Question Two NAD c268 Amps in Bridge Mode

I have the opportunity to pick up, for a very reasonable price, a second NAD c268 Power Amp in addition to the one I am already running. I am looking to run them as two mono blocks in bridge mode and am a little unsure of connectivity. I think I have it, but wanted to run it by the community to check.

I will switch both Power amps into bridge mode and run the left output from my Pre Amp to the Left (Bridge Mono) input of Power amp for left channel (PA L) and then left speaker cables to Left + and Right - speaker terminals. Right output from Pre goes to Left (Bridge Mono) input of Power Amp for Right Channel (PA R) and speakers L+ & R-.

I've enclosed a screenshot of the back of the Power Amp to (hopefully) clarify what I am talking about.

Many thanks.
Screenshot 2021-02-07 at 14.33.53.png
 

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Ugg10

Distinguished Member
Sound right to me based on the pictures. Beware that most amps in bridge mode will only drive nominally 8 ohm speakers so keep an eye on them for a while to check for overheating if you speakers are a difficult load. The BX5 look ok but no mention of their minimum impedance on the literature. You can also have some fun vertical and horizontal bi amping if you want to see which of the three configurations you prefer, but don’t forget to remove the jumpers for bi amping, and also don’t expect night and day differences, it will be subtle if anything.
 
Thanks for the reply Ugg10. I did try Bi-Amping a good few years ago with 2 Cambridge Audio Power Amps and I honestly couldn't tell the difference. I'm going to take a look at the amp on Wed or Thurs so will report back the results.
 

Redwing68

Novice Member
I have just bought a second C268 and bridged it with the NAD 658 as the pre amp. Set up as
I have the opportunity to pick up, for a very reasonable price, a second NAD c268 Power Amp in addition to the one I am already running. I am looking to run them as two mono blocks in bridge mode and am a little unsure of connectivity. I think I have it, but wanted to run it by the community to check.

I will switch both Power amps into bridge mode and run the left output from my Pre Amp to the Left (Bridge Mono) input of Power amp for left channel (PA L) and then left speaker cables to Left + and Right - speaker terminals. Right output from Pre goes to Left (Bridge Mono) input of Power Amp for Right Channel (PA R) and speakers L+ & R-.

I've enclosed a screenshot of the back of the Power Amp to (hopefully) clarify what I am talking about.

Many thanks.View attachment 1456299
Hi Mike, I have just bought a second C268 (another bargain) and am running the two as mono blocks in bridge mode. I set them up exactly as you suggest above using balanced connections. I use a NAD C658 as pre amp and my speakers are B&W 603. Works perfectly giving the meatier, rounder sound that I was after in a somewhat cluttered room.
 
Cheers Redwing. I'm hopefully going to see this Amp for sale tomorrow.
 
Just to bring this thread to a close. I visited the seller on Wednesday evening to look at the amp. I didn't go ahead with the purchase as the unit had clearly been opened several times and was in surprisingly poor condition for such a new amp. I may go for a new one in the future.

thanks for the replies.
 

Redwing68

Novice Member
A shame - I got mine as clearance from one of the main high street outlets, ex display with obviously little use over the last year and full guarantees etc. Saved £150 and as new. There are others out there.
 
I took the plunge and ordered one of these Amps online, it will arrive tomorrow. So for my next question:

At the moment my system is located on a side wall and the speakers either side of the TV facing my listening position. I can either locate the Amps in the Rack with the rest of the gear or locate them side by side under the TV cabinet. In the rack means using my existing speaker leads, 5m and 2m but a short interconnect. Under the TV means a longer interconnect (already got a 3m one) but much shorter, and equal speaker cables (1.5m)

I rather think option 2 is the better but am open to suggestions.
 

noiseboy72

Distinguished Member
I took the plunge and ordered one of these Amps online, it will arrive tomorrow. So for my next question:

At the moment my system is located on a side wall and the speakers either side of the TV facing my listening position. I can either locate the Amps in the Rack with the rest of the gear or locate them side by side under the TV cabinet. In the rack means using my existing speaker leads, 5m and 2m but a short interconnect. Under the TV means a longer interconnect (already got a 3m one) but much shorter, and equal speaker cables (1.5m)

I rather think option 2 is the better but am open to suggestions.
Shorter interconnects are normally the better option, as you will get less signal degradation with longer lengths on the speaker cable side, but quite honestly if you are running balanced signals a few metres is going to make no difference.
 
Shorter interconnects are normally the better option, as you will get less signal degradation with longer lengths on the speaker cable side, but quite honestly if you are running balanced signals a few metres is going to make no difference.
Yeah, it's a good quality balanced cable I was intending to use. I suppose any signal loss will be balanced out by the shorter, and equal, speaker cable runs.
 
So the second Amp arrived a week ago and I connected up with no issues, everything worked fine. I gave several days to positioning the amps in the two positions (in the rack with long and uneven speaker wire, or side by side under the TV cabinet with shorter, even speaker run). TBH I could hear no difference, but there is more ventilation under the TV cabinet, so that's where they are staying.

Thanks for all the comments and thoughts. My music seems to have a lot more room to move around in. Yes it is quite subtle, no higher highs or lower lows, just a more relaxed presentation.
 

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