UcD400 listening vs. Halcro & Gamut

[Alfetta87]

A few weeks and today we made an extensive comparison listening test of a slightly modded UcD400 dual mono amp: 22µF coupling caps cap bridged, Axon 5.6µF + Auricap 1.0µF in //, four times directly from the input XLR to the modules, 500VA tranny per channel, Cerafine caps with 40,000µF total, Hexfred diodes in rectifier.

The amp was compared within an existing setup:
dCS Verdi Edgar CD/SACD drive, converter Elgar Plus directly into a pair of Halcro's DM88, with Synergistic cables (active biased).
Speakers were Focal Grande Utopia, and the Top model of Electra Be (1000) series, both models use similar versions of the Berrylium tweeter.

Other setup (few weeks ago) was a fully Gamut set: L7 speakers, M200 monoblocks, D3i preamp, CD3 CD player, all wired in Wireworld.

To make it short: the Ucd came damned close to the Gamut amps, with similar tonal balance, (very slightly) less room and depth, but same musicality. For amps which cost more than 10 times my kit...

The Halcros are incredible good amps, and beat the UcD. But not by miles! First they have a different tonal balance: less bass weight, and upper band more present. They are more transparent, without any doubt (maybe I should change my coupling caps to something better?). High frequencies seem to have no limits.
One listener though preferred the more controlled, yet more forward LF band of the UcD (Grand Utopia have tendance to play on one sibgle note below 100Hz), and he said he heard the Focals for the first time that well controlled in the bass.
Image was in both cases excellent, the Halcro added a few yards to the backstage, but placement of instruments in the room was equal.

Conclusion was that for a fraction of the Halcro price (less the a hundreds), you can get so much quality is a real sensation. Bravo to Bruno and Jan-Peter.

If I would find the f@&°*µ%g camera, I would make a picture of the setup (Halcro-dCS-Focal), and post it here leter.

Cheers,
- dan

[DEQ+TheEnd]

Thanks for the review Dan!

My guess this is the version with the AD8620 input buffer that is revived here? Do you think feeding the buffer with separate 12V power lines or maybe replacing the buffer with the new LM4562 could help the UcD compare even better up against those expensive amps?

regards
Hans

[Alfetta87]

Yes, the modules are equipped with AD8620, but they are not fed with a separate PS. Will think about it! I don't know the LM4562, did you test it?
I'm quite happy with the AD, using it also at I/V converter and output amp in my CD player. Will try to get some and test them.

- dan

[BWRX]

Get rid of the coupling caps in the signal path and you'll probably find them to be even better. DC coupling is the way to go if you can do it.

[DEQ+TheEnd]

Originally posted by BWRX
DC coupling is the way to go if you can do it.

Talking about that. Have anyone testet if the DC-protection on the Hypex HG or ST supply has any sonic impact ?

[Jan-Peter]

Originally posted by DEQ+TheEnd


Talking about that. Have anyone testet if the DC-protection on the Hypex HG or ST supply has any sonic impact ?

No...the DC-protection of the HG/ST supply has NO sonic affect!

Jan-Peter

[maxlorenz]

Thanks Dan for the nice review...and for the good news

I subscribe what has being said about DC coupling.
I will soon put those LM4562 (into UCD180 first). It is a very transparent opamp. Everyone that has tried it say so.
I use it on a DVDP with excellent result.
Hypex could use them in standard UCD to avoid us the trouble

I don't know what PS caps are stock on the latest version. I replaced them for Rubycon ZL 470uF/100V and I'm very pleased with the improvement: faster, more dynamic and transparent sound. More precise.
I swapped at the same time the output filter cap for Wima MKS2 polyester, wich may account for softer and extended highs. I understand that new modules feature new Panasonic film caps.

I hope this helps,
M

[Alfetta87]

Originally posted by BWRX
Get rid of the coupling caps in the signal path and you'll probably find them to be even better.

Am afraid that some DC coupling might harm my UcD. Knowing that my personal preamp has already a CD coupling, I can bypass the one in the (input) signal path, but will leave them for "outdoor" applications (i.e. when I use it elsewhere where I don't know if the preamp is AC or DC coupled.

- dan

[Yves Smolders]

I've read about the LM4562 also...

Is this something that can be dropped in as replacement on the UCD400AD, or do I need to change anything else?

Thanks

[Alfetta87]

Originally posted by Yves Smolders

Is this something that can be dropped in as replacement on the UCD400AD, or do I need to change anything else?

Thanks

According to National's data sheet, it could be a direct replacement w/o any mods or adds.
Ordered some LMs thru my company and will try, let you guys know when done.


Cheers,
- dan