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jamesmking

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    103
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About jamesmking

  • Rank
    Limited Edition Bronze Participant

Converted

  • Headphones
    stax sr007a
  • Headphone Amps
    DIY T2, DIY joamat mini t2, DIY single box blue hawaii se, DIY hi-amp alpha centauri
  • Sources
    garrard 401, loricraft psu+plinth, hadcock 242 se, ortofon cadenza bronze, leema agena, mf v90 dac + golden reference LV psu + synchronous rectifier
  • Other Audio Gear
    quad esl 2805, leema hydra, townshend allegri, dcs 905 adc, ps audio p3, van den hul first cables, cardas golden reference mains cables, cardas golden reference speaker cable

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  1. cyberpunk 2077 will be out in 2177, this game allows you to explore the historical setting of .......
  2. T2 frequency response is at least that good so it's confirmed to be running class AB.... 7K is an awful lot of money that's shop built blue hawaii se with a really nice potentiometer and 0.1% 15ppm resistors. Or two modern full T2s if you go DIY... so its up against the best of the best. 1. does it have interstage coupling caps (bad for sound)? 2. is the signal path cap free? 3. is it using constant current sources? if so where? 4. does it have a 5M ohm resistor on the bias to protect the headphones. 5. does it have 5.1K resistors on the outputs to protect th
  3. that's the integrated amp only 4K
  4. 7K and its BASED on an amplifier that is class AB and has a cheap alps low end pot not even a TKD.... no details of the topology... no photos of the inside.... no details of the voltage swing for the stax... just the bias voltage 0.5% distortion into speakers, ok you might not be able to extrapolate from speakers to stax but... the T2 is much better than an order of magnitude better than that at (0.02% THD) at 575Vrms output. At 600V rms the T2 is starting to clip and even then the THD is still an order of magnitude lower at 0.05% THD and thats over a wide bandwidth of 20 t
  5. nice electrical isolation... I didn't realise fluke had put prototype micro optical isolators into just some of the input jacks...
  6. Thank you for the feedback Spritzer, yep I am concerned about that. I'm still working on the track routing.... first priority was getting right the pad placement. v1.3 now has isolation slots and the ac lines rerouted further from the secondary output pins.... I also decreased the ac track width from 1.5mm to 1mm just in the area around the transformer solder pads to give a bit more clearance. The transformers have been moved a bit more apart to increase primary to secondary spacing there too. I have also moved the secondary tracks further from the m5 screw hole. All the tracks are on the unde
  7. The m4/m5 screw hole looks centred in the diagram left to right but not top to bottom... looks like its displaced 2mm bellow centre on the transformer? Slightly larger holes for the transformers and slightly smaller for the 25VA. AC carrying tracks moved further apart. ALL tracks made slightly wider. added transformer windings onto silkscreen. moved mounting holes 2mm up. pcb 1.3h.zip This zip contains the gerber files. The zip needs checking for hole sizes, hole placement etc. Note some isolations slots are 0.5mm. NOTE THIS HAS NOT YET BEEN CHECKED AND VERIFIED.
  8. I can make gerbers for you - no cost for something simple. If you can post the measurements, hole spacing, track layout etc. PREFERABLY in mm not inches.
  9. how is the voltage O- to ground does it behave and vary similarly to the O+? are both channels approximately the same? Unless there is a servo to automatically adjust the offset then you will see some variation with time as the device heats up and reaches a stable temperature. My T2 takes more than 3 hours for the offsets to become mostly stable. Even with a servo there is a tendency for some low frequency oscillation since the servo will alter the current flow and the change in current current flow causes a change in the temperature of the components and temperature change e
  10. 4K on a 15.6" monitor is not really going to offer much more than 1080p - 4K only really makes sense on large screens e.g. 32" or more Are you using the gpu for anything e.g. rendering? first person games? - there is not a huge performance difference between the 2070 super and 1650TI. if you are doing colour work you need to know the technology of the screen IPS vs TN IPS is generally more colour accurate AND wider gamult. You need to know the colour gamalt and accuracy. if you are doing lots of cpu intensive work the 8 core will give some advantage. my fear with the Dell i
  11. low voltage transformer 52mm high 105mm diameter ( I like to run the heaters at a bit under 6.3V AND in my experience the transformers I buy provide a little more voltage than the specs) 2x 4.5A @ 6V for el34s 2x 1.5A @ 6V for 6922s 2x 0.4A @ 15V for balance servo, HV delay circuit and delay relay high voltage 65mm high 125mm diameter (voltages are the same as the psu board silkscreen.) 2x 0.15A @ 260V for +250, -260VDC 2x 0.15A @ 450V for +-500VDC 1x 0.15A @ 465V for -560VDC Both transformers have magnetic shields, electrostatic shields and thermal rese
  12. The site did an update and there are issues accessing attachments. The admin know and they think its been fixed now.
  13. I agree about the low temperatures of the GR psus. In my experience the GRHV seems to generate very little heat (compared to the T2 psu whos 3W resistors are inferno level hot), For my blue hawaii I managed to fit everything including a GRLV, GRHV, transformer and amp boards in a single modshop 400mm deep disapante. For the mini T2 I had to go separate box for the transformers but I still managed to fit the dual GRHV, separate GRHV for the 250V, GRLV boards and amp boards in a single 400mm disapante. In both cases the majority of the heat was from the amp boards and the overall GR transistor t
  14. your not alone, I have the same problem mini T2 thread also has members having issues with attachments in posts that were definitely working previously e.g. bom .xls and gerber .zips.
  15. Pars, I entirely agree about the seperate thread for GRHV. Almost all 680uf 550V and even 500V caps are 80mm high - too high to fit into a 2U chassis (for example mouser lists some 500V less than 80mm high but none are stocked items, for 550V 680uF ALL are 80mm) . I also like the kemets for their life expectancy (although they are not cheap). I put 550V into both positions simply because at some point I might reuse the power supply and change its output. If you are budget conscious the output caps can be 450V or 500V for 400V output. This is one of the cases where moar does not alway
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