Bart,
For reference, Variac posted a BOM for the 2016 diyaudio vfet project (two vfets per channel):
https://www.diyaudio.com/community/threads/sony-vfet-amplifier-part-2.276711/page-139#post-4991406
You should verify things from the original article: https://firstwatt.com/pdf/art_diy_sony_vfet.pdf
(Note a number of the parts in Variac's bom are no longer available or are currently out of stock, but a lot of subs are available.)
BTW, there is a build thread for that project here:
https://www.diyaudio.com/community/threads/sony-vfet-illustrated-build-guide.302380/
Good luck with your build.
Dennis
For reference, Variac posted a BOM for the 2016 diyaudio vfet project (two vfets per channel):
https://www.diyaudio.com/community/threads/sony-vfet-amplifier-part-2.276711/page-139#post-4991406
You should verify things from the original article: https://firstwatt.com/pdf/art_diy_sony_vfet.pdf
(Note a number of the parts in Variac's bom are no longer available or are currently out of stock, but a lot of subs are available.)
BTW, there is a build thread for that project here:
https://www.diyaudio.com/community/threads/sony-vfet-illustrated-build-guide.302380/
Good luck with your build.
Dennis
Depends on the transistor. With 2SJ18, take 2x.47; else with 2SJ28 take 1x .84. And a short in the second position of R2.
(I have .82 because that was in my box (the kit i got assumes 2SJ18) and I complemented it with .12 to get the original total of 2x .47 value; but I know I deviated from practice.)
(I have .82 because that was in my box (the kit i got assumes 2SJ18) and I complemented it with .12 to get the original total of 2x .47 value; but I know I deviated from practice.)
Hello,It's easy to do once you have a handy TRS headphone jack to speaker cable adapter.
Here is the headphone connected to my VFET (No. 010). I am using a SE/balanced hybrid SS/tube buffer stage with 14dB gain to drive everything.
How did you wire TRS phone jack to speaker cable adapter ? I can see some resistors.
Thanks
I'd ask a few things in addition...
1) Is the amplifier in the picture the p-channel VFET offered as a kit mentioned in post #1 of the thread?
2) If so, did the extraordinarily-skilled builder of the amplifier choose to wire their speaker binding posts differently than the build guide for their own reasons?
3) If I have a P-channel VFET amplifier built per the guide... should I connect my adapter in the manner shown in the picture?
1) Is the amplifier in the picture the p-channel VFET offered as a kit mentioned in post #1 of the thread?
2) If so, did the extraordinarily-skilled builder of the amplifier choose to wire their speaker binding posts differently than the build guide for their own reasons?
3) If I have a P-channel VFET amplifier built per the guide... should I connect my adapter in the manner shown in the picture?
I have two 220ohm 1W resistors wired from Ring and Tip to Sleeve (GND) to provide a small high impedance load for the amp - this is mainly to drain the DC offset from capacitor coupled outputs so I don’t get a big pop when I plug in the headphones for the first time. Other than that, the TRS jack is wired Ring to right and Tip to left and Sleeve to GND (per usual convention for TRS stereo).
Some people like to use 22 ohm or 47ohm or similar resistor in series to reduce the signal getting to the headphone. I don’t have that.
Be careful with DC coupled outputs as a single turn on thump or pop can destroy a sensitive headphone or earbud just like that.
Is the input impedance of the P-channel version more or less defined by the 3 x 1 MEG resistors in parallel (R2, R3, R5)?
So 1 MEG / 3 approx.?
This is a very easy driven power amp? ......more easy than many pre-amps?
I have a DAC which can be set to "pre-amp" mode (instead of fixed output). Then vol. will be controlled in digital domain (company claims it is loss free). It seems to work well. Probably because the VFET amp is easy to drive. I just wanted to experience the VFET as pure as possible. It is also the most silent setup I have experienced.
So 1 MEG / 3 approx.?
This is a very easy driven power amp? ......more easy than many pre-amps?
I have a DAC which can be set to "pre-amp" mode (instead of fixed output). Then vol. will be controlled in digital domain (company claims it is loss free). It seems to work well. Probably because the VFET amp is easy to drive. I just wanted to experience the VFET as pure as possible. It is also the most silent setup I have experienced.
I use a Cambridge DacMagic 200M. The digital preamp vol control may only be "bit-perfect" for 16-bit music......but I don't now how it is implemented.
If there is a small loss for 24-bit music they will probaby claim that it is still better than using an analog solution.
The VFET amp it self is very silent and I can't hear any added noise using the DAC as pre-amp. The RCA out from the DAC is standard 2Vpp or so. It seems sufficient for my 94 dB speakers to play load enough.
I have just switched to this setup from using a real pre-amp so I do not have a final verdict yet
If there is a small loss for 24-bit music they will probaby claim that it is still better than using an analog solution.
The VFET amp it self is very silent and I can't hear any added noise using the DAC as pre-amp. The RCA out from the DAC is standard 2Vpp or so. It seems sufficient for my 94 dB speakers to play load enough.
I have just switched to this setup from using a real pre-amp so I do not have a final verdict yet
A friend here built his own version of a Sony VFET amp and raves about, especially driven by this preamp.
https://glass-ware.stores.turbify.net/ainost.html
https://www.tubecad.com/2018/03/blog0415.htm
What amazes is me is how people here and probably lots where else can continue to build Sony VFET amps when production of those transistors ended decades ago.
https://glass-ware.stores.turbify.net/ainost.html
https://www.tubecad.com/2018/03/blog0415.htm
What amazes is me is how people here and probably lots where else can continue to build Sony VFET amps when production of those transistors ended decades ago.
Aikido is fantastic...IMHO. I can't wait to try it with VFET—when I finish them!!! Certainly a great preamp though with several other FW offerings... like M2X.