Paramours with RH -non Parafeed-

[xcortes]

I have a set of 5 Paramour 2 amps with EXO 050 (Ni) opts and EXO-03 plate chokes.

This is a fantastic setting system and I love it for movies. The presentation of voices is phenomenal. Having said that I think I can retain most of what I'm getting by going to series feed.

My plan is to cannibalize the MQ iron in these to prepare for my Quad/Ionovacs project for which I'll need at least three pairs of amps. And to install MQ Robin Hood series feed opts in the Paramours (for economy reasons, I have to admit!).

I've never built a series feed amp. Do I just skip the plate choke and parafeed cap altogether?

Thanks

[Grainger49]

Xavier,

I'm concerned about the ozone.  There was a build up of ozone in the Corinth mill where the static charge was applied to the meltblown.  We put in a slow but steady exhaust fan.

From a link I found, it doesn't mention the horrible headaches you get from too much ozone:

"The corona discharge creates ozone that can be detected by smell in the vicinity of the speaker. In those days it was not known if ozone is harmful. By today's standards, ozone has no restrictions. However, if ozone is present in sufficient quantities (120ppb), it is known to cause eye and lung irritation. It is also known to deteriorate rubber. Watch out for those rubber woofer surrounds!"

[mqracing]

I've never built a series feed amp. Do I just skip the plate choke and parafeed cap altogether?

Yes. 

[Paul Joppa]

The other consideration is the power supply. Without parallel feed, all the audio current goes through the power supply. Most of it goes through the last capacitor (especially if you have re-used the old 10 henry parafeed choke as a power supply choke) - make that cap a good one; I would say at least 30uF. Most people suggest an oil-filled motor run cap there. Take the bottom of the cap to the cathode, not to ground. I don't recall what was in the Paramour II but the cathode bypass is often set to be 3-4 times the power supply cap for a 2A3 or 300B; it makes a capacitive voltage divider that feeds a fraction of power supply noise to the cathode to cancel that noise. This way the cathode bypass is not itself in the signal current loop.

[xcortes]

Thanks Mike and Paul,

I still haven't really commited to cannibalize the Paramours. At the end of the day it's a very unique HT system. And who knows, with John Swenson's comments about the possibility of daisy chaining BH dacs, yummy!

Grainger, thanks for the ozone concern, I'll keep that in mind!

Again, the Quad/Ionovac project is a long term one but since the house at the beach is in my bucket list, and since I need a system for such place...