Small swetback
Heres a couple of pics of my CSX1 which were working until i decided to adjust the reference voltages closer to target. After changing zeners and reassembly attached probes for bias adjustment i turned on power and bang (probe touched chassis) resulting in resistor death. Disgruntled with my muppetry i left till next day, then not thinking about the fact one of the caps had no path to discharge resistor i then managed to spot weld the wire to chassis stud. (note for vfet part 2 leave more space when designing chassis.)
Heres a couple of pics of my CSX1 which were working until i decided to adjust the reference voltages closer to target. After changing zeners and reassembly attached probes for bias adjustment i turned on power and bang (probe touched chassis) resulting in resistor death. Disgruntled with my muppetry i left till next day, then not thinking about the fact one of the caps had no path to discharge resistor i then managed to spot weld the wire to chassis stud. (note for vfet part 2 leave more space when designing chassis.)
Attachments
I started building the csx1 and, due to extenuating circumstances, will be unable to complete it. I'm sure someone here would love to build this kit, so if anyone is interested in the parts, PM me. Selling the whole set as a unit for $500.
2x Antek as-4224 transformers
16x 15kuf 50v Panasonic caps
2x permaneder csx1 pcbs
2x diyaudio PS boards
3x sets of 2sj28, 2sk82 vfet scrim circuits it
2x Jensen Transformer JT-FLPCH-123 (soldered to pcb)
Various other components, including Zeners, bridge rectifiers, resistors.
2x Antek as-4224 transformers
16x 15kuf 50v Panasonic caps
2x permaneder csx1 pcbs
2x diyaudio PS boards
3x sets of 2sj28, 2sk82 vfet scrim circuits it
2x Jensen Transformer JT-FLPCH-123 (soldered to pcb)
Various other components, including Zeners, bridge rectifiers, resistors.
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I have blown up several Sony VFET prototypes, but have not yet lost one of
the VFETs.
😎
It's nice to know that even an expert can have mishaps, a while back i had the csx running with a short to earth on the output long enough for the amp to get too hot to touch. The amp and VFET's seem unnaffected by my unorthodox burn in test.
Yes, they are strong... I was measuring some curves at Vgs -2V: 4.5 Ampere x 27Volts.
That's 121 Watt. I stopped measuring any further😀
That's 121 Watt. I stopped measuring any further😀
I made a huge mistake. I bought a set of PCBs for Nelson Pass‘ CSX1 from Abraxas336 and I have almost all key parts for VFET amplifier. Big and small transformers, huge power supply caps, HexFred and Schottky-diodes, a good quads of metal can IRF240/IRF9240 TO-3 from Tea-Bag, a 2SK170 BL/2SJ74 BL matched quads from arpagon, big heatsinks, special teflon-silver wires, excellent teflon-foil and ELNA Silmic-II audio caps, some beautiful vintage Deprez-meters, etc. And I have a sensitive enough Audio Note AN-E HE loudspeakers to support CSX1.
And yes - he cries best who cries last. I left to buy 2SK82/2SJ28 pairs for the last time. Two or three month ago I checked these pairs on circiut.diy and that time they were available without any restriction. Now I can not able to find 2 pcs 2SK82 neither 2SK82/2SJ28 pairs. I may buy only 2SJ28s.
I am really so stupid man
, very-very unhappy and unlucky, indeed. Here in Hungary nobody has such an extreme rare parts as 2SK82.
On the other hand, I am so curious man about the sound and beauty of VFETs, but now I almost give up all liking for doing Mr. Nelson Pass' CSX1. I am so desperate.
I do not know. My last idea is might I replace SONY 2SK82s with Hitachi 2SK76s or with something similar? If not I am going to give up.
And yes - he cries best who cries last. I left to buy 2SK82/2SJ28 pairs for the last time. Two or three month ago I checked these pairs on circiut.diy and that time they were available without any restriction. Now I can not able to find 2 pcs 2SK82 neither 2SK82/2SJ28 pairs. I may buy only 2SJ28s.
I am really so stupid man
, very-very unhappy and unlucky, indeed. Here in Hungary nobody has such an extreme rare parts as 2SK82.On the other hand, I am so curious man about the sound and beauty of VFETs, but now I almost give up all liking for doing Mr. Nelson Pass' CSX1. I am so desperate.
I do not know. My last idea is might I replace SONY 2SK82s with Hitachi 2SK76s or with something similar? If not I am going to give up.
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I made a huge mistake. I bought a set of PCBs for Nelson Pass‘ CSX1 from Abraxas336 and I have almost all key parts for VFET amplifier. Big and small transformers, huge power supply caps, HexFred and Schottky-diodes, a good quads of metal can IRF240/IRF9240 TO-3 from Tea-Bag, a 2SK170 BL/2SJ74 BL matched quads from arpagon, big heatsinks, special teflon-silver wires, excellent teflon-foil and ELNA Silmic-II audio caps, some beautiful vintage Deprez-meters, etc. And I have a sensitive enough Audio Note AN-E HE loudspeakers to support CSX1.
And yes - he cries best who cries last. I left to buy 2SK82/2SJ28 pairs for the last time. Two or three month ago I checked these pairs on circiut.diy and that time they were available without any restriction. Now I can not able to find 2 pcs 2SK82 neither 2SK82/2SJ28 pairs. I may buy only 2SJ28s.
I am really so stupid man
On the other hand, I am so curious man about the sound and beauty of VFETs, but now I almost give up all liking for doing Mr. Nelson Pass' CSX1. I am so desperate.
I do not know. My last idea is might I replace SONY 2SK82s with Hitachi 2SK76s or with something similar? If not I am going to give up.
http://www.diyaudio.com/forums/pass-labs/276711-sony-vfet-amplifier-part-2-a-57.html
#564
The store is going to have some pairs soon so Mr Pass has said and then you can build the CSX1 instead since you have the parts for it.
Tried to register my email for product updates at DiyAudio Store (store newsletter) but there is a glitch, I kept getting "Come, Watson, come! The game is afoot" message, although I am registered at the store. I don't want to miss Nelson Pass's vfets and board offering announcement, I know how fast parts disappear at the store!
Got the same message you did. Maybe the store will send out instead a general alert note to all DIYers. My guess the store will limit a pair per buyer in the interest of fairness as granted generously by Mr. Pass. How about a lottery instead? And the 145 winners are.. TBD is a price per pair.
I have six 2SJ28 from Acronman. I am game to trade with the store [or any DIYer] 2SJ28s for 2SK82s.
Should be sold as a kit with PCB, so they are guaranteed to be used for a good purpose, and not just hoarded never to be used.
Hope in DiyAudio Store we can buy PCB's ONLY not kit
as well this give more vfets for Diyers who need it
Attachments
Yeah of course. Just like they offer pcbs separately for the F6 or you can get a F6 kit with transformers.Hope in DiyAudio Store we can buy PCB's ONLY not kit
as well this give more vfets for Diyers who need it
Just make it so the Sony fets must be sold as part of a kit not separately. However you can still buy as many Sony amp pcbs (without Sony Fets) as you want without restriction.
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