[da_burl]

I've been convinced by VC and others to post a pic of my PS, so I am giving it a try. This is also a test of my web page direct linking.

This is my "experimentin'" rig, just an old recycled computer power supply case, and I never put the top on anything hardly. Well, I will someday if I ever reach total audio nirvana.

If you look close, you can see a micro CHA47 dangling by the input and power supply leads, just kind of suspended in mid air.

The power supply is basically the SDS PS Section, which is really nothing more than a pretty standard 317/337 design. Its all hard wired point to point with good old fashioned perfboard, no pad per hole here, baby!! (well, the CHA47 is pad per hole perfboard)

The only real differences are:

MUR8100E fast recovery diode bridge, bypassed with .01 Sprague Orange Drops

I put two inductors after the transformer, probably not doing much, but I had them, and they look kinda cool.

10K 10turn trim pot and a 1K resistor replaces the resistor adj. to ground, it goes from about +/- 3V to about +/- 18V, so I could change this around some, I really need only from 9-16.4 volts (yes, this may go in the Mint Tin Gilmore someday.

1000uF Caps after the regulator

Its got the slow turn on cap of 10uF, I believe I read somewhere that this cap also helps eliminate noise in the adj. pin.

I used Panasonic FC caps, but just placed an order for some Nichicon Muse, (and have probably given up on Elna Cerafines for now

)
I also have a fairly good selection of fast bypass caps to try for the output section, Wima 1uF's, Phillips 5.6 uF, and a few other mylar speaker crossover caps laying around, some Solens even.

Future models might include top mounting trim pots, or matching permanent resistors when I decide on a final voltage, and try some different diodes (hexfreds, 4007's), and some different bypass caps.

Well, on to the ****, full frontal

Comments and suggestions welcome, especially on the ever elusive and much discussed "perfect capacitor"

 

[da_burl]

Just noticed, yes the transformer was $5.95

 

[00940]

hum, total cost ?

what's the enclosure btw ?

 

[da_burl]

The "enclosure" is just a stripped computer power supply. I will spring for a Hammond or something when I get something worth putting in it

Ballpark costs:

Transformer - (mine - $5.95 / Talima toroid - $18)

Diodes - $1-2 each (1N4007's are much less)

.1 and .01 uf Caps - don't know, I get them for pennies at a surplus place, hopefully under a buck

Panasonic Caps - the 1000uF's are around $2.50 each, and the 4700's were close to $5! The Nichicon Muses are actually cheaper!!

Fancy bypass caps can go from $3 to over $100, if you get carried away with some Hovlands or something.

So, I think you could do it for between $30 and $50, lots less if you have a surplus electronics store in your area, but remember, this is much (hopefully) higher quality than a glorified wall wart, that cost about the same.

 

[eric343]

Quote:

Originally posted by da_burl just an old recycled computer power supply case, and I never put the top on anything hardly.

I believe the enclosure is an old recycled computer power supply case.

 

[Voodoochile]

Thanks for the pics! It's nice to have a test-bed power supply with straightforward terminals on the output, isn't it?

It sounds like it helps out the '47' quite a bit, too.

I think it's a notable upgrade from a wall-wart, and probably cost you about the same. I have maybe three similar (not even partially cased, actually) power supplies. The recent one I posted pics of is the first one to make it into a permanent home

.

 

[da_burl]

I've got at least 3 abortion PS's, from back in my Szekeres days. I just recently started using decent caps though, so they will all have to be rebuilt. Used to just grab the generic 'lyltics from the surplus house. Based on this last one, its time for more Pannies or Nichicon's!
I also want to try some LT1086/33's some day, but I think these are for more high current demands, but they are supposed to be nice and quiet! Have you checked out ppl's current source for the adj pins? Looks like a possible "next level" thing.
Then of course, there's the Jung Super Regulator and the Gilmore super regulator!

 

[Tomo]

Hey,

I wish I had a digicam. I have also have PSU **** of my own.

I use LM317/337 pair standard. I cheated on my board, because I bought mine off of shelf. Then I used good parts like Blackgates. I didn't have Cerafine at my hand so I used alternative from ELNA. Later I added extra capacitance before the regulator with HFQ (Panasonic). Also, I added few more BG after the regulator.

My rectifier set is simply a generic rectifier bridge rated for 16A. I was skeptical after using IXYS FRED. (Appearently IXYS FREDs are bad FREDs, I did not know at the time.) I might consider changing to FREDs after I know which FREDs are "gooooood." I bypassed all the rectifiers with 0.1uF Ceramic. Do you think OrangeDrops are better here?

I used polymer caps to bypass my post regulator caps. Oh ... That needs upgrade. I got a huge load of OrangeDrops up my sleeves.

Trannies? I think Toroids are overrated for low power operation. Jung says in one of this articles that dual-bobbin types are better at damping high freq noise from outlet. So I used Dual-Bobbin type from Magnequest. (Toroids are more compact for given rated power.)

I am thinking about using Organic Semiconductor Capacitors such as Sanyo OSCON. I bought cup-full of them on a trip to Tokyo. I am itching to use them. Supposedly, it can do better job at bypassing than most other caps out there.

Lastly, I think Tantalum capacitors are perfectly fine for bypassing. In fact, some source suggest that some Tantalum capacitors can surpass the performance of Blackgate capacitors. I am not certain if it would give significant difference, but I am using Tantalum in my amp and pretty content with them. (Oh food for thoughts.)

Tomo

 

[puppyslugg]

Quote:

Originally posted by da_burl I also want to try some LT1086/33's some day, but I think these are for more high current demands, but they are supposed to be nice and quiet! Have you checked out ppl's current source for the adj pins? Looks like a possible "next level" thing. Then of course, there's the Jung Super Regulator and the Gilmore super regulator!

ppl told me there is about 20-30db reduction in noise. Not bad for a 25 cent fet! ppl recommended a 10ma of loading, but i've read at diyaudio, someone suggesting using more(?).

I've used ppl's fet cs with the lt1085/33's in my Corda HA-1, with good results. It was noticably quieter and blacker. A worthwhile mod not only with the lt1085/33, but with the lm317/37. As good as the lt1085/33/fet regs. are, IMO, I don't believe it's at the level of the Jung/Gilmore ps.


BTW: ppl also suggested using a 1-2 ohm resistor at the reg. output, when using large output caps.

 

[Voodoochile]

Tomo- I have two amps that have the buffers bypassed with tantalum caps... I like them pretty well.

As for hexfred bypasses in my psu, I used .33uF polypro box caps.

Who can talk to me about the small ceramic cap that some designs have bypassing the mains switch (on the primary side of the tranny)? Presuming it's for noise reduction when snapping the switch, but doesn't it leak power into the unit while the switch is open (AC)?

I'm not to be confused with an EE, even at a cocktail party.

 

[joe_cool]

I think the ceramic caps bypassing the switch contacts are to suppress arcing when the switch is opened under load. They are usually rated at a very high voltage, maybe 0.01 micro-farad at 1000 volts. The arcing will burn out the contacts after a time.

 

[Voodoochile]

Sounds good to me. Sort of like a shock absorber for the switch. It does not leak any power into the amp when off, though?

Pardon my ignorance on this, I have only recently seen this done, but really like the idea.

 

[ppl]

Tomo! Hay i used one of those magnaquest split bobins in my No gain Line driver based upon the now discontinued EL-2005 450 MHz. FET input Buffer similar to the LH-0033 from national. this had 36.5 volts series connectted both 120 & 240 50 & 60 Hz. Pri.windings. I pc Board mounted it with the core not in contact with the chassis or Hum would result so i used plastic Bolts in addition to the transformers PC mount termanals.

The Current sourced LT-1085 & LT-1033 were used as thay are slightly better sounding. but curent sourcing and voltage referencing the adj pin with a zener or somthing the sound of the Component improved as a whole the black's got blacker and the background seemed deadly quiet. Nice for a few CRd's and Zener Diodes well worth the cost.

 

[Tomo]

Ppl -

I bolted my Magnequest tranny with beefy aluminum stand ups. My tranny was really heavy so no fussying with wimpy plastic posts. In fact, I did impact testing. Yep, current aluminum posts stand up to 3 feet free fall challenge.

I have insulator materials just for the occation, but I never needed it. Appearently, my iron seems to be pretty well insulated to begin with. (Unless of course I go in there and scratch it out.)

I get no humz whatsoever.

T