I've just emailed the remainder of people on the waiting list with an invitation to buy their essential kits. There is now a maximum of 1 kit per member in order to allow as many members as possible to get a chance to build this amplifier.
If anyone is on the waiting list and hasn't got an email in a few hours time, please email contact@diyaudiostore.com and we'll sort you out!
If anyone is on the waiting list and hasn't got an email in a few hours time, please email contact@diyaudiostore.com and we'll sort you out!
I would like to ask Nelson a question if I may. I remember an earlier post where he mentioned that he had a fall back solution using Mosfets for when the all of the Vfets had been allocated. Are there any more details available for this? It may be interesting to build this as well and compare the 2 approaches.
Regards, John.
Regards, John.
Hi Everyone..
I've attached the most up-to-date BOM. It's slightly changed, but mostly the diodes are added, and 4 instead of 2 LEDs with their resistors, because why not! and hardware for the small heatsinks on the PCB. It should be useful for those getting their own parts or who want to know what the Supplemental Kit will have, to make sure they are what you want!
The Supplemental kit will continue to be available for about another week, so that anyone can get it, especially those lucky enough to be scoring a kit after the waiting lists are filled.
As always, if you have your kit then just go here to order the Supplemental Kit if you so desire:
Pass VFET Power Amp Supplemental Kit - diyAudio Store
Mark
I've attached the most up-to-date BOM. It's slightly changed, but mostly the diodes are added, and 4 instead of 2 LEDs with their resistors, because why not! and hardware for the small heatsinks on the PCB. It should be useful for those getting their own parts or who want to know what the Supplemental Kit will have, to make sure they are what you want!
The Supplemental kit will continue to be available for about another week, so that anyone can get it, especially those lucky enough to be scoring a kit after the waiting lists are filled.
As always, if you have your kit then just go here to order the Supplemental Kit if you so desire:
Pass VFET Power Amp Supplemental Kit - diyAudio Store
Mark
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Jason/Variac
Thanks for the mail. I have purchased the Essentials Kit, and the shipping for that is $80. I then attempted to purchase the Supplemental Kit, and the shipping for that was $32. Can I not put these 2 kits together to save on shipping perhaps?
I forgot to add both kits in the cart before paying due to my own stupidity and glee at being allocated an Essentials Kit.
Thanks for the mail. I have purchased the Essentials Kit, and the shipping for that is $80. I then attempted to purchase the Supplemental Kit, and the shipping for that was $32. Can I not put these 2 kits together to save on shipping perhaps?
I forgot to add both kits in the cart before paying due to my own stupidity and glee at being allocated an Essentials Kit.
i was on the waiting list for the second batch, i think. I didn't receive email from Jason. I hope i can get an essentials kit. I only need the pcb's and vfets. The brackets i will order from modushop because i'm in portugal.
Can Jason/Variac let me know what will be my fate?
i really want it! Really!
Can Jason/Variac let me know what will be my fate?
i really want it! Really!i was on the waiting list for the second batch, i think. I didn't receive email from Jason. I hope i can get an essentials kit. I only need the pcb's and vfets. The brackets i will order from modushop because i'm in portugal.
Can Jason/Variac let me know what will be my fate?
Try emailing contact@diyaudiostore.com, worked for me
Try emailing contact@diyaudiostore.com, worked for me
Thats what i did. No responde. I will wait. Thanks
A question about the JFETs for the experts:
I just finished populating my F4 boards and per 6L6's instructions, I tied the JFETs together to help their thermal tracking.
I noticed 6L6 used this technique on the F6 build too.
On the VFET boards it looks like the JFETs (Q1, Q2) are facing each other with the round side, not the flat side as on the F4 and F6. So there wouldn't be any surface area to tie them together.
I'm thinking the ties aren't necessary, then, but I thought I would check to make sure.
Thanks! Almost finished populating my VFET boards. The PCBs are a pleasure to work with.
I just finished populating my F4 boards and per 6L6's instructions, I tied the JFETs together to help their thermal tracking.
I noticed 6L6 used this technique on the F6 build too.
On the VFET boards it looks like the JFETs (Q1, Q2) are facing each other with the round side, not the flat side as on the F4 and F6. So there wouldn't be any surface area to tie them together.
I'm thinking the ties aren't necessary, then, but I thought I would check to make sure.
Thanks! Almost finished populating my VFET boards. The PCBs are a pleasure to work with.
A question about the adjustment of a fully populated PCB (read soldered VFETs).
Somehow my left channel is a bit off compared to the other.
I can get 0-5mV offset at T18, while having 65mV offset at the output OR 0-15mV at the output, but 950mV at T18.
Maybe I turned the wrong pots while adjusting bias, don't remember.
What would be the best procedure to adjust the fully populated PCB?, I don't want to de-solder the VFETS...
The thing I was planning to do; remove the drain screws from the VFETS so the drains have no power and then re-adjust T18 with P3/P4 conform Nelsons manual. After that connect the VFET drains and re-adjust the output offset with P1/P2, again conform the manual.
I think it is better to lift the sides of the gate resistors with this procedure too, but that may not be necessary...
If someone has an advice/idea , that would be very helpful.
Somehow my left channel is a bit off compared to the other.
I can get 0-5mV offset at T18, while having 65mV offset at the output OR 0-15mV at the output, but 950mV at T18.
Maybe I turned the wrong pots while adjusting bias, don't remember.
What would be the best procedure to adjust the fully populated PCB?, I don't want to de-solder the VFETS...
The thing I was planning to do; remove the drain screws from the VFETS so the drains have no power and then re-adjust T18 with P3/P4 conform Nelsons manual. After that connect the VFET drains and re-adjust the output offset with P1/P2, again conform the manual.
I think it is better to lift the sides of the gate resistors with this procedure too, but that may not be necessary...
If someone has an advice/idea , that would be very helpful.
You should be able to set the front end without removing the V-fets. Do you have 1.5V's between T6 & T7 andT8 & T9? If so you probably just need to start over adjusting P1 and P2. If you adjust one pot too much more than than the other you will have the trouble you are describing, reaching .1V on R32 with acceptable DC offset.
+1 on not removing the vfets!
Asanden, from my own experience, I think you are closer than you suspect and you don't need to start over on anything.
Recall NP's reminder that all the pots interact with each other. Let that sink in for a minute. Ideally you have multiple meters. Don't be afraid to tweak P3/4 a little. I had more offset than you report and it was just a matter of tweaking a tiny bit here or there and figuring out the direction things were going. Took me an hour or so to just get the feel of it. Baby steps. As I said, it was like balancing a marble on a pin, but then again I was shooting for microvolt offsets ;-)
BK