I wonder if Yamaha 2SJ38 would be a suitable substitute for the Sony's in this particular circuit?
Asking because I have 2 of them plus a single 2SK98.
Asking because I have 2 of them plus a single 2SK98.
First post on diyaudio
Hi fellow diyers!
Sorta ashamed this is my first post ever on diyaudio after many years of lurking and many hundreds , thousands ? (Lost count) of dollars spent at diyaudio store and countless obsolete parts and mouser, digikey, parts express orders. I think this is a incurable disease! Finally getting the email about the upcoming vfet amplifer lottery made me want to thank all those
Involved in putting these kits together at cost for the community (Nelson, Jason, mark, 6l6, zen mod (still need my translator to figure out zen mods zenglish) and many other I’m missing. Lurking so many years reading all these many posts feels like I sorta know some of them lol. I’m still very much a newbie in the presence of so many more brilliant people and always striving to learn more! So I feel like I have learned things Even in the background ! Honestly, I don’t feel like I have much of a shot at this Sony vfet amp but figured it’s a possibly after missing out on the first round of Sony vfets years ago. I did not realize they sold out in minutes ! If nothing else I will await Nelson’s release of the next part so all of us can use our Japan purchase tokin and Sony vfets. I bought a
Matched pair of each so hoping to put these expensive parts to make glorious music ! Neslon has hinted that tokins can be used possibly on higher power amps. Anybody have a ballpark on what that power possibly is? First watt power 25ish watts or more? Sorry for the rambling long post. Just wanted to thank those involved and hope to donate to a good cause. Option at purchase to give mow $$? I Hope some good karma is coming my way Wednesday ! Good luck to all!
Hi fellow diyers!
Sorta ashamed this is my first post ever on diyaudio after many years of lurking and many hundreds , thousands ? (Lost count) of dollars spent at diyaudio store and countless obsolete parts and mouser, digikey, parts express orders. I think this is a incurable disease! Finally getting the email about the upcoming vfet amplifer lottery made me want to thank all those
Involved in putting these kits together at cost for the community (Nelson, Jason, mark, 6l6, zen mod (still need my translator to figure out zen mods zenglish) and many other I’m missing. Lurking so many years reading all these many posts feels like I sorta know some of them lol. I’m still very much a newbie in the presence of so many more brilliant people and always striving to learn more! So I feel like I have learned things Even in the background ! Honestly, I don’t feel like I have much of a shot at this Sony vfet amp but figured it’s a possibly after missing out on the first round of Sony vfets years ago. I did not realize they sold out in minutes ! If nothing else I will await Nelson’s release of the next part so all of us can use our Japan purchase tokin and Sony vfets. I bought a
Matched pair of each so hoping to put these expensive parts to make glorious music ! Neslon has hinted that tokins can be used possibly on higher power amps. Anybody have a ballpark on what that power possibly is? First watt power 25ish watts or more? Sorry for the rambling long post. Just wanted to thank those involved and hope to donate to a good cause. Option at purchase to give mow $$? I Hope some good karma is coming my way Wednesday ! Good luck to all!
Interesting project.
Can anybody please give me a hint how this wil sound different to my LM3668 Gainclone monoblocks?
Can anybody please give me a hint how this wil sound different to my LM3668 Gainclone monoblocks?
From reading the description, for the FULL kits numbering 180 units, I would believe so. As the kit sounds like it comes with chassis, boards, discrete components, PSU, and partially built and mounted Sony VFET components all together. The other 20 kits are for those diy'ers already with the Sony VFETs in their desk drawers and "junk boxes".
The only thing I would imagine the kits not including possibly are the wires, solder, tools, and heat transfer goop.
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Can this amp be used with an F4 to provide more output wattage for those with less efficient speakers?
Looks like you could make monoblocks out of this amp by adding a second power supply and getting an additional PS board. My guess is that the PS is not going to be available separately.
Looks like you could make monoblocks out of this amp by adding a second power supply and getting an additional PS board. My guess is that the PS is not going to be available separately.
i already have some TO3 IRF244 , thinking of an IRF244 / 2SJ18 dream machine , let find an old sony 4650 with intact VFET 🙂
For clarification, this lottery is for the first batch of P-channel versions, correct? So will there be another lottery in a couple of months or so when the N-version comes out? 😕
The kits include everything. We want every single one of these built, so they include all hardware, wire, the heatsink goop, as well as the parts, sub-assemblies, chassis. PSU, etc... you need only to bring your tools, patience, and skill.
Thomaudio - I’m not sure what’s going on with the lottery specific to the N-channel version, I.E., if the lottery will be one big one or if it’s going to be split... Jason will have to clarify. The N-version will be released after the P-version, essentially wave number 2.
And for the record, the differences between the P- and the N- versions are effectively zero. The entire design is made to be ambidextrous and the input stage can operate with positive or negative ground. Nelson says the Sony devices are as close to true compliments as have ever been, and the two versions are merely mirror-images of each other. There’s not much difference between the two. For the sake of keeping things simple and smooth they will be released in their own batches, and no, you don't get to choose between the two.
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Using an F4 behind this would definitely have superior damping factor and higher current. And much better performance with say, 4 ohm speakers. But still retaining the VFET "magic" that's the whole point of this. (I like the F4 in case no one noticed.. 🙂)
Yeah, that's a good point for everyone reading this thread. The F4 is an always-available-forever-build for anyone. If you drive the F4 with an actual SET line-stage or amplifier it sounds like a SET (the tubier the better) which retains the magic but with real current delivery, with the bottom-end being completely cleaned up with actual DRIVE.
Everyone should build an F4 and drive it with different tubes! 😀
Everyone should build an F4 and drive it with different tubes! 😀
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Yamaha 2sj38 is a low Vgdo device. Only 55V. Supply voltage is 36V and bias may be 6-12V. Total will be less than 50 V .So you can use it. but be careful not to exceed Vgd beyond the limit.
Is it powerful enough to drive ESL-63s to moderate levels? (Used a Sony TA-N5550 ten years ago and liked the honey-dripping sweet sound, but too lean bass so I sold it on.)
I’d just like to say, in addition to Thank You, that the chassis is just gorgeous. I bought two Tonkins when this project was first disclosed, so will wait my turn. But what a wonderful opportunity to learn more about our hobby while getting a professional looking product in the end. Also, having built the B1K and adding the little power filter, I really endorse the use of a SMPS as a way to make DIY more accessible to less experienced folks who are rightly concerned about building their own PS. I know that was a big reason I was willing to tackle an Amp Camp Amp for my first project.
I am confused...
The article says that the 2SJ28 is biased at Vgs = 8 V DC (or possibly a bit higher, depending on the exact characteristics of the part). This means that the AC drive voltage cannot swing more than 8 Vpk before Vgs hits 0 V (voltage clipping). Since the 2SJ28 is configured as a voltage follower, the output voltage swing of the amplifier cannot be more than 8 Vpk, or 5.7 V-RMS (looking at the 2SJ28 curves, the amp might actually run into voltage clipping at even lower AC voltages). 5.7 Vrms corresponds to 4 Watt (RMS) into a 8 Ohm load, or 8 Watt into 4 Ohm.
However, as far as I can tell, the 8 Ohm distortion curve shown in Nelsons article does not seem to show any clipping up to 10 W. Can anyone shine some light on what's going on here? Did Nelson use a 2SJ28 part that allows higher Vgs biasing for this measurement? Or is there something else that I am missing?
The article says that the 2SJ28 is biased at Vgs = 8 V DC (or possibly a bit higher, depending on the exact characteristics of the part). This means that the AC drive voltage cannot swing more than 8 Vpk before Vgs hits 0 V (voltage clipping). Since the 2SJ28 is configured as a voltage follower, the output voltage swing of the amplifier cannot be more than 8 Vpk, or 5.7 V-RMS (looking at the 2SJ28 curves, the amp might actually run into voltage clipping at even lower AC voltages). 5.7 Vrms corresponds to 4 Watt (RMS) into a 8 Ohm load, or 8 Watt into 4 Ohm.
However, as far as I can tell, the 8 Ohm distortion curve shown in Nelsons article does not seem to show any clipping up to 10 W. Can anyone shine some light on what's going on here? Did Nelson use a 2SJ28 part that allows higher Vgs biasing for this measurement? Or is there something else that I am missing?
