bridging NAD amplifiers
Comments
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I guess sarcasm is lost on some.
Anyway....it's not so much as what a manufacturer claims or says it can do, it's more so what they don't say. After all, Polk says you can drive their speakers with 20 watts, any of you doing that ? Probably not, unless it's a tube amp and a bookshelf speaker.
Real world conditions are different than a sound chamber used to test speakers so don't take too much manufacturer info at face value. We offer you the benefit of many members experience to help you not damage anything and to up your game as best as you can. Bridging, like others said, puts stress on the amp under heavy loads. This is why most say to not run any speaker less than 8 ohms when in bridged mode. Plus you'll lose a tad in SQ in the upper frequencies.....from my experiences anyway.
There's nothing conservative about bridging. Lets face it, the only reason most want to bridge an amp is for more power....because they think power relates to volume. A mistake usually found in a thread about blown tweeters or funny noises coming from a speaker.HT SYSTEM-
Sony 850c 4k
Pioneer elite vhx 21
Sony 4k BRP
SVS SB-2000
Polk Sig. 20's
Polk FX500 surrounds
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Acoustic zen Satori speaker cables
Acoustic zen Matrix 2 IC's
Wireworld eclipse 7 ic's
Audio metallurgy ga-o digital cable
Kitchen
Sonos zp90
Grant Fidelity tube dac
B&k 1420
lsi 9's -
Another benefit of the bridging might be better imaging. This is just a guess based on my experience with my "dual mono" amp. I can definitely hear a difference when the signals go through the same board (standard stereo or non-bridged) when compared to the signals going through separate boards (bridged).Aaron
Enabler Extraordinaire -
............"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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Dual mono is completely different than bridging two stereo amps.
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"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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I just can't help it - might be genetic...
Once bridged aren't the "stereo" amps mono?
From the manual:
"This switch "bridges" the two power amplifier channels to form a monophonic amplifier"
You can only drive the left channel with the 7400 at that time and must use another amp- hopefully the 2400 - to drive the right channel. You then use the Pre-out of the 7400 right channel to supply signal to the 2400. The only change up here is that the 7400 supplies the left channel, sans cable, to the power amplifier section of the integrated amp.
I'm not sure how dual mono is completely different? My dual mono amp has separate power, boards, caps and transformer. One for each channel. It's just a space saver, I don't need two chassis'. Just to be clear I'm not bi-amping. In the classic dual mono situation (assuming I had two fully separate physical amps) I would use one amp (in this case the bridged 7400) for the left channel and left only. I would use the other amp (in this case the bridged 2400) for the right channel and right only. No more stereo from either amp. One speaker wire comes from the 7400, the other from the 2400.
I understand they weren't born as mono amps but they certainly had the surgery to become mono amps.Aaron
Enabler Extraordinaire -
Qualitive questions aside by definition those amps bridged would become mono blocs.
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Qualitive questions aside by definition those amps bridged would become mono blocs.
It's semantics, but no. They would become *monophonic*. Monoblock by its very definition is a single channel amplifier in a single chassis. A dual mono(phonic) amp is a pair of monophonic amps in a single chassis.
Not trying to stir the pot but definitions you know. :cheesygrin:"Some people find it easier to be conceited rather than correct."
"Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip -
That is true, however my point is that there is no longer a stereo amp after bridging. Whether housed in a single chassis or multiple they are mono. Therefore they are not "completely different" - see post #35 and #36.
Because of that...blah blah blah reference post #33.Aaron
Enabler Extraordinaire -
CertainlyIt's semantics
True which is really what you end up with when bridging a pair of like amplifiers since the two ch. within each now function as one.. Monoblock by its very definition is a single channel amplifier in a single chassis. -
There are notable differences between bridged amps and a purpose built dual mono amp or mono blocks. Two examples off the top of my head are that a dual mono amp or mono blocks have lower distortion and the ability to drive low ohm loads.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Absolutely. Many of the higher powered monoblocks(ie.Pass,Bryston)actually use balanced /bridged output stages but the two halves of the circuit have been closely gain matched so that common mode distortion is cancelled or reduced.Everything has been optimised for mono operation.While I have seen test results on well designed stereo amps that actually have lower THD when bridged it certainly won't be the case with ones that have poor matching between it's two channels.There are notable differences between bridged amps and a purpose built dual mono amp or mono blocks. -
Therefore they are not "completely different" - see post #35 and #36.
Because of that...blah blah blah reference post #33.
If you're looking at it as a stereo amp becoming a mono amp, yes, it's the same as a mono block because the stereo amp just turned to a mono amp when bridged.
However, the circuitry and result will be completely different.
Say we buy two different amps from the same manufacturer. One is a stereo amp in a single chassis. The other is the exact same amp built into seperate chassis (mono blocks). Both output 120w/ch.
Get another one of the stereo amp and bridge them for 240w/ch.
Driving the same speakers, the 240w bridged amps won't be able to handle low impedance like the 120w mono block. When you bridge a stereo amp, it will cut your speaker impedance by half and increase THD. -
So I bought the NAD 7020 integrated amp and am currently using it as a preamp in conjunction with the NAD 2400THX power amp. There is more than enough power to drive my Polk Audio RTA 12C speakers! Very rarely do have the volume knob up past 1/4. Any higher and the neighbors might have the cops at my front door. I'm very happy with the quality of the sound. Thanks again to everyone in this forum!
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Not sure why my photo was inverted while uploading from my iPhone. Lets try that again...
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The 7400 has the same specs as the 2400. Ditch the 2400 amp. If you need more "safe" power, get a NAD 7600 (150x2, 500 wpc tone burst). There is a *huge* difference between the 7400 and 7600 when i tested them on my rti10's.
Sorry, just saw your post stating you got the 7020. Do you hear a difference between the 7020+2400 as opposed to using the 7400 alone? -
I started this thread because I was considering purchasing a NAD 7400. However, after all of the feedback I decided against buying one. So I'm afraid I can't tell you if that would sound much different than my current setup.
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Update: I've replaced our NAD 2400THX power amp with a NAD 2600 power amp, which has had speaker relays and caps replaced. I'm quite happy with the sound quality it provides in tandem with our NAD 1300 pre amp. The 2400 will be our backup amp.
