Thanks Bob!
ZM, this is actually my one and only ‘stereo’ case. I figured this would be the final/permanent build for this case so I ditched the base plate and quick connects (for the most part). That means my next purchase will have to be a new chassis, and I got my eye on the biggest one I can find
ZM, this is actually my one and only ‘stereo’ case. I figured this would be the final/permanent build for this case so I ditched the base plate and quick connects (for the most part). That means my next purchase will have to be a new chassis, and I got my eye on the biggest one I can find
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Thanks Anand and Eric! The heat dissipation (or lack there of) has been a pleasant surprise. Having run heat monsters for a while now, it’s been nice to see heatsinks in the 40c range again This amp does match nicely to the 3U/4U 300 sizes.
I didn’t come into this build with any big expectations regarding sound quality. I knew it was a NP designed SIT amp (which says most of what we need to know), but it really is an exceptional sounding amp by any standard.
And regarding the 1W RTA - note that my Vfets were not matched between polarity or channel. Same for the VGS mosfets. Heck, I even used J74’s with slightly higher Idss then their 170 counterparts. Guess I was worried I wouldn’t have enough distortion for my taste
This amp does match nicely to the 3U/4U 300 sizes.I didn’t come into this build with any big expectations regarding sound quality. I knew it was a NP designed SIT amp (which says most of what we need to know), but it really is an exceptional sounding amp by any standard.
And regarding the 1W RTA - note that my Vfets were not matched between polarity or channel. Same for the VGS mosfets. Heck, I even used J74’s with slightly higher Idss then their 170 counterparts. Guess I was worried I wouldn’t have enough distortion for my taste
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In comparison with the P-Ch lottery amp, the VFet2 amp has a good deal more control over the bass. Subjectively, it sounds like there is a bit more bass.
This is not to say that the SE lottery amp is lacking bass at all, but the PP nature of the VFet2 amp makes a noticeable difference. I haven't swapped them in and out enough to pick up other differences through the mids and treble.
It's also getting colder here in North America as we get closer to winter, so it's time to put the AlephJ back into service. I need to some SPL measurements and make a little chart of channel level settings for each of my amps to facilitate easier swapping.
This is not to say that the SE lottery amp is lacking bass at all, but the PP nature of the VFet2 amp makes a noticeable difference. I haven't swapped them in and out enough to pick up other differences through the mids and treble.
It's also getting colder here in North America as we get closer to winter, so it's time to put the AlephJ back into service. I need to some SPL measurements and make a little chart of channel level settings for each of my amps to facilitate easier swapping.
what's not to like?
BA3 FE ( and some other type numbers which we are not going to mention) working with proper swing, nicely umbrelled VFets in OS ........ VFet Magic
Very true. It’s kinda like a ‘greatest hits’ of semi’s… K170/J74; K2013/J313; IRFP240/9240; K82/J28
… a few of my favorite things… 
Single ended amps are very speaker dependent as far as there sound stage, bass control, etc.
These low power amps are great in the right system.
I sold mine because I changed speakers to Quad ESL 989 and now the VFET2 PP amp sings.
Rush
While I don't have the earlier VFET2 PP amp to compare, I have found that my single-ended P-ch VFET amp benefits remarkably when being powered by an external linear supply. Much is the improvement is in bass extension and definition. There is also significant improvement in imaging and detail throughout the audio spectrum.
The recent VFET2 build presented in this thread looks like it is benefiting from a properly built linear supply. Makes all the difference.
The recent VFET2 build presented in this thread looks like it is benefiting from a properly built linear supply. Makes all the difference.
The linear nature of the PSU allows it to be tailored for low noise and low output impedance. I used a single rail SLB + 30 mF of extra capacitance for each channel. The extra capacitance was located in the VFET amp chassis.
Some of the new SMPS which allow substantial capacitance on their output do look promising.
Some of the new SMPS which allow substantial capacitance on their output do look promising.
