LC Audio ZapPulse modules: Worth it? Anyone use?

kidder · 9th April 2003, 02:11 AM

Greetings,

I was wondering if anyone here has used or heard the LC Audo ZapPulse modules.

Are they truly suitable for high end audio reproduction?
Does midrange and high frequency reproduction suffer?

I'm sure quality of power supply construction would be a variable.

Also, I've noticed that http://www.lcaudio.dk sells one version of the module for $193 US. While http://www.diycable.com sells what appears to be a different version of the module for $150 US.

Any info about these modules (or alternatives) would be appreciated.

Best regards,
Keith

phase_accurate · 9th April 2003, 07:22 AM

The one shown at DIY cable is the older version of it while the one shown on the LCaudio website is the latest one.

I haven't had the opportunity to listen to one so far. One thing that is disturbing to me is that they use a first-order filter at the output.

I would feel more comfortable with a filter of 2nd order at least.
Nowadys enough feedback techniques are known that would allow to even take feedback after the output filter.

The newer version of the amp is using a ferrite core with a large airgap for the output coil. This will be an advantage to the first version regarding EMC.

But the THD figures they state do still not look like those of a masterpiece. Though one still has to hear it to make a proper judgment.

Regards

Charles

AndersP · 9th April 2003, 12:30 PM

After reading the handbook ( in Danish ) I learned that the output filter is indeed a second order. The big coil works together with an MKP cap.
I haven´t auditioned this amp myself but most customers are very plased, as I understand it, from the forums that I attend.

phase_accurate · 9th April 2003, 12:36 PM

So they improved on this as well. The former documents showed only a series output inductor.

Regards

Charles

/who is a fan of switching amplifiers

UrSv · 9th April 2003, 01:21 PM

I think that there are two versions of the new one as well. One is with Black Gate VK caps.

AndersP · 9th April 2003, 02:04 PM

Charles: To my knowledge, the cap was always there, as this is the handbook of the " old " module. The schematics they publish are very scatchy and for basic product information only as they claim to have some corporate secrets and stuff to protect. Some of the pictures of the modules on their homepage are also " treated " for the same reason.

phase_accurate · 9th April 2003, 02:33 PM

That would explain some things: The 80 uH coil they stated in their first "manual" would never give an upper cutoff frequency of 80 kHz into 8 Ohms that they claimed. If you add a capacitor things look different of course.

I have seen that they even made an IC unrecognizable that I assume is the driver or even a combined modulator/driver.

I think that the circuit is quite straightforward and that it would be quite easy to copy (and also develop) except the PCB with vias.

Regards

Charles

AndersP · 9th April 2003, 02:44 PM

Yes, it probably wouldn´t be that hard. They have a Q & A on their homepage also. Some of the customers posted quite funny black epoxy on cicuit board-questions on that board I remember.

9th April 2003, 02:11 AM	#1
kidder diyAudio Member Join Date: Mar 2003 Location: Albuquerque, NM, USA	LC Audio ZapPulse modules: Worth it? Anyone use? Greetings, I was wondering if anyone here has used or heard the LC Audo ZapPulse modules. Are they truly suitable for high end audio reproduction? Does midrange and high frequency reproduction suffer? I'm sure quality of power supply construction would be a variable. Also, I've noticed that http://www.lcaudio.dk sells one version of the module for $193 US. While http://www.diycable.com sells what appears to be a different version of the module for $150 US. Any info about these modules (or alternatives) would be appreciated. Best regards, Keith

9th April 2003, 01:21 PM	#5
UrSv diyAudio Member Join Date: Jan 2002 Location: Sweden	I think that there are two versions of the new one as well. One is with Black Gate VK caps. __________________ UrSv Those who say it can't be done should not stop those who are doing it.

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9th April 2003, 07:22 AM	#2
phase_accurate diyAudio Member Join Date: May 2002 Location: Switzerland	The one shown at DIY cable is the older version of it while the one shown on the LCaudio website is the latest one. I haven't had the opportunity to listen to one so far. One thing that is disturbing to me is that they use a first-order filter at the output. I would feel more comfortable with a filter of 2nd order at least. Nowadys enough feedback techniques are known that would allow to even take feedback after the output filter. The newer version of the amp is using a ferrite core with a large airgap for the output coil. This will be an advantage to the first version regarding EMC. But the THD figures they state do still not look like those of a masterpiece. Though one still has to hear it to make a proper judgment. Regards Charles

9th April 2003, 12:30 PM	#3
AndersP diyAudio Member Join Date: Aug 2002 Location: Middle Sweden	After reading the handbook ( in Danish ) I learned that the output filter is indeed a second order. The big coil works together with an MKP cap. I haven´t auditioned this amp myself but most customers are very plased, as I understand it, from the forums that I attend.

9th April 2003, 12:36 PM	#4
phase_accurate diyAudio Member Join Date: May 2002 Location: Switzerland	So they improved on this as well. The former documents showed only a series output inductor. Regards Charles /who is a fan of switching amplifiers

9th April 2003, 02:04 PM	#6
AndersP diyAudio Member Join Date: Aug 2002 Location: Middle Sweden	Charles: To my knowledge, the cap was always there, as this is the handbook of the " old " module. The schematics they publish are very scatchy and for basic product information only as they claim to have some corporate secrets and stuff to protect. Some of the pictures of the modules on their homepage are also " treated " for the same reason.

9th April 2003, 02:33 PM	#7
phase_accurate diyAudio Member Join Date: May 2002 Location: Switzerland	That would explain some things: The 80 uH coil they stated in their first "manual" would never give an upper cutoff frequency of 80 kHz into 8 Ohms that they claimed. If you add a capacitor things look different of course. I have seen that they even made an IC unrecognizable that I assume is the driver or even a combined modulator/driver. I think that the circuit is quite straightforward and that it would be quite easy to copy (and also develop) except the PCB with vias. Regards Charles

9th April 2003, 02:44 PM	#8
AndersP diyAudio Member Join Date: Aug 2002 Location: Middle Sweden	Yes, it probably wouldn´t be that hard. They have a Q & A on their homepage also. Some of the customers posted quite funny black epoxy on cicuit board-questions on that board I remember.