Here is a report of Vfet knowing that my ears are my age and treble from 15Khz have been on leave for some time.
Note: my active line + phono preamp does not have enough gain (+ 6dB) for this amp that has low sensitivity.
Potentiometer thoroughly, it does not come out 15W. This "moves" already not bad, so there are still settings to do.
Scene: Beautiful dimension of the sound stage with a depth giving a good perspective of
listening.
This distance is well perceived between the rear and foregrounds bringing a credible
realism as well as a staggering of the plans very natural sounds on good recordings.
Message: Register coherence, realistic and dynamic level deviations allowing excellent
restitution of the sound universe. Natural tonal balance with density in different
tessitura registers.
Sound: Balance +++ of the intensity of the different registers without accentuation, respect
of the stamps with a high quality thick on the bass harmonics and luster on the upper
ones. Very good sound energy bringing a living presence.
Comparison:
- Vfet / 845 SE Diafan: Denser bass with more rhythmic impact. Medium less rich, thicker.
Treble having more brilliance.
- Vfet / Luxman MQ 360: Bass more accurate with more thickness, Medium, Treble richer
- Vfet / Hiraga 20W: Nothing to see, very different.More homogeneity, high medium and
treble more present making the copy more realistic by not emphasizing
the serious register. (Heats less than Hiraga).
- Vfet / FX D802: All in favor of the Vfet, Emotion / Sensation? maybe the dynamics?
In summary, amha, it's really a solid state amp that is closest to the tube amps (in the good sense of the word) but can be with more balance in the registers, a scene and a more realistic sound stage , a greater ability to render details, more dynamics and finally less distortion and even less saturation.
Note: my active line + phono preamp does not have enough gain (+ 6dB) for this amp that has low sensitivity.
Potentiometer thoroughly, it does not come out 15W. This "moves" already not bad, so there are still settings to do.
Scene: Beautiful dimension of the sound stage with a depth giving a good perspective of
listening.
This distance is well perceived between the rear and foregrounds bringing a credible
realism as well as a staggering of the plans very natural sounds on good recordings.
Message: Register coherence, realistic and dynamic level deviations allowing excellent
restitution of the sound universe. Natural tonal balance with density in different
tessitura registers.
Sound: Balance +++ of the intensity of the different registers without accentuation, respect
of the stamps with a high quality thick on the bass harmonics and luster on the upper
ones. Very good sound energy bringing a living presence.
Comparison:
- Vfet / 845 SE Diafan: Denser bass with more rhythmic impact. Medium less rich, thicker.
Treble having more brilliance.
- Vfet / Luxman MQ 360: Bass more accurate with more thickness, Medium, Treble richer
- Vfet / Hiraga 20W: Nothing to see, very different.More homogeneity, high medium and
treble more present making the copy more realistic by not emphasizing
the serious register. (Heats less than Hiraga).
- Vfet / FX D802: All in favor of the Vfet, Emotion / Sensation? maybe the dynamics?
In summary, amha, it's really a solid state amp that is closest to the tube amps (in the good sense of the word) but can be with more balance in the registers, a scene and a more realistic sound stage , a greater ability to render details, more dynamics and finally less distortion and even less saturation.
......If we regulate filament heaters correctly and an HT in the specifications:
- A set of GE 6550A can last 8000 hours to 10000 hours.
- A 5687, ECC82, can last 20000 hours.
I built this amp because the Vfets have the same constrcution as a triode.
And it's true, in my humble ears, the delivered sound is very similar
The diy tube is easier than the diy solid state because the wiring is simpler and can be done without circuit.
- A set of GE 6550A can last 8000 hours to 10000 hours.
- A 5687, ECC82, can last 20000 hours.
I built this amp because the Vfets have the same constrcution as a triode.
And it's true, in my humble ears, the delivered sound is very similar
The diy tube is easier than the diy solid state because the wiring is simpler and can be done without circuit.
I have a question regarding the capacitors C5 and C6. The consensus on these caps seems to be that they're DC-level shifting caps and are not to be viewed as coupling caps in a strict sense. They more or less correspond to C1 and C2 of the First Watt F4.
Searching the F4 thread, I've gathered the information that the absolute value is not really critical, and that anything above 100uF should do fine. Going lower supposedly results in turn on thumps of the amplifier, and still going lower will for a highpass form the audio signal.
Now, my question is: Is it worthwhile replacing C5 and C6 in the VFET amp with non-polar, possibly film-foil capacitors?
I haven't found any reports of anyone actually using film-foil capacitors in that particular spot in the F4 thread. We know from Nelson's previous comments that semiconductors are the elephant in the room, but since we've arrived at VFET push-pull output stages, I suppose we could at least give it a thought.
Searching the F4 thread, I've gathered the information that the absolute value is not really critical, and that anything above 100uF should do fine. Going lower supposedly results in turn on thumps of the amplifier, and still going lower will for a highpass form the audio signal.
Now, my question is: Is it worthwhile replacing C5 and C6 in the VFET amp with non-polar, possibly film-foil capacitors?
I haven't found any reports of anyone actually using film-foil capacitors in that particular spot in the F4 thread. We know from Nelson's previous comments that semiconductors are the elephant in the room, but since we've arrived at VFET push-pull output stages, I suppose we could at least give it a thought.
Weird, looks like they're 7/64" imperial, didn't even know I had an imperial bit set. Metric 2.5mm is definitely too small, 3mm is already too big.
While we're at it, does anyone have a Mouser part number for a nice TO3 mounting kit?
They should be imperial as the TO-3 metal can mounting spec is for imperial bolts so that’s what we used. In the future maybe it would be smart for us to check if there is a close equivalent in Metric, for our international crowd
The bolts that attach the brackets to the chassis are metric but have PHILIPS heads so there woulddlyt be a confusing mix pf recessedhead bolts.
Maybe we should just use Phillips on everything in the upcoming kits even though they don’t look as cool
The bolts that attach the brackets to the chassis are metric but have PHILIPS heads so there woulddlyt be a confusing mix pf recessedhead bolts.
Maybe we should just use Phillips on everything in the upcoming kits even though they don’t look as cool
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2.5mm is to small. I'm going to try and source a 7/64 key either that or just buy some metric s/s screws as 4mm will fit the vfets and 3mm the mosfets.
My build is slowly coming together with the p/s built and giving 30.5v unloaded and the heatsinks are drilled and tapped and the T bracket made. Case is from Modushop.
My build is slowly coming together with the p/s built and giving 30.5v unloaded and the heatsinks are drilled and tapped and the T bracket made. Case is from Modushop.