Passive bi-amping with a mix of amps ?

TOBYJUG posted:

So yes ... It is recommended to NOT use passive bi- amping with a mix of amps " so what was the point of your post ?

Simply to see if anyone around here has done it, Tobyjug, oh, and because the price of used NAP300's is very competitive right now and used 500's are quite rare and much more costly, that's all...

And of course, because Naim are not making Super Lumia link cables for speakers, so I had been wondering what link cables to use and Allante93 had  suggested bi-amping as a way around this dilemma... that really is all.

TOBYJUG posted:

Yes.. Try one amp with black to treble and red to bass on one speaker and the other amp with red to treble and black to bass on the other speaker ( with jumpers in place ) that way the transformers has not such a difficult load to deal with ( only if all 4 channels are equal ).

That would put the drivers at the crossover point out of phase, so undesirable. And I don't understand what on earth that has to do with the transformers and their load.   Or did I miss the big grin...?

Innocent Bystander posted:

TOBYJUG posted:

Yes.. Try one amp with black to treble and red to bass on one speaker and the other amp with red to treble and black to bass on the other speaker ( with jumpers in place ) that way the transformers has not such a difficult load to deal with ( only if all 4 channels are equal ).

That would put the drivers at the crossover point out of phase, so undesirable. And I don't understand what on earth that has to do with the transformers and their load.   Or did I miss the big grin...?

Yes... Make sure the jumpers put the speakers in phase, remember bi- amp has four channels and bi-wire has eight.

Well bless my soul, the first listening results are in...and unexpected !

The NAP300 has been running for about 3 hours, so it's warming up. 

Swapping out the 500 and replacing with the 300 reveals (of course) the different sonic signature of the amps... the 300 being much 'warmer'  and 'softer' (I hate trying to put words to feelings).

Removing the link cables and connecting the 300 to the lower terminals and the 500 to the upper terminals, the mid & high ranges remain the same, but the lower range takes on a more 'wooly' characteristic.  In Riahnon from Crystal Visions (the live performance by miss Nicks), the guitar duo at about 90 seconds in loses it's slam and becomes 'nice', but not 'awsome' (you can tell I've worked in the USA, can't you?).

George Benson's Ghetto loses a little of the bass rhythm and clarity and the strident bass line of Celine Dion's I'm Alive, diminishes significantly.

Bugger... I was expecting something better than this !  Maybe the 300 is still too cold, maybe the DR version will transform things - we'll see in a couple of days when I borrow the DR one.

So, I remove the 300 and replace the link cables, back to running with the (no-DR) NAP 500 alone...

Absolutely awesome !  My system is back to doing what it does best... making my feet tap and playing Music with a capital M !

Hmmm - at this early point in the evaluation my thoughts are turning to what HH and others recommended... add S/L din-XLR and DR the 552 & (later?) the 500.  

Tomorrow is another day, though, and the 300 will have been on for another 12-15 hours... we'll see    

Interesting...if not entirely unexpected. I don't think anything will improve I'm afraid, but good luck with it.

G

B mr Roy Gregory put thus a few years ago..

" Large transients, particularly bass transients, tend to be mixed to the middle of the soundstage assuming such flexibility exists. That means that their demands are met by both channels. Use a single stereo amp to drive both bass legs and nothing changes, but if you arrange the amps differently , with one stereo amp to each speaker then there's a big difference . Now, with its left channel driving bass information and it's right doing the treble, a large bass transient only hits one of that amps channels - it gets shared across both amps and their power supplies ".

rjstaines posted:

 

Removing the link cables and connecting the 300 to the lower terminals and the 500 to the upper terminals, the mid & high ranges remain the same, but the lower range takes on a more 'wooly' characteristic.  In Riahnon from Crystal Visions (the live performance by miss Nicks), the guitar duo at about 90 seconds in loses it's slam and becomes 'nice', but not 'awsome' (you can tell I've worked in the USA, can't you?).

George Benson's Ghetto loses a little of the bass rhythm and clarity and the strident bass line of Celine Dion's I'm Alive, diminishes significantly.

And the other way round?

No surprise. But unless you try, you don't know. If you stay with just the 500, there's two fewer boxes, two fewer speaker leads, two fewer burndies, two fewer interconnects and one fewer mains lead. Why make life complicated? My trial din to xlr is currently winging its way from Salisbury to Portsmouth, all of 40 miles, and it will be interesting to see what it does when I get it on Saturday. I'm sure it's the way to go in your system. 

I shall await your evaluation of the din to XLR with eager anticipation, HH.

...and in the meantime will see what the DR version of the 300 brings tomorrow or Friday.   I've heard the 300 DR against a regular 300 in a Naim/dealer dem a few weeks ago and although clearly an advance on the non-DR one, I'd be surprised if it's enough to replace the nonDR 500 in a bi-amp scenario... we'll soon see.

Innocent Bystander posted:

rjstaines posted:

 

Removing the link cables and connecting the 300 to the lower terminals and the 500 to the upper terminals, the mid & high ranges remain the same, but the lower range takes on a more 'wooly' characteristic.  In Riahnon from Crystal Visions (the live performance by miss Nicks), the guitar duo at about 90 seconds in loses it's slam and becomes 'nice', but not 'awsome' (you can tell I've worked in the USA, can't you?).

George Benson's Ghetto loses a little of the bass rhythm and clarity and the strident bass line of Celine Dion's I'm Alive, diminishes significantly.

And the other way round?

Haven't tried it the other way round Innocent, mainly because perceived wisdom (i.e. both dealer and Naim and also another dealer) all say 500 to mid/high and 300 to bass... and because it's anything but simple to get to the terminals behind the 802s.  And also when I ran with just the 300 alone driving the 802s, I was underwhelmed with the result... primarily judging by the midrange... distinct tapping of the feet = not!   However, I will  try it when I have the DR'd 300 in a day or so.

TOBYJUG posted:

B mr Roy Gregory put thus a few years ago..

" Large transients, particularly bass transients, tend to be mixed to the middle of the soundstage assuming such flexibility exists. That means that their demands are met by both channels. Use a single stereo amp to drive both bass legs and nothing changes, but if you arrange the amps differently , with one stereo amp to each speaker then there's a big difference . Now, with its left channel driving bass information and it's right doing the treble, a large bass transient only hits one of that amps channels - it gets shared across both amps and their power supplies ".

That is true where both channels share a single power supply. I don't know the internal topography of the 300 and 500, but  I assume the two channels are completely idependent, this borne out by the pair of cables between PS and amp -so in effect each 300 is a pair of mono amps, similarly the 500, and whatever one channel is doing makes no difference to the other.

Quick update:

The NAP300 has been running for 24 hours, so is warmed up now.  Running both amps into the 802's and then removing the NAP300 opens up the sound stage tremendously and the whole musical image comes to life.  I found this astounding actually, but it is demonstrating just what many other posters predicted, so probably forget bi-amping NAP300 & 500 together* !

Tomorrow I'm picking up the NAP300DR  from my very accommodating Chester dealer, and will place this in the mix instead of the 500, so both amps will be of similar gain etc.

*For the information of HH... I'm also picking up both the SuperLumia din to XLR and the Sarum STA din to XLR... in anticipation of the 300DR being less than hoped for, and in preparation for Plan B as HH and others suggested - install S/L din to XLR + 552 DR upgrade (I have £1900 price from my dealer), and 500 DR ££upgrade some time later.  So all in all should be a busy weekend 

Further update - NAP300 DR going home !

I've had the NAP300 DR running today in place of the non-DR one.  My dealer was suspecting that the DR amp (300) would out perform the non DR amp (500).  He was close !  Sonically the 300 DR performed remarkably well against the 500... remarkably well. All the detail was there, the midrange was just as sweet, the bass was almost as deep and powerful and the spread across the stereo soundstage was all there. In fact, had I never owned a NAP500, this NAP300DR would have been an excellent choice with my 802 diamonds...

BUT, and it's a big but... when I unplugged the 300DR and put back the 500, the soundstage opened up front to back as well as across, and the whole performance took on a much 'warmer', enveloping experience.  I did this on three occasions during the day, each time with the exact same effect.  So both the NAP300's (DR & nonDR) are going home tomorrow and the NAP500 is staying put.

So to all those who advised caution or outright against mixing 300s and 500s... thanks, you were absolutely right !!

And so we come to the revised agenda for the weekend:

I have borrowed the din to XLR versions of Super Lumia and Sarum super array... let's see what they bring to the musical experience when connecting my 552 to the 500.

If anyone has already done this comparison, it would be interesting to hear your conclusions?

Thanks,  Roger

All I can say is that I'm not surprised. I've got my new wire today and it's quite astonishing after a couple of hours: this might sound funny but it's almost too real - as if a sheen of niceness has been scraped away. I can't describe it any other way.  That's just with a 272/250 of course - things will be different with a 552/500, but one would expect even more as the boxes are that much more resolving. I've heard these wires take ages to reach their full potential. If the rough edges wear off but the increased level of connection with the music remains, things are going to be good. Fingers crossed the wires work out for you. 

Meanwhile, let us know when you do the comparison of single passive 500 aagainst biamping with 500s,  both active and passive...

An interesting experiment, RJ.  Thanks for sharing your experiences with us.  

Mike 

Posted by HH:

"Roger, these are thoughts rather than practical experience.... If it were me, I'd be getting the 552 and 500 DRed rather than adding a 300, and getting the SL din to xlr if you don't already have it. It's always been my understanding that passive biamps need to be exactly the same for optimum results. The sound signature of the 300 and 500 are quite different, as well as the gain, so it doesn't bode well. Added to that, you'll have the dilemma of which amp to use on the treble and which on the bass, which is something you could do without, I'm sure. So I'd say that as you can't afford another 500, forget it. You know it makes sense."

Well, I did plant the seed in your mind, but after I realized the 802's couldn't be activated without major surgery, I agreed with HH, right after he posted the above quote.  What the heck, 18K in Speakers, Dred front and rear end 500, with the full Loom, you'll be ok, trust me!!!!!

Innocent Bystander posted:

Meanwhile, let us know when you do the comparison of single passive 500 aagainst biamping with 500s,  both active and passive...

Don't think I haven't thought along these lines, Innocent !!  But for now, as suggested above by a number of people, it'll be 'fix the front end'... then start saving again.

I have made "voicing" crossover adjustments to the frequency response of speakers of 0.5 dB which make the difference between "just right" and "not bad, but not quite right."  I expect most on this forum would find a 1 dB change in frequency response to be obvious.  Of course, it COULD be an improvement depending on your starting point.

FWIW

Charlie