Paramour 1/45 mod filter choke question

[ssssly]

Thinking about moding my Paramour 1s over to 45s. In 2A3 guise for the MQ iron upgrade the plate choke is reused as a 270ohm ps filter choke. To switch over to the 45 I need 1600ohms resistance hence the stock choke won't work. I took a look at the MQ site and they didn't seem to have anything so I was looking at Hammonds.

Found this choke:

Hammond 154E/20H/20MAdc/1666R/300Vdc

Just wanted to do a sanity check before I waited eagerly for them to be delivered only for them not to be appropriate.

 

[matt99eo]

What all do you get out of the plate choke addition to the paramour.  Could explain this for me?  What are the 45s?

 

[Paul Joppa]

Total current will be at least 40mA, so a 20mA choke won't do the job. Best bet is to put a resistor in series with the choke; you can add another capacitor if you want for a CLCRC filter. In that case, smaller capacitors can be used since there's plenty of filtering; that in turn makes it more practical to use film caps. Just some thoughts!

 

[ssssly]

The 45s are the output tubes. Use 45 tubes instead of the stock 2A3s.

The choke changes the power supply filter from C-R-C to C-L-C. Changing the resistor to an inductor reduces noise in the power supply and if I am not mistaken decreases voltage drop (someone please correct me if I am wrong).

Long story short, in theory, it should make the amp quieter and slightly more dynamic (able to play with a bit less effort).

I'm hoping that between the choke, some new Schottkys for the diode bridge, and a snubber circuit that I can get the noise down to inaudible (my amps are pretty quiet to begin with when they are working right).

Also planning on changing the driver to either 5670 or 12ay7 driver tubes. Might just pick up a pair of both since they can be had at a pretty low price. Getting some Magnequest/Peerless tfa-2004s and ex0-001s. Replacing all the caps with PIO except the power supply caps (motor runs) and all tantalum non magnetic resistors.

And I picked up some 8X13X4 aluminum C channels to build new chassis out of. Still haven't figured out how I am going to mount the tube sockets as the C channels are pretty thick so the tubes would end up recessed.

 

[ssssly]

Total current will be at least 40mA, so a 20mA choke won't do the job. Best bet is to put a resistor in series with the choke; you can add another capacitor if you want for a CLCRC filter. In that case, smaller capacitors can be used since there's plenty of filtering; that in turn makes it more practical to use film caps. Just some thoughts!

What would you suggest for the resistor value?

If I used 50uf 440V motor runs for the CLC could I get away with a 2.0mf on the RC?

 

[Paul Joppa]

The EXO-001 is 20mA max, while the 45 draws around 35mA. You want either the 40mA version of the BCP-15, or a "Dowdy choke" for serious overkill!  :^)

I would not go below 10uF for the final PSU capacitor, and generally I like this one to be the best and the largest. I know, I know, those are often mutually exclusive! You might want to breadboard the circuit before cutting metal so you can listen to options like these before committing.

Sounds like a fabulous project - please keep us all updated as it progresses!

 

[ssssly]

Am I correct in believing that I would want a 1.1k resistor?