Sony TA-5650 VFET Amplifier Service and Restoration 

Great restoration and attention to detail. Back in the late 70's, we had four of these integrated amps in our audio editing rooms for radio and TV commercials. They sounded great, but were a pain in the rear for me to keep serviced. I spent a lot on the cost of long distance calling communication with Sony tech support. There were four engineers at Sony at the time that knew the amp inside and out. They were great with service tips and shipping out a good supply of VFETs and Sony sold them to us at cost. They gave me the same tip you detailed on using an alternate test point for the bias. Once I performed the service bulletin mods on the amps, we didn't have any issues ever again. We eventually replaced the amps in 1983 and my boss gave the Sony amps away, and I wound up with one and all of the spare VFETs. I used the last complementary pairs of VFETs about five years ago, when I did a complete restoration.

Beautiful oldschool amplifier is reborn, amazing work.

One other superbly build amplifier from the seventies.........nice job , i could trust you ....

Wildly fascinating to see the process. Great Video.

Same age as me! It's aged better than I have though lol. Great work, love this channel!

This was the first hi-fi component I purchased (new) after graduating high school in 1976. Like all of these units, mine blew up. Not once, not twice, but three times before I abandoned it in 1986. But when it was working...the sound was heavenly!

Dude your attention to details are insane. You are a real master!

Hello, i own Sony-TA-N7B power amp and it's just incredible !!!

Wow.. This is great i have the same and also the 8650 ,This is so huge for me

This is it profesional work and restoration....congrats !

Restored with love! Very nice and professional job. Thanks for sharing this i love the longer video :-)

What a great job on this amp

Well done on this amp. It polished up nice

Great video, and you obviously know you're stuff. But it would be nice for numpties like me if you showed us how you do some of the work. I'd love to know how you clean the faceplate for instance.

Great job Man, what a nice bit of kit

Nice work mate, though my focus is the service and repair/reverse engineering of metal detector technology I can fully appreciate your work and level of detail. The hardest job for us these days is parts, I buy alot of job lots of new old stock transtitors ics diodes, some old parts are just not available today modern replacements bring often more problems, but diligent searching can yield what u need there is nothing better than looking for an out of production chip and turning up so military spec metal can versions or ceramic ones, better spec than the plastic originals. Nice clean proper work top marks mate.

I have a Yamaha B-2 Power amplifier I would love to get it serviced. You do a thorough job!!

Excellent video. Thanks.

Beautiful amp beautiful work

I subbed man. Love your work. Really nice and unique pieces you work on.

Wow - you do beautiful work!

Great stuff as always man. Nice work.

Another great vid - nice work mate 👌

First time viewer. Really nice job, nice equipment! All super professionally done. I'd love to know how much time you've got total in this. When doing this extensive a restoration, I wonder what problems can be accidently induced?

Love this video !!!! Great job

Nice job , well done.

Excellent work ❤❤❤

Superb job!!!

Nice Work Top Notch! I use to fix these for Sony in the 80's the sound out of them was the best such low distortion. That speaker switch selector the wipers have carved a groove on the board carbon such a shame! Your luck the protection relay has not corroded! Again great work! We (in Australia) also had problems with corrosion on the audio plugs that go onto the boards they use to come in to the workshop green ! Yours looked ok!

Very very Nice Work

Jabardst sir ji

You can substitute the Vfets with TO-3 2N3055 and its compliment. I had that same amplifier

Great video. Thanks for the info of where else to use to check bias. I have one of these amps and did replace the 4 killer diodes on amp board also. Thanks

Great job , thanks for the video loved these ole Vfet amps -would love to ger my Sansui Au 717 done up like this its one owner thats never been opened up except once to clean with F9 dexoit learned my lession with D5 like many others -

great stuff

Thank you for sharing your work through this video with all of us. The restoration work you have carried out is outstanding, congratulations and compliments! I own the same amplifier, the suicide diodes have been replaced and the amp works very nicely, but I am really wondering if the sound would improve by getting all those old capacitors replaced. Would you share the information about how do you do the polishing of the faceplate? I also cleaned it, but I was afraid to polish it to avoid any damage to the texts. Also I am curious how did you do the polishing of the backplate and RCA sockets. Once again I am speechless on the job you've done with this amp.

wonderful

Always a pleasure to looking and learn new steps for restauration! What you use to polish the front panes?

Great restoration. I have one of these where 3 VFETS died, but I sourced them from Japan. I rebuilt the power supply and testing it out of circuit wasn't obvious as the test points voltages didn't match what I expected. Any pointers on how you tested the power supply?

Nice and meticulous work. Congratulations! What thermal pads for power transistors do you recommend? Do they need additional thermal paste?

Bautiful job. Assuming 1k - 1.5k for labor + parts. Can you comment on how difficult it would be to change out higher quality RCA input connectors and what is involved? Thanks, Don

I recently pull out of storage my old Sony TA-4650 integrated amp. Plugged it in, connected the comnponents and it worked. the only problem was teh balance was a little scratchy but I fixed that. I hadn't used it muchover the last month so when I went to play some LP's last night, the speakers cut out. I heard teh relay cycle back on but the moment Iput the stylus down .. BANG! the speakers cut out. After some investigating, it seems that when I have anything plugged into the phono inputs but without playing an LP, there is a soft repeated thumping coming out of the speakers, especially one channel. If I increase teh volume .. BANG!, the speakers will cut out and the speaker relay will recycle again. This only happens with anything plugged into the phono inputs. the tuner and AUX inputs are fine. Now, I think I may have blown something because stupid me forgot the amp was on whrn I went to plug in another turntable and it made that typical sound that I don't think I have to explain. Did I possibly cooke the phono preamp?

Outstanding work! I have one suggestion only if I may. I would very much like to see and learn how you do some jobs like drilling the holes for the transistors and polish the plugs. would it be possible to insert some very short time-lapses of these processes in future restorations? Perhaps you have already did it in previous videos but I'm knew to your channel. Subscribed BTW.

I remember this from the 70th. Green PCB's? Looks much newer than something from 1978.

I applaud you for such dedication to restoring old great ones. I have an original Sony GS10 ES receiver and was wondering if you would be interested in restoring it I live in Daytona Beach, Fl. Thanks again for the great videos.

I’ve got a tan 8550 vfet amp in the shop needing some work can’t wait until it gets done if it ever does ,those vfets are scary to work on and time consuming . There’s an old ad out there floating around on the internet with a bunch of techs standing over the amp with their white lab coats on just staring at it scratching their heads like its some NASA device their working on .

Great video! I have one question: the white cable soldered in the centre of the voltage doubler (mod @24:46) is soldered or otherwise connected to the inner front plate?

Could you share the size of the original 10000uF/50V capacitors in millimeters?

Hace 3 dìas que comprè este modelo y la verdad, me gusta mucho como suena. El video es excelente y hoy es la tercera vez que lo miro. Si puedes, comenta con que limpiaste la placa frontal. Ella quedò hermosa y me gustarìa limpiar asì el mìo. Un saludo desde Argentina.

Outstanding 👌🏻👌🏻

See you use the Panasonic FC capacitors ... I've used them in my rebuilt boards ... Think they are really nice sounding ... Is that what you have found using them ... Very nice work and fun watching ... Kind Regards in advance

Hello can you send me the name of the clips you use for measurments? BTW you have ballz of Steel, personally im not taking any Vfets on my bench :)

Hi! Great job and as you said probably better than new ! The ta-5650 isn't that expensive to buy used, I fear the full restoration cost more than what the unit worth and then the V fets no longer available. I have been trying to buy ( out of Japan ) the ta-8650 without luck. I settled for the ta 3200f amp and matching pre the ta 2000f both obviously V fets. Bought them at a good price even with shipping to Australia. The plan was to give them a restore. My fear and risk is the V fets will they all be working to spec !!! Can I ask, is it worth while as back up to purchase say the ta 3200f as a spare to pull the V fets off if needed either now or a later stage ? Would they be compatible for either the amp and pre-amp ? Many thanks... hope to get a reply.

How do I send in a unit to you for restoration? I have a mint Revox 720 preamp tuner. It would make an interesting showcase for your channel

nice 😊

Es cierto que los amplificadores con transistores vfet se queman con facilidad? Podrías darnos algún consejo para su buen uso y evitar que se puedan quemar? Perdón no se escribir en inglés! Gracias

I'm looking at buying one of these, fully restored, in the UK. Would love to know peoples thoughts on the sound, those who've heard one. This restoration is incredible, I wish I could buy this amp itself!

What’s the cost for you to redo one just like this

Great video once again. It's both enjoyable and educational - steady hand helps a lot too. 12:41 Why is there this purple wire going across the pcb? I never understood that habit, especially Japanese manufactures, of using every opportunity the get for creating a rat's nest. What's the point of having pcbs if you are going to use jumper wires like these. The other thing that annoys me is the mixed use of wire-wrap connections and molex plugs. Just make up your mind: do you want easy of assembly? de-assembly? or just solid connections? I used to really dislike wire-wrap connections and eventually got a wire wrap tool - of course now I think they are awesome. But the tools is expensive for the random diyer to get, especially if they only plan to fix one device only. These are gripes I have about all Japanese manufacturers, not just Sony. All of them were obviously using the same system of manufacturing. But you have to hand it in to Sony, even before their signature pristine boards came about in the late eighties, this device bears all the marks of quality (even thought it belong to an up-market line of products, on account of the v-fets used). The re-flowed and de-fluxed board reveals this clearly as well as other details such as the use of hinges, pcb holding brackets, bespoke heat sinks etc. 23:29 Disassembling and reassembling this adds 2-3 hours to the bill, if all goes well. 25:00 What mod is this? How can one find it? Does it apply to every voltage doubler? 25:38 Brushed aluminium is a restorer's nightmare: if is has oxidisation patches and signs of abuse it's impossible to get back to original. Anodised aluminium or - even better - painted aluminium are much better at aging well. That came out great. 30:20 It ought to sound like valves, on account of the v-fets for sure. Do you remember how it stacks up compare to the higher end v-fet power amplifier you restored? I can't remember whether it was mono-blocks or just a TA-8650...

So where you can buy SONY VFETS at a reasonable price ? I heard Nelson Pass purchased ALL of the NOS VFET's in circulation.

Warmer sound,, it ran hot. 70 mV might make sense. This Sony was one of the best. Slightly thin at 50 mV. Better than a Krell? To my ears yes.

I remember the 90mV bias . Much warmer. Sony had customers issues.

Increasing the capacity, is it not taking the system out of balance?

How much indian price & how to bring shipping.

You're like an original Sherlock Holmes.

Is that just regular carpet or anti-static carpet? I see people doing electronics on carpet and it gives me the willies.

Be aware that the speaker relays in the v-fet series are very unreliable. A black piece of plastic has 2 rivets in it to hold the contacts in place. This black plastic tends to crack and the contacts tend to move from their place.

50-80 hours work Projekt...😉

Top notch work, but I hear silpads are worse than thin mica. What gives?

These have become VERY difficult to find!!!!!

airplane camera and to much talk, check out brit guy and his positive way to find out and present electronic failure and how to fix it, on his funny style.

Wow. It sounds just like my computer speakers.

Your videos are interesting but I can't watch them. You wave the camera around so much that I feel giddy. I can't watch. I wish you'd use a tripod, or at the very least try to hold the camera steady.

Sorry to say, but because of the wild camera movements this video is barely watchable. Please give your viewers some rest.