Guest Muon N' Posted October 28, 2019 Share Posted October 28, 2019 (edited) Anti-clockwise would logically mean lower bias, and clockwise more, so to bias into class A where it is smoother and sweeter I would expect it to come from turned clockwise. Edit: But without the schematic or the user manual, who knows. Edited October 28, 2019 by Muon N' Link to comment Share on other sites More sharing options...
catman Posted October 28, 2019 Author Share Posted October 28, 2019 G'day mate, there is a circuit on the ANT website. Regards, Felix. Link to comment Share on other sites More sharing options...
Guest Muon N' Posted October 28, 2019 Share Posted October 28, 2019 OK, so It's user adjustable DC bias, so you prefer a minimal bias setting? Link to comment Share on other sites More sharing options...
andyr Posted October 28, 2019 Share Posted October 28, 2019 2 hours ago, catman said: Serendipity? G'day all, I plugged in my beloved ANT Kora 3T SE the other evening after quite a while, and tried an experiment of sorts. I have never been at all sure about that back panel 'bias' control, well it 'should' do something but I never noticed much change, in all honesty, however when I first got it I didn't think that it 'rocked' as a phono stage, but I loved its sound otherwise but I couldn't recall where the bias control was set when it first arrived. So I set it to one extreme (anti clockwise), and played a record that normally sounds slightly 'brittle', and I was somewhat stunned to note that this record sounded smoother than I expected. More listening will follow, but maybe that bias control does alter the sound quality somewhat, that might be used to 'tune' the sound quality to advantage. Regards, Felix. Very interesting, Felix. Do you know what this 'bias control' affects? The source resistor value - ie. the current through the JFETs in one of the gain stages? Andy Link to comment Share on other sites More sharing options...
Guest Muon N' Posted October 28, 2019 Share Posted October 28, 2019 (edited) @andyr This is all I could find circuit wise http://www.ant-audio.co.uk/Theory/Kora3T_Phono_Stage_circuits.pdf https://www.tapeheads.net/showthread.php?t=22215 Edited October 28, 2019 by Muon N' Link to comment Share on other sites More sharing options...
catman Posted November 15, 2019 Author Share Posted November 15, 2019 'Open Sounding' phono stages! G'day all, I am constantly wondering about the 'sound signatures' of different phono stage circuits and the like, and in particular so called 'open sounding' phono stages. In the end I think that (based on personal listening and observation), phono stages based on discrete transistor circuitry invariably have a 'open' sound. This is not a condemnation of op amp circuitry as many of these are personal favourites as well, however there seems to be something 'inherent' in discrete transistor circuitry that seems to provide this 'open' sound. Any thoughts or comments? Regards, Felix. Link to comment Share on other sites More sharing options...
Tasebass Posted November 15, 2019 Share Posted November 15, 2019 (edited) 21 minutes ago, catman said: This is not a condemnation of op amp circuitry as many of these are personal favourites as well, however there seems to be something 'inherent' in discrete transistor circuitry that seems to provide this 'open' sound. Any thoughts or comments? Regards, Felix. I own one of each Felix .....albeit they are both dedicated MC stages... yes i have to agree the tranny circuit one with a big toroidal does have a more open sound than the OP amp one with its SMPS....not by much mind I have to admit... Tase. Edited November 15, 2019 by Tasebass 1 Link to comment Share on other sites More sharing options...
andyr Posted November 15, 2019 Share Posted November 15, 2019 1 hour ago, catman said: 'Open Sounding' phono stages! G'day all, I am constantly wondering about the 'sound signatures' of different phono stage circuits and the like, and in particular so called 'open sounding' phono stages. In the end I think that (based on personal listening and observation), phono stages based on discrete transistor circuitry invariably have a 'open' sound. This is not a condemnation of op amp circuitry as many of these are personal favourites as well, however there seems to be something 'inherent' in discrete transistor circuitry that seems to provide this 'open' sound. Any thoughts or comments? Regards, Felix. Agreed, Felix. Discrete component-based phono stages trump opamp-based phono stages. Andy Link to comment Share on other sites More sharing options...
catman Posted November 17, 2019 Author Share Posted November 17, 2019 Performance and price. G'day all, in my mind, at least for DIY, I always strive for 'the best' that I can achieve, however just sitting here tonight I thought about well, regarding commercially made gear, is it logical for something twice the price (or even more), to be 'better' by the same amount? The value for money aspect is valid here, but just in terms of asking price is this a good indication of 'quality'? When I bought my first Rothwell 'Simplex', I did think that it was a little overpriced and in in fact I did tell Andrew Rothwell the same thing! However as of now I do honestly think that the Simplex is worth the price. It is a great phono stage and has 'musicality' in spades! I must really think so as I now have two of them (for different applications). I know that in the end these sorts of evaluations tend to be quite individual and only the individual can make that judgement. Regards. Felix. Link to comment Share on other sites More sharing options...
audiofeline Posted November 18, 2019 Share Posted November 18, 2019 When I was young I assumed that pricing was determined by the production, marketing and shipping (etc) costs plus a profit margin, with more expensive items reflecting better quality. I have since learned that was rather naive, and that pricing is often determined by how much the company thinks the market will be willing to pay for an item, which is not always congruent with quality. That's where I feel fortunate that we have a global internet community where the "excellent value for money" items are shared, along with educating us on the "much more money than the item is worth in comparison to the competitor's quality". And I often think of it when I read about your love of the humble diy ESP06 for what it costs to make! 1 Link to comment Share on other sites More sharing options...
andyr Posted November 18, 2019 Share Posted November 18, 2019 (edited) 21 hours ago, catman said: However as of now I do honestly think that the Simplex is worth the price. It is a great phono stage and has 'musicality' in spades! I hope, Felix, that - given your first email to him - you've now sent a follow-up email to Andrew Rothwell, to this effect. Andy Edited November 18, 2019 by andyr Link to comment Share on other sites More sharing options...
catman Posted November 18, 2019 Author Share Posted November 18, 2019 G'day mate, well yes several actually, each one praising the 'Simplex'. Regards, Felix. Link to comment Share on other sites More sharing options...
andyr Posted November 18, 2019 Share Posted November 18, 2019 15 hours ago, catman said: G'day mate, well yes several actually, each one praising the 'Simplex'. Regards, Felix. Link to comment Share on other sites More sharing options...
catman Posted November 26, 2019 Author Share Posted November 26, 2019 (edited) Getting older and your hearing. G'day all, I have a birthday coming up in December (57), and reading on other forums of late I've been wondering if my general hearing and general acuity is as good as it used to be? Last time I checked my treble hearing was good up to 15 or 16 KHz and bass and midrange were fine, and not too bad all things considered. A few years ago my hearing was worsening quite rapidly and my doctor found large chunks of solidified wax in both ears, and clearing them of this wax has made a massive difference! Still I guess general wear and tear has had the inevitable effects, but at 56 going on 57 my hearing is still pretty good! Any comments or thoughts? Regards, Felix. Edited November 26, 2019 by catman Spelling. Link to comment Share on other sites More sharing options...
Grant Slack Posted November 26, 2019 Share Posted November 26, 2019 Some people are prone to wax buildup and some aren't. Those who are, need to do regular clearing out if they want their hearing at its best. 1 Link to comment Share on other sites More sharing options...
stevoz Posted November 26, 2019 Share Posted November 26, 2019 I used to work at the now closed Coca Cola factory in Bendigo when I was 18 and we had hearing tests done as part of OH&S and they told me that I was missing upper high frequencies in my left ear and had about 70% hearing left in that ear (I suspect from headphone use) but my right ear was strangely close to 100% fine. I recently had another test (40 years later) and the results were pretty much the same, so I was pretty happy about that.....and while I do sometimes yearn for my left ear to hear the same as my right, I can still tell good sound from bad so I am happy enough. However, there is no doubt that advancing age and it's corresponding deficiencies are the enemy of those who love great SQ. 2 Link to comment Share on other sites More sharing options...
catman Posted November 27, 2019 Author Share Posted November 27, 2019 The question of 'calibration' and allied accuracy. G'day all, this is a potentially interesting and important question to anyone who dabbles in electronics at all, and relies on any kind of test equipment, even a simple digital multimeter….the question of calibration and allied accuracy. In many cases even reasonable accuracy will be good enough, but not always and I can of think of cases where high calibration accuracy 'is' important, like the speedometer in a car, where accurate speed calibration is important for several obvious and important reasons! Away from things automotive and into the realm of audio electronics, similarly I can think of the same things, like RIAA playback accuracy. Again in some situations that isn't too important in the 'real world', however maybe it is, 'depending'. Please let me try to explain my logic! On my main record playing system I normally use my Rothwell Simplex, a phono stage that I love, however initially I thought that it could sound slightly 'bright', but in any case maybe I've got used to it! The other day I plugged in one of my DIY ESP P06 units and was immediately stuck by the strength of the deep bass of the ESP P06, and the lack of any 'bright' tendency, only utter smoothness right across the audio spectrum! It is interesting as both phono stages are supposed to be calibrated against accurate RIAA references and yes although the ESP P06 has an acknowledged (and documented lower bass boost), at least on the basis of listening, the Rothwell Simplex high frequency calibration is clearly 'suspect', although it sounds good to me! See my point? Calibration is pointless if the calibration is 'out'! Maybe we should turf out every piece of test gear and just solely rely on our ears? Well....no. Good test gear 'should' be calibrated properly! Regards, Felix. Link to comment Share on other sites More sharing options...
myskylab Posted November 28, 2019 Share Posted November 28, 2019 On 26/11/2019 at 12:08 PM, Grant Slack said: Some people are prone to wax buildup and some aren't. Those who are, need to do regular clearing out if they want their hearing at its best. as long as its by a professional, remember nothing smaller than your elbow inside your ears 1 Link to comment Share on other sites More sharing options...
catman Posted December 3, 2019 Author Share Posted December 3, 2019 'Preloved' records that tell a story! G'day all, As it is now December I have started playing my accumulated collection of Christmas Records many of which are 'preloved'. Yesterday I was playing a recently acquired Goodyear Christmas record (the first I think), and I was quite impressed with the general production and pressing quality. However towards the end of both sides, some inner groove distortion was apparent suggesting that it was previously played with a heavy tracking stylus and/or a poorly aligned tonearm. I wonder. The record was obviously well cared for apart from that. Interesting. Regards, Felix . Link to comment Share on other sites More sharing options...
audiofeline Posted December 3, 2019 Share Posted December 3, 2019 I think there were many people who took good care of their records (keeping them clean, not scratching them, etc), but played them on systems that were not correctly set up. Some time ago I bought a secondhand tt, sold on behalf of an elderly family member who was described as being obsessive in the way he looked after his records and hifi - and there was no evidence of wear or damage to the tt, it was cosmetically perfect. However, it was evident that the styli hadn't been changed since the tt was purchased in the 70's. 1 Link to comment Share on other sites More sharing options...
catman Posted December 3, 2019 Author Share Posted December 3, 2019 G'day mate, yes indeed some things 'get missed'. Felix. 1 Link to comment Share on other sites More sharing options...
catman Posted December 5, 2019 Author Share Posted December 5, 2019 What is your most valuable/used vinyl record playing accessory? G'day all, with Christmas coming up I was thinking about 'accessories' to enhance 'vinyl record playing'. As it stands, those three items are my block of Magic Eraser, my Zerostat anti static gun and my carbon fibre record cleaning brush. The last two go together! Regards, Felix. Link to comment Share on other sites More sharing options...
stevoz Posted December 5, 2019 Share Posted December 5, 2019 For me, my carbon fibre brush, 'Sticky Hand' stylus cleaner and bottle of Revirginizer (or craft glue). Link to comment Share on other sites More sharing options...
audiofeline Posted December 5, 2019 Share Posted December 5, 2019 Most used would have been the Discwasher cleaner. I've recently added carbon-fibre brushes to the collection. There has been no problems with my Discwasher stylus brush over the decades. Link to comment Share on other sites More sharing options...
catman Posted December 6, 2019 Author Share Posted December 6, 2019 Has anyone ever experienced 'listening fatigue'? G'day all, this is a very interesting one to me. A few of my audio sources that sound superb to me at the start, end up sounding in the long term, contributing to 'listening fatigue' that in the end makes me feel like not listening to those program sources ever again! Usually they tend to be peaky or bright and yet sound impressive initially but eventually very wearing! It is interesting isn't it? Have others experienced such similar listening 'fatigue'? Regards, Felix. Link to comment Share on other sites More sharing options...
Recommended Posts