Folks, however entertaining, interesting or how else this discussion may look like for people around here, there is a very important point that should be understood in a honest and not-fooling-ourselves manner. And this is what I want to address in this post, so that everybody who will read will hopefully understand what is "to do" and what is "not to do".
As I said more than once around here, I myself am a DIY-er. And I'm doing this kind of stuff for some dozens of years now, saw enough different electronics devices of all kinds in those past years.
I'll start by saying that I admire and encourage people who are willing to learn and I have no intention to discourage anybody who wants to learn electronics, here or in any other forum where I'm a member.
BUT, and this is a big but, to give a crystal-clear and practical example: if we talk about any racing driver on this planet, nobody has started or starts his or her driving carrier as a professional racing driver by jumping straight into an F1 car. Simply because that is not possible, in order to reach "that" level there are some "prerequisites" that have to be fulfilled first. And to be again crystal-clear, I'm not talking here about money, I'm talking about skills.
Ok, so what I'm trying to say here - simple - similar with the above example, nobody should start learning electronics by going straight into electronic devices repairs/upgrades, being those amplifiers, cd-players, DAC's, washing machines or whatever. To put it simply and clear, that's not the right way of learning electronics. No if's and but's. No and no. Period.
If anybody wants to learn how to repair or upgrade amplifiers (of any kind), some basic knowledge must be gained first.
Now, if we talk about Sansui X-Balanced/Alpha series (any model of them, including current X-111 MOS), then things gets even more complicated - simply because, from a technical perspective, all balanced amps (Sansui or other brand, no matter) are "a class above the <normal> amplifiers". So it should be obvious that the level of that "basic knowledge" required is this case is even higher.
Ok, what would be that "basic knowledge" level, I'll give some headlines:
1 - knowledge about all passive and active electronic devices - what is their functional role, what they are commonly used for, how they look like as "symbols" in any given schematic
2 - ability to identify and "isolate" functional blocks in a given schematic that the person is looking at - which section is related to power supply, which section to signal path, which exact function every block has in the signal path or in the power supply domain
3 - knowledge about amplifier topology, like common-emitter (CE), common-collector (CC) and common-base (CB), when each of these is likely used (in which case/scenario) and ability to identify these configurations on a given schematic
4 - knowledge how to use a DMM (this means no question like "which range should I use, would that be "V" (voltage) or "A" (ampers) ?")
5 - knowledge about common transistor functional blocks, like voltage regulators, differential amplifiers, emitter or source followers - how they work, identify them in a schematic (partially common with points [2] and [3] above)
6 - last, but not least, knowledge about circuit impedances and what signal (type and level) would be required in a specific area of an amplifier or another device to drive that section, for testing purposes (like sine wave, square wave, AM/FM modulation, etc)
Conclusion - if a person "fails" on any of these points above, then there is only one conclusion - that person is NOT qualified to look into electronic devices repairs.
Nobody cracks open the car's engine or gearbox on which has more likely no idea about "how it works" and then call some mechanic on the phone for troubleshooting. As the car engine and gearbox are an area of technical expertise, so are all the electronic devices. It's just a different technical area.
Ok, now, if anybody wants to go on learning path - spend the time and read some books, or at least go and watch some dozens of online tutorials on youtube, there are plenty of such. Thinking that "reading a technical summary posted by someone experienced will replace some good few hours of self-learning" is just an illusion. You can't build the 10th floor of a building if there's no foundation and the lower 9 floors on top of that.
Buy some components and a breadboard, try to reproduce some simple schematics whatever those are, and, most important, try to understand how those simple circuits are working. And then go to more complex circuits, when you feel that "I really can do it" go and buy a cheap scrap device (amplifier if you want expertise on this area) and look into it, try to troubleshoot what's wrong and see how far you can go. And if things are going "smooth", it MAY BE the time to look into a "more serious" amplifier for repairing.
And after a couple of >>successfull<< (in the proper sense of the word) repairs for normal amplifiers, it MAY BE the time to have a look into a Sansui X-Balanced/Alpha or any similar balanced amplifiers produced by some other brand.
Again, this is my personal view based on my years of practice and all situations that I encountered. It may be wrong partially or totally, it may disappoint or it may encourage some people around here, but it's much better to have realistic (and somewhat lower) expectations and be eventually pleasantly surprised in the end than falling from the higher expectations which reality had proven to be only hype.
And remember - there's no "magic bullet" and no "cutting corners" on any technical expertise area. Any such "cutting corners" will prove much more costly later at some point. Been there and done that, take my word that it's a no-go.
Regards
