Bi-amping????


Can I use 2 NAD 2200 amps(Continuous 100 watt) as mono-blocks sending split left and right signals to each amp then use both L&R terminals on each amp to send to Paradigm Monitor 11's V.3
Sensitivity -- Room 91dB 94dB / 91dB
Suitable Amplifier Power Range 15 – 250 watts
Maximum Input Power 180 watts**
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dlewallen
Certainly, if the speakers have 2 pairs of input terminals. Some will tell you that this kind of passive biamping does no good and isn't worth the price of the extra pair of speakercables, but it's certainly worth trying.

BTW it's 'biamping', with no hyphen.
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Thanks,They do have 2 pairs of input terminals, I have waited on my children to get older before I started a 2 channel system again, I can't afford tube mono blocks So I see I have the chance to purchase 2 nad 2200, I started thinking why could I not use them that way. But I did not want to melt them down so I wanted someone who knows more about it to give me their opinion.
What you are describing is vertical biamping. Take 2 identical 2 channel amplifiers and use one channel of one amp for low frequency output to a certain speaker and the other channel of that same amp for high freq. to the same speaker. You mirror the setup for the other speaker with the 2nd amp.

If my thinking is coherant today, you either need to have 2 preamp outs from your preamp (2 right channel outs and two left channel outs), or some way to bridge the amp input signal to both channels at the amplifier (some power amps have this capabilty with a jumper or switch), or you will need "double terminated" (there is a proper term for these) interconnects from your preamp to the power amps.

Even passive biamping made a tremendous difference in my system compared to using the stock jumpers or a biwire setup. I have Magnepan 1.6's (hard to drive) with Arcam Alpha 10 amplifiers (modest power of 100w into 8 ohms).

It is definitely worth a try. If you think it through before hooking everything up you shouldn't do any damage. If you turn the gain all the way up, there is no guarantee that the speakers will handle the load though. That is a different question.

Jim S.
Thanks for your help jim, I purchased a nad pre-amp/tuner 1600 on ebay item #250060026348, and a nad c521bee cd player. I will not receive the pre-amp until the 28th. You described exactly what I am trying to do, although i am not sure if the pre-amp has 2 pre-out outs, but if it does not then I assume I will have to make some sort of 2 into 1 split to run to each amp. I am jealous, I too once had a set of maggies with jolida tube mono blocks and I sold them in the early 90's(wish I never had) The sound was very sweet.

I am curious however(may not know what I am talking about here) when Paradigm says 15-150 watts 180 max. does that mean bridged. Another words when I hook up high side from speaker to one channel on amp and Low side on same speaker to another channel on amp that is continuous 200 watts to speaker, I know it is not going to same speakers with-in the speaker but that is not too much for that rating is it?

Thanks
David
David,

If I understand your question, no, that is not going to double the power into the speaker. I am going by what I have read (here and other places) and gleaned from studying associated literature, I am not an EE, but this is my understanding.

There is an amplifier bridging technique that puts both channels of the amp in series, doubling, or exponentially increasing the power of the now mono amp. Some amps are designed for this (Classe') and some will get unstable (my Arcams).

What you are trying to do is not that kind of bridging. You are trying to duplicate the preamps output into two channels for each side (and "bridging" may be an incorrect term in this circumstance). You may have impedance issues, duplicating the preamp signal into two inputs, that will affect the sound (tilt it one way or another) but I don't know enough electronics theory to predict the outcome using your components. I can't imagine it causing any damage.

What vertical biamping is supposed to do in a passive or active configuration is reduce the load on the amp power supplies. The bass generates the heavy load and that load is now divided between the two amplifliers. Most amplifliers use a single power supply to drive both channels.

What I meant by "if you turn up the gain" is the Paradigms seem fairly efficient and might not take full power from the amps. Don't turn it up all the way at once.

There are a lot of folks here that really do understand the theory behind these concepts and you can requery if you have concerns.

P.S. - don't forget to remove the jumpers on the speaker terminals.

Jim S.
Passive biamping with a 100x2 amp is not like sending 200 watts to your speaker - it's merely a very common misconception.

The usable power going to your speakers is really still only 100wpc since that is the maximum power dictated by the voltage swing available from the amplifier.

Now, OTOH, if these amps can be bridged you would have a meaningful increase in output voltage swing as bridging operates the channels inverted from each other. When the channels operate inverted you get up to twice the voltage swing and twice the voltage swing means 4x power - provided the amp's power supply can keep up, that is.
The reason I question the power to the speaker is because Reproducing musical signals, the NAD 2200 routinely delivers over 500 watts per channel into typical
loudspeaker impedances the 2200 is a very conservatively rated 100 watts/channel power
amplifier that has an extraordinary +6 dB of dynamic headroom, meaning that it can produce more than
four times its rated power during musical transients.the unique PowerTracker control circuit
(patent pending), which automatically adjusts the amplifier’s maximum power output according to the
dynamic character of the signal that is being amplified. As befits a product designed for the
reproduction of music, the NAD 2200 achieves its maximum power output of 400 to 800 watts per
channel when amplifying wide-range musical signals that contain peaks IO to 20 dB above the average
level. But when the amplifier is fed a high and constant signal (i.e. a sine-wave test tone instead of a
musical waveform), its maximum output automatically declines to avoid overheating, and eventually
levels out between 100 and 200 watts per channel.

As far as the power it has two power supplies, switching to the
high-voltage supply when maximum power is needed, and switching to the lower-voltage supply for
cooler operation at average power levels. (The switch is called a commutator; hence the name for this
type of amplifier.)

What is the difference between passive biamping and vertical?
In most general discussions, passive biamping refers to using the speakers internal crossover vs an external crossover - although there are external passive crossovers too.

Vertical biamping refers to using the left and right outputs from one amp driving their own section of one speaker.

Horizontal biamping refers to using the channels of one amp for the lows of the left and right speaker, and then another amp to drive the mid/highs of the left and right speakers.

Don't worry about the power, you are making much ado about nothing. The cardinal rules are turn it down if the speakers start making strange noises, or if the sound takes on a harsh and or flat, non-dynamic sound.
Passive biamping means that you still use the speaker's "passive" crossover. The amps receive the full-range of the signal from the preamp and feed this to either the mid-high or the woofer section of the speaker. The spkrs' internal crossover then attenuate part of the frequencies as required.

"Active" or "line-level passive" crossing is when you split the signal BEFORE the amplification channels. Then each amp channel amplifies only the frequencies required for the drive units it's connected to -- i.e. low frequencies go to the woofs, etc. This is much better as the amp is directly connected to the drivers.

"Vertical" is just a way of connecting the amps to the speakers -- 'vertical" being when you use one channel for bass and the other for the mid-high section of spkr (i.e. it's vertical).
I take it that active biamping is better because it is less work for the amp because is not having to reproduce full range?

Would you need a certain Pre-amp with that capability?
I appreciate all you guys help, many questions have been answered.

Thanks Again

David
I passive biamp myself and use one amp in stereo for the LF and one for the HF. Even though there is no active crossover before the amp and the amp is sending all frequencies to the speaker the amp is only "loaded" at the frequencies the crossover limits. Although I didn't need the extra power of the second amp there was a sound improvement in my setup. I have biwirable speakers. As a former owner of an NAD 2200 I can't stress enough to remove the crappy stock hard wired power cable and replace it with something good. When I did it I went right to the fuse/transformer and bypassed the switch (when you open it you will see why) and used a power conditioners switched outlets as the power switch. HUGE improvement! I wouldn't try bridging, also aren't your speakers 4-6 ohms and not 8? You don't want to bridge that amp with a load under 8 ohms. I think you will like the sound best when one amp is loaded by the woofers and one by the top end. Let us know. And really change those cords!

ET

ET
Whoaru99 and Gregm have filled in some of the gaps. I have learned a little more myself.

Here is a popular link to an explanation of biamping and passive vs. active crossover configurations.

http://sound.westhost.com/bi-amp.htm

Having too much power is not necessarily a problem, just use it judiciously. It gives the amp "headroom", allowing for a lot of sound without stress on the amp. It will keep the amp from clipping at higher volumes which destroys tweeters.

My little Arcams don't create enough juice to hurt the Magnepan tweeters. The 1.6's also have a fuse in line with the tweeter section. I am not sure the Paradigm does.

Hope this makes sense?

BTW - The next thing I want to do is add an active crossover. This will allow me to bypass the passive crossovers, which seem to be generally regarded as a weak link in the 1.6's. It should also lessen the load on the Arcams, allowing them to do the best they are capable of.

Happy Holidays

Jim
One of the biggest benefits of active biamping is being able to tailor the amp to the specific needs of the speaker section it is driving.

For example, in an active biamp situation, if the mid/hf section requires 50 watts and the low section requires 200 watts, then a 50 watt amp and a 200 watt amp are all you need. This works because each amp only has to be sized to match the voltage swing necessary for the filtered range of frequencies being amplified.

In contrast, in the typical passive biamp arrangement, if you are using a 200 watt amp for the lows, you also need (should have) a 200 watt amp for the mids/hf. This is because even though the mid/hf amp is actually using only a small percentage of power from that 200 watt amp, that mid/hi amp still has to be capable of reproducing the entire voltage swing of the full range/unfiltered signal. If it cannot because a smaller amp is used, the waveform to the mid/hi will clip before the amp driving the low will clip.
Only information I have on the Paradigm monitor 11's is that they are"compatable with 8 ohm". The crossover built into the speaker is 3rd-order electro - acoustic at 2.0kHz; 2nd order electro - acoustic at 600Hz (lower bass drivers).
On the web site jim mentioned( sound.westhost.com/bi-amp.htm) they say most common question I get is ...

"Do I need to disconnect the passive crossover in my speakers?"
The answer is ... Yes, otherwise you are not really biamping at all.

If this is true then you literally straight wire your speakers to the terminals? taking out passive crossover in speaker? If so then do you use electronic crossover with same frequency as passive(out of speaker?) and where do you run the electronic crossover? before power amp?
Yup, pretty much straight from the amp to the drivers.

Not necessarily take out the passive crossover, but at least bypass it.

Yes, electronic crossover or sometimes passive crossover before the power amps so they only amplify a limited range of frequencies intended for the specific drivers.

To do it is often not very practical or necessary (IMO) for most home audio situations. The crossovers designed these days for good speakers work pretty well. I think it would be hard for the average person to improve upon the built in passive design in most cases.
Dle,

I think Whoaru99 has got you to where you need to be. But, please read and understand all that is written about using an active or passive crossover before your amplifiers and bypassing your speakers crossovers.

You cannot bypass your speaker crossovers without some sort of frequency attenuation before your amplifiers (active or line level passive crossover). Forgive me if I am repeating something you know, better for me to be an idiot, than have you bust a couple of speaker tweeters.

Jim S.
I will have to purchase a electronic crossover before I bypass the passive in speakers, Any ideas on a good one???

I really appreciate all the information you guys have provided, I am not very educated on terms, so I quess it was hard for me to describe what I was trying to accomplish, but you guys interpreted well.
Thanks Jim S, Whoaru99, electroid and greg, I will post on here again after the holidays when I get everything set up.

Also any suggestions on what guage power cable for the nad's to replace stock ones?
BTW....I bought the first NAD2200 on ebay for $200.00(great deal I think)but Looks like the 2nd NAD 2200 amp deal is falling apart(here on audiogon) You guys know anywhere else to check for a 2200?
Or is there another model NAD amp that I could purchase That would work better for 2nd amp?
This will probably be my last post re this particular situation.

I just want to conclude that the chances to make the sound worse by continuing down what seems to be your chosen path is much more likely than it is to improve the sound.

While it is really none of my business, why are you seeming so dead set on forcing your setup to a biamp configuration?

If you can't tell, I'm really trying to discourage you from tearing apart your speakers and buying a bunch of stuff that, in the end, has a high possibility of sounding worse.
I have heard biamp setup before and had one years ago(mono blocks, Personally I feel there is a drastic improvement to dynamic range, and all around sound is superior. I think I am going to leave speakers alone and just use biamp setup with pre/amp and transport.
Ah, the voice of reason. Not as much fun, but apropos.

Whoaru99, thanks.

Jim S.