at least double the capacitance of the last cap.

[BNAL]

I was hoping to get some feedback on my last post. Anyone?

[Grainger49]

There has been discussion back and fourth.  I would think that the second resistor replaced with a choke makes it closer to the audio circuit.  I think PJ suggests replacing the first resistor.  So the Triad for the first one would be a good step.

[BNAL]

Since I have a second choke I will put it in and look at doubling all the caps in the power supply to something like 470uF.

[Grainger49]

The biggest improvement in caps is the final cap.  Making it a low ESR cap makes an audible difference.

[BNAL]

Right now I'm using the supplied electrolytic caps and have a 2.0uF Clarity bypassing the last cap. I want to double all the electrolytic caps when I install the second Triad choke.

[grufti]

Doubling all the caps in your power supply is not necessarily a good idea.

There is a very nice and simple power supply design application available for free on the net called PSUD2. It lives on a site called duncanamps. You should definitely install it and play with the simulations, if you want to get your power supplies to work properly.

[BNAL]

Thanks for the information. I will give it a try and see how it works and if changing the caps makes sense.

[galyons]

+1 for PSUD2!!
Cheers,
Geary

[BNAL]

I downloaded the PSUD2 software and played with it a little, but not sure what I'm looking at. Is there a site with information on interpreting the data?