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catman last won the day on April 24 2015

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About catman

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  1. Phono stage sound 'signature'. G'day all, every phono stage 'sounds' slightly different! I suspect that slight variations in the RIAA equalisation curve are probably largely responsible, but maybe other factors are a play as well. Although I have determined my two favourite phono stage recently, both DIY designs based on opamp circuitry, last night I plugged in my Rothwell 'Simplex', which is based entirely on discrete transistors only, and it 'does' have a unique sound of it's own. How utterly confusing and annoying! I think that I have said this before sometime in that its 'sound' reminds me of my early days making and listening to simple audio preamps based on my beloved BC549 transistors. The Simplex uses very similar 'transistor' in its circuitry, and its sound is very reminiscent....and it does sound very musical and somehow 'right'. I haven't mentioned the sound of valves/tubes either and yes they have their own sound too! 'It's all too much', as The Beatles would sing! Regards, Felix.
  2. G'day mate, no not yet but I do have a metal case for the job! Regards, Felix.
  3. Finding my favourite phono preamplifier! G'day all, it's time for some hard decisions! Although I don't really mind rotating my many phono stages around it would be nice to 'mainly' use one or two. It's been a hard choosing, actually I already have one, my DIY ESP P06, a truly great phono stage but what about my many others? Well I have come to a decision (I think and hope)! My Akitika Phono Z wins! It does just about everything right, its noise floor is 'very' quiet thanks to its use of 'electronic cooling' a circuit rarity, and it has great sonics and yes it is an all op amp design and yes the op amps are either NE5532 and NE5534's, and I consider the phono preamp exceedingly well designed! So now there are two and they are both personal DIY builds, my ESP P06 and my Akitika Phono Z. Regards, Felix.
  4. The sonic virtues of good design. G'day all, I have previously sung the praises of my latest DIY phono stage effort and listening to it again today its sonic performance is excellent! Reading the accompanying article it is apparent that although a simple design, a lot of good design work has gone into it and it 'shows', and I got to thinking about design aspects generally. I think that I can probably safety assume that modern and high quality hi fi gear is well designed but I wonder if this is always the case? Over the years I can think of many examples of high quality audio gear where one little thing was considered very important in making a particular design something 'special'. I really wonder about that. Maybe so and maybe not, and possibly both! That is worth thinking about! Regards, Felix.
  5. G'day mate, basically my comments are based on things that I know to be true and factual and other only test instruments beyond my digital multimeters and capacitance meter that I have are my ears (and brain). They are good enough for me and they can be trusted! Regards, Felix.
  6. Auditioning phono stages. G'day all, as a person who has 'a lot' of phono stages that I rotate into use fairly frequently I often think about the 'best' way to listen to them and determine any clear and obvious sonic character (desirable or otherwise). There are indeed some things that I do when doing this sort of 'evaluation'. Pick one or two well pressed and recorded albums only, so as to maintain some kind of consistent playback quality. This is more important than one might imagine, as the general tonal balance of all records can vary a great deal. I tend to use a lot of good quality mid 70's releases for this application. I consider that it was a good time for record 'quality' especially considering that at that time was pretty much a bit of a halcyon time for records! Know the 'sound' of your phono cartridge well! Every phono cartridge has its own particular sound and there is no point in shifting cartridges around willy nilly! Remember that in any analog playback system every link in the chain has the potential to influence or change a sonic perception or perceived character, and one should be trying to minimise this possibility. Now we come to the phono stage! I always try to avoid looking at the phono stage in use and just 'listen', seated appropriately for stereo, if applicable . The 'appearance' of a phono stage is more influential than one could ever imagine, and (sadly) appearance and aesthetics are a major part of marketing, and in the end, sales. In the end I have personally seen many hi fi products of abominable sonic quality dressed up in pretty packages. There is a place for 'pretty', but that doesn't contribute one iota to sound quality except in ones head! Phono stages are interesting electronic devices and I have studied design considerably over the years. For any good phono stage these things are important in my honest opinion. Accurate RIAA equalisation and channel matching, low noise and low distortion. The RIAA equalisation aspect is interesting as I personally wonder about the overall importance of this, as even 'subtle' variations in the RIAA curve 'can' be audible and 'sometimes' a less that perfect RIAA equalisation curve can actually sound better to the ear. Mmmmm, yes that is true! I guess that in the end keeping the RIAA playback curve to within 1 db or so is probably preferable. No massive deviations in the RIAA playback curve please! Noise and distortion. The standard RIAA playback curve that we have in use today was in part developed to optimise the signal to noise ratio of the vinyl medium, and that is actually quite a challenge! Although 'audiophile' records are mostly an exception, it is my belief the vinyl pressing quality is probably not as good as it used to be! Likewise with phono stages it is a challenge, although electronics are at a very high standard nowadays, although I have very modern phono stages for MM cartridge use developing around 40 db (my reference moving magnet standard) that are more 'hissy' than I'd like! Very low output moving coil cartridges requiring considerably more gain make the noise challenge even greater! General distortion due to electronics 'should' be a non issue but that isn't always the case even these days, sadly! In 2019 with all things being equal, I think that we are again in another 'golden age' for viny records and playback, if everything is done 'properly', but such is the nature of all things analog! Regards, Felix.
  7. G'day mate, any good split rail (plus and minus 15 v power supply) will be fine. I used the little Jaycar KC 5501 kit configured for plus and minus 15 volt rails using the LM7815 and LM7915 voltage regulators but the ESP P05 will be fine, if it has 15 volt split rail outputs. Regards, Felix.
  8. The pleasure of audio DIY. G'day all, as I type this, a record is playing and I'm listening to The Beatles as reproduced through my latest DIY project the little hifisonix phono stage, and it is rapidly becoming a personal favourite. It is a simple, but very well designed phono stage, and it is a pleasure to listen to! I think that this is the main reason why like to DIY audio electronics, the stuff you build allows you to make and enjoy high quality music reproduction. Enough said! Regards, Felix.
  9. G'day mate, an interesting article, thank you. Regards, Felix.
  10. G'day mate, the manufacturers claim 'superior sound quality' for the OPA2134 due to its FET stage and I often hear reference to the bloated/warm sound of the OPA2134. Well maybe in some applications that sound characteristic sounds good, however less so in other applications. Specs wise anyway, the LM4562 is probably superior to the OPA2134 in any case! Regards, Felix.
  11. Hearing acuity or 'can you hear well'? G'day all, over the years in various audio based quarters I have developed a reputation for very good hearing acuity, or as one person refers to me as 'golden ears', yet in the light of recent experience I am wondering if my hearing/listening ability is as good as I think it is. My recent op amp swapping with ESP P06 has been a bit of an eye opener for me, in that whilst not being a boutique component person per se, maybe there ‘are’ sonic differences that are difficult to logically explain. Certainly the LM4562 sounds 'much' better than the OPA2134 in my DIY ESP P06, yet there should be 'no sonic difference', all things being equal. To my ears though the sonic differences between these two op amps are so obvious that in all honesty I am having some difficulty in reconciling what I am hearing! There may (should) be some logical reason to explain this but any plausible reason eludes me! In the end perhaps the sonic differences that I am hearing ‘are’ real after all, even if I can’t explain it! Regards, Felix.
  12. G'day mate, that is a very difficult question to answer! On principle, I'd say the P06 but overall differences are miniscule! Regards, Felix.
  13. G'day all, don't forget the Bruce Heran single op amp design. It is simple but a stunningly good sounding MM phono stage, and very quiet using an OPA2134 dual op amp. Regards, Felix. PS. The new one that I detailed and built recently in the DIY forum is also excellent!
  14. G'day mate, there is no need to worry! Actually the op amps are two NE5534 chips (single op amps), chosen in this design apparently for their excellent low noise performance, and the design is very quiet. Interestingly enough the NE5534 has better specs in some respects than the dual NE5532 version. Regards, Felix.
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