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jamesmking

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About jamesmking

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    Advanced Member

Converted

  • Headphones
    stax sr007a
  • Headphone Amps
    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. Well spotted Mirko, you are correct. I will update the schematic.
  2. I added the red anode mark myself when I tested the leds with a multimeter.
  3. My mini T2 amp boards. Note the screw terminals on the top to make troubleshooting easier I know JoaMat does not believe in screw terminals but I do. 😉. If you are careful its even possible to orientate the terminals so the silkscreen voltage markings are still visible 🙂 . I take a 2 terminal and cut it in half and put the original smooth side parallel to the silkscreen markings. There is not space for screw terminals for the heaters of the el34s so I (possibly temporarily) have soldered in a header pin at 45 dgrees I have used nylon m3 standoffs for the first layer so that there is no chance of the standoff shorting against anything and brass standoffs for the remaining layers to get to the required height. SMD soldering was done in a three step process. 1 apply solder paste to the pads. 2. melt the solder using a hakko 888D station at 330 degree C using a fine tip until the paste has migrated to only be on the pads. 3 Hold the component with twisers onto the pads and with my other hand use a Quick 861DA hot air station using the smallest supplied nozzle with airflow setting all the way down to 5 (even then its possible to send one of the small diodes into orbit with that air flow)... to reflow the solder onto the component. the reason I soldered this way was, 1. I could collect any excess solder with the hakko, since I dont have an electronic solder paste dispenser... 😞 2. I could be reasonably certain there was no solder paste left under a component. I use the same method for soldering Kevins' synchronous rectifiers. this is the schematic of the v0.2 pcb with valves from the silkscreen. The red components have changed since the last published schematic.
  4. Pars, here is my reverse engineering of the kgsshvpssicfetdual2new I have added in red the extra parts for the delayed turn on but there are no pads present on the gerbers for them. As far as I can tell the dual hv boards stopped at version 1.7 just before the cpc117n was added. the individual "left" and ""right" boards went to version 1.8 - which included the cpc117n and the 600ohm resistor.
  5. Pars for the golden ref HV on both my blue hawaii builds and my current mini T2 build I used the gerbers from the file kgsshvpssicfetdual2new This board does not have the cpc117n for the delayed start - but you can implement it via external relays. I made my own bom for it. Note you will need to change a couple of resistors if you dont want +-400V also if you are going golden reference dual LV you dont need the parts for the simple +-15V, the voltage regs, this are marked on the bom as for low voltage section. Hope this helps. On the silkscreen the caps are 0.047uF 1KV not 0.47uF, So you might be looking at a different board from the golden ref HV I used. Select Mouser No: 941-C2M1000170D Mfr. No: C2M1000170D Manufacturer: Cree, Inc. Desc.: MOSFET SIC MOSFET 1700V RDS ON 1 Ohm RoHS RoHS Compliant Availability 2 Dispatches Now £4.07 £8.14 Select Mouser No: 747-IXCP10M90S Mfr. No: IXCP10M90S Manufacturer: IXYS Desc.: Current & Power Monitors & Regulators 900V 1-100mA RoHS RoHS Compliant Availability 5 Dispatches Now £2.60 £13.00 Select Mouser No: 511-STN9360 Mfr. No: STN9360 Manufacturer: STMicroelectronics Desc.: Bipolar Transistors - BJT Hi Vltg fast-switch PNP pwr transistor RoHS RoHS Compliant Packaging Choice:Cut Tape Availability 2 Dispatches Now £0.697 £1.39 Select Mouser No: 512-2N3904TA Mfr. No: 2N3904TA Manufacturer: ON Semiconductor Desc.: Bipolar Transistors - BJT NPN Transistor General Purpose RoHS RoHS Compliant Availability 2 Dispatches Now £0.163 £0.33 Select Mouser No: 512-BC557BTA Mfr. No: BC557BTA Manufacturer: ON Semiconductor Desc.: Bipolar Transistors - BJT TO-92 PNP GP AMP RoHS RoHS Compliant - - Add new 4 Availability 4 Dispatches Now £0.178 £0.71 Select Mouser No: 512-KSC5026MOS Mfr. No: KSC5026MOS Manufacturer: ON Semiconductor Desc.: Bipolar Transistors - BJT NPN Si Transistor RoHS RoHS Compliant Availability 4 Dispatches Now £0.557 £2.23 Select Mouser No: 689-DN2540N5-G Mfr. No: DN2540N5-G Manufacturer: Microchip Desc.: MOSFET 400V 25Ohm RoHS RoHS Compliant Availability 2 Dispatches Now £1.01 £2.02 Select Mouser No: 584-LT1021DCN8-10PBF Mfr. No: LT1021DCN8-10#PBF Manufacturer: Analog Devices Inc. Desc.: Voltage References Prec 10V Ref 20ppm/-uC RoHS RoHS Compliant Availability 2 Dispatches Now £4.97 £9.94 Select Mouser No: 513-NJM7815FA Mfr. No: NJM7815FA Manufacturer: NJR Desc.: Linear Voltage Regulators 15V 1.5A 3 Terminal RoHS RoHS Compliant - - Add new for low voltage secti Availability 1 Dispatches Now £0.458 £0.46 Select Mouser No: 513-NJM7915FA Mfr. No: NJM7915FA Manufacturer: NJR Desc.: Linear Voltage Regulators -15V 1.5A 3 Terminal RoHS RoHS Compliant Lifecycle: End of Life: Scheduled for obsolescence and will be discontinued by the manufacturer. - - Add new for low voltage secti Availability 1 Dispatches Now £0.963 £0.96 Select Mouser No: 660-MF1/2CC1000F Mfr. No: MF1/2CC1000F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 100ohms 1% 50PPM RoHS RoHS Compliant Availability 2 Dispatches Now £0.147 £0.29 Select Mouser No: 660-MF1/2CC1001F Mfr. No: MF1/2CC1001F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 1K 1% 50PPM RoHS RoHS Compliant Availability 6 Dispatches Now £0.164 £0.98 Select Mouser No: 660-MF1/2CC1003F Mfr. No: MF1/2CC1003F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 100K 1% 50PPM RoHS RoHS Compliant - - Add new for headphones bias Availability 2 Dispatches Now £0.26 £0.52 Select Mouser No: 660-MF1/2CC1502F Mfr. No: MF1/2CC1502F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 15K 1% 50PPM RoHS RoHS Compliant - - Add new for headphones bias Availability 1 Dispatches Now £0.164 £0.16 Select Mouser No: 660-MF1/2CC2001F Mfr. No: MF1/2CC2001F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 2K 1% 50PPM RoHS RoHS Compliant Availability 2 Dispatches Now £0.147 £0.29 Select Mouser No: 660-MF1/2CC2002F Mfr. No: MF1/2CC2002F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 20Kohms 1% 50PPM RoHS RoHS Compliant Availability 2 Dispatches Now £0.164 £0.33 Select Mouser No: 71-RN60D-F-390K Mfr. No: RN60D3903FB14 Manufacturer: Vishay Desc.: Metal Film Resistors - Through Hole 1/4watt 390Kohms 1% 100ppm RoHS No Availability 0 Dispatches Now 4 Backordered £0.364 £1.46 Select Mouser No: 660-MF1/2CC2493F Mfr. No: MF1/2CC2493F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 249Kohms 1% 50PPM RoHS RoHS Compliant Availability 8 Dispatches Now £0.164 £1.31 Select Mouser No: 660-MF1/2CC4701F Mfr. No: MF1/2CC4701F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 4.7K 1% 50PPM RoHS RoHS Compliant Availability 2 Dispatches Now £0.164 £0.33 Select Mouser No: 660-MF1/2CC4992F Mfr. No: MF1/2CC4992F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 49.9Kohms 1% 50PPM RoHS RoHS Compliant Availability 2 Dispatches Now £0.164 £0.33 Select Mouser No: 660-MF1/2CC49R9F Mfr. No: MF1/2CC49R9F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 49.9ohms 1% 50PPM RoHS RoHS Compliant - - Add new 20 Availability 2 Dispatches Now £0.303 £0.61 Select Mouser No: 660-MOSX3CT521R5R1J Mfr. No: MOSX3CT521R5R1J Manufacturer: KOA Speer Desc.: Metal Oxide Resistors RSS3 5.1 5%TR RoHS RoHS Compliant - - Add new 2 Availability 3 Dispatches Now £0.181 £0.54 Select Mouser No: 660-MS1/2DCT52R3011 Mfr. No: MFS1/2DCT52R3011F Manufacturer: KOA Speer Desc.: Metal Film Resistors - Through Hole 1/2W3.01K ohm 1% RoHS RoHS Compliant - - Add new 1 for for headphones Availability 3 Dispatches Now £0.087 £0.26 Select Mouser No: 71-RN60D-F-806K Mfr. No: RN60D8063FB14 Manufacturer: Vishay Desc.: Metal Film Resistors - Through Hole 1/4watt 806Kohms 1% 100ppm RoHS No - - Add new for headphones bias Availability 1 Dispatches Now £0.201 £0.20 Select Mouser No: 594-VR37000004704FR5 Mfr. No: VR37000004704FR500 Manufacturer: Vishay Desc.: Metal Film Resistors - Through Hole 1/2watt 4.7Mohms 1% RoHS RoHS Compliant By Exemption - - Add new for headphones bias Availability 1 Dispatches Now £0.457 £0.46 Select Mouser No: 505-M100.047/1000/5 Mfr. No: MKP10-.047/1000/5 Manufacturer: WIMA Desc.: Film Capacitors 1000V .047uF 5% PCM15 RoHS RoHS Compliant - - Add new 2 Availability 2 Dispatches Now £0.64 £1.28 Select Mouser No: 505-MKS4.1/1000/10 Mfr. No: MKS4O131004J00KSSD Manufacturer: WIMA Desc.: Film Capacitors 1KV 0.1uF 10% PCM15 RoHS RoHS Compliant - - Add new for headphones bias Availability 4 Dispatches Now £0.718 £2.87 Select Mouser No: 581-TAP476K035CCS Mfr. No: TAP476K035CCS Manufacturer: AVX Desc.: Tantalum Capacitors - Solid Leaded 35V 47uF 10% ESR=800 mOhm RoHS RoHS Compliant Availability 2 Dispatches Now £3.77 £7.54 Select Mouser No: 75-561R10TCCV50 Mfr. No: 561R10TCCV50 Manufacturer: Vishay Desc.: Ceramic Disc Capacitors 1Kvolts 5pF 5% .25LS NPO RoHS RoHS Compliant By Exemption Availability 2 Dispatches Now £0.596 £1.19 Select Mouser No: 667-EEU-FR1E101 Mfr. No: EEU-FR1E101 Manufacturer: Panasonic Desc.: Aluminium Electrolytic Capacitors - Radial Leaded 25VDC 100uF 6.3x11.2mm LS2.5mm RoHS RoHS Compliant - - Add new for low voltage secti Availability 2 Dispatches Now £0.248 £0.50 Select Mouser No: 661-EKYB350E472ML40S Mfr. No: EKYB350ELL472ML40S Manufacturer: United Chemi-Con (UCC) Desc.: Aluminium Electrolytic Capacitors - Radial Leaded 35V 4700uF 20% Tol. RoHS RoHS Compliant - - Add new for low voltage secti 2 Availability 0 Dispatches Now 2 Backordered £2.05 £4.10 Select Mouser No: 80-ALC10A471EH550 Mfr. No: ALC10A471EH550 Manufacturer: KEMET Desc.: Aluminium Electrolytic Capacitors - Snap In 550V 470uF 20% 18k Hours RoHS RoHS Compliant Info: View Additional Product Info Availability 4 Dispatches Now £19.00 £76.00 Select Mouser No: 863-1N5927BRLG Mfr. No: 1N5927BRLG Manufacturer: ON Semiconductor Desc.: Zener Diodes 12V 3W RoHS RoHS Compliant Availability 0 Dispatches Now 2 Backordered £0.341 £0.68 Select Mouser No: 863-1N5934BG Mfr. No: 1N5934BG Manufacturer: ON Semiconductor Desc.: Zener Diodes 24V 3W RoHS RoHS Compliant Availability 2 Dispatches Now £0.364 £0.73 Select Mouser No: 863-1N5952BRLG Mfr. No: 1N5952BRLG Manufacturer: ON Semiconductor Desc.: Zener Diodes ZEN SUR30 REG 3W RoHS RoHS Compliant - - Add new for headphones bias Availability 1 Dispatches Now £0.395 £0.40 Select Mouser No: 625-Z4KE150A-E3/73 Mfr. No: Z4KE150A-E3/73 Manufacturer: Vishay Desc.: Zener Diodes 150 Volt 1.5W 5% RoHS RoHS Compliant By Exemption - - Add new for headphones bias Availability 3 Dispatches Now £0.402 £1.21 Select Mouser No: 863-1N4007G Mfr. No: 1N4007G Manufacturer: ON Semiconductor Desc.: Rectifiers 1000V 1A Standard RoHS RoHS Compliant - - Add new 2 for headphones bias 2 for for low voltage Availability 8 Dispatches Now £0.163 £1.30 Select Mouser No: 511-STTH512FP Mfr. No: STTH512FP Manufacturer: STMicroelectronics Desc.: Rectifiers high voltage diode RoHS RoHS Compliant Availability 8 Dispatches Now £1.27 £10.16 Select Mouser No: 575-113308 Mfr. No: 110-13-308-41-001000 Manufacturer: Mill-Max Desc.: IC & Component Sockets 8P GLD PIN GLD CONT RoHS RoHS Compliant Availability 2 Dispatches Now £0.929 £1.86 Select Mouser No: 651-5452257 Mfr. No: 5452257 Manufacturer: Phoenix Contact Desc.: Fixed Terminal Blocks BC-508X10- 2 BK RoHS RoHS Compliant Availability 3 Dispatches Now £0.805 £2.42 Select Mouser No: 651-5452258 Mfr. No: 5452258 Manufacturer: Phoenix Contact Desc.: Fixed Terminal Blocks BC-508X10- 3 BK RoHS RoHS Compliant Availability 3 Dispatches Now £1.22 £3.66 Select Mouser No: 532-581202B25G Mfr. No: 581202B02500G Manufacturer: Aavid Desc.: Heat Sinks Extruded Style Heatsink with Solderable Pins for TO-220, Flat-Back, Vertical Mounting, 12.8 n Thermal Resistance, Black Anodized, 2.67mm Hole, 50.8mm - - Add new for headphones bias for low voltage secti Availability 1 Dispatches Now £1.37 £1.37 Select Mouser No: 588-EA-T220-38E Mfr. No: EA-T220-38E Manufacturer: Ohmite Desc.: Heat Sinks HEATSINK FOR TO-220 BLK ANODIZED RoHS RoHS Compliant - - Add new for low voltage secti Availability 1 Dispatches Now £1.75 £1.75 Select Mouser No: 532-4180 Mfr. No: 4180G Manufacturer: Aavid Desc.: Thermal Interface Products Insulator, Aluminum Oxide Ceramic for TO-218, TO-247, TO-3P, 1.78mm Thickness, 23.24mm Availability 2 Dispatches Now £0.596 £1.19 Select Mouser No: 532-7721-10PPSG Mfr. No: 7721-10PPSG Manufacturer: Aavid Desc.: Heat Sinks Polyphenylene Sulfide PPS Shoulder Washers, Screw Size #4, 7.62x2.41mm Availability 7 Dispatches Now £0.31 £2.17 Select Mouser No: 532-4171G Mfr. 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  6. pars, If you are interested I have up to 3 spare dual LV (goldenreference6d) boards from my blue hawaii build they are I believe the latest release colour Blue, hot air leveled for leaded solder. Im in the UK. I dont have any spare Dual HV boards but I could get some more made....
  7. Unfortunately my electronic dc load only goes up to 100V, otherwise I would gladly do some measurements and plot some curves.
  8. Only change R8 for positive rail and R9 for negative, don't change R7 and R10 unless you have to. If you keep R7 amd R10 as stock 1.5K then + output required value of R8 20V 1.5K 15V 750ohm 12V 300ohm For negative rail output adjustment change R9. The two resistors NOT to change (R7 and R10) are the ones directly connected to the ground rail. with R7 and R10 fixed: R8 in ohms = ( (voltage you want in volts / 10) - 1 ) * 1500 if R7 and R10 are not stock R8 in ohms = ( (voltage you want in volts / 10) - 1 ) * R7
  9. For me, with the golden reference hv connected to my modern blue hawaii via a variac the golden ref hv needs an *absolute* minimum of 315.5VAC at its AC input to regulate at 404.3VDC output. In normal use I have 330VAC input to the golden ref for 404.3V output.
  10. Thank you JoaMat, I thought seperate heater supplies was the case looking at how the heater pins are connected up via resistors to other parts of the circuit.... I think your are right about going seperate LV and HV transformers. I'm going golden reference HV and LV boards and have made a golden reference HV 220V dedicated board. I want to use synchronous rectifiers for the +-15V on the golden reference LV board so I will go 2x15V 0.3A rather than centre tapped - Kevins sychchronous rectifiers dont like centre tapped transformers. Thank you for the specifications. Time to order some transformers....
  11. JoaMat, Can I ask what are the specifications for the transformer you are using? also do I need seperate heater windings for the el34s and 6922s.? thank you for your help James
  12. sorry to hear that... I hope the opa197 works for you (and me)
  13. in Jose's post there was a mini T2 in vaders hand it was just too small to see..... where as the megatron is too large to ignore...
  14. Well my blue hawaii is working fine with golden ref lv and hv boards.... I want someone to convince me to build a mini t2 seems the next logical step for me without going into rare and expensive transistors.... if only i had the amp boards... or if someone would let me have the gerbers..... <a few momments later......> Me and my big mouth.... I tried to resist but looks like I might be building a mini T2 thanks to JoaMat....
  15. I’m afraid hifi in general in the uk (and probably elsewhere) has been going down the path of high price oblivion for sometime. The market fragments, upgrade paths vanish and less people start on the hobby and good quality kit becomes unaffordable for anyone except professionals/and the rich. I remember when I was a child the local hifi store (stereo only no multi-channel) had Quad, Heaffler, Cambridge audio, castle, Radford, hafler, leak, walker, lowther, b & w, kef, Kinshaw, ferrograph, Goldring Garrard, Decca, Hadcock, Sme, wharfedale, so many British manufacturers and some others like teac, yamaha, ortofon, luxman etc. Over the years one by one as the founders retired and they were replaced by their sons and accountants (c.f. Quad ) the prices went up dramatically, the skills were lost... Quad "lost" all the design work Sir Peter walker did on the esl 57 and 63 and had to reverse engineer them from scratch and rediscover what worked and what did not before they could make any major changes hense the "replacement" to the esl 63 the esl 988 which was a copy of the esl 63 with lower build quality (plastic top and bottoms)... I went to the Quad demo of the 988 at a hifi show, they were selling quad clothing and had pretty girls everywhere... the sound was terrible - I suspect more the hifi they matched with it then the speaker. But the message was obvious buy quad merchandise. The traditional manufacturers closed one by one or got taken over by large groups c.f. Quad etc. Audiolab got taken over by tag who sold the same mid to low budget audio lab kit in expensive looking chassis for 10 times the price.... the hifi magazines where full of their advertising, raved about their products and less than a couple of years later tag vanished.... a while later I believe the original audio lab staff brought the company back and started reselling their original designs back in the original casework and sensible prices.... I remember talking to the owner of my local hifi shop and he told me that in many cases a hifi manufacturer would not let him stock individual components from their range - he either had to stock everything or nothing. This was too much of an investment for him and in some cases he only thought some of a manufacturers range was good... but his ability to pick and choose was being erodded. I read that the entire circulation of all uk hifi magazines now is less than the circulation of one of the smallest ones back when I was young… In 2018 I purchased a hifi/absolute sound issue which stated on the front “ultimate guide to headphones” I read it and was appalled. There was no research, no discussion of the topology at all, One page per product, no internal photos and almost every single review was entirely positive, in most cases the paragraph on the company history was longer than the paragraph on listening experiences. If the review was not 100% positive they added things like “but the more I listened to them the more I liked them”… So its easy to think they you have to have golden ears to appreciate any hifi over a few £100…. Now it’s tough to get started in hifi, most people are happy listening to low fi headphones and compressed music on mobile phones or through laptop speakers.... The hifi magazines refuse to write a bad review of any piece of hifi since they are worried about not being given free review samples, or being sued, or the company pulling adverts from their pages... Cameras are going the same way. Look at what happened to Olympus.... Canon changed the market with the 5D mk 1 - the first affordable full frame 35mm camera, now look at the price of the latest 5Ds and the L series lenses keep going up and up.... I see the same trend now starting with computers, only 2 cpu manufacturers, only 2 graphics cards manufacturers, only 3 memory and flash manufacturers. Graphics card prices have been sky rocketing so in general have cpu prices and especially motherboards ... (sorry for the rant) James
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