advertisement


NVO phono stage

Sorry I can't take anyone who reviews a product using cable lifters seriously.

On a more serious note these were a well regarded, low noise and distortion valve phonostage. Nothing not to like in the measured reviews
 
Based on HiFi shark they sold primarily in N America, or they are so good that of those that escaped outside of NA, few have appeared s/h.

Prices vary something like US$2500-3500

nvoaudio 22 valves, no breakdown on what they are, unlike for the ISA-2 power amp, which has 23
 
Old Valve Git said:
Tried one, really great sounding but ran unbelievably hot....... it was that which put me off purchasing.
Click to expand...

With 22 valves......... a couple of watts per.............. even that would be "quite warm" if in a confined space, on a rack.

I'd hate the idea of finding a valve that went down.................... at least that would be just 11 to go through as it is dual mono all through. At least ECC88's are "relatively" cheap.
 
vinylmonkey said:
These seemed to get very good reviews & created interest a few years back on some of the high-end forums; the designer in Cyprus apparently had a thing for Leak and Croft.
https://positive-feedback.com/Issue69/nvo_phono.htm

Massive boxes, lots (13 or 22!) of valves, great reviews...has anyone here any experience with them?
Click to expand...

Steer well clear. Too many valves/tubes. A valve/tube phono stage should only require 3. Any more and you will have a constant problem trying to keep a quiet set. Seen it so many times before. Check if the mains transformers are 240 volt versions. Anything less and you will have problems as heat has already been mentioned in a post above.

Is it me, or do people scour the web looking for obscure audio products and when they find something unusual, they think they have found the holy grail in audio...
 
I remember back in the 1980s the Audio Research SP10 and D250 nearly bankrupted ARC due to the number of returns and repair issues because of the vast numbers of valves/tubes in each of these amplifiers. Some were being returned on a weekly basis due to noise issues. The SP10 had 6 double triodes in the phono stage and 4 double triodes in the line stage, plus further 4 valves/tubes in the power supply enclosure.
The D250 had 26 valves/tubes, 16 x 6550s (8per channel) plus a further 10 valves/tubes for voltage gain duties.

The upshot was that ARC had to quickly design the SP11 which was primarily solid state but had one valve/tube in the phono stage and one in the line stage (total of 2 valves/tubes in the amplifier) just to soften the sound. Same also with the power amps after too, as these had a solid state driver stage but retained a 6550 output stage which were the only valves/tubes in the circuit. That reduced the noise issues but changed the sound completely. The sound was never as good as before the SP10/D250 era...
 
No wonder you need all that regulation with that many valves/tubes in circuit. Still it must the holy grail as someone has just discovered it! :rolleyes:
 
G T Audio said:
I remember back in the 1980s the Audio Research SP10 and D250 nearly bankrupted ARC due to the number of returns and repair issues because of the vast numbers of valves/tubes in each of these amplifiers. Some were being returned on a weekly basis due to noise issues. The SP10 had 6 double triodes in the phono stage and 4 double triodes in the line stage, plus further 4 valves/tubes in the power supply enclosure.
The D250 had 26 valves/tubes, 16 x 6550s (8per channel) plus a further 10 valves/tubes for voltage gain duties.

The upshot was that ARC had to quickly design the SP11 which was primarily solid state but had one valve/tube in the phono stage and one in the line stage (total of 2 valves/tubes in the amplifier) just to soften the sound. Same also with the power amps after too, as these had a solid state driver stage but retained a 6550 output stage which were the only valves/tubes in the circuit. That reduced the noise issues but changed the sound completely. The sound was never as good as before the SP10/D250 era...
Click to expand...

Good gracious Graham..you do bring back memories. I had both a ARC SP 10 and SP11 and M300 power amps. You are right the two preamps were very different in tone and presentation. The challenge was to find quiet valves. I can not recall the time and money spent trying to find them. The 6550 in the power amps were notorious for taking out components as they were configured to work at the extreme of their operating limit. I know that Richard who serviced ARC for Absolute sounds was working 12 hours day just to keep up with the servicing issues! Another brand that sits in the same category was Counterpoint. I had the SA9 phono and SA11 line stage; again they had 20 + valves in each, same issues with finding valves but seemed to be slightly more reliable. Anyway that was then and this is now and i have seen the light. I now have a different approach that allows me to experience my LPs as the should be and not worry about reliability, valve failure or the next bit of kit to replace what I have........it is called TRON.
 
G T Audio said:
Steer well clear. Too many valves/tubes. A valve/tube phono stage should only require 3. Any more and you will have a constant problem trying to keep a quiet set. Seen it so many times before. Check if the mains transformers are 240 volt versions. Anything less and you will have problems as heat has already been mentioned in a post above.

Is it me, or do people scour the web looking for obscure audio products and when they find something unusual, they think they have found the holy grail in audio...
Click to expand...

Mad
 
perhaps it's apples & oranges, but I've been running, on a daily basis: (1) a Croft Mega Micro II preamp with 12 valves in its PSU and another 5 in the line/phono stages, (2) a Croft Series V power amp with 14 valves in it & (3) a Leak Troughline tuner with a further 8 valves in it -- 39 valves, all told. the only valves ever to fail or give me noise trouble have been, very occasionally, the signal (?) valves, which I've been rolling anyway. the sound of the Crofts is fabulous & I prefer the Series V to the hybrid 7R monos (which I also have).

more relevantly perhaps, I understand Croft also made a 20-valve MC headamp. I saw one for sale in Germany a while ago, but it was too expensive (& was sold to Japan). my own Croft headamp sports a measly 2 valves.
 
You must log in or register to reply here.


advertisement


Back
Top