morgan Jones HT caps & Anode Loads

[bullpeters]

If I am not wrong,the great Morgan Jones, who I have read from back to front and back again several times espouses "Polypropylene HT Capacitors and Wire Wound Aluminum Cased Anode Loads", in his EL84 amplifiers (my favorites)
I have a deep respect for MJ but rocking horse poo looks common compared to the above. I have only the entire WWW to look in but i cant find either in the values that would seem desired for the stated purpose. What gives

[SY]

Don't know about Oz, but here in the US, they're common as can be- standard and inexpensive items at places like Mouser and Digikey.

[andyjevans]

Polypropylene caps are common everywhere - just look for motor run. Not motor start by the way.

Wirewound resistors sound great. I prefer the sound of the vitreous enamel types e.g. Welwyn green types to the aluminium clad ones. Depends on the wattage, but I'd avoid aluminium clad if I had an alternative.

[kevinkr]

Aluminum clad are OK as bypassed cathode resistors and in power supplies, but as has been suggested perhaps best avoided in the audio path proper. I like both Mills non-inductive types and the green Welwyns mentioned.

[zigzagflux]

My vote for the capacitors. Save the motor runs for when you need high capacitance values. For that first small cap after the rectifier, or the ones he recommends around DC chokes, these can't be beat. They are shown in stock at Mouser's Australian store.

http://www.cde.com/catalogs/940C.pdf

[costis_n]

Originally Posted by kevinkr

Aluminum clad are OK as bypassed cathode resistors and in power supplies, but as has been suggested perhaps best avoided in the audio path proper. I like both Mills non-inductive types and the green Welwyns mentioned.

So, a cathode resistor in not in the audio path?

[kevinkr]

Originally Posted by costis_n

So, a cathode resistor in not in the audio path?

Note the operative word "bypassed" The AC signal current in this instance flows through the bypass capacitor until Xc is appreciable compared to the cathode resistor.

Note I'm more than likely to use fixed bias in a situation where this sort of cathode bias resistor might be used.