If such a festival can be arranged, perhaps we might even see the
granddaddy of them all, the Sony 40th Anniversary VFet amp. 🙂
I am going to release one more batch (and then I will really be out of parts).
I saw the DIYaudio email too late and missed the last V-Fet sale. I will definitely buy when you have this third round. Hopefully I don't miss it this time around!
Thanks
Do
I've been reading Papa's DIY Vfet article and am trying to understand the
adjustment for the Vfet bias. Would someone be able to verify that the
minimum voltage of T16 (resp T17) should be about 6.4V (resp. -6.4V)?
Thanks,
Dennis
adjustment for the Vfet bias. Would someone be able to verify that the
minimum voltage of T16 (resp T17) should be about 6.4V (resp. -6.4V)?
Thanks,
Dennis
I have been really gratified by the success of this effort on several levels -
1) DIY Audio has done a great job of getting these out, and at an
incredibly reasonable price. For that, many thanks.
2) The design is apparently build-able by DIYers and I am confident that
we have enough spare parts to cover the usual incidents and accidents...
3) Everybody seems to love the sound.
I am not certain as to which of these three is the most important to me,
but taken together I am delighted.
I am going to release one more batch (and then I will really be out of parts).
Hi Mr pass
Sounds really good. When i found out that they where for sale they where all gone. When will you sell the last batch?
And thank you very much for making these unobtanium parts available to us
For the first batch we "had" to wait for about one year (see post #87). The second (and supposedly last) batch took another three months or so to happen. To make all this happen, it must have been an incredible effort and expense of time for those involved, and I am very grateful that Nelson and the folks from diyAudio made it happen.
I suggest you have some more patience.
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Patience? Is that a virtue or something? Is asking a question impatience, or is it asking a question? Isn't prudence also a virtue?
I'll be patient. I'm not very good at it though, so if I ask again in a little while, please be patient with me. 😉
Asking multiple times won't accelerate the release of the 3rd batch, the same way that looking at a kettle heating water won't make it boil faster... 😉
Sorry but I do not completely understand your question to be able to give a response. Are you talking about when you do the voltage test of the board? If so the voltages do not have to be dead on, just close. Nelson states 10V but there is some leeway until the pots are turned correctly. I do not remember having to check V at T16 or T17 when biasing up the front end or V-fets.
Hi Wdecho,
My question is actually related to the part where you adjust P1 and P2
to get voltages at T16 and T17 to be about 1 Volt away from the Vgs test
voltages of the Vfets. For example, as you increase the resistance of P1,
the T16 voltage should drop.
What I am wondering about is how low can the voltage at T16 get. (I'm
thinking this should occur at the max resistance of 5K for P1 with
T19 about 7.5V, but I don't know if I'm understanding the voltage drop
across R22 correctly.)
My interest in this is that I have some vfets where for Vds=19V, the Vgs
is about 6V @ 1A, so I'm curious if they will bias up correctly with the
circuit as-is.
Thanks,
Dennis
I'm sorry but I cannot give an answer. Maybe someone else can. I just set mine up as described in NP article with no problem.
That's ok. It's more of a theoretical concern for me right now since it may
still be a while before I'm in the position to build anything.
Thanks,
Dennis
Dennis - As one of the bias regulator set resistors is a pot, there should be enough adjustment range in that circuit to get the bias voltage to your required amount. But as I only have a completed amp I have no easy way to test it.
Also, the "stuff in the middle" as I call it (R21, C5, R23 and their mirrors) isn't for dropping voltage off the bias regulator, but rather to stop the Front-End signal (the music) from having any effect on modulating the set point of the bias regulators. So the signal voltage can't travel upstream to the regs and rather goes to the gates of the Vfets as intended.
Also, the "stuff in the middle" as I call it (R21, C5, R23 and their mirrors) isn't for dropping voltage off the bias regulator, but rather to stop the Front-End signal (the music) from having any effect on modulating the set point of the bias regulators. So the signal voltage can't travel upstream to the regs and rather goes to the gates of the Vfets as intended.
Tizman is trying to show enthusiasm and commitment IMHO. And he has reason to worry!
Not sure how Jason is going to handle this. I'm the production department and he takes care of the orders.
It's a new development, as we just finished a big effort on what we thought was the final batch at least for quite a while, and suddenly there are potentially more VFETS available! I'm now focused on the Supplementary Kits which we promised to do, so the final batch of Essentials Kits won't even be started being packaged for a couple of months. In fact Nelson still has to test the VFETS.
HOWEVER since people now pay in advance for the kits, Jason could open the ordering at any time and he probably will as he needs to know how many brackets for example to order and they take at least 2 months to manufacture and ship.
We'll do our best to warn you all in this thread first.
Mark
Not sure how Jason is going to handle this. I'm the production department and he takes care of the orders.
It's a new development, as we just finished a big effort on what we thought was the final batch at least for quite a while, and suddenly there are potentially more VFETS available! I'm now focused on the Supplementary Kits which we promised to do, so the final batch of Essentials Kits won't even be started being packaged for a couple of months. In fact Nelson still has to test the VFETS.
HOWEVER since people now pay in advance for the kits, Jason could open the ordering at any time and he probably will as he needs to know how many brackets for example to order and they take at least 2 months to manufacture and ship.
We'll do our best to warn you all in this thread first.
Mark
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That's fantastic. I would love to pay in advance for a kit and wait (impatiently) to receive it. In the meantime, I'm going to do a little experiment with watching the kettle. I'm pretty sure that it boils faster when I watch it. Something to do with entanglement or something. Only a careful scientific analysis can properly answer that question.