next turn would be nec k70/j20. I know they limit D-S almost twice as low ref k60/j18, about 80V or so, but they can deliver up to 40A current, so damping factor I expect to be noticeably higher.
Presents, for me?
My Boards Arrived 😀
Much faster than I expected too so kudos to the DIYaudio store too
Better get my thinking hat on, Haven't even got a chassis yet 😱 But feeling good that I've got all the potentially tricky to get bits though, at least I think so at this point.
Should be a good project; *Almost* makes up for the initial mistake that make the V-Fets available in the first place
Andy
My Boards Arrived 😀
Much faster than I expected too so kudos to the DIYaudio store too
Better get my thinking hat on, Haven't even got a chassis yet 😱 But feeling good that I've got all the potentially tricky to get bits though, at least I think so at this point.
Should be a good project; *Almost* makes up for the initial mistake that make the V-Fets available in the first place
Andy
G'day to All!.
Have question: my last build is a bit deviated from plain vanilla design, changes are:
1. k76/j26 instead of k82/j28
2. irf630/irf9630 instead of j313/k2013, which have higher Vgs(threshold) so:
3. R34-R35 are 1kOhm instead of 221 ohm.
well, having all DC offset at the front end and OS fully set up almost to zero AFTER warming all up, I faced the situation with almost +1V DC at output and +4V DC at T18 right after turning on at COLD amp. Resulted in sensible punch on Woofers. Speaker delay is only 15 sec, I can make it up to 30-40 sec max, but still it is about 0,4VDC at the output after 40 sec run. Everything settles to acceptable 0,1V only after 4 mins of run, there's no way to extend speaker on delay.
I tried many combinations of T18 and 0+ adjustments, pushing them both into opposite offset, but nothing helped.
Since I am out of J28/K82, I tried J18/K60 which are almost the same on Vgs. Did not help, as well.
Why is it so? May be I have to deal with Q5/Q6? Matching them on Ids/Vgs or whatever?
All ideas appreciated, thanks in advance.
Have question: my last build is a bit deviated from plain vanilla design, changes are:
1. k76/j26 instead of k82/j28
2. irf630/irf9630 instead of j313/k2013, which have higher Vgs(threshold) so:
3. R34-R35 are 1kOhm instead of 221 ohm.
well, having all DC offset at the front end and OS fully set up almost to zero AFTER warming all up, I faced the situation with almost +1V DC at output and +4V DC at T18 right after turning on at COLD amp. Resulted in sensible punch on Woofers. Speaker delay is only 15 sec, I can make it up to 30-40 sec max, but still it is about 0,4VDC at the output after 40 sec run. Everything settles to acceptable 0,1V only after 4 mins of run, there's no way to extend speaker on delay.
I tried many combinations of T18 and 0+ adjustments, pushing them both into opposite offset, but nothing helped.
Since I am out of J28/K82, I tried J18/K60 which are almost the same on Vgs. Did not help, as well.
Why is it so? May be I have to deal with Q5/Q6? Matching them on Ids/Vgs or whatever?
All ideas appreciated, thanks in advance.
I have looked, but have been unable to find how to test the Sony Vfets in my possession to ascertain if they are matched. It is true, I am not good at finding things. Any help in this regard would be greatly appreciated. Thank you!
Here is some info:
Sony VFET Amplifier Part 2
Example of power supplies:
Sony VFET Amplifier Part 2
The VFET being tested should be mounted on a heat sink.
VFET pin outs:
Sony VFET Amplifier Part 2
Sony VFET Amplifier Part 2
Example of power supplies:
Sony VFET Amplifier Part 2
The VFET being tested should be mounted on a heat sink.
VFET pin outs:
Sony VFET Amplifier Part 2
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Mr. Mah Thank you! And Mr Pass, I cannot thank you enough for your generosity. I have been reading and building your projects for the last 20 years or so.
One important thing about testing VFETs. VFETs are fully on and passing maximum current when Vgs=0. So when testing, always turn on Vgs first and make sure Vgs is maximum. Measure Vgs at the VFET with a voltmeter. That way you don't have to worry about whether you have the pot connected CCW or CW. Only turn on Vds when you are sure Vgs is set to maximum.
My Troels Gravesen TQWT MKII speakers now built and paired with Sony VFET2 amp. Better deserving amplifier 🙂
An externally hosted image should be here but it was not working when we last tested it.
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Pass DIY Addict
Joined 2000
Paid Member
Sweet set up! I've been eyeballing a number of Troels' designs lately. So many to choose from 😉
SONY VFET Version 2 gerbers
Dear Mr. Pass,
I would like to build your SONY VFET Version 2 amp where two pairs of VFET's are used per channel since I fortunately now have enough matching ones, but I can't seem to find anyone that still has the PCB's and would be in need of the gerbers to order them myself.
Could you please do me a huge favour and share the gerber files with me?
I will of course only use them for my own project and not distribute them anywhere.
Best regards,
Brzzl
Dear Mr. Pass,
I would like to build your SONY VFET Version 2 amp where two pairs of VFET's are used per channel since I fortunately now have enough matching ones, but I can't seem to find anyone that still has the PCB's and would be in need of the gerbers to order them myself.
Could you please do me a huge favour and share the gerber files with me?
I will of course only use them for my own project and not distribute them anywhere.
Best regards,
Brzzl
good memory, to where are they located
though, I knew that I have these (even if not remembering from where I got them) and - luckily - I've read his post twice - he's asking for iteration with 2 pairs per channel
which is Part 1
OK, Papa's nomenclature is sometimes confusing, at least for my peanut brain ........ ignore me claiming Part 1
here it is : https://www.firstwatt.com/pdf/art_sony_vfet_pt2.pdf
I can't remember Papa shared Gerbers for these
though, I knew that I have these (even if not remembering from where I got them) and - luckily - I've read his post twice - he's asking for iteration with 2 pairs per channel
which is Part 1
OK, Papa's nomenclature is sometimes confusing, at least for my peanut brain ........ ignore me claiming Part 1
here it is : https://www.firstwatt.com/pdf/art_sony_vfet_pt2.pdf
I can't remember Papa shared Gerbers for these
