Rickresource Rickenbacker Forum

No. The value of a capacitor in microfarads does not change. It is a constant, regardless of the ability of a solid-state rectifier to pass a certain amount of current without overheating at the junction and failing open. A capacitor stores energy to prevent a sudden change in voltage, and to do so it can provide sudden changes (increases) in current (which is needed to prevent voltage sag). An inductor stores energy to prevent a sudden change in current.

"But aren't the caps MFD capacity limited by the rectifier?"

I meant valve amps.

total filtering MFD is limited by the valve rectifier.

damn!

hey TM infringement!

Yah tube rectifiers have a limit with how large of a filter you use after them. A GZ34 specs out a max of a 60uf filter after it, and some modern manufacture ones don't even like that high. A 5U4GB has a max of 40uf. Solid state doesn't really care, so if you want to use large filters in a tube amp, you need to use solid state rectification, or use a SS setup that emulates the sag of the tube rectifiers like a Weber Copper Cap for example. For a tube bass amp, I would want to use solid state rectification and large filter caps to get a nice and tight bass response. For a tube guitar amp, I like the sag and warmth of the tbe rectifiers, so I'd deal with a lower size filter and the extra hum and saggy bass those have.

Tube rectifiers limit the amount of capacitance used with them because of the tube's eventual internal breakdown with too much capacitance. The inrush current at turn-on would do a tube rectifier in.

From the Audio Precision archive website:
"The damping factor indicates the ability of an amplifier to resist a change in its output signal.

Damping Factor is a measurement of the regulation of an amplifier. It is also an indirect measurement of the output impedance. It is the ratio of the output voltage (under standard conditions) to the measured output voltage change when the load is removed."

Adding capacitance to a power supply would aid damping factor, to a point.

Thus the SUNN 2000S-2 5AR4's!

Yah, and the 2000S is right on the limit of what two GZ34's can do. Personally I'd change to a Weber Copper Cap WZ68 (or two) and get plenty of capability and then go much larger with the power supply caps if I was using it for bass. Something at least 100uf for that first stage would do wonders for a tighter bass sound. The Copper Cap would simulate the sag of the tube rectifier to a certain extent. You could also just use straight solid state rectifiers and get an even tighter bas sound.

Capacitors, Plate voltage, Rectifiers, ya'll talk purtier than a twenty-dollar wh*re!
But seriously, from a technical perspective, tube amps rock!