Amp kits with lower sensitive speakers

marcus1 · 23rd December 2010, 05:46 AM

I'm thinking about buying either the LM3875 or LM4780 kit to power my less sensitive 85 dB/watt speakers but have read that GC's in general work best with speakers in the 90 to 95dB range. I asked Peter the same question and he replied:
"LM3875 will work with your speakers, but it's hard to predict the results. You may also consider LM4780 which will deliver double the current and can be also supplied with premium resistors. Soundwise, they are very close".

I don't have much experience with GC's so would be interested to know if anyone else has had the chance to try out AS kit amps with lower sensitive speakers such as mine and what your thoughts are.

Hmmm....what about bi-amping my speakers with either of the amps - would this help negate the sensitivity issue?

Thanks

Tim (marcus1)

Peter Daniel · 23rd December 2010, 01:09 PM

I just did a quick google search and this thread came up: What are the best speakers you've heard with a gainclone? - Page 2 - diyAudio

Colin · 24th March 2011, 08:57 PM

The LM3875 is 50 watts or so - or 17dB over 1 watt. So with 85dB speakers you'll get 102dB at one metre. You're using two speakers in a room but sitting farther away so the levels won't be too far off that. Maybe a little low for peaks in the music.

Doubling up to bi-amp won't add a huge amount to speakers which cross in the 2-3kHz range as most of the musical energy will be in the bass-midrange driver. the treble amp won't be contributing much.

I'm looking at similar issues. I'm hoping to go active, which will get rid of the power-sapping crossover and give more control. (In my case, the drivers will cross at 300-500Hz so the benefit of two amps is more real.) But the higher power amp for the bass may be a good idea in any case.

I've been using some actives recently and one of the things I like about them is the sense of limitless headroom and no vague sense of strain on musical peaks. this is even when the average listening level doesn't seem too high.

Can we have an active crossover kit please, Peter?

23rd December 2010, 05:46 AM	#1
marcus1 diyAudio Member Join Date: Jul 2004 Location: New Zealand	Amp kits with lower sensitive speakers I'm thinking about buying either the LM3875 or LM4780 kit to power my less sensitive 85 dB/watt speakers but have read that GC's in general work best with speakers in the 90 to 95dB range. I asked Peter the same question and he replied: "LM3875 will work with your speakers, but it's hard to predict the results. You may also consider LM4780 which will deliver double the current and can be also supplied with premium resistors. Soundwise, they are very close". I don't have much experience with GC's so would be interested to know if anyone else has had the chance to try out AS kit amps with lower sensitive speakers such as mine and what your thoughts are. Hmmm....what about bi-amping my speakers with either of the amps - would this help negate the sensitivity issue? Thanks Tim (marcus1)

23rd December 2010, 01:09 PM	#2
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	I just did a quick google search and this thread came up: What are the best speakers you've heard with a gainclone? - Page 2 - diyAudio __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

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24th March 2011, 08:57 PM	#3
Colin diyAudio Member Join Date: Aug 2003	The LM3875 is 50 watts or so - or 17dB over 1 watt. So with 85dB speakers you'll get 102dB at one metre. You're using two speakers in a room but sitting farther away so the levels won't be too far off that. Maybe a little low for peaks in the music. Doubling up to bi-amp won't add a huge amount to speakers which cross in the 2-3kHz range as most of the musical energy will be in the bass-midrange driver. the treble amp won't be contributing much. I'm looking at similar issues. I'm hoping to go active, which will get rid of the power-sapping crossover and give more control. (In my case, the drivers will cross at 300-500Hz so the benefit of two amps is more real.) But the higher power amp for the bass may be a good idea in any case. I've been using some actives recently and one of the things I like about them is the sense of limitless headroom and no vague sense of strain on musical peaks. this is even when the average listening level doesn't seem too high. Can we have an active crossover kit please, Peter?

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