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catman

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About catman

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  1. G'day mate, assuming that the soldering is ok then I suggest checking that the M97xE stylus is fully inserted into the generator 'body', as the output level will drop if the stylus is not fully inserted. Regards, Felix.
  2. G'day all, please indulge me for a moment! As a trained former telecommunications maintenance technician and active Amateur Radio operator, I know my way around electronics pretty well yet I have encountered project faults that have defied successful repair, along with strangest symptoms, reminiscent of 'gremlins'. Most of these faults have involved radio circuitry and logic type circuitry. Most of the time, thankfully faults with audio circuitry, whilst they can be 'tricky' are generally essentially straightforward, in general terms. Thank God for audio! Regards, Felix (vk4fuq).
  3. Catman's Analog Musings

    G'day mate, no I haven't but I hear good things about it. Regards, Felix.
  4. Catman's Analog Musings

    G'day mate, point one, very good with the supplied wall wart (not an SMPS, but a linear transformer based design). SLA's are slightly cleaner but only marginally. Point two, no I'm still working on the 'Phantom Audio' preamp' Point three, the ESP P06 is just noticeably 'hissy' at high volume, dependent somewhat on the op amps used, and OPA2134's are the most hissy, but interestingly enough the Schiit 'Mani' is actually more 'hissy'. Regards, Felix.
  5. Catman's Analog Musings

    Good points and bad points of my various phono stages. G'day all, instead of rigid technical analysis, I've decided to rank my various phono stages in purely verbal terms, i.e. good points and bad points. This could be 'fun'! Schiit 'Mani'. Good points: Heaps of potential gain, 100 pf input capacitance, good sounding, good dynamics. Bad points: Slightly more 'hissy' than possibly desirable. QED DS1: Good points: Musical sounding, low noise. Bad points: Low gain at 31 db, it should be in the 40 db range. Lounge Audio LCR MK3. Good points: Good gain, low noise. Bad points: Somewhat 'overrated'. Not the clearest. Cambridge CP1. Good and musical sounding, low noise. Bad points: 220 pf factory input capacitance, too high for many 'typical' setups. Overall gain marginal but generally adequate. DIY ESP P06. Generally excellent, superb dynamics and excellent gain (changeable), input capacitance changeable by constructor. Bad points: Slightly hissy but acceptable and some DIY modifications are worthwhile improvements. Akitika Phono z. A technically interesting DIY design with generally superb (technical) performance and good dynamics. Constructor adjustable input capacitance and filtering and gain options (quite useful in practice). Bad points: Not the most musical sounding, but endearing! Lucid Labs 'Catalyst'. A good sounding budget phono stage, good gain and low noise and good dynamics. Changeable input capacitance between zero pf and 100 pf (useful). Generally excellent technical performance. Bad points: Sadly no longer in production. A curiosity: prone to oscillation at low capacitance setting with open inputs. Continued! ANT Kora 3T SE. A most interesting all FET phono stage and a personal favourite. Very 'organic sounding' and good gain, if slightly low. Input capacitance is 'acceptably' low. A very 'nice' sounding phono stage. Bad points: Again apparently out of commercial production but may be available as a kit. Various versions of the DIY Bruce Heran simple op amp design. Good points: A real giant killer, stunningly good for such a simple and basic design! Great sounding and as it is a DIY design, tweakable to constructors needs. Excellent general technical performance. Bad points: Seems to perform best with the OPA2134 dual op amp. Regards, Felix. Rothwell 'Simplex'. Somehow I'd completely forgotten about this one! Good points: An all discrete transistor design, low noise and good gain, 'acceptable' input capacitance' Bad points: When new, there was a tendency to noticeable stridency and occasional 'roughness', however with use all of this tendency has disappeared. At least in this case break in use has helped enormously! Observations and comments: Although this thread was intended mainly as a listening analysis, certain vaguely technical things have come to light which are interesting and indeed fly in the face of many popular audiophile 'upgrades' like op amp improvements. In fact many of my best sounding and lowest noise op amp based phono stages use the now old and 'antiquated' NE5532 dual op amp. It may date from the 1980's but it is still an excellent op amp stage for top notch phono stage applications. In addition, I've realised that a few of my collected phono stages use input (electrolytic) capacitor coupling, and all these phono stages sound excellent. Yes capacitors do have their limitations especially when heat is a factor and with passing time in general (yes they have definite lifetimes), but sonically they are fine, and dare I say it, a lot of audiophools, especially the non technical ones, are just fooling themselves. Some things are real and some things are completely in the mind. Yes I really think so. Regards, Felix.
  6. Catman's Analog Musings

    Something curious about the Schiit 'Mani' circuit. G'day all, just trying to sort out the mess of audio wiring in here this morning and having my Schiit Mani connected and playing music, I happened to disconnect the inputs at one point and noted with interest that as the inputs were reconnected the music from the turntable do not return 'instantly' as is usually the case with my phono stages of 'normal' design. That can only mean one thing, and that is the inputs are likely coupled via a large capacitor to the active amplifier stage, and that is indeed interesting. Giving that the 'Mani' is such a good sounding phono stage, the input capacitor seems to have no negative impact. Looking at photos of the Mani circuit board online there does appear to be two quite large electrolytic capacitors near to the RCA inputs. Mmmmmm. Regards, Felix.
  7. Catman's Analog Musings

    G'day all, there are a couple of electrolytic coupling capacitors in this design but as explained in the article they cause no problems, and having built this phono stage myself, it is excellent! https://www.akitika.com/PhonoPreamp.html Regards, Felix.
  8. Catman's Analog Musings

    G'day all, yes it's all part of the fun that comes with analog circuit design. Bypass caps on high speed op amps are practically mandatory, generally 10 uf in parallel with .1 uf (ceramic), but more often than not, they are made necessary by 'compromises' in power supply arrangements (speaking from personal experience). I recall building a simple op amp project that screamed with oscillation until I remembered omitting any bypass capacitors. As it turned out only .1 uf monolithic ceramic capacitors were necessary! With the bypass capacitors in place all oscillation simply disappeared. It was remarkable to observe the difference! I prefer not to use electrolytic capacitors in coupling applications but I have seen well regarded audio projects that have done so with absolutely no ill effects, 'when properly used'. Regards, Felix.
  9. Catman's Analog Musings

    G'day mate, DC offsets in low impedance circuits for example Regards, Felix.
  10. Catman's Analog Musings

    G'day mate, sometimes given the circuit an electrolytic capacitor in the signal path is sometimes 'unfortunately' necessary! Regards, Felix.
  11. Catman's Analog Musings

    Trying to explain 'break in'. G'day all, this is a subject that I constantly debate, even whether it is real or not! Well let me say this, I think 'some' kinds of break in are real and quite noticeable like aspects of mechanical break in. I have seen (and heard) this sort of thing many times over the years. What about 'other' kinds of break in, like for example electronic component break in? Well this is where I think that it gets exceedingly murky, and examples of simply 'getting used to a given sound' is much more likely! Yet maybe not always! If there is one component that 'might' change is a discernable way, it is the humble electrolytic capacitor. They are interesting things, and at least one respected authority not prone to this kind of 'subjective nonsense', actually thinks that electrolytic capacitor behaviour change could very well be real. My own experience has a bit of both! Over the years I have used/built/bought audio gear that simply didn't change performance/sound in any noticeable way except maybe through a fault condition. Having said that though there have been one or two examples that did, and in those cases there was 'always' a reasonably large electrolytic capacitor in the signal path, so what am I to think? Possibly! What about so called 'professional' audio gear? In this area, gear just simply has to work properly and be ultra reliable. That is the ultimately important thing! I saw many examples of this in my telecommunications technician work days, and to be honest I can't say that I ever noticed anything remotely similar to 'break in'. So again, quoting a song lyric, 'what is real and what's for sale'. I don't really know....maybe. Regards, Felix.
  12. G'day all, another great song from way back when. Regards, Felix.
  13. G'day mate, great memories of '75! Spirit in the Sky....one of my all time favourites! Regards, Felix.
  14. G'day all, this made me smile this morning. One of our local AM sports radio stations has a habit of playing a few seconds of pop songs as links in between program segments. Today they played a few seconds of James....'Laid'. Frankly I was shocked by the lyrics (the original version of the song), and I realised that it was years (literally) since I'd last heard the song. Talk about forgotten 'one hit wonders'! Regards, Felix.
  15. Catman's Analog Musings

    One or two db! G'day all, ah the subject of decibels or 'db's'. Going back to my telecommunication technician days the term decibels or db's is fundamentally important, not as a 'unit' per se, but a level reference, however I will admit that even today I do find the terms slightly confusing as sometimes 'one or two db' difference in level can be quite audible and significant. Listening to my Cambridge CP1 tonight, it's official gain of 39 db, slightly less than my general phono stage reference of '40 db' is actually quite noticeable when setting my line preamp levels! I have some phono stages (DIY and commercially made) of considerably less than 40 db gain and they sound to me overly quiet and lacking audio drive! I wish that the CP1 was 40 db and not 39 db, but as it is a very nice sounding phono preamp, I can accept the 1 db difference, (but only just). Being a logarithmic scale, the level difference compared to a linear scale is sometimes hard to fathom. However 'decibels' are part of the electronic language for better or worse! https://en.wikipedia.org/wiki/Decibel Fun! Regards, Felix.
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