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Old 13th August 2011, 02:13 AM   #861
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Quote:
Originally Posted by sofaspud View Post
Because there is a need for it, and it's well-designed.

If you think you can match that output with the Lepai and the Polk speakers, let no one stop you. I've been contemplating a 2nd sub for my system, diy style.

Duly noted. I wouldn't intentionally steer you wrong.

I mentioned the Dayton's in the context of running them with a sub. If you just want 2.0, the Polks are fine and at a great price. I have some Polk speakers on another PC, and heaven knows I've gotten lots of mileage out of them.

Sorry, I never meant to imply anything of the sort. My point was just that if we're gonna talk purity, the Lepai needs to be coupled with a very efficient pair of wide response speakers. Big budget speakers mostly.

I agree it should. It and thoughtful speaker placement can go a long way IMO.

Not at all. Sorry if I seemed to antagonize. The Lepai sounds surprisingly good when kept below clipping. It should drive the Polks to moderate SPLs. Probably not rattle-the-room SPLs, but a decent system that you can live with and expand upon. Let us know how it comes together.
You hit the nail on the head. I think I'll purchase the speakers and Lepai amp, but one more thing, I've heard remarks that the Lepai makes a loud "pop" sound when turned off (and on?), should I be worried about this?
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Old 13th August 2011, 04:25 AM   #862
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Default Where oh where is my lepai

Howdy - I got mine from Alibaba! Checkout Alibaba dot com for about 1,000,000 things to buy for peanuts. I recently purchased a 2020 class T amp, a 7" Android tablet and a fob watch (why?) for less than AU$100.00. Unreal!
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Old 13th August 2011, 05:56 AM   #863
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Quote:
I've heard remarks that the Lepai makes a loud "pop" sound when turned off (and on?), should I be worried about this?
From what I've seen and experienced, this was a problem with earlier versions of the Lepai (the thru-hole models in particular). But there seems to have been some redesign and it is no longer an issue. I've never experienced the on-off thumps with mine. Apparently the first? fix was simply to put the Tripath chip in standby mode when switched off, leaving power to (most of) the rest of the circuit. Whether that remains the case I don't know. I haven't taken a DMM to mine. I think they use a relay delay on the outputs now, though.
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Last edited by sofaspud; 13th August 2011 at 05:58 AM.
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Old 13th August 2011, 08:19 AM   #864
meeotch is offline meeotch  United States
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Just bought a 2020+ for a trip to the desert in about a week. Will be running off 12V SLA battery. The amp sounds pretty good & loud in my apartment, driving an old set of Cambridge Soundworks Ensemble II satellites + sub. 6 ohms - I'm not sure what the sensitivity is, but I don't think it's very good. But I can't take these speakers with me to the desert...

Can anyone suggest speakers that are 1) efficient / low impedance, 2) cheap? (Like really cheap - less than $100 pair, used is o.k.) I'd like to find something that sounds at least as good as these Cambridge sats/sub, with equal or better bass & volume when driven by the Lepai.
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Old 13th August 2011, 08:58 AM   #865
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Replying to myself, since edit window seems to have expired.

How about something like this: Amazon.com: Pyle-Pro PADH879 - 300 Watt 8'' Two-Way Speaker Cabinet: Musical Instruments Pyle Pro PADH879

8 ohms, but the sensitivity seems good. A reasonable choice for outdoor use?

Or these: Amazon.com: Pyle Home PDWR50B 6.5-Inch Indoor/Outdoor Waterproof Speakers (Black): Electronics

4 ohms, 95dB
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Old 13th August 2011, 09:17 AM   #866
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I have it on good authority that you want the The Boominator - another stab at the ultimate party machine thread.
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Old 13th August 2011, 09:26 AM   #867
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Thanks for the reply. But isn't that thread specific to projects using separate drivers and building them into a homemade cabinet? Unfortunately, I don't think we've got the time to do any of that... Hence the question about pre-built speakers / PA cabinets that would pair well with the Lepai 2020.
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Old 13th August 2011, 07:56 PM   #868
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Lightbulb Tone control mod for center-level response.

There are a lot of comments on the tone controls in the original LP2020 degrading sound quality, and an analysis shows why - The component values are weird. In fact, with the original model's values, no control setting gives a level response. Putting textbook values in makes a huge difference to sound quality, even without bypassing the tone stack.

Bass control:
Change the 47n pair (green, between pots) for 100n
Change the 1.5k pair (behind the bass pot) for 1k.

Treble control:
Upper capacitor should be 1n, lower cap should be 10n.
These are usually OK. But, check.

On the TA2020's opamp input pins 9/10/12/13:
Change the 8k2 pair for 27k
Change the 22k pair for 68k
These should be metal film to keep noise low. They are located in two pairs between the pots and the chip.

You can experiment with the rolloff frequencies by changing the caps, just keep them in a 1:10 ratio for correct action. For a finer adjustment range with good speakers you might prefer 470p/4n7 and 22n/220n.

Not sure if this applies to the new SMD model as I don't have one yet.

BTW, if you have a bad switch-on thump, ohmmeter the ground lines under the chip for cracks. Particularly the one which goes via a heatsink mounting lug.
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Old 14th August 2011, 11:51 AM   #869
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Lightbulb Additional thoughts..

You can use this 'center-level' mod with DrLex's tone stack if you prefer.
In that case, retain DrLex's values and only change the TA2020's opamp input resistors:
8k2 pair for 47k (instead of 27k)
22k pair for 120k (instead of 68k)
Reason; the 10k center resistor demands that these values also be higher.

Superbass mod:
If the bass range is still insufficient, for each channel handwire a 10n capacitor and 150k resistor in parallel, and then place this assembly in series with one end of the 20k/22k feedback resistor of the 5532 preamp.

Not one for the purists but makes for a much rounder sound with high-sensitivity speakers. Be aware that your max undistorted volume will be less than without the mod (general rule of this universe says you can't get anything for nothing!) and that running into distortion is not good for your speakers.
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Old 14th August 2011, 04:06 PM   #870
meeotch is offline meeotch  United States
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Anteaus - I've found that my Lepai 2020+ sounds pretty reasonable with the ton controls engaged (mostly to boost the trebel), but quite "tin canny" with them disabled. The problem, of course, is that with the controls engaged, I can't turn the volume up past halfway without distortion.

Which, if any, of the mentioned mods will allow the tone controls to be used while getting more volume out of the thing? Is there something specific to the tone controls that cause this problem, or is it just a general amp mod that's needed?
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