NVA Cube 2

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steve s
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#31 Re: NVA Cube 2

Post by steve s »

On the day we used 2 amps Eds F6 pass labs clone and my 5 watt Set amp, steves latest speakers sounded well on both these amps being quite efficient ( alot more efficient than the cubes) and as so, the outcome on the day was not as steve had reported with his own system, my view is, and to be fair to the cubes they need an amp that is designed for them to give thier best, and with steve already having good results with his own amps at home, there was something going on at mine that was not a good match
They where used on both amps and were swapped in and out of my system quite a few times during the day

We had a play around with placement which did not rectify the performance so it was a bit of a washout for the cubes
We all said that owston would be probably be better for them when they where coupled with the NVA amps , and we could then comment on their performance with some authority
Sorry ..

We should really comment about steves new creations on his own thread, as he specifically wanted to hear them on my amp so i'll leave that to steve... but they worked very well on my px25 amp on the day

The main thing for me was to get the lads listening to my new creations, it was nice for me to overhear Ed describing them as the best yet that I've made,
I cant disagree with that comment... For me i would love to hear them side by side with the top of the range living voice system... Im sure as a system it would not disgrace its self in that sort of company...
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
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cressy
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#32 Re: NVA Cube 2

Post by cressy »

Possibly something to do with the px 25 and f6 damping factor? i notice from the manual that Mr p quotes 16 for the f6 which I think is fairly low for a sand amp, my f5 is quoted as 40 which is reasonably low itsself
Id reckon that mi dads pp amp is closer to the f5, and the docs nva amps probably a fair bit higher, but i cant say as ive not looked at nva amps before

I heard them on the end of the pp amp in his room which is about 13x13 feet, and liked them. Pretty similar to the flat ones.

Shove some poke up them at owston from an nva amp or nicks p6 I think they need it to get the driver swinging
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Dr Bunsen Honeydew
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#33 Re: NVA Cube 2

Post by Dr Bunsen Honeydew »

Doped drivers are bound to be less efficient, it is part of the trade offs that always happen in audio. It seems to me if you want SE valves then horn honk (unless a fortune is spent) and efficient full range driver midband grain (my experience) is the trade off. You need decent power (more to do with current gain than voltage gain) and stiffness in the amp to push doped drivers in acoustic suspension. Watts have little to do with it beyond a certain point, NVA AP10 and AP20 will drive Cubes (15 and 25 if you want to talk watts). Cressy valve amp must be sufficiently stiff for the job.

Also it should be remembered that semi-omnis are different, you cannot just plonk them where other speakers sat, they wont work. Cressy knows the set up procedure as it will be the same for his flatbacks.

They also don't like shite speaker cable, what was used.

Good session and important information into the mix.
steve s
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#34 Re: NVA Cube 2

Post by steve s »

To be fair doc it was some cheap maplins cable that i aways use at shows, ( scalford and owston) so thats another factor..

Like i said all hifi needs to be in the correct surrounding to sing, and im not prepaired to comment on them in those circumstances at mine

Its a shame steve had not brought his amp ... But I'm looking forwards to next weekend when hopefully they will be on song...
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
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Dr Bunsen Honeydew
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#35 Re: NVA Cube 2

Post by Dr Bunsen Honeydew »

It is odd how most transistor amps and some valve amps show cable differences and others don't. In the valve case I put it down to the output transformers which have pretty high reactance which swamps cable differences. I also find less efficient especially acoustic suspension speakers tend to help in the cable show up process, maybe because of the amps they need.

I remember back in my Acoustic Reseach days proposing we should look at cable (circa 1973). We used decent sized mains cable. I did some experiments with RS stock cable types with AR and 1st generation NAD amps (much better than the hyped flavour of the month ones that came later), and hearing differences which I reported. The tech dept in the US said I was being daft.
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