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About zeta4

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  • Location
    Oxford, , United Kin

Wigwam Info

  • Turn Table
    Rock 7
  • Tone Arm & Cartridge
    excalibur benz micro
  • SUT / Phono Stage
    own design with SUT
  • Digital Source 1
    Tom Browne Starlight
  • Digital Source 2
    Mirand usb Dac
  • DAC
    Discrete r2r
  • Pre-Amp
  • Power Amp/s
    300B SE/Ucd400
  • My Speakers
    own design
  • Headphones

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  1. zeta4

    Does rfi makes a system sound brighter?

    Just out of curiosity how do you test equipment for susceptibility to rfi? I mean for effect on the usual measurements. Do you inject rfi into the mains. The only simple way I can think of testing is merely a with and without comparison. In the past the only time I came across rfi affecting an amp was when I think it was causing marginal oscillation. That did affect sound quality but there was a design problem with that amp Otherwise Ive not seen any hard evidence.
  2. zeta4

    Tell me more about Hybrid Class A

    I use a 400W class d (ucd) to drive the bass and either a 9W 300B dht valve amp or JLH 15w s/s one to drive the mid/treble. Both are class A. Crossover is at 400hz. I realise this is not practical for everybody but for me I think I get the best of both worlds. Plenty of power to drive the relatively inefficient bass drivers and at the same time allowing the class A amps to do what they are best at. One extra advantage with the valve amp is that it makes for a better o/p transformer as it doesnt have to deal with low frequencies. I suppose you could call this hybrid class A. Another approach is the Devaliet (sorry if spelling is wrong ) take on the Quad Current Dumping
  3. zeta4

    What pre-amplifier for £2-3k

    I bet it sounds special. Ive just built a 2P29L headphone amp which can double as a preamp from the design on Ale's website. Probably cost a little bit less as I had some of the bits, and the 2P29L's are as cheap as chips. Sounds wonderful.
  4. zeta4

    What pre-amplifier for £2-3k

    Dont know whether your into building your own but the DHT pre amps mentioned above are in a class of their own in my opinion. Either with 26/01A/10Y/4P1L valves. Should cost a lot less than 2/3K. Theres a thread in the DIY section on a build by Awkwardbydesign of this parish or there's lots of info on the Bartola Valves website.
  5. zeta4

    Adding mass to CDs

    Nearly forgot. For a quick evaluation a 9V Ni Cad or Ni Mh could be used with a switch. This would power the onboard +5V reg on the Trichord Clock. Just be sure you connect the connect the battery with the right polarity.
  6. zeta4

    Adding mass to CDs

    Hi Ive done it both ways. Sometimes with a separate switch and when I get round to it with a relay powered by one of the players supplies. To try it out just use a switch but turn it on first so that the clock generator is already running. Depending on the voltage needed Ive used 6 & 12V Lead Acid ( Ive used ones made by Haze which are designed for a low current demand type of operation ), also 1.5V nickel metal hydride (Eneloop) and now 3.7V Li-on. All see to work equally well with noise well below solid state regulators. Life will depend on current demand of course. Reasonable size LA batteries are about 2000 maH as are smaller Ni-MH while you can get 4000 maH with Li-on which is why I now use them. I cant remember how much current the trichord clock takes probably about 20ma so you can work it out from there. My current DAC is a Tom Browne Discrete R2R Starlight which is completely powered by batteries. This draws about 75 ma for both channels so I have a voltmeter on the front of the player to monitor battery voltage. I usually get about a couple of weeks listening before recharge. My player uses a PC as a transport and I use one of its supplies to recharge my batteries overnight when I need to. I did do an auto recharge circuit for a commercial player and when I get the time I intend to add that to my player. Hope this is of help.
  7. zeta4

    Adding mass to CDs

    Parity checking and Cyclic Redudundancy Checking will tell you that you have an error but not where it is. I wish it did ,it would have solved a lot of problems in the past. Re the Never Connected Power Supply. The name is a bit misleading in that its not quite never. The switching mosfet is always in circuit even when its switched off. This means the devices capacitance can still pass some diode switching and other mains noise albeit a lot ess than other supplies . The rectifying diodes were changed to soft recovery type on the early versions for this reason. Its a good power supply but not perfect. I found batteries to be better.
  8. zeta4

    Adding mass to CDs

    Good thing to do. Have you tried powering the clock with a battery? Graham,s clocks are very good but even they benefit from the best power supply you can provide in my experience..
  9. zeta4

    DIY Townsend Seismic Speaker Platform

    Yes heat shrink tubing can be used. Max has used it. The first damper/spring assemblies used Citroen 2CV steering rack gaiters which were just the right size. I believe Citroen UK were quite puzzled by the sudden usage of this part and at one time stock ran out.
  10. zeta4

    Adding mass to CDs

    The error correction system used in CD is very much more sophisticated than simple parity checking. As well as detecting errors it can correct them in most cases. It does this by recording a lot of extra data ie nearly as much again as the music data and by spreading it about across the disk. It can even correct for holes drilled in the disk However because of the limitations of the amount of data on a CD the error correction is not as robust as that for data disks . So the possibility exists for there to be uncorrectable errors on a CD when error concealment is brought in. This happens extremly rarely. On some early CD players you could read the uncorrectable error flag. I never saw one come on. Even if this was the reason for the suggested sonic differences the uncorrectable errors would have to be happening all the time which is just not technically feasible. What might (just!) be possble is that any extra load put on the transport might modulate the power supply which might in turn affect the playback electronics. It would be have to be a pretty poorly designed CD player though to let this happen. Clock generators are particularly susceptible to noise on the power supply. Such behaviour could be easily measured. Incidentally clock crystals can be affected by external vibration which could be one reason to put a brick on top !
  11. zeta4

    DCT (deep cryogenic treatment)

    I can quite understand scepticism about the reduction in bulk resistivity without confirmation, I would feel the same . I observed the measurement between the two samples of copper strip taken from the same reel one of which had been cryo treated . I thought it was TPC but could be wrong. It was not loudspeaker cable. As a physicist I think it s feasible that cryogenic treatment could affect the crystalline structure of copper which in turn could affect its resistivity. However Im sceptical that this could affect sound quality in any way. Lets leave it at that.
  12. zeta4

    DCT (deep cryogenic treatment)

    I do have references but not for publication at least by me. There might be something published by Keith Howard as he was the first to suggest dct treatment for audio use. I did specify TPC which is the commonly used (ie cheapest) wire. and contains more impurities that OFC to show an effect of dct treatment. Of course as you show if OPC was dct,d there almost certainly wouldnt be any significant change in resistivity. I dont know if there is any claimed benefit in dcting OFC wire. I can wind the transformers I mentioned, the only difficulty I can foresee is getting them to be exactly the same. Otherwise you couldnt be totally sure that any differences heard (or measured) were due solely to the wire. I think something like this is the only way to resolve the issue..
  13. zeta4

    Another visit to the opticians.

    Ive found that the various makes of varifocal vary considerably. Unfortunately for my wallet Ive found Zeiss to suit me best particularly their Drive Safe range. They have a wide middle distance corridor and smooth transmission between the various segments. My latest pair are the best Ive ever had with far, middle and close up all in focus. I dont need my reading glasses anymore. It was my optician who suggested these for my particular needs. Im sure other makes will suit other user. I think its important to go to a good experienced optician rather than a high street chain.
  14. zeta4

    DCT (deep cryogenic treatment)

    By the way there is a change in the metals bulk resistivity when it is cryogenically treated at least as far as TPC ( Tough Pitch Copper) is concerned. Comparing two samples taken from the same reel of insulated TPC wire, one of which was treated showed a bulk resistivity reduction in the treated wire . Coppers bulk resistivity varies according to the amount of impurities in it and it seems that cryogenic treatment changes the effects of these impurities . I believe Hitachi tried to use this to reduce losses in power transmission cables but couldnt do it economically. Now Im certainly not saying that this is the reason for any supposed sonic differences just that such treatment can alter coppers characteristics just as it does for steel. I would think a good test might be to wind two, as near as possible identical 1:1 small signal transformers one dct wire and the other untreated, insert them in a suitable signal path and compare them blind. As there is usually over 100 metres of copper wire in such transformers this should show easily up any sonic effect due to the metal treatment.
  15. zeta4

    Electrostatic HB3s. Sort of!

    Hi Do you have a frequency response plot for the panels ? Ideally both near field and with the dipole roll off. I cant seem to find anything even on the german site. I suppose I could ask them but if youve got anything I would appreciate a copy. That coupled with your impedance plot should give a better idea of what a suitable crossover design could be. Judging by the low value of ithe step up transformers primary inductance it looks like the intended crossover point is quite high. I cant read the freq scale on your plot ( my eyes are getting bad - Yes I did go to Specsavers) to get an idea of what that might be.. Thanks