Modify Sony TA-5650 with half Vfet per channel as in 4650

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lorcoll

Member
Joined 2008
#1
Hi to all.
Having purchased a TA-5650 with half working Vfets, I wanted to ask the experts what modifications is necessary to make it work with only one pair of Vfets per channel, as in the 4650. The voltages for the power transistors are almost identical and it is probably only necessary to modify the values of some resistances. Thanks for the help
 
#2
Can anyone help me? In the 5650 the two pairs of vfets in each channel are connected in parallel, so it shouldn't be difficult to modify it to work with just one pair. I think it's a very common problem in the 5650 and it could be very useful to be able to make the change to save many amps
 
#3
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andrew_whitham

Thread 'Another Sony TA 4650 V-fet thread'

Hi all,

Another thread on this Vfet amp – this one was known to be deceased from when bought from E-bay. However, through a well-trodden tale of woe, I have a set of V-fets for it, just a case of figuring out what caused a problem in the first place,

First of all – service manual, I have refurbed a TA5650 previously and you can download plenty of V-fet information readily. You may have to have several goes before you find a really clear copy, but you are looking for the service manual and any bulletin you can find, either for the TA4650 or the TA5650.

Second of all it arrived! Since...
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#4
Thanks so much for the reply. I had already read this thread and I have already made all the modifications (Electrolytics caps, suicide diodes and doubler voltage mod) and everything seems ok. I need clarification on the changes shown in Fig.2, can you explain better what to do to use the 5650 with only one pair of Vfet per channel?
 
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