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In the Forum: Audio Discussions
In the Thread: The loudspeakers for a powerful SET
Post Subject: Following ....Posted by Romy the Cat on: 4/15/2008

 Gregm wrote:
It doesn't seem prudent to look at the speaker without considering the amplifier at all. We would be designing a speaker that would work with a theoretical amp -- but not one that's available.

You are right but the opposite is true as well:  it is difficult to design an objectionably performing powerful full-range SET without considering speaker, particularly the moment of LF section damping. It is not always the case the MF, HF and LF would require the same loading but it said by the person spoiled with DSET. So, in a case of powerful full-range SET we need to determine loading only by LF. Lamm ML3 had for those exercises adjustable feedback. I see it as a half-ass solution. My idea for my large amorphous LF DSET was to run tryfilar coil with one coil cares main impedance transformation and two smaller coils care 2% of impedance with ability to connect the supplements coils in phase and out of phase. BTW, it would be able a half-ass solution….

What actually might be fun to deal is some kind of impedance conversion mechanism on the speaker side. Pretend a large speaker with bass driver that has interchangeable voice coils. Scratch it - it would lead to crossover alternation but it might be some kind of impedance transformation devise on the speaker side… My point is that today large speakers are very expensive monster with 50K-100K price tags. Our cars cost as much, or perhaps even half of it but our cars have huge amount of on-board intelligence permitting us to get a lot of use from our cars under different conditions. The damn loudspeakers have 3-4 drivers and a wooden box. Why not to load the loudspeaker with some sound not-degrading intelligence? Why loudspeaker? I feel because if we put some intelligence to our powerful full-range SETs then SET imidetaly get converted into DSET and the idea of “powerful full-range” evaporates….

 Paul S wrote:
There are a couple of Gm70 SET amps out there that have 50 watts.

I do not think so. None of the commercial amps that I have seen use GM70 over 900V and it was the subject of my bitching for a while. With typical (and foolish) for GM70 use of 750-800 and 35-40W, the conventional 95dB sensitivity of load and average room size the GM70 will run deep into grid currents. In fact it is might be interesting to look how different powerful SETs deal with the A2 problems and with the compelling recharging. I just never looked careful in this direction as I tend to look toward higher sensitivity then toward to more power.

BTW, Lamm did some tricks most likely in his new amps. If you look at the pictures then ML3 has coupling capacitors between second and third stage rated at 1000V. This is kind of interesting. The GM70 let say minus 200V on grid and the 6H30 let say 200V on plate. That makes 400V necessary for the cap. The Electrocube that Lamm uses has 400V, 600V and 1000V caps. Why Lamm did not use 600V? Vladimir is a frugal guy and he would never go for overboard cap as he needs to keep the price of the amp under $136.000.

The caT

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