rabski

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rabski last won the day on March 26

rabski had the most liked content!

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About rabski

  • Rank
    Everything in moderation
  • Birthday 17/06/1956

Personal Info

  • Location
    Kettering
  • Real Name
    Richard

Wigwam Info

  • Turn Table
    Well Tempered
  • Tone Arm & Cartridge
    Dynavector XX2/AT-F2
  • SUT / Phono Stage
    Kairsound/valve DIY
  • Digital Source 1
    Stable platter
  • Digital Source 2
    Computer and HiFace
  • DAC
    AD1865/AudioSector
  • Integrated Amp
    Various
  • Pre-Amp
    Various, all valve
  • Power Amp/s
    845 SET/KT88PP/other
  • My Speakers
    Living Voice
  • Headphones
    AKG
  • Trade Status
    I am not in the Hi-Fi trade

Recent Profile Visitors

4,834 profile views
  1. There is I suppose the possibility though that a vauxhall one might burst into flames when nobody is looking. A Tesla one would be environmentally friendly, but would probably run out of power at an unfortunate moment. I think I'd probably prefer Volvo or SAAB. A touch ugly, but would keep going no matter what. Kia ones might depend on their satnav, which experience suggests would be a bad idea because they'd end up at the wrong bedside.
  2. There is a thought that the MA252 and Harbeths might not be the best combination going, but that's a different argument entirely. I respectfully suggest that the combination is more than good enough to be able to discern even the slightest difference between DACs, streamers, cables, next door's cat, etc. The old argument of 'your system probably isn't high enough resolution to tell the difference between wonder product A and wonder product B is the oldest trick in the book, and it's 99% utter rubbish. If you can't hear the difference between A and B using an MA252 and harbeth P3ESRs it's because there isn't enough of a difference. Beware of the path of ever-increasing expenditure to try and fix a non-existent problem. Your earlier suggestion of paring it back a little and living with it for a while is by far and away the best idea as far as I can see. You could easily spend thirty grand on a 'better' amplifier and speakers and still not be able to hear much of a difference.
  3. Similar. If it was mine, I'd start off by simply putting a 20K resistor on the input line in the power amp. Solder in line with the wire to the RCA socket. Usual caveats apply about disconnecting, leaving time for capacitors to discharge, etc. A voltage divider would be ideal, but needs more calculation based on the coupling capacitor values and the circuit. Putting a resistor in line isn't going to drop the effective impedance or do any possible harm.
  4. I'd normally wince, but that Douk one suggests it's a 'proper' Alps blue pot, which isn't at all poor. For £30, it's not the end of the world if it murders the sound quality (which it's very unlikely to). I don't suppose you're handy with a soldering iron?
  5. It's usually 'suck it and see'. It might be worth seeing if anyone has a set you could borrow short term. Probably 10dB would do it, but it's a guess.
  6. rabski

    Valve info

    Field coils I've still not got round to trying the 2P29Ls, but I've got a pile of them. That was down to Ale and Geoff banging on about how good they are, and one of the Russian sellers I've used had a 'buy ten' price I couldn't resist. I know Geoff has had success with them on a headphone amp, but also suggested they can be very prone to oscillation. PSRR and power supply impedance are apparently crucial issues. I really need to clear some of the other stuff first, but it looks as though we might have more 'spare' time available than any of us would have normally anticipated so I might get an opportunity to try them. I did contemplate using them in a first gain stage for the 'new' 845, but it's probably unnecessary complication and grief. Headphoen amp looks sensible though. I don't have one at the moment...
  7. Not unusual, as you're right at the 'bad' end of a potentiometer. Any sort of attenuation between the pre amp and power amp will be fine. It's a valve power amp (and pre) so there should be no issue at all with impedance matching, because valve power amps have a high input imedance in general.
  8. I would have a simple answer to the first question in the thread (where did I go wrong?). The answer is in assuming there are going to be massive benefits from spending increasing sums on a streaming source. Purely IME, assuming a competent DAC (in whatever flavour suits your ears), the differences between streaming sources, cables, power supplies, et al. are comparatively small. For that matter, so are the differences between DACs with the same architecture. I'm not saying there are no differences. Just not mahoosive ones.
  9. Mrs Tony giving him a whack for watching it?
  10. rabski

    Valve info

    Makes the haircut easier when it's all standing on end
  11. rabski

    Valve info

    Full of good points there. I've always used ceramic sockets, even for small signal valves. And preferably, older ones. Plating looks pretty, but beauty is often surface deep. As much as anything, constant tinkering inevitably involves soldering, desoldering and resoldering on a regular basis, so anything with the possibility of heat softening or poor contacts is a bad idea. Stepping back and thinking is always best. Think first, check second, measure last. Always with one probe terminal clipped to something, one hand kept in the pocket and clear elbow space behind. The last one was taught to me many years ago, because no matter how careful you are, the body's automatic reaction is to jerk backwards in response to unexpected stimulus. Not necessarily electric shock, but just something flashing or making a noise is enough. Bang your elbow on something, and the reaction in turn is to jerk forwards again, which might make a bad job worse. Anyway, 'safety first' out of the way, what are you playing with?
  12. rabski

    Hifi Pig

    Not necessarily. It means that the renewal cannot be external. In other words, the client has to do the renewal via the domain registrar. It's registered through godaddy, who seem to do this, though it's not unique. Client transfer, client update, client delete and client renew are all locked. basically, it means you're tied into godaddy for everything, including domain renewals, and it's very difficult to move the domain to another hosting company. The expiry date shows as February 2021, so it was renewed a couple of months ago.
  13. rabski

    Valve info

    Morning James! Very good point about the bases. Even some fairly standard types are getting a bit thin on the ground. Very beautiful and potentially very dangerous indeed. Mind you, as I've said before, the person signing the post mortem won't care whether it was 200 volts or 2000. I actually like working with much higher voltages. It's sometimes a bit too easy to get blase with a couple of hundred volts.
  14. rabski

    Valve info

    Radio transmitters Wilson. The majority of large, directly-heated triodes were designed for RF transmitters and many are capable of handling massive power at very high frequency. There are some medium-power valves designed originally for telephone systems (300B is one), but few few requirements for big power at audio frequencies in the past, apart from public address systems and cinemas. However, there were lots of radio transmitters. And of course radar, especially in WWII. Out of all the big directly-heated triodes, I think only the 845 and 211 were actually designed for use down to audio frequencies. Every valve will work down to very low frequencies, but not necessarily work well. There are lots of issues, but many types are not particularly linear across the audio range and a lot have quite complex requirements in the best way to drive them or have particularly unhelpful characteristics. There is a tendency for designers to come across a valve, discover one property that looks good, and then try to design a circuit. Sometimes the results are surprisingly decent, but often they aren't. The same thing applies to all valves of course, not just big triodes. Valves designed for military or aviation use need to be physically and mechanically very robust. Valves designed for computer use need to be reliable over many cycles and able to run in a down state for extended periods without cathode degeneration. Valves designed for medical equipment need to be reliable and accurate, etc. Sometimes those requirements align well with audio use, but often they don't.