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RiStaR

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Posts posted by RiStaR

  5. Khozmo Attenuators

    in Do It Yourself

    Posted

    seeing how they are built, if I had the time, I could design and build one

    that would never ever fail. Would have pure silver contacts et all.

    Would probably take 2 hours per section to assemble. Plus silly amounts

    of time to cast the silver pieces.

     

    Kevin, if you do this and leave your signature on it, I'm sure many (including me) on this forum would buy one ;)

     

    Just out of curiosity, have you ever tried LDRs? Or do you think a digital/shunt attenuator are the best you've heard?

  7. Khozmo Attenuators

    in Do It Yourself

    Posted

    they have assembly issues. if you take them apart and resolder all the resistors and

    then carefully adjust the wipers, they should last quite a while. they are shunt

    devices with only 2 resistors in the circuit at any time, and do sound good.

    they do however as default have a common ground, which you may wish to defeat.

     

    Hi Kevin,

     

    Hopefully this isn't too elementary, but I haven't been able to find possible reasons online. I've just recently soldered my own shunt attenuator and I actually wired it all to a common ground - can you share reasons why it may be necessary to defeat it? Is it to do with noise/interference?

     

    Best,

  10. i'm on a roll... the kgsshv

    in Do It Yourself

    Posted

    As usual, gerber file to make boards is available from Dr Gilmore. Just ask nicely. :)

     

    I am waiting for the peek screws to test with the new mini amp boards which use all new devices. When everything is done, I will try to compare with my old KGSSHV. Sonic differences... might be yes, but very small, I guess. The main advantage is everything can be sourced from a single vendor which is a huge plus. Mouser now has the 2.5" Aavid heatsinks so we don't have to order them from Digikey. I compared the Aavid with the 2.5" Ohmite in my BOM and the former is a clear winner.

     

     

    Group buy will be opened in a day or two. Thinking of what other boards should we order? :)

     

    Cools! Looking forward to your A/B comparison. As to other boards... maybe the prototype Megatron? :P

  14. i'm on a roll... the kgsshv

    in Do It Yourself

    Posted

    I had some issues with the casing, since fixed (today), but haven't had time to finish it.

    Just hope I don't have an early 4th of July when I reconnect the wires. >:D 

    The Stax jacks are for Justin's.

    The letters in the back are too big for my taste, but don't feel like writing another 90.00 check to FPE. They do a great job.

    The only amp I currently have is not even an amp: SRD7Mk2.

    I know, the IEC is cheesy, but have not received the new one yet.

     

    Nice build eggil!

  15. i'm on a roll... the kgsshv

    in Do It Yourself

    Posted

    Just some updates guys:

     

    • KGSSHV still working great :)
    • Haven't found time to measure current draw - really I haven't found time to figure out how to squeeze the probes between the sinks to reach that resistor
    • My latching switch arrived, so I got that done instead
    • So strange thing - previously I had some problems tapping the 12V from the 15V line on the amp boards so I decided to lengthen the wires to the PSU board; since I was doing that I thought I'd do the same for the ground. Well that turned out to be the wrong decision... Once I took the ground from the switch from the amp board I couldn't get the DC offset for BOTH amp boards down. Turning the pot will bring the voltage down from 7V to about 5V and further turns will bring the voltage back up pass 7V. Just really, really odd. So if anyone has issues getting DC offset to work linearly, this may be something you want to choose to investigate.
    • In any case, everything working again now (not enough sleep from the night before because of that little exercise, though). Always the little things like simple switches I guess!

  16. high quality balanced DAC (small-ish, lightweight a plus)

    in Home Source Components

    Posted · Edited by RiStaR

     

     

    - The unit supports all PCM sampling frequencies from 44.1 up to 192 KHz (no 384) and just DSD64, not the newer fancier DSD128. On PCM it works at 24bits which is the default (and it seems that not customizable) setting on OSX. As said above, to use the whole connection speed range, there's need to install drivers and using either FW or USB2.0.

     

     

     

    Since I have the same DAC, just want to add that it does support DSD128 on the 1.7 firmware - it displays Hdsd on the screen in that mode.

     

    I also noticed Justin's worries about folks figuring out how to use the PC, and I think a properly setup Foobar player would work here. (the interface is simple enough to know that it's a song list and I just double click on the song I want to hear). 

     

    DSD really is great and works great for a lot of genre, but sometimes high-res PCM really do sound better for me. For some reason the "grittiness" of PCM works for some material (As I have no clue what the original master files format are for the various recordings it could be that the original master source is PCM)

     

    Somethings that I've found out and aren't often mentioned (or not often enough) with regard to the Mytek and DSD in general:

    • DSD playback is unmolested through Foobar and if you have lots of DSD tracks from various albums be prepared to have your hand on the volume knob between track changes. Volume differences can and will be high most times.
    • As above, none of the DSP plugins work - e.g. HTRF etc
    • Even with Native ASIO there may be pops/static noise if switching between PCM and DSD material
    • PCM to DSD128 through the Foobar plugin actually makes essentially all my PCM material sound better (maybe my ears has just bought into the DSD character?)
    • Depending on your beliefs with regard to burn-in (your ears getting accustomed or components) the Mytek will sound better with time. Out of the box it sounded very tinny to me
    • You can trick Foobar to play 352k/384k material as DSD128 by playing a DSD64 file then immediately switching to the high-res PCM file
    • There's a simple USB cable hack that means you don't have to worry about expensive USB interconnects - the Mytek has a ton of inputs so you can use 2 x USB cables or 1 x USB cable and 1 x Firewire and let the cable connected to USB2 just handle signals by covering pin 1 & 4 of the cable.
    • Torpedo mentioned this, and I do think the ability to handle volume through the Mytek with analog; digital; bypass really offers flexibility for folks with different tastes which may be great for Justin's potential clients.
    • Insane number of inputs means folks can come by with their own source material (even analog if they really desire) without ruining your main PC playback setup.

  19. i'm on a roll... the kgsshv

    in Do It Yourself

    Posted

    I really wouldn't hope for the best in your situation...

    I had one channel that was doing similar things (after some initial damage by accident,) but I didn't try if it were able to produce sound after the damage.

    I reaplaced the blown resistors, powered on without any problem, and it ran some 4 hours before I turned it off.

    Meanwhile, I tested the current draw across the damaged resistors against the other working board, and the resistors that were damaged (replaced) were drawing some 30%~40% more current (forgot the specific values.) I also wasn't able to get the offset to 0V with the default resistor values.

    Right now, I threw that damaged board out because I couldn't identify the cause... and the newly populated board is running flawlessly. (left on for some 10 days during the longest run.)

    Good luck on the build, but just as back up, I would get some spare boards and parts just in case if you decide to toss the current one out.

    By the way... trying to fix the damaged board wasted almost a week of my time while populating the new board only took me one afternoon.... a much easier and quicker fix.

     

     

    I had one board which just didn't work no matter how many parts I swapped out. 

     

    Thanks for sharing those experiences guys; since that incident I've clocked another 12 hours or so on it (it really is quite addictive to listen to; did I say I'm really glad I'm working from home this week? :P) and touching wood things seem to be fine there - had to bias and offset again but they are all in millivolts whereas when it blew it went up to 20-40volts.

     

    Which reminds me; the static sound that I heard on that one occasion it happened again as I was trying to get everything up again. It had to do with my pot ground - bad soldering job maybe? (had 4 small wires from the pot leading to one ground cable - I've redone it and connected it to another part of the chassis and that's all sorted). What happened then was it'll be low volts as the pot is brought close to ground, but once I hit the limit of the pot it bumps all the way back up to 20+ volts. This makes me think that maybe I was balancing it wrongly previously because my pot ground was giving me wrong values which I used for balancing? Which may account for why things went south?

     

    At this stage I may try to find some time this weekend to do some measuring on the board.

     

    I guess the new variant of the KGSSHV that's ramping up may be right on time. Then I can put to rest some of my inklings to try my hand at the Megatron when the boards are ready for it.

  20. i'm on a roll... the kgsshv

    in Do It Yourself

    Posted

    Nicely done with the build, and good luck! I didn't switch off my on-board KGSSHV for a month as a torture test (safely), and it didn't break a sweat.

     

    Anyway, in regards to the potential group buy, I'm up for re-distributing the boards for the Aussies if needed, along with some sand (I've still got ~50 spare 4686A if anyone needs some).

     

    And on that note, are there any notable performance differences between the 4686A's and the 01N100D's as the output devices?

     

     

     

    RiStaR, I wonder why your parts blew. I have left mine for long hours before and never had any problems.

     

     

    Deadlylover and eggil, I'm not sure why those parts blew as well. It's essentially been on (except for one hour) since I got it up the other day (so more than 24 hours). The weird thing really is how it continued to work (music was coming out fine) after those parts blew. After the repair I had it on for another 6 hours and it all seemed fine. Hopefully nothing major there!

  21. i'm on a roll... the kgsshv

    in Do It Yourself

    Posted

    Congratulations RiStar ! Good to see more builds.

    Look Mah! No heat sinks!   :P  

     

     

    Nice work! RiStaR :laugh:

     

     

    Thanks for the kind words guys!

     

    Unfortunately, disaster struck earlier... It's really my fault I left it on the whole night and I wanted to listen to it during the day (My wife calls it the "men with new toys syndrome" :P)

     

    After some analysis, I blew two resistors and an LED (which I found out later). The 2nd 25 ohm resistor between the 4686A and the IXYS part was really charred (I saw arcing); The 50k below the C2240 was slightly brown so something wasn't right there and I changed it. The LED at the top right hand corner was also blown.

     

    Had only changed the two resistors and powered it on again, the LED didn't turn on, but the 4686A parts above the IXYS parts started to turn hot really fast. Changed the LED and all is fine again. 

     

    I have to say though; even after it blew the KGSSHV was still kicking out tunes (I didn't hear anything through my headphones and only smelt something funny)

     

    Hope it all works out from here on out! (And I'll remember to switch it off every now and then :P)

  24. i'm on a roll... the kgsshv

    in Do It Yourself

    Posted

    Congratz!

    Another HV sees the light of day.

    or is it the light of night? 

     

    Impressions? What cans do ya got?

     

    Hey Livewire! Like you when you first built the KGSSHV, I'm just riding the SR202 for now (I made a deal with myself that I'd only get the O2Mk1 if I could build a working KGSSHV - so yay when I get to Japan in August :P). With the 202s, I think you're right... it's pretty much at its limit. I do notice a difference in terms of detail and depth in comparison with the 252A that I have though. I haven't actually done an AB test, yet. The 202s have been plugged into the KGSSHV the whole day :P

     

    Very nice build, what case is that? 

     

     

    It's next on the list and I'll start shrinking it today.  I had done a "mafia version" earlier but I'll see if I can make this one better. 

     

     

    Thanks!
     
    Case was bought through a local shop (he probably got it made from China for me). It's aluminum and pretty nice (they screwed up cutting up the backplate for me - was lucky the PS fit by flipping it around.) The size is about 423 x 410 x 130 usable space inside is really 390 x 399 x 120 (you can probably push it by another 10mm in width but you'll have to do some creative drilling.)
     
     
    Did another adjustment in the middle of the day earlier. The balance and dc offset are all 0.4v or less... I'm gonna stop now - so addictive to open it up to tweak... guess i'm trying to milk my money's worth with the pot tool lol.

  25. i'm on a roll... the kgsshv

    in Do It Yourself

    Posted

    It's late over here, but just finally got my KGSSHV onboard version up and running :)

     

    Looking forward to this newer version and probably going to try the offboard version, so this is just in time!

     

    Edit: Too tired to pull pics out of the cam... tomorrow. In the meantime, thanks to everyone who helped! (Tran; Geoff; Birgir; Victor) for parts KG for the design (of course) and Victor for helping me check my stuff before I powered everything up each time!

     

    Edit 2: Updating the post with pics :)

     

    Some notes for myself, or hopefully helpful for anyone building:

    • Had to change the resistors in series with the DC offset pot to 1.2k (couldn't get the offset up from one of the boards)
    • I used Op07s (predecessor to the Op27) instead because the local shop didn't have any on hand... after an hour the balance and dc offset is within +-1V so I guess it works?
    • I initially tried to pull the 15V from one of the amp boards instead of the 15V source - there was a burning smell, so I disconnected that cable (I'm not too sure if it's the 180ohm resistor in the heatshrink that was smelling funky or what else... will redo this when I get the right switch.)
    • Will need to shorten some of the cables - it's not exactly fitting in the "lines" I had in my mind when I did the cabling!
    • The bottom-right-most 4686as on both the amp boards (above the C2705) seem cool to touch; its as if the warmth of the heatsink comes from the surrounding sinks?
    • It's been random and it's only happened once, but there was static sound when the volume pot was set to minimum - it went away when moved just a touch up [haven't been able to replicate it but will check my grounding again to make sure]
    • I confused myself between the Alpha pot; Birgir's circuit boards + help and my DMM. Figured it all out when I realized I was looking at pin1 with the legs facing me while Birgir was referring to pin1 with it pointing away. Either way easy to figure out.
    • My Mytek DAC actually has a pretty "Hot" (I think it goes all the way to 12Vrms) balance output but the KGSSHV is handling it perfectly :)
    • I bought two types of sinks and I understand why some folks are having difficulty with them. The legs on the ohmite sinks are smaller whereas the ones most of the builds here seem to be using is about 0.5mm thicker. I used a philips head screwdriver (the ones you use for glasses) to widen the wholes so they fit much easier.

     

    First power up:

    btvFwiC.jpg

     

    View from the top:

    Xy0en5o.jpg

     

    At it's temporary location:

     

    lCSxWLI.jpg

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