[rhing]

great stuff, thanks. and I just noticed mouser is just a couple of cities over from me. even better!

I really like Mouser's service and responsiveness. I was really glad when they picked up Panasonic caps and Elna Silmic II caps. I still have to split orders between them and Digikey, but it's a small inconvenience. You ought to check if Mouser offers will call for local pick-up, and save on shipping although their shipping rates are reasonable when shipping via USPS First Class.

Jameco Electronics and Master Electronics are in the San Francisco Bay Area, and I will buy products from them and pick up my orders at will call. Their will call desk seating areas have many liquidation items that include soldering equipment, power supplies, parts, etc. I am grateful that I work in Silicon Valley where there are many surplus electronics stores and places like Jameco, Master and Fry's Electronics nearby. I also support the little family-owned electronics supply stores like Al Lasher's Electronics in Berkeley, and San Mateo Electronic Supply in San Mateo. I feel like I'm in the geek capital of the U.S.

[thaddeussmith]

good suggestion. this is TX, so "just a couple of cities from me" means 150 miles round trip.

The cost in gas > usps shipping and a couple days of waiting.

[rhing]

I've been considering an alternative to my modified Power One MAP110-S148 SMPS power supply, so I've been researching regulated linear power supplies and battery power supplies. While browsing Craigslist, I came across an Astron RS-12A regulated linear power supply. A guy had it listed for $20. At discounted prices, these power supplies sell for almost $100. I figured I could meet the guy at his workplace, plug it in and test it with my DMM. He offered to test it for me, since he had a nice Fluke DMM at work. Without a load, the Astron's output measured 14.02V DC. The unit is in excellent shape as the previous owner has had it for years, but never really used it for his HAM radio system.



When I brought it back home, I cleaned it off and cleaned all the contacts with contact cleaner. It's in mint condition and the enclosure does hum without any damping from the huge power transformer. I just placed a paperback book on top of the case, and that took care of it. I'll probably add some chassis damping sheets later on to deaden the enclosure from vibrating.

After playing music through my system using the Yuan Jing TPA3116D2 "blue" amp with this power supply, I am impressed by the improvements in sound quality.

• The soundstage has grown a bit larger and deeper.
• The imaging is clearer and more stable with complex passages.
• The background is blacker as in less noise (even though I didn't notice any before).
• The tonality is richer. The music has greater presence.

I'll probably evaluate battery power at some point, but I think I'll be content with this power supply for some time. I have yet to test it with my Sure Electronics TPA3110D2 amp.

[Folsom]

You could mod it. My PSU shames the SMPS I used.

I can give you a BOM, if you like. It's not currently regulated; but I don't think you'll care when you hear it.

Take some pictures of your new one's insides, we'll see what difference could be made.

[rhing]

You could mod it. My PSU shames the SMPS I used.

I can give you a BOM, if you like. It's not currently regulated; but I don't think you'll care when you hear it.

Take some pictures of your new one's insides, we'll see what difference could be made.

I figured you would chime in with some ideas. I'll open it up tomorrow after work and snap some photos. I know it's got an oversized EI power transformer, some huge filter caps and two regulators mounted on heat sinks in the rear. For a box that about half the size of a large shoe box, it's pretty heavy. I know there is a site that has mods and maintenance tips. Apparently, Astron power supplies are known for the ruggedness and over engineered designs. For $20 I just couldn't pass it up.

[Folsom]

I typed a long message... Stupid iphone.... The short of it.

Soft recovery diode bridges (if it doesn't have them) and Felix on it's power cord. Low noise transistors (if they are not). Transformer design prevents other filtration.

[snerdly]

ummm could someone provide a link to the proper caps to do the upgrade?..and maybe a power supply source...being a novice I need all the help I can get. thanks

[thaddeussmith]

Quite a red letter evening. My YJ tpa3116 blue board came in tonight. I got it put into place inside the dynaco st-120 chassis. I also happened to read rhing's comments about the linear power supply. Guess who's father in law is a retired electrical engineer + HAM nerd + parts hoarder? So is topped by his place on the way home and he managed to dig out a 12.35v 7A linear power supply for me. It's open chassis, so I probably won't keep it long term, but it's good enough to play around with for now.

I've got all of 10 minutes with my ears on this new combo, but when paired up with my Cornwalls there is no lack of bass or clarity and I can echo all of Rhing's observations. Very cool.

[rhing]

Give the YJ 3116 blue amp some more time to burn in. With that power supply, you'll more goodness out of your Cornwalls. Klipsch speakers seem to marry well with these Class D amps.

[thaddeussmith]

Cool. Now that this board has arrived I'm planning to stop swapping amps for a while. And you were definitely right about getting that noisy switching supply out of the enclosure. I know this board has an output filter, but I'm using a generic I shielded hookup cable between my RCA jacks and the board, no ferrite beads, and the noise floor is silent at 6ft when using my laptop (which was previously a noisy combination).

I didn't notice any cold solder joints and I'm having zero channel imbalance or static issues. I may just not touch a thing and be perfectly content with that.

[Folsom]

Ferrites are bad for all things audio if yo ask me.

You can't identify the noise that affects class D, except by the improvement of the lack there of... as in it isn't something you can pick out from a set of sounds. You hear its affect on the music, not it. Unless you have a major flaw somewhere; which would make you repair or replace because it'd be obvious.

Snerby what board?

[thaddeussmith]

here's pics of my amp insides and caseless power supply. eventually I'll rewire that power supply with a new cord for a direct connection to the wall socket and maybe throw it in a case with a power switch and iec socket so I can connect the amplifier via female iec plug.

[rhing]

I've seen those Lambda power supplies at the surplus electronics stores here in Silicon Valley for about $5 to $10. I think these must have been popular among scientists and engineers. That's a good score. You might consider 2-3 Panasonic FM 2,200uF / 25V caps wired in parallel next to your YJ amp's power supply input for additional filtering.

[thaddeussmith]

I think these must have been popular among scientists and engineers.

Thanks! my father in law is a retired electrical engineer, so your assumption is correct so far. ..hard to beat free!

Not sure if you noticed, but I do have a panasonic 1800uf/25v currently in place at the amp's power supply input. I wasn't sure how many I could/should stack up there.

[Folsom]

Thaddeus, how big is that cap in the PSU? Also, is it on the DC side? It looks like you have woefully insufficient capacitance. Voltage my be regulated, but if you don't have capacitance then ripple and stuff is all over.

[thaddeussmith]

no clue. sounds good though..

[rhing]

Sorry, I missed that cap. If it sounds fine in this configuration, stay with that. I am just amazed at the sound quality improvements with a better power supply. I really don't feel any need to mod this thing anymore. So far, I've only added a couple Panasonic FM 1,500uF / 25V caps in place of the stock Nichicon HD 1,000uF / 25V caps.

I think I'm ready to stick this amp in an enclosure and invite some audio friends for a get together to hear this amp and compare it to my Dynakit Stereo 35 and a friend's pair of 300B SET monoblocks. My friend has sunk in over $1,200 into building these transformer interstage-coupled SET monoblocks and he'll be shocked when he hears how this will compare to them. This amp is really challenging my Dynakit Stereo 35 for play time in my main system. The Crites-upgraded Klipsch Forte II's are really kicking with this Yuan Jing amp. I've thrown large scale orchestral, jazz and classic rock at this thing and it is handling everything beautifully. I would characterize the sound to be similar to a friend's Conrad Johnson MV75-A1 6550 push-pull amp, but with improved Pace, Rhythm and Timing (PRaT) and inner detail.

[thaddeussmith]

both caps are on the DC side. not sure what to make of these markings..

[Folsom]

I'm lucky and just use a meter I have... you may not have one. they don't look very good.

You should certainly create a capacitor bank prior to the 3116 board, but near it, 8-10kuf or so, I prefer smaller 1kuf caps to make up that amount ESPECIALLY with linear power supplies for better performance. They discharge faster, but the big ones have undesired affects with a PSU that has ripple/rectification (I don't know about your PSU). You can dig through oodles of topics and replies on DIYaudio if you want to know about that stuff anymore than just spending $5-10 on some Panasonic FC's or something. Technically you could put a large enough reservoir in the power supply, but I'm unsure of the schematic and regulator, so I can't say for sure where besides right before the out on it. It's not a bad idea given the distance, but also maybe those caps already are just that. I can't tell.

Also you can replace the ones on it. If you have a capacitor bank you can use any value on board (I'd recommend 220-1000uf, generally 220uf or 470uf being good (may improve coupling) if you have a capacitor bank right before the amp for when you need big, low noise, current. Otherwise just replace them with Panasonic FC, Elna Silmic II, Nichicon FG, or something else if you like. The Elna's and Nichicons are known to be a little nicer, about twice the price.

I'd say upgrade the diodes but I can't even see them to know what package would work. Soft recovery are best for low RF, a serious problem in class D. But whatever your level of discipline happens to be, work at your comfort level. Diodes have directions you don't want to screw up etc.

I feel like I'm a regatta, in the bow of a boat, driving all the DIY mods    I could probably just leave you guys alone and let you enjoy any of them even in stock form...

[thaddeussmith]

shrug. with some things i'm a "that's good enough" guy. the speakers sound better than they have through various gear swaps and modifications over the past few months. far better than that tiny switching power supply. i've just about reached the TGE status.