Sony TA-F7 vs Nakamichi CA/PA5 mkII


I have a Nakamichi CA/PA5 mkII set, that has served me very well for 15 years. But after reading about Sonys vFet-amplifiers (Nelson Pass is a big fan of these) I have become more and more interested in trying of of these, for example the TA-F7 integrated amp. But there are several problems. First of all I have never heard one, and because they are so rare I don't think I will get a chance unless I buy one. So my first question is: How do they sound, especially the TA-F7, and will they match the Nakamichis? Second question is the reliability. Many of the Sony vFet-amps went bust. Is the TA-F7 better or worse? And if I want to buy one from abroad, how do I make sure, that it works and isn't repaired in a wrong way? All replies is welcome!
olefelsb
hmm...no replies yet so I guess not so much love vor Vfet amps here ???
perhaps, or perhaps the TA -F7 is so rare that no one heard it :)

I never heard the TA-F7 either but I own two TA-N7s and a bunch of other Vfet separates. The TA-N7 and TA-F7 are virtually the same amplifier where the TA-F7 is an integrated version of the TA-N7 (with minor differnces in the amp circuit as well). Sound wise thay are very similar, according to those that own both. Since my weakness is separates, I prolly would never own a TA-F7.

The N7/F7 are not pure VFET amps. They are mixed BJT/VFET output stage. That yields several important advantages, but also makes up a different signature and behaviour all together (it’s not a pure VFET amp).But Sony’s cascode BJT/VFET design remains a engineering and sonic marvel that must be heard to be believed.

To summarize the sound signature: very detailed all around, very tight bass. An acurate amplifier which demands a good source to leverage its full potential.

The down side of these rare beasts are weak anciliary components that Sony, Yamaha and others used. When these vfet amplifiers fail, they fail because of deferred maintenance and allmost allways because of anciliary componenet reaching the end of their usefull life. The first gen Sony integrates such as TA-4650/5650 also fail because some crappy "death diodes" which are actually veractors and not diodes.

All in all, if you find a decent unit and someone to restore it for you, it is worth gold in terms of sound and totally worth adding to your collection. There are very few ppl in the world that work on these things. If you end up getting a unit...and based on your geographic location, I can point you in the right direction.

One side of caution is that no Vfet ampifier like hungry speakers. anything below 4 ohms is a Big NONO!
Thx a lot for your interesting and informative reply, Sonetduo. As I understand you, the N7/F7 doesn't have the infamous "death diodes", and that's good news. But I'm aware, that a lot of other things can fail. I live in Denmark, so please let me know if you know some people with experience in repairing these amps. And by the way, when we talk about fragility: Would you dare to get one shipped? I ask because I'm looking at one that a little far away for pick up.  

@olefelsb,
If you are interested in an expert that could service these fantastic amplifiers, the closet person to you, whom I am aware of, is located in Holland. If you are interested, send me a PM and I will pass you the contact information.

As far as fragility and transportation, these amps are not especially heavy and if packed well, they would survive long distance shipping.

I have just received one bought in Germany and shipped to Denmark. No problems in shipping. And thank you very much for advice. I will send a PM.