UCD180 questions

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#2,122
You can either connect the power supply ground to the chassis and then the chassis to the AC ground via a 5 or ohm 5w resistor, or if you respected double insulation distances and have double insulation transformer then leave the PS ground and AC grounds floating and connect the signalgrounds to the chassis.

You may have to experiment for least hum. If there is hum you can try to have all equipment on the same AC circuit to avoid ground loos.
 
#2,124
guyv: I've never experienced hum with the ucds...
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I have noise but I think it is not 60Hz I have, the UcD400 on my woofers is very quiet. It is more like a low-level buzz in both UcD180s, not objectionable during music but very much so during silence.

I have two boxes, each with one UcD400 and two UcD180 with three power supplies. The UcD400 powers two woofers a UcD180 is for the mids and the other for the tweeter.

Here is what I reported in the Orion forum:

As suggested by Bruno Petzey (the inventor of the UcD), I used double insulation rules and components and did not connect the AC ground to the chassis. As per his suggestion I instead connected all three RCA connectors to the chassis. The amps are completely silent when the inputs are short-circuited - however I cannot get rid of low level hum when the amps are connected to the ASP. I had no trouble with hum with commercial amps (after connecting everything on the same power strip).
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Well I tried star grounding the three power supplies in one box with the two UcD180 and one UcD400 and... there was medium-loud hum in all three amps when any two RCAs (or all three) were connected to the ASP; I was even concerned that low frequencies were endangering the tweeter.
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Any suggestion welcome. I have not tried a power conditioner.

Guy
 
#2,125
I double insulated everything and used plastic risers to keep the boards away from the chassis. I earthed the mains onto the chassis and am using 5amp fuse on the HG.

There's a slight hum from the transformer but not loud enough to make any difference.
 
#2,126
I solved my noise problem!

Disconnecting the cable-TV coax got rid of noise in the mids and tweeter.

I will try using "a pair of 300 Ohm (twin-lead) to 75 Ohm (coaxial) TV antena matching transformers connected back to back, with at least one of them isolating (measure between each of the 300 Ohm terminals and the 75 Ohm center conductor). They're available with a male F connector and screws, and with female F connector and wires so you won't need anything else. " as suggested by Mac in http://orion.quicksytes.com/viewtopic.php?p=3460#3460

Guy
 
#2,128
Fyi

There's an interesting newspost @ hypex' site... No idea how old that post is (no date) but I don't think it's been posted around here yet so:

Meridian is using 100W@8ohm class D modules in their new G95. A UcD180 OEM version I presume... JP?
I've never really liked the (older) Meridian amplifiers but they're amongst the very best sources for both cd&dvd audio & video.
It'd be really cool if they used your modules in their (digital) speakers too!

www.hypex.nl
 
#2,133
MisterTwister said:
ok, i unplugged ucd modules from power supply. it measures 86 volt.
it's 36v above recommended. what should i do now?
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Take LOTS of pictures and post them here. We will then be able to advise. I personally don't have time for the 1000 words, I need to cut to the chase with the picture.

From what I have heard so far you may have the primaries in series instead of parallel. Which would explain the high secondary voltage. Pictures would confirm.
 
#2,135
guyv said:
I solved my noise problem!

Disconnecting the cable-TV coax got rid of noise in the mids and tweeter.

I will try using "a pair of 300 Ohm (twin-lead) to 75 Ohm (coaxial) TV antena matching transformers connected back to back, with at least one of them isolating (measure between each of the 300 Ohm terminals and the 75 Ohm center conductor). They're available with a male F connector and screws, and with female F connector and wires so you won't need anything else. " as suggested by Mac in http://orion.quicksytes.com/viewtopic.php?p=3460#3460

Guy
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Hi Guy,

Maybe you have talked about it before. Personally would like to know how the Orions sound with the UcDs? Have you compared the sound with other amps?

The reason I`m asking is that I have basically a very similar setup, dipole woofers and mids and vifa ringradiator tweeter. I use an active system with UcD400 for woofers and Ucd180 for mid and tweeters, same as you. I never tried any other amps but the sound quality is incredible (at least for me). I use a deqx digital x-over with the UcDs.

I have the feeling that the Orion would sound (much?) better with UcD than with the conventional recommended amps (by Linkwitz).

Best regards

Gertjan
 
#2,138
ghemink said:

Personally would like to know how the Orions sound with the UcDs? Have you compared the sound with other amps?
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The difficulty is that I am comparing whole systems: my Orions+UcDs to the memory of my Magnepans+Tripath which are stored in France while I am in Colorado.

The UcDs are much better than the Alesis RA300 amps I tried before. I am still struggling with highs, probably because I was so used to the true ribbons in Magnepans 3.6 and 3.3. The highs became really excellent when I shorted the input caps on the UcDs and used Auricap at the input, but now they are sometimes strident depending on how I adjust the gain for highs although this maybe related to the rear tweeters in my room so I may need to reduce their output a little more.

I have such a memory of Magnepans in my huge room with Tripath amps synergystically matched with a REL subwoofer that I won't make my mind until the day I can compare both setups in the same room. My current room is small but I am moving to a bigger room with vaulted ceiling.

I am planning to replace the UcD's AD8620 input buffer with a LM4562. I am also building a two channel high-power tripath amp (80V DC rails) which is the same I used with bi-amped magnepans and I will see the difference. Two more of these Tripath amps are also in various stages of completion so eventually I will be able to compare a 6 channel UcD setup with a 6 channels Tripath setup.

I am also considering buying two or four new audiophile UcD180HGs when they become available and also SKAs. There is no real need for all these amps but I am picky and curious. Also the highs subjectively change when a good subwoofer is perfectly matched (seldom achieved) so I am also building Thor subwoofers with the appropriate analog crossover from Linkwitz.

Anyway the UcDs sound very very good and I will report on amps comparison with the Tripath in the future. I would love to try UcDs on Magnepans as well.

I am a firm believer in dipole speakers. But I also think that a point source is like two open holes in the virtual wall between you and the soundstage, while rectangular Magneplanars are like two open doors between you and the soundstage. The sweet spot might be slightly less defined with Magneplanar but the openness of the sound might be more natural. This is all from memory - I have heard Orions in a huge room and they sounded much more like Magnepans in a huge room so we can't compare when not in the same room.

Guy
 
#2,139
Hi there,
i fixed my first UCD1810, only on a piece of wood coze i wait my enclosures, and plugged it on the preout of my Harman Kardon amplifier. There is only one channel, the right one !:smash: The left is plugged to my HK amp part. I did this to compare.
All the parts of my UCD bloc is from Hypex (transformer 160 VA, HG PS, Softstart, UCD 180 "normal" and the signal cable).
The drive is MArantz 5001+DAC NorthStar M192 and speakers DIY like SF Cremona or Venus Cassiopée, means lot of power to "make sound" !😎

My first impression :
nice sound but it's missing "something".....😕 There is no "power" anymore, it's soft as i compare with the HK. I thought it could come form the CD and i changed it. With another one (Soundtrack of Ghost in the Shell 2, song #2, 2"22s), the drums have nice sound, very clear, like real drums and not like "boom box" (sorry but i don't know the english word....😀 ) but it seems that the drum player doesn't to make too much noise.:dodgy:

I am not disappointed but thought that after fixing my UCD, my HK will go to his box and it seems that i will use it little bit longer than expected....... 🙁

Do you think that maybe i plugged it on unbalanced cable ? I will get my balanced outputs pre soon and will try my UCD with XLR cable later or i will try another RCA cable tomorrow.

Regarding the mod on AOP supply, i visited the Hypex site and the mod on the HG PS. It's the same......:whazzat: How can i remove this "via" that i don't find on my PS ???

Thank for reading me and forgive me for my mistakes in English.....:apathic:
 
#2,140
I am no expert but my personal belief is that 160VA transformer is not adequate if you are powering a complete speaker with passive crossovers. My best guess is that it is sold on the Hypex site because this a way to make a UcD system (with the ST supply) for non-audiophile amplification. It would be adequate for a UcD180 driving just a tweeter (as in my case, I am using a similarly sized transfo for the highs) rather than a complete speaker. But there is no consensus about this point so take it with a grain of salt and read my next point.

More probably the softness you are hearing may come from what the standard UcD180 module is.
In my experience the input caps on the standard UcD180 do not provide audiophile sound (muffled non-clear highs?), I think there is a near consensus on this. I have not tried different input caps but I understand the choice of input cap has a definite impact on the highs. In my case the difference was dramatic. There is still something in the sound that does not satisfy me fully, some people say they don't like the sound of the AD8620 input buffer so maybe that is my case.

Regarding bass I understand people (T.) have made some changes that resulted in tighter bass.

Don't get me wrong, anything can always be improved, but the standard UcD has parts chosen for cost reasons rather than audiophile performance. Hypex has an upcoming audiophile "HG" version of the modules that is intended to provide audiophile performance out of the box while the current modules (UcD180 and UcD400 are not).

So when you read people raving about the wonderful sound of the UcD, remember that in general they have made one or more changes to the unit before they can rave about it.

Guy
 
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