Survey: SMPS with or without stiffener cap?

[Davet]

I have a modified SI using a 10,000 MFD 75 volt stiffener cap. This sounds better to me than the same amp without the stiffener. I must point out that I am using the stiffener cap on an adjustable linear 3 amp power supply operating at 13.2 volts.

I have been listening to a stock TA-10.1 the past week. This has a SMPS and no stiffening cap. The bass sounds good, but the SI with the stiffener seems to have more control, ie.e more percussive on bass drum etc. Otherwise, the imaging and soundstage sound the same.

I will try the stiffener cap on the TA-10.1 at some point and I will report my findings.

[Hikari1]

You guys seem like experts on stiffening caps.

The back of the Meanwell is labelled:

+V, -V, ground, N, L

Right now the dc output is running to the amp from the +V and -V.

If I hook up a 50V, 2,200 uf cap between +V and ground on the power supply this should work, correct? The positive lead of the cap would go to +V and the negative lead to ground, correct?

[Neil Davis]

Originally Posted by Pano

For me the stiffener cap has always sounded better, therefore I always use them.

You would probably enjoy playing with the "Tripathogee" amp I made. It's the amp I built to help me decide whether I should to do any more work with the Tripath designs. It's got two modulators--the DDX8001 and the TC2000, with a multiplexer to switch between them. STA517B outputs with 48V supply.

The reason this amp is relevant to this thread is that it also has a power supply board with some decent relays for testing caps and regulators. You can switch between the linear power supply or a switcher. You can switch in a bank of 60,000uF "stiffener caps" or send the supply voltage through a low dropout linear regulator (follow the link for more info). And you can do this blind-folded with the remote control. There is a connector on the back for monitoring the input and output voltages on a scope.

My own conclusion was that the additional caps didn't do anything.

[FoMoCo]

One thing to keep in mind is that external capacitance may cause instability of the power supply. It can affect the phase margin of the feedback loop. It's unlikely, but if it happens it'll be a bear to figure out the problem.