Chimpleton
New Member
Diodes changed, switches and pots cleaned. All systems are go!!!
Thanks for the help guys
Thanks for the help guys
Sony TA-5650 v-fet matching and 1N4148 diodes
- Thread starter Jeff W.
- Start date
Excellent. Give it plenty of room to breathe and keep in mind that it is only 55wpc and you should be good.
You could also use these Epcos 10000uF 63V Caps 35.70mm x 80.70mm.
http://parts.digikey.com/1/parts/1875849-cap-alum-10000uf-63v-20-screw-b41456b8109m.html
Wire Nut
Active Member
Guys, I just bought a 4650 and am going to referb it. I was thinking it would be nice to have one definitive thread with explanations and photos so the folks that are not used to re-doing a vintage piece can even follow along. There are several threads out there- but this one has a lot of info... what do you think about this idea?
Hello. Im new on this forum 
im from Finland. Just buyed this amp 5650 and tuner 5950 for 200€, in mint condition! What a nice machines! I have readed this thread over few times to understand everything and next few questions.. I have opened amplifier cleaned it and put some electronic cleaner/oil in balance switch. I looked that there is those original diodes with grease on top of them, just thinking if this machine has made it to 40 years is it really need something to fix? Recapping isnt on my list now cos i think it too hard to execute for beginner like me. Thank you allready for your answers.
im from Finland. Just buyed this amp 5650 and tuner 5950 for 200€, in mint condition! What a nice machines! I have readed this thread over few times to understand everything and next few questions.. I have opened amplifier cleaned it and put some electronic cleaner/oil in balance switch. I looked that there is those original diodes with grease on top of them, just thinking if this machine has made it to 40 years is it really need something to fix? Recapping isnt on my list now cos i think it too hard to execute for beginner like me. Thank you allready for your answers.
Hello Alekk,
Welcome to Audiokarma and congratulations on a fine pair of gear at a bargain price!
The reason most of these amps have failed in the past 40 years is because of those diodes. This is a fact that can not be overemphasized and is well documented. They are ticking time bombs and if they do fail you will likely have a mint condition "door stop". They will take the V-fet output transistors with them and the likelihood of finding replacement V-fets is very slim unless you buy another working TA-5650. The cost of new 1N4148 replacement diodes will be a Euro or two at most. Please have someone service your amp replace these before you use it if you can not do it yourself. If you pay to have someone install them it shouldn't be too expensive. It is not a difficult or time consuming task. Just make sure the service Technician understands that the originals are a double diode. The 1N4148's are a singe diode and two must be joined in series to replace the original double diode at each location.
V-fets will never be manufactured again. You are now the steward of six of these devices. Please heed this advice.
Electrolytic capacitors from the era when this amp was built were designed to last 20-25 years at most. They are well beyond (2 X) their intended life span. Having them replaced will greatly increase the chances that your amp could last another 40 years. You will also likely notice improvement in low end response. If one or more capacitors fail you could be looking at another "door stop" scenario. If it is too costly to have them all replaced then I would recommend replacing the ones on the driver board at the very least and then on to the power supply next.
I have restored two TA-5650's, two TAN-8550's and one TA-N7. I still have one TA-5650 and the TA-N7. They are wonderful amplifiers and well worth preserving. Congratulations, once again, and best of luck with them.
Welcome to Audiokarma and congratulations on a fine pair of gear at a bargain price!
The reason most of these amps have failed in the past 40 years is because of those diodes. This is a fact that can not be overemphasized and is well documented. They are ticking time bombs and if they do fail you will likely have a mint condition "door stop". They will take the V-fet output transistors with them and the likelihood of finding replacement V-fets is very slim unless you buy another working TA-5650. The cost of new 1N4148 replacement diodes will be a Euro or two at most. Please have someone service your amp replace these before you use it if you can not do it yourself. If you pay to have someone install them it shouldn't be too expensive. It is not a difficult or time consuming task. Just make sure the service Technician understands that the originals are a double diode. The 1N4148's are a singe diode and two must be joined in series to replace the original double diode at each location.
V-fets will never be manufactured again. You are now the steward of six of these devices. Please heed this advice.
Electrolytic capacitors from the era when this amp was built were designed to last 20-25 years at most. They are well beyond (2 X) their intended life span. Having them replaced will greatly increase the chances that your amp could last another 40 years. You will also likely notice improvement in low end response. If one or more capacitors fail you could be looking at another "door stop" scenario. If it is too costly to have them all replaced then I would recommend replacing the ones on the driver board at the very least and then on to the power supply next.
I have restored two TA-5650's, two TAN-8550's and one TA-N7. I still have one TA-5650 and the TA-N7. They are wonderful amplifiers and well worth preserving. Congratulations, once again, and best of luck with them.
Jeff W,thanks for your quick and comprehensive answer.
The thing is that here is hard to find someone who will do this recap for me. I have opened this amp and i think that those diodes are pretty easy to change for myself ,I know i can do it pretty easily BUT those electrolytic capacitors littlebit got me thinking that maybe its too hard for me. And i dont want do my learning recapping with this amp. Is that list what you made complete? If i order those capacitors +them diodes and get them to somebody who can change them. Is there something i should pay attention?
The thing is that here is hard to find someone who will do this recap for me. I have opened this amp and i think that those diodes are pretty easy to change for myself ,I know i can do it pretty easily BUT those electrolytic capacitors littlebit got me thinking that maybe its too hard for me. And i dont want do my learning recapping with this amp. Is that list what you made complete? If i order those capacitors +them diodes and get them to somebody who can change them. Is there something i should pay attention?
OK now i readed again this thread and i understand more n more everytime.
So the main caps will be nippon chemicon and other caps Panasonic FC or FM, every cap should be the same value that old ones.
Can you tell specific model on those main caps?
Can you tell me which serial number have maded those mods what you told on post #42?
I have unplugged my amp and decided to do a full recap to it because it has made me so in love in it! never heard nothing like this!
Not sure yet do i have courage do it my self or just try find somebody to do it, but first im gathering all parts i need.
Tell if something is missing: Capacitors what you made list of on post #26, Mica insulators for TO-3 transistors and silicone heat sink compound and of course those 1N4148 diodes 8 pieces, right?
One thing there is what i didnt quite understand is that bias setting, i have service manual but this page 5 is just so crappy that i didnt get all of it. if you have better service manual i will be more than pleased to get it?
What you think should i change capacitors to my tuner also?
So the main caps will be nippon chemicon and other caps Panasonic FC or FM, every cap should be the same value that old ones.
Can you tell specific model on those main caps?
Can you tell me which serial number have maded those mods what you told on post #42?
I have unplugged my amp and decided to do a full recap to it because it has made me so in love in it! never heard nothing like this!
Not sure yet do i have courage do it my self or just try find somebody to do it, but first im gathering all parts i need.
Tell if something is missing: Capacitors what you made list of on post #26, Mica insulators for TO-3 transistors and silicone heat sink compound and of course those 1N4148 diodes 8 pieces, right?
One thing there is what i didnt quite understand is that bias setting, i have service manual but this page 5 is just so crappy that i didnt get all of it. if you have better service manual i will be more than pleased to get it?
What you think should i change capacitors to my tuner also?
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I'll have to go back and check my list. I started this thread so long ago I'll have to review it myself. I don't have time to do it tonight.
I do have an electronic copy of the service manual and the owner's manual. If you message me and provide your e-mail address I will be happy to send them to you. I highly recommend obtaining an original physical manual. They come up on e-Bay from time to time. It's so much easier having it on the workbench and is much easier to see all the details of the schematics.
For capacitors the Panasonic FC's and FM's are still good recommendations. Better are the new Panasonic FR's. Nichicon UPW's are good as well. These capacitors are all rated at 105 degrees C (these are typically rated for much longer life than 85C capacitors) and and have low ESR. You will find different opinions on capacitors. The Panasoinc FC, FM and Nichicon UPW lines have all been recommended by "Echowars" here on AK. He is a knowledgeable and experienced technician that is a long time subscriber to this forum. He is well advanced of myself and knows V-fet amps very well having worked on many. I went with his recommendations.
I do have an electronic copy of the service manual and the owner's manual. If you message me and provide your e-mail address I will be happy to send them to you. I highly recommend obtaining an original physical manual. They come up on e-Bay from time to time. It's so much easier having it on the workbench and is much easier to see all the details of the schematics.
For capacitors the Panasonic FC's and FM's are still good recommendations. Better are the new Panasonic FR's. Nichicon UPW's are good as well. These capacitors are all rated at 105 degrees C (these are typically rated for much longer life than 85C capacitors) and and have low ESR. You will find different opinions on capacitors. The Panasoinc FC, FM and Nichicon UPW lines have all been recommended by "Echowars" here on AK. He is a knowledgeable and experienced technician that is a long time subscriber to this forum. He is well advanced of myself and knows V-fet amps very well having worked on many. I went with his recommendations.
OK THANK YOU again. Just got the receiver to the electrician shop and gave him all that i know, he started order those capacitors (i just cant wait anymore so i gave him that your old list of capacitors) because you seem to be very exact guy so i trust it. only if you can send me the manuals so then he can start doing it. Im so thankful that i have found so much good help, not so foregone conclusion at these days.
We made a deal with my technician that i order those capacitors because he has so much work. Now i have founded allmost every capacitor from Panasonic FR series and few from Rubycon, Only these large-can power supply caps is problem, not found them anywhere. Digikey have something what i think shoul fit (http://www.digikey.com/product-search/en?mpart=E36D500LPN103TA67M&vendor=565) <--- Is these right ones?) but its gonna be hard to get them because there is all kind of things when order from US. How important is to change them? i have understand that they might not be so bad than the others? If i change everything else but leave them there, is it bad decision?
Those look like they will work for the main filter caps. Of all the capacitors to replace these are probably the least urgent. However, of all the caps these could yield the biggest sonic improvement by restoring low end response. Be patient and search a little more. Farnell has these: http://fi.farnell.com/cornell-dubilier/cgs103u050r4c/aluminum-electrolytic-capacitor/dp/1162207., but they are probably too tall.
So maybe i order those from digikey, is that 85 celsius ok?
How about this
http://www.tme.eu/en/details/gt1h109m35060sb/screw-terminal-and-others-el-capacitors/samwha/
How about this
http://www.tme.eu/en/details/gt1h109m35060sb/screw-terminal-and-others-el-capacitors/samwha/
The 85C is fine. There aren't many choices when it comes to these. The one you show in the link could work. I don't see a dimension for lead spacing. It has to be close to 12.5mm. the 12.7mm spacing on the one from Digi-key will work, but you have to file open the PCB a little bit where they mount. It's not a big deal. You'll need to find out this specification by contacting them.
ilimzn
Well-Known Member
It seems no-one mentioned a VERY important thing: the VD1221 or replacements that are in thermal contact with the transistor, MUST be in thermal contact with the transistor, and in fact the white silicone grease often dries up and crack and fall off. When the diodes are replaced, new grease and (highly recommended) heatshrink tubing should be used to keep the diode in thermal contact with the transistor. Without this, the output stage will go into thermal runaway and you end up with (initially) blown fuses 'without a reason'. Do this enough times and VFETs will die.
ilimzn, I know you have vast experience with the Sony V-fets if I am remembering you correctly from the past. Please see posts #4-6 of this thread. I attempted to duplicate contacting the transistor and replacement diodes as documented there. Echowars advised that he didn't think it was very important. I had tried to duplicate it as, obviously, Sony thought there was a reason to do it.
I did follow Echowars advice (knowing he has much experience with these amps as well) and they have not been in thermal contact on my TA-5650 since I rebuilt it over 5 years ago. I use mine frequently and sometimes many hours at a time and have never experienced any problems. No fuse has ever blown. Maybe I've just been lucky so far (of course I am, I have a working TA-5650
).
Regardless, would you happen to have a photo or two you could post that would illustrate how to best accomplish this? I'm always for the "ounce of prevention" school of thought. Especially given the pound of cure may not be available at any price.
I did follow Echowars advice (knowing he has much experience with these amps as well) and they have not been in thermal contact on my TA-5650 since I rebuilt it over 5 years ago. I use mine frequently and sometimes many hours at a time and have never experienced any problems. No fuse has ever blown. Maybe I've just been lucky so far (of course I am, I have a working TA-5650
). Regardless, would you happen to have a photo or two you could post that would illustrate how to best accomplish this? I'm always for the "ounce of prevention" school of thought. Especially given the pound of cure may not be available at any price.