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Post by Deleted on Jun 1, 2013 13:18:40 GMT
Sorry Dave,
What Class A has your builder built for you?
Thanks.
Chong
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solderdude
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Post by solderdude on Jun 1, 2013 14:25:49 GMT
The 'AK class-A' on Will's PCB which is 'inspired by' the familiar Silicon Chip magazine design with the familiar modifications and add-ons.
The latest PCB has a small error on it where the schematic and layout were not coinciding.
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Post by Deleted on Jun 1, 2013 17:11:22 GMT
Thanks Frans, the 15 Watter SC Class A. Seriously, enough power, Dave?
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Post by Deleted on Jun 1, 2013 18:41:23 GMT
Seriously, enough power, Dave? Chong, with the appropriate speakers in the appropriate room, 15 watts could quite easily deafen you.
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solderdude
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Post by solderdude on Jun 1, 2013 19:05:58 GMT
90dB/W speakers will do 102 dB SPL BUT you have 2 of them thus 105dB @ 1m (think chainsaw at 2m distance level) The SPL drops about 6dB per doubling of distance (in free field) and less in a room due to reflections e.t.c..
So at 2m distance you will still have > 99dB SPL and at 4m this is > 93dB SPL which is still pretty loud think jack hammer at 2m distance. When one considers 85dB is a pretty LOUD listening level already and reflections in a room ensure the drop is less than 6dB/doubling of distance it will still be quite loud.
Also to play twice as loud 2 x 150W is needed.
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Dave
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Post by Dave on Jun 1, 2013 19:14:10 GMT
Hi Chong, To reinforce what Frans has said, my speakers are nothing unusual, namely Mission 774s, and I only use 15 to 20% of the available rotation on the volume knob in a 5m x 4m room. Cheers, Dave.
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Post by Deleted on Jun 1, 2013 23:52:40 GMT
Thanks everybody for furthering the understanding. I just ask as I formerly had 2 class T 10 Watters at 6 ohms driving a pair of 90+dB/W speakers in a vertical biamp configuration and they didn't have the oomph to play them in a dynamic way of my expectation. Heh, heh, another pair of speakers at 86dB/W similarly volume was pass 12 o'clock and I gave up not to say. After I changed to a pair of 125Watter at 8 ohms, the whole picture changed quite remarkably. The loudness is there but still not quite up the mark in dynamic expectation. Maybe I'm using a passive pre. But I don't like adding an active pre and going against the purist way. Perhaps, adding more S/N, distortion and phase thru an active pre may just cure my expectation.
Enjoy the music everyone!
PS: Sorry, forgotten to mention room size to get a better perpsective. 23' x 15'. Semi open with some windows open. Excuse me as lazy to convert to ISO measurement.
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solderdude
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Post by solderdude on Jun 2, 2013 7:00:40 GMT
I use 2 x 200W amps myself (+ 1x 200W sub). When I was running electrostats it was 2x200W (60Hz-150Hz fill in dynamics) and 2x300W (electrostats with about 85dB) + 1x 100W (sub) One of the amps has power meters (log type so it also shows low power) and under normal 'household' circumstances I rarely go above 1W. (89dB/W) Turning up the volco rapidly increases the output voltage (volco's are log type) and as soon as I get to serious levels I regularly have peaks above 20W.
So yes for serious listening (at 'realistic' levels) 15W is a bit on the small size and will limit the system in that it will be hard to throw a party with it. For background music it will sure be enough.
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Post by Deleted on Jun 2, 2013 7:23:01 GMT
I use 2 x 200W amps myself (+ 1x 200W sub). So as to make sure and scare to lose, I too have much power in reserve too. Current: 2 X 180W (stereo amps) at 6 ohms, 2 x 600W (mono amps) Class D subs in a vertical biamp configuration. Waiting for time and dose to do a triamp XO for a tri-amp system with the tweeter using a hybrid or tube mono amps. Must go disturb Chris, as he had bought the XO PCB some time back. Btw, Frans has you guided Chris to complete that XO kit. Never thought about it again until this interaction. That's what forums are good at when we interact constructively.
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