catman

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About catman

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  • Birthday 12/14/1962

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    Queensland
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    Felix

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  1. G'day all, well just on harmonics and such please consider the question of RIAA equalisation that calls for an 'ongoing' 6 db/octave roll off starting at around 2.1 KHz. Are harmonics beyond the audio spectrum relevant here? Also, many popular modern op amps don't go too far beyond 20 KHz in absolute terms before running out of steam. In that respect 'discrete' devices fare far better, but in all honesty does it really matter assuming a linear 20 KHz audio bandwidth in any case? Regards, Felix.
  2. G'day all, interesting stuff. The question of the audibility of possible harmonics/response on either side of the audible spectrum is contentious. I recall that years ago that NAD made a point/feature of not broadening the audio bandwidth of their amplifiers excessively for good technical reasons (filtering out unwanted rubbish outside of the audio spectrum). To be honest I have mixed feelings about all of this. It is worth considering live unplugged acoustic and vocal music as a comparison of real music spectra. Interesting indeed. Regards, Felix.
  3. G'day all, I ask that because a lot of program sources that I frequently listen to, whilst of good audio bandwidth, are generally not 20 Hz to 20 KHz in audio bandwidth, yet still sound great! I appreciate that reasonable HF extension does sound good but is a response to 20 KHz (on the high side) really necessary to be 'hi fi'? Regards, Felix.
  4. G'day all, I have probably done this before but I thought it was time for another 'ranking' of my various phono stages in the light of recent purchases. At the top and equal, are my DIY ESP P06 (superb dynamics and transient response and spacious soundstage), DIY Akitita 'Phono Z', various DIY versions of my Bruce Heran single op amp phono stage, and my Rothwell Audio Products 'Simplex' phono stage, (particularly good with electric guitar for some reason), ANT Kora 3T SE all FET phono stage, (very 'organic' sounding) and finally the rather excellent Lucid Labs 'Catalyst' phono stage....very ESP P06 like sound signature, and generally very high quality and build quality in absolute terms. All of these phono stages are subtly different sound wise and low noise, but all excellent! They are all for 'typical' MM cartridges of normal/'high' output. At number two and 'almost' with the others is the very inexpensive TCC TC-750, all up pretty good as 'stock', but 'improvable' with a few relatively simple circuit modifications. For the low price, it is actually recommended for Audiophiles on a restricted budget! Lastly lowest on my list, my most recent purchase is the NAD PP2e MM/MC phono stage. This is a 'curious' phono stage as it definitely sounds 'voiced' to me, possibly designed to make records sound 'warm'. Apparently it is a very popular phono stage and one well regarded audio store tells me it is a very popular sale item. Maybe so, but to my ears it was a slight disappointment overall mainly because of the way it sounds voiced to me, but others may love it! Regards, Felix.
  5. G'day all, actually I had completely forgotten about the Akitika, to my complete shame! Yes that one, and the ESP P06 and the Bruce Heran simple one op amp design. All three are superb! Regards, Felix.
  6. G'day all, this is a subject that I've often vacillated about....that of 'specifications'. Coming from a technical background myself, I do find general equipment specifications useful and valuable but less so when it comes to 'hi fi' gear, and there is an aspect of 'truth in advertising' evident here too. I have personally seen some audio gear come with great specifications yet did not really meet the real world performance in an allied way. I was 'burned' by an example of this just recently actually. However it goes the other way too, some companies will not publish equipment specifications for good reasons. My Tivoli Radio One is such example. It is a curious case, as it is a wonderful sounding radio despite the almost total absence of published specifications and this is apparently company policy. So, do 'specifications' actually mean anything? Well, sometimes they do and sometimes they don't! Regards, Felix.
  7. G'day mate, I'm slightly guessing, but based on current day standard NAD practice, I'd say, very likely a value of around 200 picofarads at 47 k. Regards, Felix.
  8. G'day all, my apparently insatiable desire for different phono preamps has kind of burnt me out of late and I'm thinking of a 'single' desert island type of system that I would be happy with without any further changes. With my unfortunate track record, at least when it comes to phono stages, that wouldn't be an easy task I guess. However after all this time and evaluating different phono stages, my favourite DIY ESP P06 of many years still ranks very highly along with my beloved Shure M97xE, so at least those two components have probably been decided! Is my elusive search for record playback perfection on a reasonable budget all in vain? Probably! Regards, Felix.
  9. Further Adventures with my new NAD PP2e. G'day all, this is getting a trifle confusing as I'm really getting to like the sound of my NAD PP2e on my 'main system'. Why it sounds good on that system and only 'ordinary' on the system in here is frankly weird. One thing I noticed on the main system this afternoon is how 'quiet' it is. That was quite unexpected. Maybe it is a lot better than I initially thought. Mmmmmm. Regards, Felix.
  10. G'day mate, all noted and interesting. I still think 100 pf would be an preferred input capacitance because as it stands the input capacitance of the PP2e is too high for my M97xE in here which sounds its best at 47 k and 250 to 300 pf (overall). Actually I am thinking about building an input 'buffer stage' for this reason. As for input 'series' capacitors, I have mixed feelings about their use, but in any case high quality capacitors are essentially mandatory and necessary in this application. Regards, Felix.
  11. G'day all, further adventures with my NAD PP2e. I'm not really sure why I'm spending so much time with this phono stage, however on a whim this afternoon I decided to plug it in on my main system in another room in this residence. The equipment is similar to what I use in here, including the phono cartridge, but the room is much larger and carpeted, and for whatever reason the PP2e sounds 'impressive' on that system. I will say that it is clearly 'voiced', but pleasant with a definite warmth and a sense of mellowness. I was playing a Slim Dusty Australian Country album, but it's an album that I know well and the overall tonal balance sounded entirely different as rendered by the NAD PP2e compared to any of my other phono stages used on that system. I have read an online review somewhere that suggested the PP2e was perfect for Jazz and I can understand why as this type of apparent colouration would work well for Jazz, I suspect. I think that I'll keep the NAD PP2e on that system where it plays nicely. For this room and system in here, and maybe room acoustics are a factor, my other phono stages are a better 'fit' in here, but on my other system the NAD PP2e although clearly 'voiced' sounds endearingly pleasant. Don't we all love the complexities of record playback? Yes....sort of anyway! Regards, Felix.
  12. Further observations and a bit of shock! G'day all, well I managed to pull the case of my new NAD PP2e apart no problem and have a look inside for preparation for possible well documented circuit modifications, and inside was a bit of a shock. 99 percent of all components are surface mount, completely different from the earlier PP2 model and there is no real way to 'work' on it. There seem to be electrolytic capacitors everywhere (electrolytic type but not surface mount types), probably in the signal path. I think the op amp is probably surface mount too. All very neat and tidy assembly, but impossible to work on, perhaps deliberately. 'PP2i' is marked on the printed circuit board, apparently the latest 'hardware' version. Oh well....chalk this one up to experience! Regards, Felix.
  13. G'day all, further observations on the NAD PP2e and to be honest I'm not sure whether I should like it or hate it! It is quite an 'ok' phono stage, but there are some things about the circuit that are clearly quirky design for no logical reason, like the (presumed) use of a single ended power supply to the op amp (an NE5532?), which necessitates the use of series (electrolytic) capacitors in the signal line from the cartridge to prevent the appreciable flow of DC into the cartridge. Why not just use a 'normal' split rail/bipolar power supply and obviate any need for series input capacitors? Why NAD opted for this circuit approach is just plain weird and simply doesn't make any real circuit sense to me. Bizarre! NAD seem to have fallen for the old advertising trick of trying to make strange design sound like a design 'feature'! The use of input coupling capacitors will inevitably start to roll off the lower bass frequencies through pure and simple high pass filtering action which is what series capacitors inevitably do. While this sort of sub bass filtering does have its practical value, NAD appear to be 'careless with the technical truth'. Mmmm. Also why set the MM cartridge input capacitance at 200 picofarads, which is a poorly chosen load capacitance value for no apparently good reason (imho). Maybe this is an EMC legislative requirement, but this certainly doesn't help with MM phono cartridge optimisation! As I've previously said, the NAD PP2e does sound quite good, however with simple circuit modifications it could be so much better. My simple DIY op amp phono stages based on the Heran full feedback approach easily develop gain in the 40 db range, have no issues with input capacitors, are easily optimised for input capacitance, and the best of all, sound great! NAD, just one question please, why has the circuit of the PP2e been designed this way? Regards, Felix.
  14. G'day all, well my new NAD new PP2e phono stage arrived by courier earlier this morning and after a very quick and easy set up I'm listening to it now fed by my Shure M97xE. Subjectively it sounds fine and despite a slightly higher load capacitance load than I'd like (around 385 picofarads overall), purely on the basis of listening there is no real evidence of upper treble roll off. The voltage gain at 1 KHz is quoted at 35.5 db, slightly low compared to my nominal 40 db 'standard' for MM cartridge phono stages, however this NAD PP2e plays essentially equally loud (with BTO's 'Not Fragile') as my other phono stages with gain in the 40 db gain range. Sonically it seems fine with good clean, low noise and 'neutral' sound quality....overall quite pleasant and satisfying to my ears. I read that there is a non-defeatable sub bass or infra sonic filter in circuit, and I think that I can detect a very slight 'lightness' to the lower bass frequencies, however again all sounds fine. My unit came in the 'traditional' grey NAD metal case that I personally like, and it is a small case, only slightly larger than the diminutive metal case used with the Lucid Labs 'Catalyst' phono stage. The power supply wallwart is a 24 volt or is it 23.5 volt DC supply (switch mode based circuitry)...both values are mentioned in the NAD documentation but is subjectively free of any apparent 'switching' noise....however I have a marked personal dislike of switch mode power supplies for other reasons such as RF broadband noise, but this unit seems clean. Summarising, there are no real disappointments with this new NAD PP2e phono stage. The MC section has not been tested as yet, but hopefully soon! This is an honest, good sounding phono stage. Regards, Felix.
  15. G'day all, very interesting stuff. One thing that worries me about the input capacitance of the MM section is '200 picofarads,' as that is just too high a value for a cartridge like the Shure M97xE once interconnect and tonearm wiring capacitance are added. As I stated elsewhere, 100 picofarads would be a much more practical and indeed workable value. 200 picofarads is just bad design in my opinion. Regards, Felix.