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Post by savvypaul on Jul 18, 2018 10:37:33 GMT
I own the same model. I'm happy to bring it to bake-offs...
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Post by Firebottle on Jul 18, 2018 12:07:35 GMT
I have given the NVA2 a run for its money and appreciate being able to post a review without it being deleted.
I am of course interested in the technical aspects as well as the ultimate audio performance, I am after all a retired electronics engineer.
Firstly there is not a lot in it. I am a big advocate of the simpler the better and I think this NVA has achieved this admirably.
Modern chips have exceedingly good performance figures, so there is no need for complicated or sophisticated power supplies.
Using separate supplies for each channel is a good move as the ultimate channel separation can be achieved, with the audible result of a larger and more dynamic sound stage.
The cartridge loading is a fixed 470 ohms, so this does affect the sound you will get from your MC cartridge.
The noise level is commendably low (due to the modern chips performance) and the choice of split RIAA EQ is IMO an good one for the two stage design. The top octaves are equalised with a passive network whilst the bottom octaves are done with a feedback approach.
However the frequency response shows a slight bass lift starting below 100Hz, this will have the effect of making smaller speakers sound fuller, rather like the response used in the Croft phono pre amps. I personally prefer a perfectly flat RIAA response.
As for overall presentation it is bl**dy good, certainly one of the best Solid State stages I have heard. Ultimately for me though, having been through a design exercise myself with an op-amp based phono stage, even given the very low published distortion figures of modern chips, the sound stage lacks the depth that can be achieved with other approaches.
In my opinion (each to their own) a valve based phono stage can give greater micro dynamics, dependent of course on the circuit and topology used. I have heard quite a few even nudging up to £10K.
So for the price it certainly knocks spots of other SS stages at rather higher prices.
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Post by julesd68 on Jul 18, 2018 12:12:49 GMT
What more needs to be said? Quite a lot more could be said as there is not much written about it anywhere. If it performs well or is a giant killer then we need to know. Hopefully bigman80 will provide. Absolutely - the point of bake-offs (aside from the social of course!) is getting to hear new gear and being able to compare - the NVA wasn't able to strut its stuff at two recent bake-offs, so for those of us who have never heard it, any reviews by people who have heard its peers will be of interest! |
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Post by julesd68 on Jul 18, 2018 12:18:16 GMT
I have given the NVA2 a run for its money and appreciate being able to post a review without it being deleted. I am of course interested in the technical aspects as well as the ultimate audio performance, I am after all a retired electronics engineer. Thanks Alan, appreciate the review ... |
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Post by Deleted on Jul 18, 2018 13:01:28 GMT
I have given the NVA2 a run for its money and appreciate being able to post a review without it being deleted. I am of course interested in the technical aspects as well as the ultimate audio performance, I am after all a retired electronics engineer. Firstly there is not a lot in it. I am a big advocate of the simpler the better and I think this NVA has achieved this admirably. Modern chips have exceedingly good performance figures, so there is no need for complicated or sophisticated power supplies. Using separate supplies for each channel is a good move as the ultimate channel separation can be achieved, with the audible result of a larger and more dynamic sound stage. The cartridge loading is a fixed 470 ohms, so this does affect the sound you will get from your MC cartridge. The noise level is commendably low (due to the modern chips performance) and the choice of split RIAA EQ is IMO an good one for the two stage design. The top octaves are equalised with a passive network whilst the bottom octaves are done with a feedback approach. However the frequency response shows a slight bass lift starting below 100Hz, this will have the effect of making smaller speakers sound fuller, rather like the response used in the Croft phono pre amps. I personally prefer a perfectly flat RIAA response. As for overall presentation it is bl**dy good, certainly one of the best Solid State stages I have heard. Ultimately for me though, having been through a design exercise myself with an op-amp based phono stage, even given the very low published distortion figures of modern chips, the sound stage lacks the depth that can be achieved with other approaches. In my opinion (each to their own) a valve based phono stage can give greater micro dynamics, dependent of course on the circuit and topology used. I have heard quite a few even nudging up to £10K. So for the price it certainly knocks spots of other SS stages at rather higher prices. Sounds a fair assessment Alan. Shame you didn't word the HFS review in similar terms. I don't have issues with the bass but use with floorstanders. I would add that it has outperformed some more expensive valve designs as well as solid state. If you now have a better sounding stage congratulations and would love to hear the comparison. RD has already an improved version as you are aware (which I haven't heard) - Phono 3 available with much larger power supply single or twin. The single big PS I believe is available now for the Phono 2. |
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Post by Firebottle on Jul 18, 2018 13:15:55 GMT
Shame you didn't word the HFS review in similar terms. It wasn't for the want of trying but any perceived criticism was swiftly removed. |
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Post by dsjr on Jul 18, 2018 15:08:20 GMT
UMMM. Croft RIAA playback eq used to be usually within .25db over the audible range and only went awol at very high frequencies due to a mismatch of the tape outs on the integrated amp not matching properly the test gear (I'm told). (I'm using the Colloms/Choice test of the original Micro and the Stereophile test a few years ago). I don't believe Glenn has changed the basic design of his phono stage design apart from altering the output side of the stage so lower value pots could be used and this would have been a very long time ago now and I believe long before the curren ten year old range. I wonder how the 'low bass lift' conclusion could have been reached here? I have to ride this by saying I've only ever listened to a Croft preamp from inputs to the variable gain output sockets, not the Tape Output sockets.. I note that the recent bake-off didn't use the dedicated Croft phono stage (£600 for the basic version and this from a dealer and the 'R' version with extra supplies might have been more realistic in my opinion).
I find it difficult to talk of the Phono 2 for fear of providing incorrect information, but it's my *experience* in the past that most MC cartridges don't change much in performance from 100 ohms upwards. Maybe one or two of you can usefully contradict this impression, but 470 ohms always *seemed* an excellent overall setting for 99% of cartridges unless these have massive errors that need taming with an unusually low input impedance on the phono stage. It's my thought that MC's aren't hugely good in current output anyway, so a higher input impedance should - possibly - help them deliver their tiny output? If you really insisted on a non-standard value and even non standard gain, this can be done in the final build and testing stage, but as I said, is practically un-necessary for practically all cases.
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Post by The Brookmeister on Jul 18, 2018 15:36:45 GMT
What more needs to be said? Quite a lot more could be said as there is not much written about it anywhere. If it performs well or is a giant killer then we need to know. Hopefully bigman80 will provide. We need to know as in who dude? It is a giant killer as far as I am concerned otherwise why would I dip my hand in my pocket when I have access to 100's of phono amps at trade prices? When it was plugged in at my bake off and the music was played there was so much detail and the sound was so good it was frightening (well to me anyway). Lots of manufacturers stuff their websites with features and benefits which is OK but hifi needs to be heard, simple as that. Ignore this at your peril is my opinion on it. It sounds best with 2 external power supplies so 3 boxes in total. My next meeting is in August perhaps you should attend (train station 30 seconds away) and plenty of hotels/guesthouses nearby. |
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Post by MartinT on Jul 18, 2018 16:14:39 GMT
Thanks David. I'll see if I can make this one but strangely August is quite busy for me. PM me the date when you have it.
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Post by Firebottle on Jul 18, 2018 16:16:57 GMT
most MC cartridges don't change much in performance from 100 ohms upwards. I have to disagree with that, I have altered loading on a ZYX R-100 and a Lyra Clavis and the flavour of the sound does change. Without being judgemental I do wonder when I read some opinions whether the particular system used has adequate openness and linearity to be able to hear subtle differences. My door is open to anyone wishing to hear my system. |
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Post by dsjr on Jul 18, 2018 16:39:37 GMT
I can't remember what was used when I heard the ZYX R100 Fuji - clear body - (could have been a Tron 7 Reference - around £3k? - and it was a few years ago, I don't know the exact MC loading as standard, but the HFN review indicates 184 ohm on the Tron). Lower than this may duck the top, wouldn't it - can't bloody remember, damnit! Shame if this is so, as the R100 seems very 'Decca-Like' as I heard it anyway and not in the slightest bit harsh or obviously 'toppy' as I recall... I assure you the system I heard this in was very open to subtle changes... sadly, the importers chose to put the prices of all GT and distributed products up through the roof. According to the manufacturer website, Zyx recommended >100 ohms for this model. When I played with such things, I remember that dropping the MC input impedance down much below 80 ohms (on a stage with variable adjustments), the gain seemed to be sapped away and the sound deteriorated and this seemed consistent with quite a few MC cartridges I had the use of at the time. A long time ago now and I'm not able to play regularly with more recent pickups to check if this is so still. Going over 100 ohms didn't seem to make any real difference at all with the MC cartridges I had at the time and today, I can't really see the need to constantly twiddle if the rest of the system is working properly and the speakers don't take off at high frequencies.. Just a personal vibe though.
edit - P.S. The first I remember noticing 470 ohms being used to load MC cartridges was in the Naim K boards of yore when the Karma cartridge arrived.. not that that's any real recommendation. Oh - and I believe they changed the capacitive loading slightly. You could still use the previous Asak and Supex 900E cartridges into K boards though I remember although like sheep, we followed the party line in the absence of any real objective reasoning...
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Post by Deleted on Jul 18, 2018 16:45:15 GMT
Well AT specify 100 ohms and above for the models I own. I have certainly detected marginally more openess in sound using higher values (with an adjustable stage). With the NVA I can only conclude in that design the higher loading is a positive thing, and since it's not supposed to be load sensitive is a pretty universal value. With some stages I don't doubt there may be a preference for a lower value. Surely this may be system dependent. However I would agree with DSJR there aren't any great differences above 100 ohm in most cases.
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Post by bigman80 on Jul 18, 2018 17:55:39 GMT
Well AT specify 100 ohms and above for the models I own. I have certainly detected marginally more openess in sound using higher values (with an adjustable stage). With the NVA I can only conclude in that design the higher loading is a positive thing, and since it's not supposed to be load sensitive is a pretty universal value. With some stages I don't doubt there may be a preference for a lower value. Surely this may be system dependent. However I would agree with DSJR there aren't any great differences above 100 ohm in most cases. Can only agree that higher loading has been massively beneficial. I now load my Kontrapunkt b at 470ohms. |
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Post by Deleted on Jul 18, 2018 19:20:34 GMT
Well AT specify 100 ohms and above for the models I own. I have certainly detected marginally more openess in sound using higher values (with an adjustable stage). With the NVA I can only conclude in that design the higher loading is a positive thing, and since it's not supposed to be load sensitive is a pretty universal value. With some stages I don't doubt there may be a preference for a lower value. Surely this may be system dependent. However I would agree with DSJR there aren't any great differences above 100 ohm in most cases. Can only agree that higher loading has been massively beneficial. I now load my Kontrapunkt b at 470ohms. Interesting. Depends on circuit but checking I find Kontrapunkt b is 50-200 ohms and Kontrapunkt a is 50-500 ohms. So likely they suit values well over 100 ohms better. |
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Post by DaveC on Jul 18, 2018 20:02:48 GMT
most MC cartridges don't change much in performance from 100 ohms upwards. I have to disagree with that, I have altered loading on a ZYX R-100 and a Lyra Clavis and the flavour of the sound does change. Indeed, they can change in frequency response and dynamics, some for the better, others for the worse. YMMV but this is easily measurable and repeatable. |
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Post by MartinT on Jul 18, 2018 20:39:32 GMT
My Shelter 5000 is supposed to like a 100 Ohm loading. To me, despite the tilt towards the bass end, it sounds a little 'sat upon'. Switching the Aurorasound to 47k loading corrects that and sounds much more open.
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Post by dsjr on Jul 19, 2018 11:18:03 GMT
My experiences are from a long time ago and mistakenly perhaps, I decided that a higher input impedance wouldn't do much if any harm at all. A MC preferring 47k is a bit of an exception I suggest, but I have a memory of an MC stage on an integrated amp keeping the MM 47k load and just changing the gain and I don't recall any ill effects at all in doing this, listening to a few cartridges available to me at the time.
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Post by Deleted on Jul 19, 2018 11:23:53 GMT
<abbr>Alan commented
"Firstly there is not a lot in it. I am a big advocate of the simpler the better and I think this NVA has achieved this admirably.
Modern chips have exceedingly good performance figures, so there is no need for complicated or sophisticated power supplies.
Using separate supplies for each channel is a good move as the ultimate channel separation can be achieved, with the audible result of a larger and more dynamic sound stage.
As for overall presentation it is bl**dy good, certainly one of the best Solid State stages I have heard. Ultimately for me though, having been through a design exercise myself with an op-amp based phono stage, even given the very low published distortion figures of modern chips, the sound stage lacks the depth that can be achieved with other approaches."
Certainly would agree with the modern chips quoting ultra low noise floors, slew voltages and large bandwidth, low distortion figures, however it is the implementation that delivers the results.
Correct grounding, dual mono isolated power supplies will all help with stage depth, texture, separation and linearity.
Personally I prefer fully discrete designs, yes more 'real estate' required, however the results can be quite special if more long winded!
</abbr>
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