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RoHo

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About RoHo

  • Birthday 18/03/1964

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    Australia
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    Melbourne

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  1. Thanks for the reply, Dave. You have cleared things up considerably. I don’t think it’s a total hijack as these are the fundamental issues related to DIYing interconnects. Me, I’ve given up DIYing interconnects. I never found worthwhile differences between the “recipes”. My last soldered CAT5 jobs broke at the connections after a few years and I could never justify spending the dosh on a good crimper just to make a handful of cables. So I ordered a bunch from Blue Jeans and am totally satisfied 😁
  2. I was thinking along the lines of what I have done on the internal of my DIY tube amps: two conductors for Sig/Gnd and a shield connected at one end to the chassis. Obviously not practical for an interconnect but I was more thinking about the theory. My experience is with tube amps where you treat each small section as one loop which includes signal and ground - the current flows equally in both. So noise in the ground is definitely a problem. A big difference in the interconnect situation, I'm thinking, is the that the current is minute. Does this explain what you mention above about noise?
  3. What I'm really getting at is, is it good practice to have the shield and signal ground as the same conductor? I guess compared to a typical unshielded interconnect cable there are advantages. But the function of a shield is to trap all the HF hash and funnel it to earth, right? You don't want it connected to SG I would have thought, ideally.
  4. Trying to get my head around why 2 conductor coax cables are seen as optimum for small signal audio . Why isn't it better to separate the signal ground and shielding functions to different wires? ie three conductors with shield going to the chassis and +/- to the signal circuit? Or do you use two runs of the co-ax for each channel, which may be the obvious answer 😀
  5. My experience is that at low listening levels I'm less able to determine the fine details and imperfections in the music. So my theory is that a less than optimum SNR at low levels is less objectionable than the same SNR at higher levels.
  6. Theoretically I believe that analog attenuation before the A/D conversion is more likely to decrease signal to noise ratio. But practically, in your system? Have you compared each? I would think that at low listening levels there will be very little difference. Volume control after the DAC is ideal except that in a multi-channel (active crossover) situation is is going to be complicated or expensive or both. If you were really keen on being technically optimal you could put fixed analog attenuation (resistive divider) after the DAC and have this calibrated so the volume control before the A/D is near the end of it's travel ie attenuating less. But is it worth the effort? In my situation with a MiniDSP 2x4HD going from analog via pre-amp to digital in to the MiniDSP resulted in noticably less hiss.
  7. Coupla points. As mentioned critical listening is a skill that improves with experience. Certainly some are probably are more naturally talented in this area but almost certainly most are initially poor at it and equally as certainly you can improve thius skill with practice. But doing the listening in different showrooms makes it much more difficult to pick real differences due to the different room and layout. If equipment was all equally excellent in its engineering and sounded similar there would be no point of difference for the manufacturer to shout about ie some things are built to sound different and stand out from the crowd. For example B&W speakers with their tilted up treble. A smart person once said to me "cables do sound different but should they?" Things to ponder....
  8. Was just looking for exactly the same pots and Element 14 appears to have them for $28. With the Chinese ones there is the risk of fakery and I don’t know how to tell which is which. Does it actually mean anything if the description says”genuine” 😙
  9. Gee, things have changed a bit since I last made a PCB! Masking tape, scalpels and ferric chloride baths. Those were the days 😀
  10. Small signal valves are cheap and last a long, long time. He’s got a nice amp, he should use it. Too many people worry needlessly about valve amps 🙂
  11. Just realised I haven't updated this in a loooooooong time so here goes. Star of the show is the custom redgum unit. Very solid and versatile. Amps now use 6CB5A tubes which have more power than the 6B4Gs and being indirectly heated don't have any of the problems/complexities of directly heated tubes. Being egalitarian I have built both a push-pull amp (top left) and a single ended (bottom right). Both use the power supply unit at right centre, only one at a time. MiniDSP 2x4 HD has replaced standard 2x4 which was used on the sub only. Now I am taking optical out from the CD player straight into the MiniDSP then onto main&sub amps, so no analog to dig conversion. The turntable only gets occasional use and goes into the MiniDSP analog input via DIY phono stage (Rod Elliott/ESP Sound). I had set myself two lockdown projects: 1) Redesign the speakers crossover. I used XSim software and 9 full iterations and hundreds of measurements later I accomplished that to my satisfaction. And what a massive improvement! Actually it's made me less inclined to to play with the amps as the gains there are......not as massive, sadly. Unfortunately there's nothing to see as the XO is internal but here is a pic of the leftover components! Apart from a few leftovers they were obtained from Nigel at Speakerbug, very highly recommended. This was massive learning curve but the gains were likewise huge. I would love to use this knowledge to create something bigger and better, so to speak, but my woodworking skills are non-existent. A puzzle to be solved..... Project #2 came about with the realisation that some of the music I wish to buy is just not available on CD. I had been following the computer music trend from a distance but I had issues I get no pleasure from working with computers and my skills are limited so setting up a PC system with all the stuff was not attractive. Plus I'm a frugal, DIYer at heart so I am never going to buy a multi $K streaming product. You might have guessed the answer.... Raspberry Pi 4B hardware and Moode library/player software.. Just bloody awesome! I have the simplest combination, just the Pi and a 250GB USB SSD for the music. Was quite simple to set-up and works a treat. I don't have immediate plans to set up streaming, maybe I will get there but I'm really not that interested ATM. I also bought the HifiBerry case and spdif/optical hat for the Pi. I compared the optical to the USB Pi outputs and there was no significant difference in sound quality. MiniDSP has remote switchable optical and USB inputs so I compared the optical from the CD with the pi's USB and again no significant difference. So I can leave both CD and Pi connected to the MiniDSP easily switch between these two sources remotely. Really handy for comparisons. A question for those more familiar with music via computers. I now have two digital volume controls, one on the MinDSP and the one on Moode. What is the best way to juggle these? Keep the MiniDSP set near max and only use Moode? Halfway on both?
  12. No need to add a binding post. You could just attach a wire via an eye or spade connector to one of the chassis screws on the earthed unit. I have an alligator clip on my turntable ground wire and just grab on to the closest chassis screw. Does the job.
  13. Is the pre-amps chassis connected to signal ground in the pre-amp? If not, give it a try. I take it there is no power to the pre-amp? So no earth from a mains socket?
  14. I think Sir SZ's needs are complicated by the fact that he wants a resistive, analogue volume control somewhere in the chain. I assume this is to mute the input and thus prevent an accidental full-scale digital blip blasting a hole in his exotic panels 😁 I don't know how likely this sort of occurrence is but I can't blame him being cautious. How much do you trust a computer?? 100%? Repairing or replacing a panel would be a whole lot more difficult than just replacing a blown tweeter.
  15. You can buy good quality kits including cabinets here in Oz Loudspeaker Kit . I would especially consider the ones using the SB Acoustics drivers - really good bang for buck drivers. The prices are not cheap, however. The value in these sort of products really drops when you want the cabinets included. Avatar is Wayne Coyne of The Flaming Lips, one of my rock and roll heroes.
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