[stvnharr]

I have designed, built, and installed a new power supply in my LF55 amp.  This is an idea I had been thinking about for some time, but Hugh's introduction last October of his new psu with the coilcraft chokes really got me going.
I decided to use Jensen 4 pole caps and the IR16 8A 200V 3 pin diodes. I also added a small smoothing film cap and a bleeder resistor.  Hugh helped me with some board design issues and suggested having a diode bridge for each power rail.

My thoughts on the above design was that the Jensen caps included a choke/inductor in their design. The schottky's seemed like a good idea is all. I also decided to go with a much larger cap, 6800uf, rather than standard 4700uf.  I also wanted all components on one side so as to mount the psu to the case with standoffs and machine screws, rather than do a 2 sided board and glue.
Chokes and a large cap on one side make for a very large board.  As is, the new psu board is about twice as large as the old LF/Aksa psu board.

I was hoping with the design for possibly a little more bass, slightly faster responses, a little more detail, etc.  It was all just an experiment really.  Since I have learned to design boards and have them made, it has increased my options for doing things, and a new psu was a fairly simple project.

I've had the new psu in the amp now for a couple days.  All expectations have been met, and I think the bass improvement has surprised me the most.  Faster responses and details are more in the subtle arena.  And it's really hard to know precisely without a direct comparison to amp with old power supply.  But from what I've heard thus far, it's a nice improvement.

I can't say for sure, as it hasn't been tried, but same power supply with a separate choke and the  same large cap should perform about as well, and cost a lot less.  The Jensen caps are expensive.  Board design in small quantities is expensive.

You can look at photos in my gallery: http://www.audiocircle.com/index.php?action=gallery;area=browse;album=2815

Steve

[TimS]

Hi Steve

The new power supply looks good in the photo's - would you mind providing a schematic of your design; one using separate choke and caps rather than the Jensen caps you used?

Thanks

Tim

I have designed, built, and installed a new power supply in my LF55 amp.  This is an idea I had been thinking about for some time, but Hugh's introduction last October of his new psu with the coilcraft chokes really got me going.
I decided to use Jensen 4 pole caps and the IR16 8A 200V 3 pin diodes. I also added a small smoothing film cap and a bleeder resistor.  Hugh helped me with some board design issues and suggested having a diode bridge for each power rail.

My thoughts on the above design was that the Jensen caps included a choke/inductor in their design. The schottky's seemed like a good idea is all. I also decided to go with a much larger cap, 6800uf, rather than standard 4700uf.  I also wanted all components on one side so as to mount the psu to the case with standoffs and machine screws, rather than do a 2 sided board and glue.
Chokes and a large cap on one side make for a very large board.  As is, the new psu board is about twice as large as the old LF/Aksa psu board.

I was hoping with the design for possibly a little more bass, slightly faster responses, a little more detail, etc.  It was all just an experiment really.  Since I have learned to design boards and have them made, it has increased my options for doing things, and a new psu was a fairly simple project.

I've had the new psu in the amp now for a couple days.  All expectations have been met, and I think the bass improvement has surprised me the most.  Faster responses and details are more in the subtle arena.  And it's really hard to know precisely without a direct comparison to amp with old power supply.  But from what I've heard thus far, it's a nice improvement.

I can't say for sure, as it hasn't been tried, but same power supply with a separate choke and the  same large cap should perform about as well, and cost a lot less.  The Jensen caps are expensive.  Board design in small quantities is expensive.

You can look at photos in my gallery: http://www.audiocircle.com/index.php?action=gallery;area=browse;album=2815

Steve

[stvnharr]

Hi Steve

The new power supply looks good in the photo's - would you mind providing a schematic of your design; one using separate choke and caps rather than the Jensen caps you used?

Thanks

Tim

I don't have a schematic.  You could browse around the net and probably find one though.
I started by browsing around the net and finding some general schematics, but ended up just copying the design on the Aksa power supply board, and adapting that to what I wanted

[stvnharr]

After a couple more days of varied listening, I'd like to make some further comments on the new psu.
One thing I notice with most every piece I listen to is an increase in channel separation with more distinct and defined sounds.  With whacked or plucked instruments, like say drums and guitars, there is such an increase in the speed of the sounded note, often nearly like a live feed. This is all much easier noted on close miked recordings, though I hear this also on my classical recordings.
I would attribute these things to the schottkys, and schottkys on each power rail.

The bass improvement is truly surprising to me, as I did not expect such low end heft that I now get, and with such speed.  It could be just lucky synergy with the dual voice coil woofer, but it's only a 7" woofer.
I upped the cap value to 6800uf.  I now wonder about an even larger cap.

I suppose one could experiment and change parts on the existing psu board, changing diodes to the 3 pin schottkys, and caps to larger KG caps. This would be about a $50 option.  But maybe it's not enough change to be very noticeable. I don't know.

[hybride]

Hi Steve,
Nice to hear that the sound of your LF55 has improved a by making a faster PSU.
I have a LF100 and you triggered me to add some ultra low ERS elco's to the existing original Nichicon's.
Not that i have serious complains, but fast current delivery can have benefits in faster and more control of complex music.
So i tried adding 4 x 2000uf Panasonic FM. The different is subtile but audible. It is like you say faster responses in details in the subtle area.
I think i will keep them. Thanks for the tip.

[stvnharr]

Hello once again,
I have installed my new power supply in my other Lifeforce amp, as I am now in the US, and want to bring this LF up to the same as my Australian LF.  I have found the results to be the same as with the first amp installation.  The psu is the same as in the pic, although I did use a different brand of 3 pin Schottky's from digi-key.
One thing I was able to do this time, was to check for system quietness.  My Ballarat system has a GK-1, and there is a small amount of hum, so I could never assess the quietness of the amp.  But my American system has only a cd player and the amp.  When system is on and the volume is at full, it is DEAD quiet, almost like it was not on.  I actually did a double check to make sure everything was on.
Unfortunately I did not do the above before I removed the old psu, so I can't really give a comparison.  It was too late before I thought to do this.

I realize that the expense of the Jensen caps would likely put most people off doing this, that and lack of a board.  However, if any out there are interested, I can have some more boards made.  In order for this to be feasible, it would need probably take a minimum interest of having 4 boards made.  This would make the cost of a board around $25 each.  I have no idea if there would be even that much interest, although I have noticed that my gallery pic has gotten quite a few views. Anyway, the offer is open.  Post here or in email if interested.

Steve

[AKSA]

Steve,

Thanks for the posts, that's a LOVELY board, your latest?

Hugh

[stvnharr]

Steve,

Thanks for the posts, that's a LOVELY board, your latest?

Hugh

It's the board you helped design, and the one that is in the amp in Ballarat.  I didn't take a pic of the one I just built, as it's the same.  Yes it is indeed a very nice looking board.