Recent content by Radford Revival

Possibly unpopular opinion: Stick JJs in all the holes, do the diode mod, job done Edit: With the caveat of not necessarily using a JJ GZ34 ;)

Quite literally - The loadline on the Class-AB amp goes off the conventional loadline plot, you have to extend it to negative current!

If you're needing more output from an amp then strictly speaking, yes, if you're driving the amplifier out of its Class-A region, the load on the amplifier will increase and the mains transformer will get hotter. Some amplifiers can't leave Class-A, like single ended amplifiers, and very...

Another thing to note is switching noise is unlikely as the valve rectifier switches off gradually

Hmm, does the equivalence not depend on the specific system though? Here is my reasoning: Imagine you have a free moving voice coil with mass in an infinitely long magnetic circuit, like a woofer with infinite x-max and no suspension. assuming no Le (superconducting shorting ring!) and no Re...

High passing a speaker with passive components is a bit of a pain as that generally means using a large capacitor of some sort, which in of itself isn't a problem. The issue is that the woofer suspension / air spring of the speaker looks like an inductance which will resonate with your high...

£200 fully populated cleaned / defluxed etc

I stopped populating them years ago - these boards are 1:1 copies of the Woodside STA15/25 replacement boards which have provisions for them. Basically an electrolytic has a far lower ESR than a 33k / 39k anode resistor! 390R is correct, I just fit 470R to run things a little cooler.

A new one but it's the same:

The Radford SC22 balance control works in the same way, weird!

The RFC Rubatos are legit good and are around 90dB efficient

I've seen them pictured in a magazine ad or brochure, but unfortunately can't remember where exactly! I have a feeling there was an actual cartridge too, ISTR seeing the specs listed. I've never seen one in real life

Hi all I have a Radford TT100 for sale on behalf of a customer. It has been fully worked through by myself with all age related issues addressed such as dried out caps, etc. Fully recapped with high quality replacements (these really do tend to need it) so it's plug and play with no worries for...

We used to use JJ E34L but now just use the plain JJ EL34 - they work!

You're quite right, in practice a signal that's not grossly overloading the amp won't really change the DC reading much, certainly not to an extent that matters. In this instance it's fine to have the amp connected to speakers while measuring, you'll get a tiny crackle in the speakers as your...