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partyjups 25th January 2002 09:30 PM

Magnatec class d amp sulution
Hi I just wonder if any one have used this class d sulution
from magnatec.
they cost as follows if you have a registred company.I belive,
SDV1015-600 (600Wrms amplifier module) cost 102 each for a batch of 10
SDV1015-600 (600Wrms amplifier module) cost 69 each for a batch of 100

SDV1015-300 (300Wrms amplifier module) cost 71 each for a batch of 10
SDV1015-300 (300Wrms amplifier module) cost 48 each for a batch of 100

So It,s not very low cost.

I have an application note from magnatec with some interesting
circuits that for protection / compresion

but don't know how to attach it here but i can sent it bye e-mail if any one is interested.

subwo1 26th January 2002 12:13 AM

One reason it is so expensive, I suspect, is that each amplifier is basically two amps bridged together. The audio is output out of phase, while the switching frequency is output in phase so as to cancel at no load. When the input audio is increased, the switching frequency at the speaker increases with the audio.

With a standard Class D configuration, using only one amplifier, the switching signal is at a maximum when the audio is 0. By the way, Tripath uses neither of these methods as far as I can tell, but I think the way Magnatek does it is similar to the way the Texas Instrument's TDA200X series does it.

km 26th January 2002 05:46 PM


why do you think its expensive?

i mean compared to say the b&o or the lc audio modules.

full bridge amplifiers do not have to be more expensive than half bridge ones , the lc audio is half bridge and seems much more expensive to me :)

yes please email me the memtioned applications.

and feel free to contact me (again) directly if you have soecific questions regarding class-d amplifiers.

bye k madsen -

ps. didnt you order the lc audio modules you talked about a couple of months back?

silvermoon 1st September 2004 11:09 PM

These amps are brilliant!
I've been using one of Magnatec's 600W modules in a bass guitar amplifier for onstage use for a little over a year now. It has run faultlessly night after night with some 'robust' handling from the roadies! I run it into 2x Ashdown 600W 4x8" cabs at 4ohm load.

I used to use a Peavey 450W amp that was heavy and expensive, and I will now never go back to analogue amps! The difference in sound with the new Magnatec amp is amazing - in particular the bass end is MUCH punchier and clearer.

I contacted Mr Bacon at Magnatec to discuss options when I bought the unit and I ended up buying the module that is described in the application note you mention, complete with all protection circuitry around it etc. It came mounted onto a little bracket/chassis with speakon and neutrik connectors (nice touch). I also bought the matching power supply.

Compared to the cost of equivalent systems, this was extremely cheap! It is also incredibly small and light, fitting neatly into a 1U 19" rack case, and weighing in at under 3Kgs (better than the Peavey's 26Kgs!).

Call Magnatec now, and get one of these systems to try out - they're absolutely fantastic!


phase_accurate 2nd September 2004 01:46 PM

I know that one should not make any judgement from specs alone. But switching amps that take feedback directly from the output stage shouldn't be built or used. They are hopelessly outdated ! ;)

And there are in fact cheaper solutions around that don't have to be bought in multiples of ten pieces !



silvermoon 2nd September 2004 04:07 PM

Hopelessly outdated? Anything older than a year or so in the electronics industry is outdated, and anything older than about 30secs in the audio industry is the same! However, these amps work - they sound good - they're 'affordable', and they're easy to get hold of. Just because something is old, does that mean it 'shouldn't be built or used'. How about valves? They too are surely 'hopelessly outdated' although they are obviously still very much in demand! Of course, the audio industry is proliferated by opinions - this is just mine.

Also, please note that as I mentioned: I bought ONE of these units, not 10.

You say that other cheaper options are available. Please let me know where since I am yet to find a comparable system that offers better value.

Best regards,


P.S> No I am not affiliated with Magnatec, I am just very pleased with their product!

Jan-Peter 2nd September 2004 04:29 PM


Pehaps you wants to take a look on our products;
UcD180 - 180W at 4 Ohm
UcD400 - 400W at 4 Ohm

In this thread has Dan Fraser made a review;

This Class-D amplifier has feedback right after the outputchoke and a low impedance of <0.010.



silvermoon 2nd September 2004 04:58 PM

Thanks for the info - these look good. Some quick questions though:

1) Any heatsinking required for continuous operation (at maximum power) ?

2) Any plans for a matching switchmode power supply? Weight is a prime concern so a largbe toroid is simply out of the question.

3) Any plans on releasing a higher power version?

Many thanks,


Lars Clausen 2nd September 2004 05:11 PM

km: I see my name being mentioned :D I have looked with great interest on the Magnatec page referred to above, it looks neat.
I would say the SDV1015-600 compares more or less with our ZAPpulse 2.2SE.
Our solution costs 123.18 (@1 pcs) compared to Magnatec's 102 (@10 pcs) (quoted from above). So Magnatec is cheaper than our card.

But then our module includes:

1..the output filters, and also effective short circuit protection. The high temperature shutdown has proven worthless, as it works much too slow in case of a short circuit of the output. Further we also include a
3..DC servo to keep the DC level under 20 mV, so the module is suited for electrostatic speakers like Quad ESL or any Martin Logan model.
4..Our module will drive 2 Ohms loads (And even 1 Ohms loads!) without parallelling 2 modules.
5..You don't need to add the +/-10V supply for the inputs, with a ZAPpulse like you need with the Magnatec's.

All in all i don't think our solution is all that expensive km. At least not when compared with other options. And should you wish to buy 10 or 100 units, i will surely match these prices listed above ;)

Phase Accurate: Did you ever build anything in the real life, or just comment on everybody else's work? I don't think your comment on Magnatec's modules is quite justified. The reason why we or Magnatec or many other's use the feedback directly from the output stage is not, that we are too dim, old or outdated to take it after the filter coil. :D It might be because we have good reason to believe it's a better solution.

Jan-Peter: Very interesting, what is the switching frequency of your UcD modules?

All the best from


Jan-Peter 2nd September 2004 05:14 PM


Ofcourse you need some cooling, all Class-D amplifiers have an efficiency of 90%-95%. For a bass guitar an aluminium plate of 15x15cm will be enough.

At the end of the year we will have available something between 700 to 1000W.

At the moment we have no plans for a SMPS. SMPS are still less reliable as with a traditional toroidel transformer and not to forget the price is much higher.



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