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stereodave

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About stereodave

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  1. stereodave

    Tell me about 300B tubes.

    So why are 300Bs so much more expensive than other output valves? Are the materials inherently more expensive or is it just an exclusivity premium?
  2. stereodave

    Subsonic PM1 MKII

    I have owned the Subsonic PM1 Mk Is for thirteen years and they have never had a problem, the same goes for their HT speakers and Sub. I compared them with Ambience ribbon hybrid speakers and felt I couldn't justify changing over, both speakers had their strengths but the PM1s held their own. I have briefly listened to the PM1 MK IIs, not a direct comparison with mine, but in a retail store. I couldn't fault them but would want to listen in my room to be confident that they were an upgrade. You need to listen yourself, but in my experince Subsonic is a good reliable Aussie brand.
  3. stereodave

    Looking for the best loudspeakers for classical music

    At 100 kg each the VAF i93 might be a little inconvenient to move for every listening session. I wouldn't knock them back if you were giving them away though.
  4. stereodave

    Brigadiers Audio Group

    website link http://www.brigadiers.audio/#
  5. stereodave

    The power supply!

    My experience with ESP projects is that, built to spec., they are pretty robust. It sounds like you have suffered a component failure, maybe a regulator, a fried resistor or blown capacitor should be obvious. In theory a battery supply should be cleaner than a mains supply, even with the transformer outside the case. I run an MC head amp off a battery supply but I was caught out a couple of times when the battery voltage dropped. I installed an indication LED with a zener diode to provide a warning when the voltage dropped. Depending on the current draw and extent of use having to recharge the batteries can become inconvenient, it really depends on how much improvement you think you can hear for it to be worthwhile. Does "smoother" equate to less detail?
  6. stereodave

    Marten Speakers

    I purchased a clamp for my Gyrodec in mid 2011 from Jeff Knox. Jeff invited me to listen to his Marten speaker based system, very impressive but well beyond my budget. I can't see that you would have anything to lose by having a listen.
  7. stereodave

    Marten Speakers

    Knox Audio http://www.knoxaudio.com.au/
  8. stereodave

    Pre Amp hum with dual PSUs

    Progress! The comments about earth loops and drawing a schematic got me thinking and looking at the PSU schematic. On each PSU one of the AC inputs, which are themselves connected, is connected to the ground input pin, so grounding the headphone amp at the output ground pin could create a loop. I have disconnected the headphone amp ground wire from the second PSU and reconnected it to the output ground pin of the original PSU. The hum has gone. Any reason why it can't stay like this?
  9. stereodave

    Pre Amp hum with dual PSUs

    Photo of original layout attached. The new layout has an additional PSU next to the original, top left, with AC supply daisy chained from the original PSU AC power inputs. The DC supply & Ground connection from the original PSU to the headphone amp, bottom right, was disconnected and connected to the second PSU. Decky, The plug pack recommendation effectively provides a "second box" for the transformer. The hum disappears with the second supply disconnected so the regulators are probably OK. Ken, Higher wattage resistors may allow other PSU components to overload, I'd rather avoid that path, it exceeds the designer's recommendation. Hochopeper, Thanks for the link, but I was happy with the previous performance and am just trying to get back what I had. The ground loop issue may still be present irrespective of the quality of the supply, although I suppose a single larger supply is a possible solution.
  10. stereodave

    Pre Amp hum with dual PSUs

    Thanks for the reply Decky. The 16 V AC plug pack is what Rod recommended for the power supply, the wall wart transformer has an earth pin but it only has a two core cable for 16V AC output. There is only low voltage connected to the boxno mains.
  11. My ESP based pre amp ran quietly with no hum with a single regulated +_ 15V power supply, fed from a 16 V AC plug pack, powering: a pre amp, phono stage, headphone amp, remote volume control receiver, muting relay, motorised pot and a couple of indication LEDs. After almost two years of reliable service the current draw must have been too much and a couple of psu resistors were cooked. It's fine after replacing the resistors, but on re-reading the instructions I noticed a separate power supply was recommended for the headphone amp. I duly purchased another psu pcb & components, but when installed, powered by the same AC plug pack and only supplying the headphone amp, a strong hum had developed. The hum is independent of volume and is still present when the muting relay isolates the input signal from the pre amp. Connecting the grounds on the two psu pcbs reduces the hum level slightly, connecting the new psu ground to what could loosely be called a star earth from the original psu reduces hum more, but it is still present. There is no chassis earth connection. Should I connect outputs from the two psus so that they are working in parallel? Or would this not be good for the LM317 & LM337 regulators? Any other suggestions?
  12. stereodave

    PASS Aleph pre amp, DIY

    I purchased an R core transformer for a pre amp a few years ago from Selectronic: http://www.selectronic.fr/c/electricite-transformateurs-blocs-secteur/transformateurs.html The current models seem to have pcb pins rather than flying leads.
  13. stereodave

    Silver plated copper

    I have speaker cables made from Wireworld Orbit cable. This has eight copper conductors in each core, four are silver clad & four uncladd. So the electrons can decide in which type of conductor they want to flow. It makes for a happier sound if the electrons have freedom of choice and aren't disgruntled.
  14. stereodave

    Lenehan ML II Reference Limited Edition

    Bhobba, "My ML3 Reference - poof - gone - a joke " If you want me to take them off your hands and relieve you of any embarassment I'm sure I could arrange it.
  15. I would have to agree that the Kyrons were the most impressive sound at the show, with the integrated amp/processor unit they looked a bit like two Daleks and a dishwasher. The best small speakers I listened to were the Equinox Eclipses, more impressive than the KEF LS50s. The Osborn speakers were also amazing with great impact, a lot of speaker for the money. The Lenehan/Once Analog room was small and usually full, it did restrict the musical style at any one session though, I had to go back twice before they weren't playing jazz. The speakers sounded very good and certainly never stressed. The VAF room was most interesting with lucid explanations of speaker design aims and differences between the various models played. Phil Vafiadis even kept cool when the class A amp he was using overheated and shut itself down mid demo. The speakers delivered a good sound when the amp was working. Other impessive speakers were the Magnapans, big B&Ws & Dynaudios. So I would agree with Atavid that the show was mostly about speakers. I hadn't listened listened to Naim gear before but their complete system, electronics & speakers, was also impressive. They did a demo with & without the separate power supply for the preamp. It did sound a little more dynamic with the additional box. They showed the discrete component regulator compared to the standard component in the preamp. It seemed a little churlish to ask why they didn't just put the better device in the preamp to start with. All in all an enjoyable day. For future shows I would hope that there is a financially viable option for more local small manufacturers to be involved.
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