Hello Jan-Peter,
Thank you for your reply. The only reason for maximum power is that my loudspeakers change from time to time and I don't want to have "underpowered" amps for the future. It is not that important to get the maximum out of the UcD400 but it would be nice to get close. You never know wether I need it in the future.
I managed to get some 80V Nichicon 10.000 uF caps which I wil be using in the power supply (80.000 uF per module). So if 300VA is no problem I wil use 300VA. It wil be nice to have an amp which is in a small casing anyway. (I also have 2 Aleph 5's an they are absolutly not small...)
Jan
Thank you for your reply. The only reason for maximum power is that my loudspeakers change from time to time and I don't want to have "underpowered" amps for the future. It is not that important to get the maximum out of the UcD400 but it would be nice to get close. You never know wether I need it in the future.
I managed to get some 80V Nichicon 10.000 uF caps which I wil be using in the power supply (80.000 uF per module). So if 300VA is no problem I wil use 300VA. It wil be nice to have an amp which is in a small casing anyway. (I also have 2 Aleph 5's an they are absolutly not small...)
Jan
@leeuwarden:
Bruno claimed in the UcD180 post 441 that the needed caps can be calculated. Roughly you can use "50.000 / speaker-R" per rail, per module.
So 12.500uF per rail is enough for a 4 ohms load, 25.000uF per channel.
Another post (which I can't find) claims (not confirmed by Jan-Peter or Bruno) that when going under 4 ohms, the max output stays 400W because of the current limitation. Don't know if this is true.
So 60.000 should be more than enough to drive just about anything you throw at the Ucd's.
Bruno claimed in the UcD180 post 441 that the needed caps can be calculated. Roughly you can use "50.000 / speaker-R" per rail, per module.
So 12.500uF per rail is enough for a 4 ohms load, 25.000uF per channel.
Another post (which I can't find) claims (not confirmed by Jan-Peter or Bruno) that when going under 4 ohms, the max output stays 400W because of the current limitation. Don't know if this is true.
So 60.000 should be more than enough to drive just about anything you throw at the Ucd's.
*** warning: long post - maybe it should go into a "UCD listening" thread***
Day 2:
Installed heat sinks on the T's.
Connected both modules to my old receiver's power stage, 4 temp speaker terminals installed on a plastic box for testing. Connected pre-out of the receiver to the UcD's inputs. Test... massive ground loop hum. Can't seem to get rid of it.
Dug up old 3-head cassette deck, switched the deck to monitor for crude volume control. Disconnected DVD player from the receiver and routed them to the in jacks on the tape deck. Test... No hum, liiitle bit of noise from the tapedeck.
Listening test:
The modules need some time to "settle" it seems, just like any electronics heating up, played some music for 15 mins without listening, then came back.
A few comments on some tracks...
Lord Of The Rings sountrack - Fellowship theme: Very engulfing soundstage, a lot of detail in the instruments. When the lead woodwind (flute?) starts playing, eyebrows were raising, it's not just a "tone" from the flute I hear, but also the air blowing through the instrument, it's that detailed. Dynamics are just right - everything is there without any stress in high SPL passages.
St. Germain - Sure Thing: Like in the earlier single channel test, much improved bass response, not boomy at all, very dy and correct. John L. Hooker's voice tingles the spine, power "on tap" seems to be unlimited.
Gladiator OST - The Might Of Rome: has a choir of male voices that are a lot more defined and lifelike, and amazing dynamics, almost scary.
Gladiator OST - The Battle: Very high SPL level that needs a lot of reserves, if you don't know this track, just think about any heavy Wagner passage souped up with electronic sounds that Hans Zimmer likes to use. On cheaper speakers this comes out as a mess, on the 804's is was more defined, but this amp brings it alive, it's almost scary. I know now that the DSP-A2 was already compressing hard at moderate levels, the UcD's just sing along, I still have the urge to turn the volume down because I'm scared of clipping... no need to do that anymore
Heroines OST: Studio female voice recording, just amazing definition, tears to the eyes.
And a lot more... overall, again the authority, large dynamics, pin point soundstaging (when moving your head away from the sweet spot, there's less changing in the sound like there used to) and very "free" sound, even less the feeling there are speakers present. Microdynamics (this is concentrating on a "quiter" instrument in the musical image) is lots improved, there's so much more to piano's and brass instruments, and more airy sound to woodwinds.
Only thing I needed to get used to is the highs. They sound very... refined, but also very different. It was almost like there was less treble, but my guess is that it's truly what's in the recording, and the class-AB "added" harmonics or something. It's getting used to but in the end it's better.
Last thing: My modules are in a "flat" setup with the sink screwed to the T. The T runs a lot cooler than without the sink, but the piece at the tip of the T (don't know what part it is) runs very hot, it's possible to put a finger on the tip of the T but it shouldn't be much hotter to be impossible. This worries me a bit.
Conclusion:
To use a famous 80's TV action characters words...
I pity the fool that spends more than 1000€ on a stereo amp! You should audition UcD's first.
It's a pity I can't test the amps on even better speakers, i'm sure they are able to handle even more. For my setup it's just perfect, it reminds me of the sound I heard at the store when auditioning 805/804 and Signature 805. That was on a Classé setup....
Congratulations on Bruno for the UcD concept, and bravo to Jan-Peter and his crew for bringing this quality to us at this level.
In time I'm going to power my front stage (3 channels) with this, and if money permits, 5 to 7 channels. For me this is the amp for the next years to come.
Day 2:
Installed heat sinks on the T's.
Connected both modules to my old receiver's power stage, 4 temp speaker terminals installed on a plastic box for testing. Connected pre-out of the receiver to the UcD's inputs. Test... massive ground loop hum. Can't seem to get rid of it.
Dug up old 3-head cassette deck, switched the deck to monitor for crude volume control. Disconnected DVD player from the receiver and routed them to the in jacks on the tape deck. Test... No hum, liiitle bit of noise from the tapedeck.
Listening test:
The modules need some time to "settle" it seems, just like any electronics heating up, played some music for 15 mins without listening, then came back.
A few comments on some tracks...
Lord Of The Rings sountrack - Fellowship theme: Very engulfing soundstage, a lot of detail in the instruments. When the lead woodwind (flute?) starts playing, eyebrows were raising, it's not just a "tone" from the flute I hear, but also the air blowing through the instrument, it's that detailed. Dynamics are just right - everything is there without any stress in high SPL passages.
St. Germain - Sure Thing: Like in the earlier single channel test, much improved bass response, not boomy at all, very dy and correct. John L. Hooker's voice tingles the spine, power "on tap" seems to be unlimited.
Gladiator OST - The Might Of Rome: has a choir of male voices that are a lot more defined and lifelike, and amazing dynamics, almost scary.
Gladiator OST - The Battle: Very high SPL level that needs a lot of reserves, if you don't know this track, just think about any heavy Wagner passage souped up with electronic sounds that Hans Zimmer likes to use. On cheaper speakers this comes out as a mess, on the 804's is was more defined, but this amp brings it alive, it's almost scary. I know now that the DSP-A2 was already compressing hard at moderate levels, the UcD's just sing along, I still have the urge to turn the volume down because I'm scared of clipping... no need to do that anymore
Heroines OST: Studio female voice recording, just amazing definition, tears to the eyes.
And a lot more... overall, again the authority, large dynamics, pin point soundstaging (when moving your head away from the sweet spot, there's less changing in the sound like there used to) and very "free" sound, even less the feeling there are speakers present. Microdynamics (this is concentrating on a "quiter" instrument in the musical image) is lots improved, there's so much more to piano's and brass instruments, and more airy sound to woodwinds.
Only thing I needed to get used to is the highs. They sound very... refined, but also very different. It was almost like there was less treble, but my guess is that it's truly what's in the recording, and the class-AB "added" harmonics or something. It's getting used to but in the end it's better.
Last thing: My modules are in a "flat" setup with the sink screwed to the T. The T runs a lot cooler than without the sink, but the piece at the tip of the T (don't know what part it is) runs very hot, it's possible to put a finger on the tip of the T but it shouldn't be much hotter to be impossible. This worries me a bit.
Conclusion:
To use a famous 80's TV action characters words...
I pity the fool that spends more than 1000€ on a stereo amp! You should audition UcD's first.
It's a pity I can't test the amps on even better speakers, i'm sure they are able to handle even more. For my setup it's just perfect, it reminds me of the sound I heard at the store when auditioning 805/804 and Signature 805. That was on a Classé setup....
Congratulations on Bruno for the UcD concept, and bravo to Jan-Peter and his crew for bringing this quality to us at this level.
In time I'm going to power my front stage (3 channels) with this, and if money permits, 5 to 7 channels. For me this is the amp for the next years to come.
Yves Smolders said:*** warning: long post - maybe it should go into a "UCD listening" thread***
Day 2:
Installed heat sinks on the T's.
Connected both modules to my old receiver's power stage, 4 temp speaker terminals installed on a plastic box for testing. Connected pre-out of the receiver to the UcD's inputs. Test... massive ground loop hum. Can't seem to get rid of it.
Dug up old 3-head cassette deck, switched the deck to monitor for crude volume control. Disconnected DVD player from the receiver and routed them to the in jacks on the tape deck. Test... No hum, liiitle bit of noise from the tapedeck.
Listening test:
The modules need some time to "settle" it seems, just like any electronics heating up, played some music for 15 mins without listening, then came back.
A few comments on some tracks...
Lord Of The Rings sountrack - Fellowship theme: Very engulfing soundstage, a lot of detail in the instruments. When the lead woodwind (flute?) starts playing, eyebrows were raising, it's not just a "tone" from the flute I hear, but also the air blowing through the instrument, it's that detailed. Dynamics are just right - everything is there without any stress in high SPL passages.
St. Germain - Sure Thing: Like in the earlier single channel test, much improved bass response, not boomy at all, very dy and correct. John L. Hooker's voice tingles the spine, power "on tap" seems to be unlimited.
Gladiator OST - The Might Of Rome: has a choir of male voices that are a lot more defined and lifelike, and amazing dynamics, almost scary.
Gladiator OST - The Battle: Very high SPL level that needs a lot of reserves, if you don't know this track, just think about any heavy Wagner passage souped up with electronic sounds that Hans Zimmer likes to use. On cheaper speakers this comes out as a mess, on the 804's is was more defined, but this amp brings it alive, it's almost scary. I know now that the DSP-A2 was already compressing hard at moderate levels, the UcD's just sing along, I still have the urge to turn the volume down because I'm scared of clipping... no need to do that anymore
Heroines OST: Studio female voice recording, just amazing definition, tears to the eyes.
And a lot more... overall, again the authority, large dynamics, pin point soundstaging (when moving your head away from the sweet spot, there's less changing in the sound like there used to) and very "free" sound, even less the feeling there are speakers present. Microdynamics (this is concentrating on a "quiter" instrument in the musical image) is lots improved, there's so much more to piano's and brass instruments, and more airy sound to woodwinds.
Only thing I needed to get used to is the highs. They sound very... refined, but also very different. It was almost like there was less treble, but my guess is that it's truly what's in the recording, and the class-AB "added" harmonics or something. It's getting used to but in the end it's better.
Last thing: My modules are in a "flat" setup with the sink screwed to the T. The T runs a lot cooler than without the sink, but the piece at the tip of the T (don't know what part it is) runs very hot, it's possible to put a finger on the tip of the T but it shouldn't be much hotter to be impossible. This worries me a bit.
Conclusion:
To use a famous 80's TV action characters words...
I pity the fool that spends more than 1000€ on a stereo amp! You should audition UcD's first.
It's a pity I can't test the amps on even better speakers, i'm sure they are able to handle even more. For my setup it's just perfect, it reminds me of the sound I heard at the store when auditioning 805/804 and Signature 805. That was on a Classé setup....
Congratulations on Bruno for the UcD concept, and bravo to Jan-Peter and his crew for bringing this quality to us at this level.
In time I'm going to power my front stage (3 channels) with this, and if money permits, 5 to 7 channels. For me this is the amp for the next years to come.
Yes, the highs of UcD are something special. Cymbals suddenly sound like cymbals and much less like some noisy metal sound, the definition of the UcDs is really very good. You talk about a 1000 Euro amp, these guys blew away my 3000 Euro Accuphase amp (Accuphase amps are a lot cheaper in Japan than in Europe, that's why I bought one a few years ago).
They keep sounding clean, whatever the power level, I can turn up the volume much higher than with my previous amps, just because there is no harshness in the sound, it stays clean.
This is indeed very good value for money, maybe some people think they can not be that good since the price is so low.
If you use these amps in active speakers, you get even more fun for your money. Without all those coils, capacitors and resistors in the crossover network you get a direct connection between UcD and driver.
Best regards
Gertjan
Yves Smolders said:
Hi Yves,
I calculated somewhere that the maximum power is delivered at 3 Ohm. This is because the amp can deliver a peak current of 20A. With a 3 Ohm (resistive) load, this will be reached at a 60V output voltage (you need than more than 60V power supply). Assuming the signal is a sine wave with 60V peak voltage, the RMS voltage is 42.4V, giving a power of 600W. For lower resistances, the voltage will drop. At for example 2 Ohm, peak voltage is 40V at 20A, so power will be 400W, at 1 Ohm it will drop to 200W.
Best regards
Gertjan
Thanks for clearing that up, I couldn't find that post anymore.
so 3 ohms, ok, that would be about 16600uF per rail to be optimal for a single module.
I'm going to use 30000uF per rail for a stereo model Ucd400, on 1000VA. It should handle all but the most extreme situations (heavily compressed techno @ 3 ohms, sustained full power - hmm shouldn't happen at my place )
I don't need it, but if Hypex consider truly high-end modules, price no objection, it should include even higher peak amp output (and oversized heatsinks on the module)
20A is a lot, don't get me wrong, but the "superpowers" out there (Krell, Classe at about 50x the cost of UcD) can do better. I'm so pleased with the UcD400's sound, i'm sure there could be a revolution soon, pricewise and qualitywise vs the "old guard" designs.
so 3 ohms, ok, that would be about 16600uF per rail to be optimal for a single module.
I'm going to use 30000uF per rail for a stereo model Ucd400, on 1000VA. It should handle all but the most extreme situations (heavily compressed techno @ 3 ohms, sustained full power - hmm shouldn't happen at my place
)I don't need it, but if Hypex consider truly high-end modules, price no objection, it should include even higher peak amp output (and oversized heatsinks on the module)
20A is a lot, don't get me wrong, but the "superpowers" out there (Krell, Classe at about 50x the cost of UcD) can do better. I'm so pleased with the UcD400's sound, i'm sure there could be a revolution soon, pricewise and qualitywise vs the "old guard" designs.
Yves Smolders said:
sign me up for one of those supermodules - my speakers eat amps for breakfast... they go to 2.5 ohms and only begin to sound good once you feed them a few hundred watts each. At this point I am considering to simply build 4 channels of UCD400 modules or keep my current space heater amps for the mids and highs and feed the bass with the UCDs (but then you hear all these good things about the UCD highs...)
decisions decisions.... but I know before the summer I am building at least 2 channels to see what all the fuss is about
Peter
Try at low volumes with 2 modules first. Your "heater amps" might be surprised - you could also wait for the rumoured UcD700/UcD1000... 
If you like the sound, make another amp with 2 modules and bi-amp your current-eaters
You'll be happy you tried, and you'll be down about 1000 euro's in parts (w/o case)
Yves
- you could also wait for the rumoured UcD700/UcD1000... If you like the sound, make another amp with 2 modules and bi-amp your current-eaters
You'll be happy you tried, and you'll be down about 1000 euro's in parts (w/o case)
Yves
speaker protection
Somebody mentioned about speaker protection in UcD 180 post. Does anyboby used it in your UcD project? What is it's advantage and disadvange? I already order 2 UcD 400 modules but not receive yet. I would like to buy relevant parts before receive UcD 400. Thanks in advance.
Somebody mentioned about speaker protection in UcD 180 post. Does anyboby used it in your UcD project? What is it's advantage and disadvange? I already order 2 UcD 400 modules but not receive yet. I would like to buy relevant parts before receive UcD 400. Thanks in advance.
My project is still in a test phase, so I haven't put the DC protection in yet.
It's been mentioned the velleman 4701 I want to use is not good, because of the bad relay (for audio use)
I'll test it soon, and see if the difference is noticeable.
I have (for me at least) expensive speakers which took years to save money for, I don't want to blow them up because of a mosfet blowing up.
Maybe the velleman can be altered to cut the power between amps & caps when DC is detected (problem is, the relay then needs a kind of "hold" circuit so that the power remains cut even when the DC is gone.
Cutting the power might not be quick enough to save the speakers though...
Yves
It's been mentioned the velleman 4701 I want to use is not good, because of the bad relay (for audio use)
I'll test it soon, and see if the difference is noticeable.
I have (for me at least
) expensive speakers which took years to save money for, I don't want to blow them up because of a mosfet blowing up.Maybe the velleman can be altered to cut the power between amps & caps when DC is detected (problem is, the relay then needs a kind of "hold" circuit so that the power remains cut even when the DC is gone.
Cutting the power might not be quick enough to save the speakers though...
Yves
Hi all,
have been reading these threads a lot lately as i've just bough two UCD400's. In my previous amps i've always used DC protection relais, but i'm not very happy with the ones in my current amps (maybe i should just replace them but ok..) Anyway, i'm looking into crowbar circuits at the moment and this is the idea i came up with
do you guys think this could work or am i missing something completely? Any comments welcome!
Peter
have been reading these threads a lot lately as i've just bough two UCD400's. In my previous amps i've always used DC protection relais, but i'm not very happy with the ones in my current amps (maybe i should just replace them but ok..) Anyway, i'm looking into crowbar circuits at the moment and this is the idea i came up with
An externally hosted image should be here but it was not working when we last tested it.
do you guys think this could work or am i missing something completely? Any comments welcome!
Peter
I'm afraid the idea has no purpose as a method of DC protection as you are only interrupting the primary, therefore your DC smoothing capacitors are free to dump their considerable charge into your drive unit upon DC fault.
What are you unhappy with about your current amp relay? Maybe all you need to do is try a decent relay!
What are you unhappy with about your current amp relay? Maybe all you need to do is try a decent relay!
the idea is that I will interrupt the primary and at the same time trigger the crowbar (the triac on the right side). This will almost shortcircuit the secondary (current will be limited by R2) and hence make sure the capacitors won't dump their charge in the speakers. Hope it makes more sense this way!
These guys have amazing stuff! Too bad you can't order online - I'm going to give them a call...
The DC protection is great (has its own power supply, I guess it keeps the relays open in case of problems)
I want the slow start as well....
You can use this to start the unit at audio signal (like a subwoofer)And those 47.000uF Caps!
Are these good specs?
In the picture I see +/- 20% capacitance error...
If the crowbar were used, I wonder if it would be safer to do both rails simultaneously if even possible to get perfectly synchronized. Otherwise the stresses placed on some components could be from reverse polarity as one cap discharges slightly into the other like if it contains a little more charge due to having more voltage or capacitance present.
I have a question about this module (the one leeuwarden mentioned on the THEL site)
DC protection
The link is german but the drawing speaks for itself:
Apparently, it can handle 3 channels but you need to connect the speaker mass of the 3 channels together.
Can this be done with UcD modules? Should I use resistors like mentioned? What is the effect on sound quality when linking the grounds of the speakers together?
Thanks
Yves
DC protection
The link is german but the drawing speaks for itself:
Apparently, it can handle 3 channels but you need to connect the speaker mass of the 3 channels together.
Can this be done with UcD modules? Should I use resistors like mentioned? What is the effect on sound quality when linking the grounds of the speakers together?
Thanks
Yves
richie00boy said:
I was wondering about that too. I've looked at some cap specs and it seems that charge-discharge is garanteed for 10^6 cycles with small effect as long as you keep the time constant above 0.1s. This is rated for a repetition cycle of 1 second with the cap at max voltage, so I guess in practice you could go a lot lower as the cap temperature is probably the limiting factor here (and i'm using 100V caps in a 60 V supply). This would mean that if I use 20000muf caps I should keep R2 above 5 ohms. (and if dissipation is the limiting factor 5 * (60/100)^2 = 2 ohms and an RC of 0.03 or something)
The big question is then if that will be sufficient to save the speakers
subwo1 said:
It wouldn't be too difficult to add a second crowbar to accomplish simultaneous crowing
. I left it out because I thought the bridge rectifiers would keep the reverse voltages out (apart from two diode voltage drops), but I guess that even the odd 1 or two volts might not be so good for some of the electronics.....