Discussions of alternate "energizing"/charging PS units for use with UltraCap LPS-1 (not that any will make ANY difference to output)

[JohnSwenson]

What I noticed is that the periods of high current draw by the LPS-1 appears non-deterministic, but certainly dependent on the load the LPS-1 is driving. There is some degree of randomness in the periods of high current draw for charging a supercap bank inside. I find this rather fascinating.

 

 

There is another process going on, when the system switches banks it starts charging a string, it charges to full voltage (determined by the output voltage), then stops charging. If the output current is low, such that it takes a long time to discharge the string connected to the output, the freshly charged string drops in voltage a little bit (there is always some current draw on a string, primarily running the logic circuits that control the bank regulator). There is a "topping off" process that turns the charger back on for a very brief time if the voltage on the "charging string" gets a little too low.

 

If the output current is high this topping off process will never happen, but for a low output current the topping off will happen every few seconds to keep the string near the upper voltage so it has a full charge when IT gets connected to the output.

 

You could very well be hearing the topping off in addition to the main charging. The exact timing of the topping off can vary a little due to noise on the ADC measuring the string voltage.

 

John S.

[JohnSwenson]

40 minutes ago, gstew said:

I MAY be the heaviest user of LPS-1’s around, with 8 in various positions in my 2 setups.

 

Of course, energizing that many means a bunch of separate power boxes & a lot of AC outlets.

 

I did repurpose an early computer music player linear supply with dual outputs as an LPS-1 energizer… but it was not enough.

 

Earlier this year I started to build 2 quad-output power supplies just to energize my LPS-1s. They started with:

 

1.       A hefty toroid with 2 10V/10A secondaries (surplus buys, so surprisingly inexpensive)

2.       Diode bridges using good fast-recovery diodes (same family as the often-used MSR860) with John Swenson transformer ringing suppression snubbers

3.       47,000uf post-diode filter caps (also surplus from Ebay and inexpensive)

4.       2 LT1083 7.5A  regulators per side (sadly obsolete, but I had a sufficient stock in my parts boxes) for 4 outputs per supply

5.       Another 47,000uf filter cap on the output of each regulator

6.       Hefty wire all the way to the output connectors

7.       All in a good cost-effective EBay case with good heatsinks

 

These should EASILY put 3-4  amps into each output all-day/all-night.

 

Done, right?

 

Wrong!!!!

 

On the plus side they worked VERY well as LPS-1 energizers. On the negative side, the SQ of my systems went subtly south with these units installed. Of course, what you feed an LPS-1 with DOES NOT IMPACT THE OUTPUT AT ALL! No questions on that. So they must be feeding noise back into my AC circuits.

 

First, you have to understand I am a FANATIC about AC power… so much I’m looking at a solar power setup so I can take my audio systems off the grid! To get the best AC power I can, I have the following:

 

-          A PS Audio P10 in each system powering the main audio gear only, with at least a couple stages of parallel AC filters ahead of each P10.

 

-          ALL audio-related, but not core audio gear are on a separate AC circuit, again with multiple parallel AC filters. This includes my music servers and associated networking gear.

 

-          The music servers and associated network gear are all chosen for fairly low-power usage to help keep their electrical noise low AND all are powered from linear supplies (mostly DIY’d).

 

-          There’s a LOT of noise filtering in the house… clamp-on chokes on every household item that produces noise and a large number of parallel filters around the house on the circuits powering those noisy items.

 

-          An Entech AC noise analyzer used to determine where to place these filters AND confirm effectiveness.

 

These LPS-1 energizing supplies were of course plugged into the non-core audio gear separate circuits. AND still I got a subtle, but noticeable drop in SQ.

 

Back to the bench… replace the fast-recovery diodes with some higher-current Schottkys and an dual-snubber setup. 47,000uf caps at the output of each regulator come out and after some experimentation, get replaced with much smaller 1,800uf caps. Add more filtering on the AC input. Try some series resistance on the secondaries to lower the filter capacitor charging peaks… these quickly came out as they caused too much drop in available output current.

 

Testing this all on my bench, the final setups seemed to function almost good AC filters too… just plugging in the energizing supplies almost eliminated AC line noise as indicated on the Entech... and the magnitude of drop helped me confirm some of these changes.

 

Put them back in the system for a trial yesterday (as before, I’m just plugging them into the separate AC power circuit to assess SQ impact, they weren’t powering LPS-1s at that point)… And DANG, not only did the SQ not drop, but it subtly improved ,with a small drop in background noise (to my ear). It was even more improvement (again to my ear) than SQ drop before!

 

HOT DANG!

 

And it got a little better when I pulled out the various LPS-1 energizing supplies I’d been using (none of which had ANY optimization, but all were much lower power supplies and less likely to cause significant AC line pollution) and used these supplies  to power my LPS-1s.

 

Gotta love progress!

 

Attached is a poor picture of one of the units on my bench… and a couple shots of my output checking setup showing no-load versus a 6 ohm test load (which should cause about a 1.9 amp draw). They handled that nicely with only a small voltage drop, which stays about the same when all 4 outputs are loaded simultaneously. 

 

And in the systems, each energizing 3 LPS-1s right now, they are at room temp, no heat at all (which was not true of the variety of supplies I used earlier).

 

Gotta love DIY!!!!

 

Greg in Mississippi

Hi Greg,

yep the huge spikes caused by large caps on a standard bridge to cap supply generate a lot of noise. Going to smaller caps helps a lot but doesn't completely eliminate the problem. But then you don't have a lot of cap to handle short term large current changes.

 

This is why I have the circuit that is in the JS-2 which uses a small initial cap, feeding a high current choke, then a large cap. The circuit is carefully tuned such that the load on the diode bridge is almost resistive, thus no big spikes, but there ARE large caps on the output which can supply a large amount of short term current. The whole thing is tuned so the output will respond very quickly.

 

Of course all that is useless for a LPS-1 feeder. So just going with a small cap is fine.

 

John S.