UCD180 questions

[samsagaz]

for an subwoofer an UCD180 is the best choicE?

[lbruynseels]

Hello all,

a question about dc protection of the speakers: is it necessary to protect the connected speakers with a dc protection relay? What happens if one of the mosfets fails (short circuit) to +/- power?

Related to this, if I do you use such a dc protection, can the UCD work properly with no load connected to it?


regards,

Ludo

[ewildgoose]

Originally posted by ghemink
I know many people are interested in this. So finally I did it. I built up a stereo ZAPpulse based amp using exactly the same power supply as I use for my UcD180 amp.

Very interesting review! I only have the Zappulse, so I can't compare them, but I hope to get a pair of UCD 400s soon.

The Zappulse needed a LOT of breaking in. It's had >100 hours so far and it's still softening up. At first it was very "harsh", and had a lot of "ringing" in the upper treble. This has softened quite a lot now, but I would have to have another good listen to really see whether it's really gone completely.

My reference amp is a Meridian 557, and in comparison the Zappulse has *incredible* imaging! Everything is very well positioned, and little things with ambience (like a glass smashing) suddenly have a real ambience and a sense of spaciousness. In the example of the glass smashing I had a sudden feeling of the glass pieces scattering backwards into the stereo image and even outside to the speakers. I have never heard anything like that from my Meridian

(Speakers are Proac 1.5 by the way)

However, at least up until very recently I didn't enjoy turning the Zappulse up beyond easy listening levels. It just became "harsh" and annoying - not very pleasant at all to my ear. It has smoothed off a lot as it's broken in though, and it's on the bench at the moment so I won't be using it again for a few days (got the Meridian in again to compare).

I hope to see some more reviews of UCD vs other designs (tripath, etc). Also anyone else who is familiar with what I am describing about treble harshness and ringing might put my mind at rest that I am not inventing these things! I am using a similar powersupply to Gertjan by the way.

Thanks Gertjan, and well done Hypex!

[Bruno Putzeys]

Originally posted by lbruynseels
Hello all,

a question about dc protection of the speakers: is it necessary to protect the connected speakers with a dc protection relay? What happens if one of the mosfets fails (short circuit) to +/- power?

Related to this, if I do you use such a dc protection, can the UCD work properly with no load connected to it?


regards,

Ludo

I tend to put the DC protection relay in the power supply, not the speaker line, to keep it out of the signal path. It is not on the modules for the simple reason that most people make multichannel (well at least 2 channels) applications and one relay will do fine there.

UcD is completely stable and functional under no-load conditions, even if you clip it.

[Jan-Peter]

Ludo,

Indeed in a case of failure you will have DC at the output of the UcD modules. We are working on some powersupply board herein will also be a DC protection.

When you have some costly loudspeakers it is good idee to use a DC protection. Use a relay to switch the + and - powerlines in a case of DC. On the Forum there must be enough schematics for a good DC detecting circuit.

Regards,

Jan-Peter

www.hypex.nl

[matjans]

samsagaz: hypex also has a sub-plate amp; check their site: www.hypex.nl

complete with lowpass etc

[ghemink]

Originally posted by Sjef
Hi Gertjan,

there is one thing I have noticed when comparing amps with the DEQX PDC as preamp. I don't know if it is that critical when using it as fullrange amp but if you want to compare them in a three-way setup be sure to make two measurements under the same conditions, one with each amp in place. Then make two exactly the same correctionfilters and load them into the PDC. This is because the PDC also compensates for any gain, frequency and phase response differences in the amplifiers.

Do you think there will be any interference between the amp modules when building a six channel amp ? The Zappulse provides an external clock input for that to keep them in sync.

Does anyone have compared this modules (or the Zappulse) with the better Classe A or single ended triode amps out there ? (excuse if this question has been asked before, the thread is becoming to big to read it all) That's what I am interested in (well personally, I allready have SE triode amps). I have never heard an AV receiver (even some very expensive ones) sounding good so that's very easy to beat with DIY. In my very humble opinion I find all of the Denon's Yamaha's, Marantzes etc sounding crap, there are a lot of DIY projects out there wich sounds much better than that.

Hi Sjef,

I on purpose did not do any correction with the PDC, just corrected the gain since the ZAPpulse has higher gain. I did not want to do a correction since I want to listen to the differences between the amps.

Best regards

Gertjan

[ghemink]

Originally posted by ghemink



Hi Sjef,

I on purpose did not do any correction with the PDC, just corrected the gain since the ZAPpulse has higher gain. I did not want to do a correction since I want to listen to the differences between the amps.

Best regards

Gertjan

Hi Sjef,

About the 6 channels that I need, I will not built a 6 channel amp. I will built two stereo amps to be used for mid and high, each stere amp will have its own power supply, so one mid and high amp share a power supply. Then for the woofers, I`ll built two monoblocks.

Gertjan

[ghemink]

Originally posted by ewildgoose


Very interesting review! I only have the Zappulse, so I can't compare them, but I hope to get a pair of UCD 400s soon.

The Zappulse needed a LOT of breaking in. It's had >100 hours so far and it's still softening up. At first it was very "harsh", and had a lot of "ringing" in the upper treble. This has softened quite a lot now, but I would have to have another good listen to really see whether it's really gone completely.

My reference amp is a Meridian 557, and in comparison the Zappulse has *incredible* imaging! Everything is very well positioned, and little things with ambience (like a glass smashing) suddenly have a real ambience and a sense of spaciousness. In the example of the glass smashing I had a sudden feeling of the glass pieces scattering backwards into the stereo image and even outside to the speakers. I have never heard anything like that from my Meridian

(Speakers are Proac 1.5 by the way)

However, at least up until very recently I didn't enjoy turning the Zappulse up beyond easy listening levels. It just became "harsh" and annoying - not very pleasant at all to my ear. It has smoothed off a lot as it's broken in though, and it's on the bench at the moment so I won't be using it again for a few days (got the Meridian in again to compare).

I hope to see some more reviews of UCD vs other designs (tripath, etc). Also anyone else who is familiar with what I am describing about treble harshness and ringing might put my mind at rest that I am not inventing these things! I am using a similar powersupply to Gertjan by the way.

Thanks Gertjan, and well done Hypex!

Hi Ed,

Sorry, I had no time for a few hundred hours break-in, both ZAPpulse and UcD have only played for 10-20hrs or so.

Imaging is very good for both ZAPpulse and UcD, as you noted for the ZAPpulse. Both amps are clearly better sounding than the Marantz Tripath. I have not listened to extreme soundlevels, so can not really confirm the issues that you have noted.

About the noise, as I said, noise level is similar as for the Tripath, but higher than my Accuphase, the UcD is extremely silent. Do you find the ZAPPulse noise level to be high in comparison with your Meridian? I guess that especially for users with active speakers, the noise level can be an issue, especially with higher sensitivity tweeters and mid drivers. For me that is the case, although my tweeters are not exteremely efficient, the UcD gives me more dynamic range when listening at low levels because of the lower noise floor. When you always listen at relatively high level and with passive speakers, the noise difference may not be an issue. I`m a bit surprised that I have never heard any comments about the noise from other ZAPpulse users. Is it because my Accuphase is very silent in comparison with other amps?

Best regards

Gertjan

[kwhilden]

I have both the ZapPulse 2.2SE and the UCD180 stock running. The noise on the Zap is very annoying... nothing I can do will make it go away, however some things minimize it to the point where is only audible with the ear next to the speaker. The sound quality of the Zap kills the stock UCD180, but I have also modded the Zap beyond the original form and use it with the clock frequency at 750kHz. But hey, this modded Zap kills the stock Zap too...

I am going to mod-up the UCD180 soon with AD8620 and no coupling caps. Ar there any other suggestions on essential mods to include on the UCD?

KW