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The DIY Sony VFET Amplifier

amirm

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#21
Nelson Pass is completely up-front with the measurements of his amps.
What explains the shock and horror of the people who bought his amp design then?

Answer: a few specs buried some place has no meaning to people. What do they know about 0.01% or .001%. It is only when it is put in context of others that horror ensues together with protests: https://www.audiosciencereview.com/...pass-aca-class-a-power-amplifier-review.9741/



As they say, a picture is worth a thousand words. :)
 

pma

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#22
I will attest that having wine with him is extremely fun.

I personally come down on @ta240 's take- it is sold for what it is, entertainment, not SOTA performance.
Honestly - why it would be an entertainment for a common user. Especially the things like ACA or ZEN. A colleague built that ZEN “power” amplifier and I am aware of nobody who would like it in a level matched AB test with a “normal” amplifier.
The only one whom I can imagine to have some “entertainment” with those supersimple circuits is a total beginner who is just wire wrapping his first DIY amplifier nest and it produces some sound. The problem is that those circuits make technically ill-oriented people who assume them as some standard or a good circuit design.
I still regret a mistake I made when I posted the “Mosfet Power Follower” project 20 years ago at Rod Elliott web.
 
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DSJR

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#23
He's gutting good old Somy amps for THIS??????? FFS :mad:

I had a TA-5650 at home for several months and loved it (slightly loose bass but more and better reproduction of venue reverb than many far eastern confections of the period). A long standing pal had another 5650 in almost daily use for thirty odd years until the infamous blow up happened and it took his speakers with it (dry joints on critical diodes around the output stage?) - it was sadly scrapped. Sony should have kept this and the 8650 going (we never had the 4650 in the UK I think) but eighteen months was it before some not so nice crap replaced them, this way before the ES series was conceived..
 

restorer-john

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#24
He's gutting good old Somy amps for THIS??????? FFS :mad:

I had a TA-5650 at home for several months and loved it (slightly loose bass but more and better reproduction of venue reverb than many far eastern confections of the period). A long standing pal had another 5650 in almost daily use for thirty odd years until the infamous blow up happened and it took his speakers with it (dry joints on critical diodes around the output stage?) - it was sadly scrapped. Sony should have kept this and the 8650 going (we never had the 4650 in the UK I think) but eighteen months was it before some not so nice crap replaced them, this way before the ES series was conceived..
The Sony range comprised the integrateds, up to the the 3650 in bipolar, until the 46/56 and above with VFET. Unbelievably good for their time. Beautifully constructed and after the 3650, essentially no expense spared.

I have a few of them and a TA-3650 here in my collection right now if anyone wants to see how well it was built (and performed). For what was a relatively medium priced amplifier, it was amazing.

Scrapping and gutting these Sony classics, along with some of the equivalent Yamaha integrateds from the same era should be a crime.
 
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#25
What explains the shock and horror of the people who bought his amp design then?

Answer: a few specs buried some place has no meaning to people. What do they know about 0.01% or .001%. It is only when it is put in context of others that horror ensues together with protests: https://www.audiosciencereview.com/...pass-aca-class-a-power-amplifier-review.9741/



As they say, a picture is worth a thousand words. :)
Nelson Pass has never shied away from a certain amount of distortion, though the ACA is a particularly bad example.

I owned a Pass Labs X150.5 for several years and, yes, I liked it. The fact is that X150.5 had fairly high distortion, especially 2nd & 3rd order, though not nearly as bad as the ACA. The day came when it was time for me to move on: today I own a Purifi amp. In fact the Purifi has far better resolution, transparency, and dynamics than the X150.5. (My apologies to those who believe that all amps sound the same.) Granted then Purifi doesn't have the Pass' touch of mellifluous warmth.

There is an argument out there that 2nd & 3rd order harmonic distortion actually sounds agreeable while higher order HD sounds harsh. I tend to subscribe to that conjecture.
 

DSJR

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#26
The Sony range comprised the integrateds, up to the the 3650 in bipolar, until the 46/56 and above with VFET. Unbelievably good for their time. Beautifully constructed and after the 3650, essentially no expense spared.

I have a few of them and a TA-3650 here in my collection right now if anyone wants to see how well it was built (and performed). For what was a relatively medium priced amplifier, it was amazing.

Scrapping and gutting these Sony classics, along with some of the equivalent Yamaha integrateds from the same era should be a crime.
I have an early HiFi Choice test on the 5650 and it came out well. The front cover of said issue (A5-ish size books rather than magazines) had a pic of the top front of the innards. if you could take the case off one and post pics I for one would love to see them please.. Naive snobbishness prevented me ever looking at the nicely made 3650 in the same league to be honest...

Just so's you lot know what the eff we're talking about, here's the 5650 on the Vintage Knob -

http://www.thevintageknob.org/sony-TA-5650.html

Didn't Sony use V-FETs in the better subsequent slimline amps they replaced these oldies with? The far eastern market wasn't so well regarded by the late 70's onwards in the UK and less and less of the 'good stuff' found it's way out of Germany or even Japan at the end. Lord we were/are an insular lot when we have a mind to be...

I seem to remember the output stage had to be replaced as a set? Are the parts still available or have they long gone now?
 

ta240

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#28
What explains the shock and horror of the people who bought his amp design then?

Answer: a few specs buried some place has no meaning to people. What do they know about 0.01% or .001%. It is only when it is put in context of others that horror ensues together with protests: https://www.audiosciencereview.com/...pass-aca-class-a-power-amplifier-review.9741/



As they say, a picture is worth a thousand words. :)
The massive amount of hype added by his fans has set expectations really high on that one.
That amp has a life of its own.
Granted he doesn't counter their rave reviews either but there is just no way it could sound as good as 99.9% of the reviews say. It was designed to be simple and safe to build, not sound amazing. But at the same time most of the users of that amp are never going to push it to the volume levels of you or your test so they may not notice some of that. I know I wouldn't want my name associated with that amp and I know I wouldn't have spent $100 building one if it hadn't had his name attached. So I'm far from a fanboy after throwing the amp away. I guess he doesn't need to make flowery claims about his amps when so many other people do it for him
 
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