UCD180 PS Designs

dawaro · « **on:** 17 Nov 2005, 03:33 pm »

I am looking at building a 5 channel amp using the UCD180 modules but I have not been able to find very much information on building a power supply for this type of configuration.
Can someone point me in the right direction?

JoshK · « **Reply #1 on:** 17 Nov 2005, 03:57 pm »

Actually, the PSUs shown for other UcD modules will work in this case too, with just a few changes. First, lets determine your budget because that will determine how far you want to go with this. Also, do you want to keep this all in one chassis? If this is for HT, then one large and aptly designed PSU should be ample. You just need to size the transformer and cap bank appropriately so you have enough joules to play loudly if you wish.

What are you ideas on what you wish to do and then we should be able to help you get there.

Josh

dawaro · « **Reply #2 on:** 17 Nov 2005, 05:09 pm »

The amp will be for HT use so it will all be in one chassis. I was thinking an 800va 40/40 Avel toroid would be enough for five channels. I had also planned on using a pair of the Panasonic 10,000mfd caps for each channel.

JoshK · « **Reply #3 on:** 17 Nov 2005, 05:14 pm »

800va should be sufficient, probably more than. Kevin of DIY Cable has suggested that he thinks it is not neccesary to use seperate PSUs for each module, so you could put all those caps together in one bank to feed all the channels, which would be a lot of joules. Any of the well designed two channel PSUs will work fine for you application too, with more capacitance and your larger transformer. If you want to go all out, check out JM's PSU schematic posted on page 4 or 5 of the diy hypex ucd amp thread.

Kevin Haskins · « **Reply #4 on:** 17 Nov 2005, 07:26 pm »

Should work fine.... the benefit of the Hypex power supply is that you get DC protection. You would need three of the standards supplies and that is much more expensive than buying some of the 10,000uF Panasonics and a couple bridge rectifiers. From my quick calcs it's $170 more to go with the Hypex power supplies which would give you a nice neat package/install, DC protection and they toggle the mute function during power up/down.

It's your call if you think it's worth the extra $170.

Your also going to need the softstart or a thermistor on the primary of the transformer to keep from blowing fuses.

dawaro · « **Reply #5 on:** 17 Nov 2005, 11:24 pm »

What about the HG supply? Could you run more than a pair of 180's on it?

Kevin Haskins · « **Reply #6 on:** 18 Nov 2005, 12:36 am »

You could probably get away with running five channels off one. It would be a little less total capacitance over what I'd use building my own supply but it should work. Bruno uses 4700uF per rail in his reference amp and you would have 4000uF per rail per module. Since they are shared across all modules you don't need the same as you would with a mono block type application.

What type of speaker load are you looking to drive?

The disadvantage is that you only get two channels of DC protection so that feature is pretty much useless with a multichannel application. The mute on/off function will work though and the split foil caps are excellent.

JoshK · « **Reply #7 on:** 18 Nov 2005, 01:08 am »

You could go with 2 HG supplies, one for L&R, one for center & rears. That would work out well. One tranny would be fine for this.

art · « **Reply #8 on:** 18 Nov 2005, 01:23 am »

I don't know the details of the supplies in question, but......

You may find that your sanity is better off with 5 independent ones, as opposed to sharing supplies.

Ground loops, EMI issues........

But, it your project. Just my 2 cents.

Pat

JoshK · « **Reply #9 on:** 18 Nov 2005, 01:28 am »

Pat, iirc, early on in the long ass diyaudio thread there was some discussion and apparently the opposite is true, that grounding is easier with one supply (stereo amp) than with dual mono. Who knows, just what I read.

Kevin Haskins · « **Reply #10 on:** 18 Nov 2005, 01:43 am »

The easiest to deal with from a ground standpoint is one long continuous rail of caps. That gives you one PS ground reference and use short large gauge wires to go to each UCD module.

I've always run a star ground to chassis, one from the power supply and the other leg from the IEC ground. The power supply ground is floated to some degree with a 10R resistor in parallel with a .22uF film cap. The 10R resistor helps keep ground currents from easily flowing and the cap filters HF power ground noise.

Bruno & Jan-Peter recommend floating the entire PS supply. They recommend not wiring the chassis to power ground because it will only pick up noise. This of course leads to the issue of not having the chassis electrically protected in case of some kind of short.

They also recommend grounding the signal ground at the point of entry or the pin 1 in case of balanced inputs.

I'm experimenting now with some of these recommendations. I've never had noise problems with my method but grounding is a complex subject and single ended inputs used in audio are simply stupid. Why there are not better standards and use of them is beyond me.

dawaro · « **Reply #11 on:** 18 Nov 2005, 01:26 pm »

I am looking at using the 2641's and LCR's for speakers. I am not sure of the exact configuration just yet.

I think the dual HG PS idea might be the way I go.

Kevin Haskins · « **Reply #12 on:** 19 Nov 2005, 12:34 am »

The UCD-180s will drive them wonderfully. I voice all the crossovers with the UCD amps. They are EXTREMELY hard to beat for the money. In fact they are extremely hard to beat for twice the money.

kfr01 · « **Reply #13 on:** 19 Nov 2005, 06:20 pm »

Same goes for the 2641s.

I've been meaning to write a full review, but haven't had the time.

The 2641 speakers are -very- capable towers. The bass is deep and complete, the midrange is detailed and accurate, and the highs are smooth and balanced. You won't be disappointed.

Kevin Haskins · « **Reply #14 on:** 19 Nov 2005, 11:54 pm »

Quote from: kfr01

Same goes for the 2641s.

I've been meaning to write a full review, but haven't had the time.

The 2641 speakers are -very- capable towers. The bass is deep and complete, the midrange is detailed and accurate, and the highs are smooth and balanced. You won't be disappointed.

Hey... I'm glad they are meeting your expectations!

I simply love my pair. Every once in awhile you find a combination of equipment that is very satisfying. I've had a few systems over the years where I hit on something that really is a satisfying. I've never been smart enough to just stop and I've sold them and pursed other "better" systems. I'm now at one of those points and hopefully I'm older and wiser. The 2641s in a 2-channel set-up do everything I want in a speaker. Oh... I'm sure I'll find ways of improving this or that but it will be minor corrections not big changes. They play all types of music with equal ease, they are not the best speaker at any one parameter but they are so good at so many characteristics that they I don't ever feel like there is something out there that greatly improves upon them.

I know I'm tooting my own horn but hey... I'm enthusiastic about them for a reason.