Yamaha NS1000M - Tweaks

[drSM]

Hi Qwin
Super thread - from a base old pair of Ns1000Ms to passive X over upgrade to Electronic X over in a matter of months and quite superb analyses of the sonic benefits !
I am afraid u lost me once u got into the active electronic X over. Lovely work.
For the benefit of 'non electronic me' could u summarise what amplification u settled on.
Presumably 3 stereo power amps
I see a Nakamichi Power amp at the bottom of the stack on the floor.
What model is that?
While we are on Nakamichi do u have an opinion on the Nakamichi PA7 and its suitability to drive the NS1000(passive)?

btw i hve an unmolested pair of NS1000s that i love.
Have thought about upgrading the X over but dare not !
Ta
Shahrin

[Qwin]

Thanks for the kind words Shahrin.

The set up is like this:
The two outputs from my Croft Micro 25 Pre Amp plug in to my crossover box. Each channel is connected to a KMTech board, that splits the signal, without any further amplification, into Hi, Med and Low frequencies. So three line level outputs per channel making six outputs in total. These plug in to my Nakamichi AVP1 on which I use six of its seven channels. All channels have identical amplifier boards, each giving around 110w into 8 Ohms and the Croft controls the volume level, what ever the signal it outputs the crossover passes it through at more or less the same level to the Power Amp. The Tweeter and Mid driver on the Yamahas (or any other speaker) needs far less power than the bass driver and as there are no gain controls on the power amp I added a stereo volume pot to the Hi and Mid outputs inside the crossover case, to turn down the output levels for these. To give you some idea, the output from my CD player is about 2V, this passes through my Pre amp which is zero gain and the crossover which is also zero gain, so the bass channels on the power amp sees roughly the same 2V. When the volume pots in the crossover are set by ear to give the best balance between the drivers, the Mid and tweeter outputs sent to the power amp are around 0.75V for the same 2V sent from the CD player.

The Nakamichi AVP1 is a superb AMP and although designed as an AV amp handles audio in a very nuatral and matter of fact way. One of the best things I can say about it, is when folks have listened to my system and a couple of others I have heard, using these, no one comments about the amp performance, it just does its job without fuss and to a standard that does not draw attention to itself. Capable of tremendous dynamics and slam yet sweet and refined when needed. The only down side is a slight hum through the speakers that is more noticeable when using the unbalanced RCA inputs rather than the balanced XLR's. This is only small and not noticeable from the listening position.

As for the Nakamichi PA7 I only know these from reputation. A beast of an amp knocking out about 250w/channel of quality sound. A look at some of the reviews shows a well built product using quality parts and a sound that was highly regarded. I would think it would drive your Passive Yamaha's well.

Enjoy your speakers.

[drSM]

Ta Ken
That i could understand
The Nak AVP1 is a 7 channel AV amp huh.
Currently my refurbished AU111 drives them quite nicely
I swap in the 9500 sometimes and even the little 70 does a decent job
They are not to difficult to drive to modest levels
I ve wondered if a 200 wpc SS amp might exert better control.
Cheers
Shahrin

[Qwin]

I ve wondered if a 200 wpc SS amp might exert better control.

This was my thought when getting the Naka and it seems to work out in that respect. It's a debatable point as to weather the amps damping factor is as important. The Naka has quite high damping, but I have seen arguments that beyond a certain level it's irrelevant.
To me a good big'un usually sounds better than a good little'un but if your happy as you are, then don't change anything.

[Mika K]

Before you have tested the NS-1000M's with some really powerful power amp you do not know what it is capable of with that 12" bass driver. Thinking now something like monster Krells etc doubling their output to bigger loads from 8 -> 4 -> 2 -> 1ohms. The downside is that quite rare of these monster have the delicate nature that the Be-drivers again wish for, so it will always be compromise until bi-amping comes along..

[AlfaGTV]

As Shahrin said; Good thread!

And i agree with Mika's thoughts, they do benefit from some major powerhouse up their rears!
Mine are driven by a Karan KA S270, a dynamic bias Class A jobbie with one the highest damping factors ive heard of.
They sure sound fine that way, but also do a great job with a small EL34 pentode tube amp. A lot less bass though, which is a good thing as it is nowhere near as well controlled as with the big Karan.

[YNWaN]

Before you have tested the NS-1000M's with some really powerful power amp you do not know what it is capable of with that 12" bass driver. Thinking now something like monster Krells etc doubling their output to bigger loads from 8 -> 4 -> 2 -> 1ohms. The downside is that quite rare of these monster have the delicate nature that the Be-drivers again wish for, so it will always be compromise until bi-amping comes along..

My NS-1000M's are run semi-active; passive mid and tweeter on a 75wpc amp (into 8Ohms) and active bass run from a 300wpc amp 8Ohms, 600wpc 4Ohms (Lab-gruppen IPD 1200).

[Mika K]

That should do the job.

If I remember correctly NS-1000M was one of the example speakers used at the study of amplifier measurements with the difficult speaker loads and there NS-1000M bass driver was stated to be very difficult because of the phase coherence. The measurements were done by Finnish professor Matti Otala who did some major research e.g. for Philips and Harman Kardon and is usually remembered because of the Transient Intermodulation Distortion..

[drSM]

I do not have the know how to go active.
Down the road i will prob get help to spruce up the passive X over and what Ken had done here in the earlier part of the thread is what i will prob do.
I ve heard of guys using the Quad II to drive these
I get lovely mids and highs with my AU111 - bass is there but is a wee bit untidy.
Overall the tone is v nice i feel.
I have read that one should not overpower these babies. they are rated 100 watts i believe.

[drSM]

Seems to me that if i were to do anything at all to my NS1000 s it would be to go active
I found this very impressive Aussie range of products http://deqx.com/
The opening video is q cool
I sent them a message and got a nice reply from Alan Langford its founder
The model he recommends is the Express II pre amp which has a DAC, lots of dig inputs, is an electronic X over with 3 sets of analogue outputs and is also a room correction device.
Alan Langford tells me that they have a number of DEQX users that have converted the NS-1000 to DEQX active and can also provide NS-1000 calibration filters to help
Building an active X over system from scratch as Ken has is impossible for me so this may well be the way forwards
All i need is about $3495 and 3 stereo power amps (or your Nak power amp) !
Any thoughts on DEQX ?