Zap Pulse 700XE received today

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#281
raintalk said:


Hi Jan-Peter,
I never really understood the comments made that clipping adds a DC component to a signal. Rod Elliot has a great article on this http://sound.westhost.com/clipping.htm.
It seems though - that a amp could be designed to be stable through clipping. Possibly and amp could provide feedback to pre-signal processing to adjust to the clipping condition. Not just global limiting, but to do something more hi-fi - like compress the HF content as much as the LF it being compressed by clipping. Of course at extreme clipping, this would be the same as a clip limiter. But it would be nice to see an amp handle some lower levels of clipping gracefully.
Click to expand...


I believe the 700 does that, not sure about the others, but I'd like to know if the latest revisions share such a feature, and if so what the thresholds are?

"Because of this DC component you will drive the step up transformer of the ESL in saturation, and the amplifier will see on that moment (only during clipping) only the DC resistance of the step up transformer as a load. This is a very low impedance, so the amp will go in short circuit protection."

I'm sure you'd agree these are rather abnormal conditions, equivalent to a dead short to ground. At such levels you'd definatly want the amp to shut down.
 
#282
classd4sure said:

...
I'm sure you'd agree these are rather abnormal conditions, equivalent to a dead short to ground. At such levels you'd definatly want the amp to shut down.
Click to expand...

Personally, no - I'd rather the amp adjust to the conditions (turn down or lower the supply voltage, or ...?), and let me know why it's turning down, like turn on a light, and/or log to to eeprom 🙂
But only shutdown as a last resort after it's tried everything else.

I'll never forgive an amp that shutdown once while I was playing a solo. 🙁
 
#283
I guesse we are talking about two different things....
Some points;
- the UcD amplifier are always stable, also when the amps goes in full clipping.
- when you have a music signal, this is an AC signal. However when the amp goes in clipping against one of the voltage rails, the signal will not be an AC voltage anymore. This clipping happens never completly symmetrical. So there will be a DC component in the signal becuase of the none-symmetrical clipping.
- when you drive a transformer with a DC signal, the amps sees only the DC resistance. This DC resistance of the transformer is pretty low, so the current will be pretty high.

But in practice none of our ESL users are complaining about problems, so you can save use the UcD with ESL loudspeakers.

BTW: the link doesn't work...

Regards,

Jan-Peter
 
#284
Calvin said:
Hi,

@BGT
soundstage is a matter of freq-response of the speakers distribution character the positioning in the room and roomacoustics to name a few of importance. The effect of symmetrical layout is way down the line -if there is anyhow such an effect at all.
I´m not sure which caps are used, but I know that Panasonic caps are used in the power amp -but You are always free to change those for megahyped stuff 😉 By layout other caps as well as another input-OPamp are usable.

@classd4sure
Wattage and wattage can be some very different terms for different companies. Looking at the power supply and voltages the HiFiAkademie is quite comparable to UCD400. The numbers from HiFiAkademie are rated very conservatively. Comparing measurements -at least those I´ve seen- both amps perform on such a high level, that I wouldn´t rate one of them clearly superior.
Recently I saw some measurements of UCD180 and HiFIAkademie
http://www.ibtk.de/project/class_d/measurements/ucd_20050118.htm for UCD and
http://www.nacl.de/audiomap/test_sound.htm?CUSTOMERNO=15058668&t=de805583058.1149834382.132d56c2 for HiFIAkademie
keep in mind that the measurement setups differ (freq-range, soundcard, sampling freq, etc.) but on first glance I can´t see any really bad number that regards one or both amps not to perform on high quality levels.
As an addition I just got my hands on a EMV-measurement.
It was taken in a normal living room at 1m distance without any housing for the amps. The only difference between the two diagrams is a very slight rise in average value when the amp is on (lower diagrams blue curve). The peaks around 47MHz and 88-108MHz are TV and Radio stations. The amp doesn´t interfere with those. And incasing the amp (shielding) will reduce these values even further. So I don´t see any probs - and I haven´t experienced or heard of any in practise either.
BTW. This is another sign for a good layout of the PCB since especially the layout around the powerbridge is critical in EMI-terms.
External PS with quite long supply lines for example are definite NOs at this place. You have to have some caps as close to the bridge as possible.

Comparing prices of two UCD400 + PS I end up at the same price level as HiFiAkademie and for the preamp You have to consider that the touchscreen display, connectors and everything else is included.
The menu is programmed so that the preamp is very comfortable and flexible -from simple stereo to 5.1 channel- and still very easy and logical in handling. Even though You don´t have any knobs on the front imo everybody who is capable of handling a simple IR is capable to handle the amp too without consulting the manual. Sonically it played on a high level and I haven´t heard of anybody who criticized the sonics versus price relationship. Symmetrical in- and outputs are not foreseen in standard preamp versions. There is technically no significant advantage for home-users that outweigh the disadvantages, but You can easily mod the amp with 1:1 trannies or other solutions.

And again, it´s not my purpose to disregard the UCDs in any way. For my needs they were strong contenders but not prime choice.
Others may decide different, but at least is my decision based on my clear aims, comparisons and ears and not on -imo silly and mostly false- assumptions. The amps perform very well, that´s a fact.
The only mediocre at best performance is classd4sure´s 🙄


jauu
Calvin
Click to expand...


Calvin,

Obviously you're an ESL enthusiast. You'd have us believe that speaker/placement/surroundings are the be all/end all of soundstage and imaging, do you also build your house on a pad of floating air? Point out that the symmetry sucks and all of a sudden it's of no importance? Well argued, I'm a believer.

...I don't see any numbers of value either, nice try though
😀

Maybe you'd like to also post some screenies to run us through those purty, so user friendly even you can use displays. Does it also feature a demonstration mode? I sure hope so.

Here's one fact for you, there's definately at least one knob in front of your amp.

If it was your intention to present an alternative amp to the 700XE then you're at fault for originally bringing up the UCD module, with a slew of outright false statements about it, of an obvious and entirely questionable nature.

There's at least one statement we can agree on, your needs are well beyond the offerings of the UCD. 🙄

Additionally...

Here's your affiliation, I'll connect the dots and everything for all to see:

http://hifiakademie.de/.?id=0.9&si=MTE0OTg3Mjg5My40NTU3fDY2LjE4Ni44My4yMjB8IA

"impressum

Diese Site wird betrieben von:

Dipl. Ing. Hubert Reith"


..read up to a few posts below this next one as well

http://www.diyaudio.com/forums/showthread.php?postid=546843#post546843

"Hi folks
...and highly respected disciple"

..and this is just for you Calvin

"affiliation

n 1: a social or business relationship; "a valuable financial affiliation" "

How's my performance now, punk?
 
#285
zkaiser said:
Duck-Twacy , hi

may I ask you to take a shot of your modules with some real camera, ofcourse when you find some free time to do that . . . ok regards, buy , ...
Click to expand...

Sry, but I forgot my digicam in a cab in Edinburgh. Is has been found, but I wont have it back before August, when my friend comes over to Holland.

Maybe I can borrow a cam from a relative, but also that will take some time.
 
#288
ChevyDK said:
I just talked to Hans Nielsen from LC Audio.
He told me that that 700XE was out of production now, and that they are on the way with a 800XE witch is a dual design (2 amps on one circuit board).
He promised to mail me as soon as he knew more.
Click to expand...


And they still offer the 700XE saying it is 'soon in stock'.
I purchased the modules in advance and sent them my 2.xx in order to get a better price.But I did so because I trusted the knowledge of Lars Clausen and thought they would outperform other similar amplifiers.
Since LC no longer work for them I wonder who is designing the 800XE and what other changes there will be than putting both channels on one board.Will it sound like the 700XE? Better?Worse?



:violin:
 
#289
@classd4sure

Hi,

well, maybe I´m a bit blind from time to time getting somebody´s point. But eventually I understand that its Your sole purpose to do some bashing. So every try to give some useful information to interested people will be just more food for a troll.
Even though You cite my posts completely -which is simply rudeness against anybody, because we all can read- You don´t seem to read properly as Your draws and assumptions are most of all but rubbish.
The same as someone might have got valuable infos from me through one of the forums I visit, Mr. Reith got an info about the coating I use for my ESLs. Your assumption of any affiliation for promotion purposes are utter nonsense, as is most of Your other scribble scrabble too.

I doubt You have the class to not respond to this post, but I´d appreciate if You could at least just shut up Your fingers after a last final response regarding my posts. I´m simply not interested in fights with guys who don´t behave constructive and positive.

jauu
Calvin
 
#290
Anzgar said:


It's nice to hear about other modules and discuss other modules than only the LC Audio ones. As the original thread seems to have served its purpose or sooner never reached it.(Only Duck-Twacy has received a pair and I can't wait to hear how he experiencies its perfomance).I think we had better close this 'received today' thread and begin a new, something like 'Class D amplifiers and DIY modules and combine this original thread with the thread about Lars Clausens new modules.We would then have one thread to monitor instead of two and would not have to excuse
for being off topic.What do you think, gentlemen?


:cheers:
Click to expand...
And don't think that Lars C. would be happy to see the 700XE entering his thread about the New class D module... But there is an old thread about the XE700 by Lars himself.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=61794&highlight=

Anyway, given the unclearness about the status of "my 700XEs" (are they fixed, or just original ones with the supposed fault?) it may take a while before I dare to connect them to my mid/high speakers (a VonSchweikert VR1 or later a CQuenze/Morel combo, bit too expensive). I will probably be testing the amp on a pair of 25 year old Akai speakers for a few weeks first to see if nothing bad happens. So comparing them with something else will not be easy at first.

Today I want to to do some modifactions to my (much too large) case. I bought a 3 mm thick alu plate (600*260 mm) on wich the modules and the predators will be bolted, The toroids and softstarts etc. are below that plate. It is a bit hot today however...
 
#291
Duck-Twacy said:
I will probably be testing the amp on a pair of 25 year old Akai speakers for a few weeks first to see if nothing bad happens. So comparing them with something else will not be easy at first.
Click to expand...


Good thinking, don't blame you. Have you any plans on testing the protection circuitry before making the big move with them, seeing as that was one of the issues..

Anzgar I think you're starting to see the problem now. Since Lars is not there and they are obviously not consulting with him on the module they're not benefitting from his past experience/knowledge. Whoever they do have couldn't fix whatever bug they had without a total redesign, and now they're saying they're complicating it by adding a second channel?!?

I'm imagining they're doing it with the intent of bridging them to reduce stress on the output stage.. I think Lars will have a module ready for you before you ever see anything from them.
 
#294
UCD's and ESL's

Hi Jan-Peter,

In regard to suitability of class D amplifieres to drive ESL's I would really like to know if further optimization of the standard UCD 180 or UCD400 modules is possible/feasable if the modules are to exclusively drive full range ESL speakers like ESL63, 988, 989 (they all have similar impedance curves/amplifier loads).

Regards,
Zvon
 
#296
Lars, sorry for being so specific (UCD's) in this thread. My question actually pertains to all class D modules available to DIY-ers in general including Zap's, 700XE & 800XE and your new modules.

At present I use a pair of older type 2.2SE's (with BG's) and ESL63's with success. However, these modules are made a wide range of different speakers, not optimised for a specific (ESL) type.

And for your information, another winter day in Perth, sunny, clear sky about 20degC.🙂

Regards
 
#297
Great, for once in history we have here in Denmark hotter weather than you guys, with 28 deg.

For driving ESL's i would say a Class D amplifier without DC servo would be preferable, since it has no subtle DC effects, from the delayed feedback of the DC servo. But of course no DC component must be present at the output. (< 10mV).

I don't know if a UCD has DC servo or not.
 
#298
UcD has NO DC servo!

For your ESL the UcD400 or the UcD700 would be the perfect choice because hereby is on the modulator mounted a DC-offset potentiometer. All amplifiers are adjusted to have a DC offset below 2mV. Supose you would bypass the coupling capacitors, you could readjust the DC offeset voltage to <2mV. Don't forget to short circuit the symmetrical input of the UcD module.

Cheers,

Jan-Peter
 
#299
classd4sure said:



...................
Anzgar I think you're starting to see the problem now. Since Lars is not there and they are obviously not consulting with him on the module they're not benefitting from his past experience/knowledge. Whoever they do have couldn't fix whatever bug they had without a total redesign, and now they're saying they're complicating it by adding a second channel?!?

I'm imagining they're doing it with the intent of bridging them to reduce stress on the output stage.. I think Lars will have a module ready for you before you ever see anything from them.
Click to expand...

They are designng a completely new stereo amplifier which is not based on Lars Clausens amplifier.Of course I am not willing to trade some 700XEs for it.
But as the 700XE still is on their site as soon in stock the talesman 'does'nt think' it has been taken out of production...
I'll buy a set of Lars' new modules anyway as soon as they become available.



:violin:
 
#300
I got a responce today from the LCAudio director:

"We have withdrawn 700XE from the market because it is not stable.Instead we introduce a stereo module 800XE which have very good specifications and is totally free from on/off bumps.
This amplifier is now used as BBC studio monitors and will appear at LCA's home site soon.":violin:
 
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