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
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
Input buffer?
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
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
Input buffer
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
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
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.
BWRX said: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 ?
DEQ+TheEnd said:
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
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
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
BWRX said: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
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
Is this something that can be dropped in as replacement on the UCD400AD, or do I need to change anything else?
Thanks
Yves Smolders said:
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
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.
Also... as stated, bypass the input caps if you know your source is DC free.
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
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
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
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
Pics from the setup
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.
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
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.

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
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Attachments
LM4562 built in
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
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
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
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
maxlorenz said: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
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
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
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