UcD400 listening vs. Halcro & Gamut

[Kevin Haskins]

I'd do the seperate regulated supply for the AD8620. It makes a fairly significant difference for the little effort it requires.

Also... as stated, bypass the input caps if you know your source is DC free.

[maxlorenz]

Hi Kevin,
When one does the separate PS for opamp, do you recommend also addressing the on-board decoupling?

I swaped the SMD ceramic cap next to OPA2134 for BG-NX (in a most reckless way) for the UCD400 and I like the sound better now: less nervous/harsh; more elegant and precise sound.

Thanks,
M

[Kevin Haskins]

I've not swapped the de-coupling caps so you have the advantage on me.

[maxlorenz]

All the caps swaps were made de brute force and were subject to mechanical or electronic catastrophe; so did some mates here. Luckilly, experiences were positive.
I am interested in hearing the expert's opinion. I mean, what is the use of trying an elaborate PS if we retain the same on board configuration, soundwise and "ringwise"
Some mates could even maintain the darlingtons, wich, as I understand, must be taken off.

This low voltage circuit has been examined here and there but not with the depth of thought (yours, not mine) that we should, IMHO.
There must be out there some scopes and spectrum analizers wanting a warm up...Chris?

Best regards,
M

[Alfetta87]

As promised, here are some pics from the setup with which we made the listening tests (sorry for the bad quality). Not that most of all devices have been used partly, but the conclusion is only for the best gear.

[IMG]setup1.jpg[/IMG]

On the rack
(top shelf, from left):
- preamp Audio Research SR16
- Halcro Logic 5 channel amp
(second shelf from top)
- tube amp Audio Research VS55
- UcD400 dual mono amp
(third shelp)
- stacked up: dCS Verdi Encore, dCS Verona (ext. clock), dCS Elgar Plus
- Halcro DM 10 preamp (not used in our tests)
Lowest shelf: some Sony S-Master surround amp and SACD/DVD player used in 5.1 setups.

Beside the racks the hefty (55Kg/120lbs) DM88 from Halcro.
Wired in "enlightened" (some blue LED's at the end or beginning of each cable, powered with 5 PSU!) Synergistic research cables. Shuntaya power filter.

Speakers Grande Utopia Be by Focal

[Alfetta87]

A closer look

[Alfetta87]

The coupling caps are now totally gone, and the LM4562 placed and burned in for weeks. Now separate PSU yet, comes later. The lack of bass weight I had at the beginning is totally gone, means the LM's need a long burn in. But good choice of cables is mandatory, thin sounding cables can reverse the balances. I use Neotech balanced (OCC copper), which are excellent to me.

New listening vs. the Halcro confirms the quality of the UcD, where improvement are still possible (caps).

cheers,

- dan

[maxlorenz]

Glad to hear that. Amazing the amount of detail, don't you think?

OCC copper, I'm fond of it! I use it as hookup signal wire and also for DIY interconnects.

My setup is comparable to yours. Other mate stated that separate main power supply was even better (Halcro does it, wright?). Maybe I'll try it later.

Regards,
M

[Alfetta87]

Originally posted by maxlorenz
Other mate stated that separate main power supply was even better (Halcro does it, wright?).

I don't know. If I'd open the Halcros, my boss would probably write my notice directly on the back of my hand...


cheers,
- dan

[maxlorenz]

He, he...
I'll check the net-->yes, they do have separate PS:
http://www.halcro.com/powersupply.asp

I don't know if it applies to your units...

Bye,
M