amp with choke vs amp without

[pula58]

Let say you have two identical amplifiers with two identical speakers. One amplifier has a 1K reistsor as the first element in the power supply filter chain. The other amp has a choke in-place of the resistor.

Does the amp with the choke have more or less sag/feel that the one with the resistor (I forgot to mention, both amps have a tube rectifier).

Or, what exactly is the difference ? Would there be a tonal difference? Or a difference in "feel" ??

Thanks!

P.

[Guitar Josh]

Read the thread on the JVM choke mod. It's quite a pronounced difference.

[dazco]

I have gone back and fourth A/B'ing just that with my EL34 build. What i find is that the choke sounds/feel better w/o a doubt. But let me also say that it totally depends on the amp. I also have a 6V6 build and with that amp theres no perceivable difference between the two. Yet the EL34 amp show a big difference. the difference is that the choke has a more solid tight feel with the choke, while with a resistor it seems sorta tinny and not as tight. Not REAL tinny or ratty, but just not as thick, tight and punchy. But actually it's more of a feel thing than sound.

If you want sag i would suggest leave the choke but add a 30 watt chassis mounted (to pull the heat away) resistor of aroun 150 ohms in the B+ rail right before the first cap can. That will make the amp sag nicely. You may want to re-bias after that unless the amp is cathode biased.

[donnyjaguar]

The function of the choke has everything to do with the value of capacitor (if any) in front of it. If there isn't one you get much better regulation.

[SatelliteAmps]

It all really depends on the amp itself.

[mojo2001]

The function of the choke has everything to do with the value of capacitor (if any) in front of it. If there isn't one you get much better regulation.

But the voltage will be a bit more than half of cap input ~ 0.7 x 1/2 secondary. Also before the tubes draw enough current to make it work like a choke input filter, it will act likea cap input filter ~ 1.4 x 1/2 secondary volts.

Basically the amp has to be designed as one or the other due to the power supply output issue.