@maximax77, my mate's bandsaw was only used for slicing the heatsink, everything else is done with a pillar drill and hand tools.
I gave up on audio shows a long time ago.
I gave up on audio shows a long time ago.
Almost there! I've been doing the internal hook-up wiring today and have done some initial checks/adjustments/tests - voltages are what they should be! I just have to connect up the input phono sockets now before I can finish checking and, hopefully, listen to some music - sadly that will have to wait for a few days as I'm out of time today.
I've been listening to my VFET project this afternoon and it is already making exquisite music - I say already simply because there is definitely more to come as I'm only using a Samsung Galaxy phone as the source and my Noir HPA to drive it for now.
I listened initially with my workbench speakers but the gain of the Noir (9dB IIRC) wasn't enough for anything but a test listen, but once it was clear all was OK I moved to my listening room and hooked up my Lowther BLH speakers - these were efficient enough to have a good listen at a reasonable volume. Firstly thing to note, bearing in mind the efficiency of the Lowthers, was that with nothing playing there was silence, absolutely no hums, buzzes or whatever...
I have to say that the VFET and Lowthers seem to have a really promising synergy; with my SE-OTL amps I always had a nag that the balance was a little forward and the bass a bit light but not with the VFET, which delivered a robust but sweet and subtle sound quality - I had one of those listening sessions where you start to go through your recording library! Tomorrow I will try one of my DSD DACs as the source.
I've not quite finished the build as I still need to contrive some sort of front panel for the chassis - maybe get something 3D printed.
A big thank you to Papa Nelson for sharing this design and enabling me to enjoy such a positive experience.
I listened initially with my workbench speakers but the gain of the Noir (9dB IIRC) wasn't enough for anything but a test listen, but once it was clear all was OK I moved to my listening room and hooked up my Lowther BLH speakers - these were efficient enough to have a good listen at a reasonable volume. Firstly thing to note, bearing in mind the efficiency of the Lowthers, was that with nothing playing there was silence, absolutely no hums, buzzes or whatever...
I have to say that the VFET and Lowthers seem to have a really promising synergy; with my SE-OTL amps I always had a nag that the balance was a little forward and the bass a bit light but not with the VFET, which delivered a robust but sweet and subtle sound quality - I had one of those listening sessions where you start to go through your recording library! Tomorrow I will try one of my DSD DACs as the source.
I've not quite finished the build as I still need to contrive some sort of front panel for the chassis - maybe get something 3D printed.
A big thank you to Papa Nelson for sharing this design and enabling me to enjoy such a positive experience.
The original 2sj28 'lottery' amp uses a constant current source and is optimized for an 8 ohm load.
For this 'Part-3' 2sj18 version, there's a mu-follower used. One can use the same PCB with the 2sj28 and retain the original constant current source design with a few resistor changes. But suppose one wants to use this amp with say a 4 ohm load, would it make sense to build it with the mu-follower instead?
Thanks,
Dennis
For this 'Part-3' 2sj18 version, there's a mu-follower used. One can use the same PCB with the 2sj28 and retain the original constant current source design with a few resistor changes. But suppose one wants to use this amp with say a 4 ohm load, would it make sense to build it with the mu-follower instead?
Thanks,
Dennis
The vfet3 kits are all gone and new kits are not expected at the diy store according to Jason. Any hope for those who still have the sj18 or sk60 in their drawer? Gerbers perhaps? The surplus boards from the pcb-house I would get will be available for other owners of those poor and lonely orphan sj18/sk60 of course...