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In the Forum: Horn-Loaded Speakers
In the Thread: Deep End DIY - Australian take one Macondo.
Post Subject: A warning and disbelive...Posted by Romy the Cat on: 7/3/2017
 anthony wrote:
You can see the little 2-way standmounts that I am currently listening to behind which are the 'wings' onto which I will build the DSET.  

This is perfectly fine but if you willing to experiment with any low power SET (including Milq) then be very careful with this approach. Some of the small two way monitors have relatively badly defended tweeters. They are fine when you drive them with high power SS amps but driving them with low power SETs frequently kill the speakers. You see, when you drive the 90dB sensitive monitors with a few watts you drive the amp into clipping. You might not recognize it from listening (it take some experience to hear it) but as the clipping take place SET generate very nasty HF high order distortion that kill some tweeters topologies. The tweeter might not burn but rather gets very ugly “burned-type” of sound. Then the tweeters need to be trashed as it is not recoverable. So, by-amp only and do not use SET on your monitors.

 anthony wrote:
I've been in a conundrum with the preamplifier.  In the past I have never been happy with anything that I have tried and as a result have direct connected my dac to amplifier, but I do love my FM and find that if I have to change cables that I just stay listening to the source that is playing and don't listen to the other.  In desperation I managed to find a second hand Placette Active Linestage but when it arrived I was quite underwhelmed by the hit to dynamics and some problems with HF in particular.  As you may recall, the Placette does not have feet of its own (at least mine has no feet) and since I recently completed the audio rack I plugged the Placette back in and sat it on a towel and it does sound much more capable than I originally thought.  I am hoping that once I get it on one of my anti-vibration platforms that I will hear in it enough potential to persist with it and try to make it work better.  It is quite surprising how much difference the rack with damped shelves and the towel to further decouple it has made to the sound.

Sorry, I do not buy it. I do not deny the contribution of proper feet under a component of a popper isolation platforms but the difference should be not even near at the magnitude you describe. It cannot go from “underwhelmed” to “much more capable” if you put it on a better feet or into a better rack. If you are positive that the difference was as dramatic as you describe then I would look for other variables: like electricity change between two listening sessions or etc… Generally if the Placette works properly then it would be more transparent than any other component you have, at least it is my case, and it is possible that what you do not like in the sound of your power amp, front-end or anything else. It is hard to debug your playback remotely and I do not know what you use. You can very easy to conduct the Placette bypass test to confirm that it has no own impact. If you have a hit in dynamics and HF with Placette then you do want to experiment more with it as I feel you do not use then Placette properly. I did not see any preamp that do not eat dynamics …except Placette. As far as HF concern… the Placette runs video signal with low distortions, which is a few mHz!!!I personally do not find any problem with Placette HF with only exception of some “coldness”. It takes time to understand that the Placette coldness is not own coldness but a lack of the HF euphoria that we are so accustomed in hi-fi. Using less colored amps, tweeters, proper HF crossover, time alignment and cables will convert the “Placette coldness” into Placette’s neutrality. This is at least my finding. You might not come to the same conclusion, wish is fine. You might use any preamp of your chose but if you are going to go with Miq DSET filtration at the aps input then you would need a preamp the can drive a lot of current and that has VERY low output impedance. You will have difficulty with typical 200R-300R output impedance that is fine to drive a single loading resistor at the apm’s input. The Milq DSEt will have 6 filter by 30K each connected in parallel. You will need a VERY powerful output stage to drive all of it. The vest would be to have output impedance near 0R, kind of a short circuit, or a preamp with a positive current feedback but this is an exeriment for another day… :-)

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