New V3 users chime in

LTMS · « **Reply #120 on:** 11 Jan 2010, 02:22 pm »

Hello, new to this forum and i have a question

I have two ref9V3 newly updated to V3 and one of the amps do not start properly, if everything is shut down, preamp and all the other things, the amp will make this sound like its going up and down in frequense, cant find the right word for it, i am from Sweden

If i then start the preamp, Onkyo 806 receiver, the amp will turn on with a big thump and then it works like it should, i think

If i dont turn on the preamp and shut the ref 9 off it sometimes do not start again, completely dead until i unplug the powercord and plug it in again and then it is the same story all over again, WHY?

Please bare with my english, by the way: The V3 sounds great when i manage to get it right

Thomas

mcullinan · « **Reply #121 on:** 11 Jan 2010, 02:43 pm »

I would take it back to where you got it updated. Sounds like there is an issue. Or contact Casey at Nuforce.
M

LTMS · « **Reply #122 on:** 11 Jan 2010, 02:50 pm »

Thanks for the answer, when they did this upgrade they had it running for 24 hours and they should have heard this problem to?

Caar · « **Reply #123 on:** 11 Jan 2010, 02:55 pm »

Maybe they were lucky on those 24 hours...
or
they didn't run the amps at all after modification...
I would bet on the last one.

After you have solved this problem - by sending back the mono - you'll be in possession of a great amplifier, indeed.

Carlos

maligue · « **Reply #124 on:** 12 Jan 2010, 06:45 am »

I want to check with persons who are more technically proficient than I am about the following. The input impedance of the V3 board appears to be 22 KOhms, whereas the V2 sports double that - 44 KOhms. I wonder why the reduction? A cursory review of specs for many amps shows that standard spec for input impedance is 100 Kohms!
For me this means the following ... I think. I run a tube preamp with the Ref 9 V2 SE monos. The former runs with a relatively high output impedance of 3.5 Kohms. It seems the link between preamp output and amp imput should be, at the least, 1:10, that is, for 3.5 I should mate to an amplifier with at least 35 KOhms. Lower than that ratio, treble rolloff, muddy bass, and other nasties.
Thus the maths speak for themselves. I should not upgrade to V3 should I wish to stick with the tube preamp ... or I should implement another preamp (for instance Nuforce's P-9).
Am I correct? Thanks
Edward

steve_sf · « **Reply #125 on:** 12 Jan 2010, 07:41 am »

You're right about the big input impedance reduction. Something to watch out for. I wish it had stayed at 44 KOhms. I use a passive preamp so I'm concerned the upgrades won't work in my system. I will try V3 demos at some point, though, to see if they're compatible with my system.

worldcat · « **Reply #126 on:** 12 Jan 2010, 10:24 pm »

I have notice that the V3 doesn't have near much gain as did V2!! So far it sounds very good, different from the V2. I did make a lot of changes at once. I have about 85 hours on my amps now it has been some getting use to some songs sound amazing others not as good. I don't know if they need to be broken in much more or if they will.

beachbum · « **Reply #127 on:** 13 Jan 2010, 02:35 pm »

I ve gone back to RCA instead of Balanced ICs between my Audio Horizons tubed 2.1 preamp and V3. The gain had to be turned well past the point i used with V2. You are correct maligue and like steve mentioned go the audition route first and see how V3 works with your current gear.
I totally enjoy the sound of V3 over V2 and happy with the upgrade but it may not be for all.

Maybe Cassy can step in and answer some of these concerns.

Mike

gammajo · « **Reply #128 on:** 13 Jan 2010, 03:14 pm »

Beachbum - I have the AH 2.1 too. With the V2 and my speakers and room, for loud volume I used 10 o'clock with RCA and 11 o'clock with balanced. I prefer balanced for increased three dimensionality. What setting do you think I would need with the V3 to duplicate loudness?
Thanks, Joe

beachbum · « **Reply #129 on:** 13 Jan 2010, 11:01 pm »

Hey gammajo with v 2 playing classic rock and roll using balanced ics just past 12 was appx 95 db with higher peeks. with v 3 i was at 2 and was not reaching 95 db. I believe i was loosing as maligue explained good sound. no doubt to my ears rca is the way to go with v 3 and 2.1.
i dont know why v 3 had to lower the input impedance so much i am hopping Casey will explain this concern that has shown itself at this point.

Caar · « **Reply #130 on:** 14 Jan 2010, 12:04 am »

After 150 hours of burning -first 70 hours with Isotek CD Full System Enhancer - I gave V3 a listening of some reference CDs.
It is not evident to me things are better, different yes, but better I'm not sure.

If I remember well, bass was more defined with V2 than with V3, depth seems to be better with V3, still wondering about the high frequencies V3 seems to be less graspy than with V2.
I use NuForce P-9 preamplifier - with V2 at position 5 was very loud, with V3 I have to increase to 10 to get to the same level.
That's a huge difference - maybe my ML Summits are showing the less amount of power received.

Carlos

maligue · « **Reply #131 on:** 14 Jan 2010, 07:22 am »

I am including below the answer I received from a prominent audio engineer to my question about impedance matching. Judging by the explanation, the issues some of you are having with gain, when comparing the V2 / V3, are not directly related to impedance matching.
But first to 'Carlos'. ML speakers have a high sensitivity. The Ascents I use are rated at 90dbl at 1 m. Hardly ever, regardless of the amplification implemented, have I been able to go beyond 10 am on the dial; the typical setting is 9.00 am! It appears from what you write that I would indeed 'gain' (pun intended) were I to implement the V3!
Now for the info. regarding impedance matching.

Thank you for your mail and the interesting point you address.
The 10:1 ratio for input impedance vs. output impedance is not based on science. It is a totally random choice made by uninformed people.
A little explanation on impedances and driving them:
Driving a high impedance from a low impedance is a near 100% voltage transfer.
The lower the input impedance and the higher the output impedance, the more current is going to be transferred relative to voltage.
When input impedance reaches about the same value as the output impedance, current and voltage transfer are in balance, and their product (power) is at its maximum.
There are many cases where it is advisable to have the input impedance equal the output impedance. This guarantees maximum power transfer without any losses (when done right).
It is very well possible to even do it the other way round, having a high output impedance driving a very low input impedance.
The only difference is that now we are driving a variable current into the input, instead of a variable voltage.
(Of course there should not be a frequency limiting component in that signal line, like a capacitor.)
There are several brands that actually use this technique, like Krell with their CAST connections.

Anyway, back to the ProLogue 3 and the NuForce: The PL3 is very well capable of driving the 22kOhms input impedance.
The limit where low frequency rolloff will start to be audible lies around 10k input impedance. This is caused by the output capacitor of the ProLogue 3.

In itself, the output stage of the ProLogue 3 is capable of driving down to 1k input impedances when it comes to harmonic distortion, when we disregard the bass rolloff.
The output level will drop when low impedance loads are driven, but the distortion does not increase, not even relatively, contrary to most other preamplifiers.
The output signal level drop with 22k compared to 44k however is only 0,2dB, which is totally insignificant.

This said, we can conclude that your ProLogue 3 is very well suited to drive the newer version of the NuForce amps with total confidence.

worldcat · « **Reply #132 on:** 14 Jan 2010, 06:39 pm »

I have 144 hours on my V3's now they seem to have stabilized and sound much more coherent. The clarity and depth of the music is awesome. The imaging i never heard it so good before. There is a lot more blackness in between the instruments as well. I did make a lot of changes at once, to nuforce interconnects, speaker cables, magic cube and to V3. Each day it has been getting better and better!! The only thing i am having problems with is the volume control with the gain, its a little tricky but i am getting use to it. I have been driving mine with PS Audio Perfect Wave Dac and Trans. I have a Theta Gen VIII series 2 which has a analog volume control it seems to work much smoother than the PS Audio although it is not that bad.

beachbum · « **Reply #133 on:** 15 Jan 2010, 01:35 am »

Worldcat i believe the wire takes longer than the amp to get broke in. The description of the sound your hearing is right on with most others. V 3 does take me further into the music and that makes me a happy audiophile. mike

worldcat · « **Reply #134 on:** 15 Jan 2010, 02:40 am »

Yeah i have new speaker cable and interconnects! I believe they are going to get better and better. I do not know if the magic cube's need breaking in. The sound i am getting right now which is at 151 hours is amazing and getting better each day. How long do you believe the wire takes? V3 has taken me much further into the music and the DEPTH is incredible. I have a very large room and very revealing speakers so i am able to really tell when something is different. Makes me wonder what they will do with REF 18!! I would like even a more fuller and liquid sound!

rustydoglim · « **Reply #135 on:** 15 Jan 2010, 10:06 am »

About the gain issue, we discussed it in the FAQ (http://www.nuforce.com/hi/faq/faq-V3.html)

For those using the Magic Cube, after listening with it for some time, remove it to get what you're missing.

Welborne · « **Reply #136 on:** 15 Jan 2010, 11:14 am »

My v3 ia-7 is now into its close 200 hours.

Spending with the amp with more time and going through my cd collection, now I am able to speak a bit more exactly about the difference between v2 and v3.

Definitely the treble of v3 is not as ear grabbing as v2. Whether v3 is better than v2 depends on your preference and system. Both have good extension and on paper the v3 is better, but I understand those who have lived with v2 for long time would miss v2 for a short while after moving on the v3. Treble of v3 is by no means lacking. some frends of mine who heard it here said the v3 is more accurate. My ears were adapted to a slightly tilted upward tonal balance. I like exciting sound that easily gives an illusion of fast transience.

On the other hand, the image depth and blackness in v3 is so much improved. Music is further extended into the front wall behind the speakers. On some very good vocal recordings such as Cantate Domino (from Proprius) and Priests (the trio vocal from North Ireland) you can feel the church is just inside your room extending into the next room. The slightly ear grabbing treble presentation sometimes gives a more forward and shallower image. I short, the V3 is much mroe holographic. I believe the treble perforance and this holographical presentation is closely related.

beachbum · « **Reply #137 on:** 15 Jan 2010, 01:28 pm »

Jason the FAQs had slipped my mind thanks for reminding us with the answer to the gain question.
Casey did mention to me that he preferred RCA ICs with his amps.

Worldcat aint life grand with a super revealing system with music that flows for hours on end. I see you added those last bunch of hours mighty fast. I m the same way in fact i m going to play a LP before going to work this morning. Mike

worldcat · « **Reply #138 on:** 15 Jan 2010, 08:28 pm »

Right now i am at a full week of playing my system and listening! Almost at 170 hours i will be listening for 4 or 5 hours tonight and i will see where they stand then. I agree with Welborne on the treble, i believe V3 is more accurate. My speakers have a ribbon twitter. To me i am really enjoying the V3 treble even more now its toned down a little. Not that it was bad with V2 its just V3 sounds much better.

nuforce-casey · « **Reply #139 on:** 15 Jan 2010, 09:21 pm »

Quote from: maligue on 12 Jan 2010, 06:45 am

I want to check with persons who are more technically proficient than I am about the following. The input impedance of the V3 board appears to be 22 KOhms, whereas the V2 sports double that - 44 KOhms. I wonder why the reduction? A cursory review of specs for many amps shows that standard spec for input impedance is 100 Kohms!

The 10:1 is really meaningless. In the pro audio, all the input and output are matched to 600 ohm to maximize signal transfer (i.e. 1:1). For no good reason, in consumer audio, we tend to have a 10K input impedance and a 100 Ohm output impedance. However, these numbers are really arbitrary.

What it means is we have more voltage transfer if the input impedance is higher than that of the output, and we have more current transfer in reverse. A tube preamp, if they have a highish output impedance relative to the input impedance, simply mean they are required to pump a bit more current relative to a preamp with a lower output impedance.

What really matters is that the higher the input impedance, the higher the THD and noise, that's why we try to get it down as much as possible, while still making sure that the low frequency corner frequency remained well below 20Hz.