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Dominick22

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I just finished a bi-amp design based on the LM4780 chip.

I finally got the cahoonays to really crank it and DOUBLE WOW! My Ascent i's sound better than they did at the Tweeter I auditioned them at.

There is no sibilance and the transients are literally spatially deceiving. The stage has increased to an almost enveloping degree. It is as if the surround sound is on!

I just can't describe it as anything other then surreal. I have tried so hard to get that perfect balance and life-like reproduction and I can finally say that I am satisfied! Truly!

Maybe it is becuase I built the amp with my own design goals-so I got what I perceive to be the best sound, but it is...to me!

I only wish I could here a high end Krell to compare!

Has anyone else had this kind of success?? Any other DIY'ers on here??

I have fallen in love with ML again!
Dominick
 

JonFo

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Hi Dominick,

Congratulations!

Sounds like you are achieving your goals.

Can you say a bit more about how you enclosed the amp, what you are driving it with, etc.

Also, what is the total current output of this amp and do you feel the current delivery is adequate for bigger ML's?

Thanks,
 

Dominick22

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JonFo,


The LM4780 is actually two 3886 amp chips in one package. Each 3886 will deliver 68 watts into a 4 ohm load. What I did was buy 4 LM4780's for my Ascent i speakers. I have each LM4780 paralleled to put out around 120 watts. So , essentially, both woofers and both panels are able to utilize there own source of 120 watts for a total of 480 watts between the two speakers.

I actually have noticed that many people use metal box's etc. to make the enclosure. This did not appeal to me, so I used cedar wood and plexi glass (clear). The Cedar comes from a source in Cali and was around $80.00. This is about the average of what people spend on some metal enclosure I think.

I do think that this amp drives these speakers incredibly and I will never buy another store bought amp...unless the Krells are superior...I have not heard a high end Krell yet! Even so, the cost difference is in the thousands. I spent less than $400 on this amp start to finish. And that includes many upgrades such as gold plated terminals, carbon pot, etc.

Currently, I am working on a snubber network for the bass amps to see if that further improves the sound. I will post the results when it is done. The nice thing is trying a snubber is cheap when you build it yourself. If I dont like it-then hello trash can!LOL

As far as driving larger speakers...How large? Which ones are you thinking about. And ultimatley, I probably could not say for sure. I will say that this is best amp I have heard on Ascent i's including in store demos so for a few hundred and for the sake of a fun project, it is worth a shot. If you dont like it on your ML's, I am sure you can find another more conventional speaker that they will do well with.

Not sure what you mean by what I am driving the amp with. I am using two toriodal transformers that are 22V and 450 VA each with dual secondaries.

I am considering making a Descent specific amp utilizing the same chip now.
If you are still curious, just ask. I would love to see another successful DIYer on here. If two people reported good results with this, we might start a trend on this site!LOL
Dominick
 
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