Sony vFET Amplifier Part 2

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#1,621
#1,624
Nelson Pass said:
Currently preparing more tested pairs using biological neural networks in
meditation mode with Thievery Corp playing in background.

Drives 2005 Freestyle. 😛

Still trying to decide allowance for blown up devices.

Any finished builds yet? How about pictures?

😎
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Not building yet but today I picked up something I was working on a few weeks ago - extremely simplified amp - basically the F5 front end, cap coupled to a fixed bias complementary pair of 2SK82/2SJ28. Sound was *very very* good in the garage, scope traces looked nice as well.

Has anyone else tried something like this? What's the downside of not having the intermediate stage?
 
#1,625
We order Keratherm for the diyAudio store, and I'm a fan. For 240 and 9240 MOSFETS mostly. It would be VERY expensive to use for attaching the brackets to the heatsink, and WORSE thermally because there is no need for electrical insulation, so you just need grease between the 2, no insulation. It has to be ordered by the distributor in the US from Germany, which takes at least 3 months. Possibly better access in Europe.

But why would you? Nelson prefers mica and grease- partly because it has excellent specs, and partly because it's unlikely to be punctured and short out if people tighten the bolts like crazy- which some people will do.

AND since the only logical thing for the brackets is grease, you'll have grease already,why not stay on theme. Your kits have mica insulators for both the MOSFETS and the VFETs. And the grease! And what would be more proper with old school TO-3 Devices?


soundhappy said:
Oops 😀
Keratherm are available in biger square foil and you can cut to dimmension you need for perfect thermal bracket to heatsink contact.

Thermally conductive film 0.25 mm 6.5 W/mK (L x W) 190 mm x 190 mm Kerafol from Conrad.com

http://www.produktinfo.conrad.com/d...en-WAERMELEITFOL_86_82_ROT_190X190X0_25MM.pdf
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#1,626
I've got my BOM from Digi-key just about done and I'll be able to give you all a price on the electronic components kit very soon so those interested can sign up for the kit. Quite a high end list, very similar to what Pass uses in his high end amps, with Vishay-Dale metal film resistors and Silmic ll "silk" caps, Bourns trimmer pots, the active components, but not the VFETS of course, however including JFETS from the store, matched, and the small heatsinks, and LEDs and, and! The price should be about they same as you ordering direct from Digi-Key and the shipping, even overseas should be cheap as the box will weigh very little! I'm afraid it will probably take 2 months to get packed though.

Mark
 
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#1,628
Variac said:
I've got my BOM from Digi-key just about done and I'll be able to give you all a price on the electronic components kit very soon so those interested can sign up for the kit. Quite a high end list, very similar to what Pass uses in his high end amps, with Vishay-Dale metal film resistors and Silmic ll "silk" caps, Bourns trimmer pots, the active components, but not the VFETS of course, however including JFETS from the store, matched, and the small heatsinks, and LEDs and, and! The price should be about they same as you ordering direct from Digi-Key and the shipping, even overseas should be cheap as the box will weigh very little! I'm afraid it will probably take 2 months to get packed though.

Mark
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I would be very interested in such a kit if you are able to remove the lsk jfets. I have my own stash of matched toshiba's.
 
#1,630
That makes sense. I was more concerned with grease application and issues I've seen on the IT servers where a system will fail because the grease dries out.

Variac said:
We order Keratherm for the diyAudio store, and I'm a fan. For 240 and 9240 MOSFETS mostly. It would be VERY expensive to use for attaching the brackets to the heatsink, and WORSE thermally because there is no need for electrical insulation, so you just need grease between the 2, no insulation. It has to be ordered by the distributor in the US from Germany, which takes at least 3 months. Possibly better access in Europe.

But why would you? Nelson prefers mica and grease- partly because it has excellent specs, and partly because it's unlikely to be punctured and short out if people tighten the bolts like crazy- which some people will do.

AND since the only logical thing for the brackets is grease, you'll have grease already,why not stay on theme. Your kits have mica insulators for both the MOSFETS and the VFETs. And the grease! And what would be more proper with old school TO-3 Devices?
Click to expand...
 
#1,635
Kit / parts or soo !

Hi here all diy people 🙂

I am kindly asking here, if it's still possible to get/buy parts for this amp. ?

I have been reading a lot of this thread, (but not all) and it's not clear to me at all, what the status is right now (I live in Europe / Denmark).

I need ofcause the rare part's, and maybee pcb etc...

I want (If possible) to build the highest possible Wattage (10-15W ?) My speakers is around 91dB.

Thanks all, and hoping you all bare with me, asking thoose quistions here !

Regards; Jesper,
 
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