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Bi-amping KLF-20's

Mighty Favog

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Biamp means to defeat in internal passive crossover network and replace it with an outboard 'active' network and a separate amp for each (set of) driver/s. You would take a preamp output, route it to a low level active network which PRECISELY replicated the action of the passive network, then route the two or three signals from that active crossover to two or three separate power amps. From the amps to the drivers directly without going through any additional crossover networks. Benefits? Better dynamics, focus, detail etc. Chances to mess it up? Huge. Costs a lot. Very difficult to accomplish.

Passive biamping is done with a pre out going to two amps (since the speaker has two inputs lo and hi). Then go from each amp into the passive network of the speaker without the jumper straps between the two sets of speaker inputs.

Benefits are to be had, but not as great as with active biamp setup. Also the amp levels must be matched so as not to upset the tonal balance of the speaker.

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I wonder if your experimentation with using passive biamping to "level adjust" the two networks may have been born out of my inquiries about using passive biamping to tame the extremely hot highs on my KLF20's? I'm glad to hear you like the idea! I gave it a shot but must have wired something incorrectly since all I could get was the HF. Gave up until tonight when I tried something else.

Figuring I had messed up the Y-connector splits, I thought I would just try running the pre-outs on my NAD receiver directly to the main-in on my NAD3020 integrated just to test whether or not something was wrong with the 3020. It worked, and with some noticable improvement in sound. Then I tried the pre-out on the the receiver to the aux-in on the integrated and WOW! I was amazed at how my speakers suddently sounded like they're supposed to! TOTALLY different sound than the receiver. MUCH better balance, blend, and low and behold, the low end finally made an appearance! Almost too much low end on some recordings. Or maybe it just seems like too much relative to the total lack of it that I'm used to. Overall the sound was so much warmer and listenable. No more harshness. Then, since it was late and my son had just gone to bed forcing me to listen at very low volume levels, I tried the loudness botton on the integrated (blasphamy!) and was further amazed at how it brought out the fullness in sound at the lower volumes. What the heck does a loudness botton do anyway? For those purists out there who would never consider actually engaging a loudness botton I must wonder, if they're so bad why would NAD put one on the 3020 that was so highly rated? The receiver does not have one.

Anyway, I can only conclude one of a few of things; 1. The old NAD 3020 simply sounds better than my new NAD receiver by a long shot, proving that it's reputation is well deserved, and that amps really do sound different, or 2. The preamp section of the NAD 3020 imparts more or better tonal balance than the preamp section of the receiver (by the way, is it bad to be running a signal first through the preamp of my receiver then right into the preamp of the integrated via the aux-in, essentially double-preamping the signal?), or 3. There is something wrong with my receiver which is causing the signal sent to my speakers to be poorly balanced and lacking in fullness and low end, or finally 4. The cheap Walmart 16 gauge speaker cable I switched to for this experiment sounds far better than the expensive Kimber cable I normally use. Not sure I buy into the argument that cable makes that much difference.

So to get back to the original topic of this thread, now that I know my old integrated does indeed work, I will attempt the passive biamp setup again tomorrow. If I can finally figure out how to hook it up correctly, and since my two amps seem to have totally different tonal qualities, I think I'll try switching back and forth with one first on the HF, then on the LF to see which combo sounds better. I think I may be amazed! I, like Mdeneen, kind of like the idea of being able to level adjust the two networks to smooth the sound depending on the recording. If I can't get it to work I think I may permenantly bypass the amp section of my receiver in favor of running instead to the aux-in on my old NAD 3020. The NAD 3020 has another connection right next to the main-in called a lab-in. Can anyone tell me what that's for?

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I finally got the passive biamp thing to work...but didn't like it. I have finally settled in on pre-out from my NAD C740 receiver to the aux-in on my NAD 3020. I chose this setup for the following reasons;

1. I couldn't get good sound with any combination of amp/HF/LF/wire combination with the biamp setup. I also had a problem with some serious hum with the biamp setup. Hope I didn't damage anything! Still can't help thinking something is seriously wrong with my C740 receiver since I don't think it sounded this bad when I first got it.

2. Although I got better sound than the receiver by going to the main-in on the 3020, I chose to go aux-in instead as it offers the opportunity to take advantage of the 3020's apparently superior tone controls, loudness button, and warmer top end.

This has yielded by far the best sound yet from my KLF20's. Sort of disappointing that it's so much better than the C740 since I could have saved myself some time and money by simply utilizing my old 3020 and buying a separate receiver instead. Again, there MUST be something wrong with the C740 since I swear it sounded better when I bought it! The only drawback to the 3020 is the rated power of 20wps, although my listening levels will rarely if ever push it anywhere near the limit.

Mdeneen, you say that most receiver amp sections are just okay, with emphasis placed on power rather than sound. However, NAD's design philosophy is founded on countering exactly that weakness with most manufacturers. They focus on sound first and believe that most power ratings are, well, overrated. It's not continuous power rating that matters, it's the ability to deliver the short bursts as needed. You won't see huge continuous power ratings on NAD equipment, but they claim their units have the ability to deliver short bursts as needed far beyond the continuous power rating. So, while I did get better sound quality by routing directly through the amp of my 3020 instead of the receiver amp, the REALLY BIG gain in sound came when routing through the 3020's preamp via the aux-in. Would this suggest there really isn't much difference in the amps on the two components, but a huge difference in what the preamp sections are doing to the sound? Again, anybody see any equipment-damaging reasons why I shouldn't be running pre-out on the receiver to the aux-in on the integrated? Seems like double-preamping to me, but it sure sounds good. Could the two stage preamp be filtering the sound in a way that sounds better? Surpressing the high end a little by going through so much circuitry?

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Try running from the Tape Output on your receiver then into the Aux input on the integrated. You won't have the tone, volume, balance controls of the receiver affecting the signal. At that point, only the preamp controls on the integrated will be in the signal path. Should sound better.

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