DC protections
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
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
Re: ZAPpulse versus UcD
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!
ghemink said:
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!
Re: DC protections
UcD is completely stable and functional under no-load conditions, even if you clip it.
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.lbruynseels said:
UcD is completely stable and functional under no-load conditions, even if you clip it.
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
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
Sjef said:
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 said:
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
Re: Re: ZAPpulse versus UcD
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
ewildgoose said:
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
noise floor
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
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
I think there is a big difference between the Zappulse and the UCD :
The UCD has feedback loop after the output filter and is load-independent
The frequency response linearity of the Zappulse wiill depend on impedance curve of the speakers
alain
The UCD has feedback loop after the output filter and is load-independent
The frequency response linearity of the Zappulse wiill depend on impedance curve of the speakers
alain
Let me see if I have this right.......
The ZapPulse has an annoying noise...........origin not stated.....and it sounds better than one amp that has no such annoying noise because you believe that you have minimised it.
Correct???
Jocko
The ZapPulse has an annoying noise...........origin not stated.....and it sounds better than one amp that has no such annoying noise because you believe that you have minimised it.
Correct???
Jocko
Re: noise floor
Hi, I don't mean to hijack the UCD thread, but can you comment a little more on why you think the Zap is better than the UCD? At least that's what I think you are saying?
How did you adjust the clock freq (I have the LCAudio clock board, but it's not obvious how you choose freq on it)) Did that make much of a difference...? (The cookbook notes suggest not)
Also, what did you do to minimise the "hiss" on idle? On a relative level, the hiss for me is a little louder than that of the Meridian, but not audible from a seating position. Was it just improved grounding...?
Any other mods worth mentioning?
Please write offlist if this is inappropriate for the UCD thread.
kwhilden said:
Hi, I don't mean to hijack the UCD thread, but can you comment a little more on why you think the Zap is better than the UCD? At least that's what I think you are saying?
How did you adjust the clock freq (I have the LCAudio clock board, but it's not obvious how you choose freq on it)) Did that make much of a difference...? (The cookbook notes suggest not)
Also, what did you do to minimise the "hiss" on idle? On a relative level, the hiss for me is a little louder than that of the Meridian, but not audible from a seating position. Was it just improved grounding...?
Any other mods worth mentioning?
Please write offlist if this is inappropriate for the UCD thread.
Re: Let me see if I have this right.......
Rocket science is a heavy subject. I think only kwhilden can answer your question
I didn't understand it either
🙂
Jocko Homo said:
Rocket science is a heavy subject. I think only kwhilden can answer your question
I didn't understand it either
🙂UcD DC Protection
Hi Jan Peter,
From discussions with Bruno on the SMPS for UcD thread the subject of DC protection came up and he mentioned that you were looking at a PSU module that incorporated this and that future modules might have a status pin output.
Could you please give comment on this and when it might be available?
Robin
Hi Jan Peter,
From discussions with Bruno on the SMPS for UcD thread the subject of DC protection came up and he mentioned that you were looking at a PSU module that incorporated this and that future modules might have a status pin output.
Could you please give comment on this and when it might be available?
Robin
Re: noise floor
Hi KW,
Interesting post, of course we all want to know how you got the ZAPpulse more silent and how much more silent you got it. What have you modded, input integrator? feedback loop? On what sonic point does it kill the stock UcD180?
Please keep us updated on your experiences with tweaking the UcD modules. I have added BG caps after the voltage regulators, to use the AD8620, you have to lower the voltage coming out of those regulators by replacing two zener diodes, but I guess you know that.
Best regards
Gertjan
kwhilden said:
Hi KW,
Interesting post, of course we all want to know how you got the ZAPpulse more silent and how much more silent you got it. What have you modded, input integrator? feedback loop? On what sonic point does it kill the stock UcD180?
Please keep us updated on your experiences with tweaking the UcD modules. I have added BG caps after the voltage regulators, to use the AD8620, you have to lower the voltage coming out of those regulators by replacing two zener diodes, but I guess you know that.
Best regards
Gertjan
I think it's best that I not say too much until I have had a chance to compare apples to apples. Something I should finish by the end of next week. I think the modded UCD will beat the modded Zap handily on sonics. The UCD already has the Zap beat in other areas... no annoying high frequency hiss coming out of the speakers, and no awful turn-on/off thump. I also have to say that the engineers of the UCD are a pleasure to work with. Such 'intangibles' are quite important IMO.
Cheers,
KW
Cheers,
KW
since the ucd180 has differential inputs, would'nt a single-ended -> differential converter/preamp be nice? would this have any (benficial?) impact on sound quality?.
just a thought...
just a thought...
Wholly unnecessary. You can get all the benefits of a differential input from a single ended output, especially if you make a "matched dummy ground impedance" as described in the Jensen papers.matjans said:
Actually, the added circuit would simply detract from sound quality. If you have a circuit that has balanced/differential processing already, it's a good idea to take a balanced feed from it, but not if it requires you to put in an extra amplifier circuit.
For these reasons, AES recommendations require the impedance on hot/cold to be balanced, but to actually produce a signal on the cold wire is optional.
googling on 'dummy ground impedances & jensen' and derivatives turned up about 5000 hits. do you have a link or do you know how to obtain these papers?