[beppe61]

Dear Sirs,

is there anyone who has tried the UcD modules with off-the-shelf dual switching power supplies ?
I would appreciate any opinion on this subject.

Kind regards,

beppe61

[JoshK]

I don't know anyone who has tried it but I don't know why it wouldn't work.  I think, though, given my modest experience with these modules is they will need some improvement in the filtering and noise from the switcher.  Alternatively you could build a standard bypass cap bank in parrallel and charge the caps with the switcher.

[Kevin Haskins]

Why do you want a switcher?   The real reason switchers are popular is that they are cheap.  

A VERY well designed switching power supply MIGHT outperform a linear supply but I doubt you would hear the difference between a good linear vs. a good switcher on the UCD.  They might sound different but not better/worse.     Just speculation on my part but I wouldn't waste my money on a cheap switching power supply.   It's just going to be a step backwards from a simple linear one.

[beppe61]

Dear Mr. Josh,
thank you very much for your extremely kind and valuable reply.

>  

I don't know anyone who has tried it but I don't know why it wouldn't work.  
I think, though, given my modest experience with these modules is they will need some improvement in the filtering and noise from the switcher.  

Very interesting. You obviously mean high frequency noise.
I am thinking to use a 200VA EI trasformer for power a UcD180 ( do not know if a ST or AD model though).
That EI transfo should provide a good level of high-frequency filtering.

>  Alternatively you could build a standard bypass cap bank in parrallel and charge the caps with the switcher.

I understand that an off-the-shelf unit is not usable without mods.
Just out of curiosity, do you listen through these modules?

Kind regards,

beppe61

[beppe61]

Dear Mr. Haskins,
thank you very much for your kind and very interesting advice.

>

Why do you want a switcher?  
The real reason switchers are popular is that they are cheap.  

And efficient and compact. You can place it about every where.

>  A VERY well designed switching power supply MIGHT outperform a linear supply

Very interesting.

>  but I doubt you would hear the difference between a good linear vs. a good switcher on the UCD.

That is what I wanted to know in the end. My curiosity ends here.
Thank you so much for saving me the pain to look around for a very high quality switcher.

>   They might sound different but not better/worse.    
Just speculation on my part but I wouldn't waste my money on a cheap switching power supply.  
It's just going to be a step backwards from a simple linear one.

Dear Mr. Haskins,
I would like to take profit of your great kindness and expertise to ask which would be your 1st choice for a transformer to power this modules.
I have read about a good filtering needed and I am thinking even to a massive 200VA EI transformer per each UcD 180.
What is your choice?

Thank you so much and kind regards,

beppe61
ITALY

[Kevin Haskins]

Dear Mr. Haskins,
thank you very much for your kind and very interesting advice.

>Dear Mr. Haskins,
I would like to take profit of your great kindness and expertise to ask which would be your 1st choice for a transformer to power this modules.
I have read about a good filtering needed and I am thinking even to a massive 200VA EI transformer per each UcD 180.
What is your choice?

Thank you so much and kind regards,

beppe61
ITALY

You are correct.... switchers have an advantage in efficiency and space requirements.   Both of those factors also make them cheaper.   The space requirement makes the up-front cost cheaper because a manufacture doesn't have to spend as much on the enclosure.   A large toroid is heavy and requires a sturdy enclosure.   You can save a LOT of money on the enclosure if you go with switching power supplies and lighter enclosure materials.   I don't think that is a bad choice for a manufacture but it's an unwise one for a homebuilder.   The cost of the enclosure to the DIYer is far less of an issue.  

The EI will have the advantage of not having as much capacitive coupling and will allow less HF noise through the transformer to the secondary.   It has a disadvantage in cost; size, availability and they throw a larger magnetic field.  

The toroid will be cheaper, easier to mount and a lower profile.   I've not used EIs simply because it's difficult to find them in an appropriate size, voltage without having them custom made.   The only reason they MIGHT sound different is due to the HF noise coupling.   I guess you could argue that they would resonate different than a toroid.  

I don't have any first hand experience in comparing the two choices but once again, the room speaker interface is MUCH more important than the transformer choice.   Most amps use toroids.   If they where that bad I doubt they would dominate the market as they do for this type of application.

[JoshK]

I mostly agree with you Kevin, except I think the advantages for going with EI core tx over toroid tx for the DIYer are more than you might think.  I am doing this experiment now with my UcD modules.  If the Felicia project taught us anything, it is that this can make a very nice contribution to a good system. I do think though that speaker/room optimization is a better effort though, but this goes for most all fretting with audio.

[Kevin Haskins]

I mostly agree with you Kevin, except I think the advantages for going with EI core tx over toroid tx for the DIYer are more than you might think.  I am doing this experiment now with my UcD modules.  If the Felicia project taught us anything, it is that this can make a very nice contribution to a good system. I do think though that speaker/room optimization is a better effort though, but this goes for most all fretting with audio.

Your right... we would stop fretting with a lot of things.  

I'll defer to your judgement on the EIs.   Like I said... I've never tried them.    

Just out of curiosity though, do they only make a sonic improvement only when there is HF noise on the AC line?   That would jive with the capacitive coupling issue.

[JoshK]

Quite possibly.  I have no real basis to infer otherwise.  We here in the NYC area have lousy power.  Plitron for instance though sells many (all?) of their tx's with the option of ES shield.  This would provide the same benefit me thinks.  Trouble is, plitron txs aren't cheap.

[beppe61]

Dear Sirs,

thank you so much for your really great and kind advice.
Just to explain how ignorant I am, I prefer the EI type transfos above all other things because the secondary windings terminals are clearly marked  0-V-0-V letting me connect them more easily !
(I mean to connect the two terminals marked 0 together to form the ground).
In a toroid the secondaries are not always  marked clearly(so I cannot understand which are the 0 and the V terminals!).
From the data sheet I see that the UcD180 limits output current at 10A.  
I hope they are enough to power my current hungry Dynaudio.
Anyway my listening room is limited in size(4,5x6 meters).

Thank you sincerely for your very kind support.

Kind regards,

beppe61
Torino (Winter Olympic Games 2006 city)
ITALY