pete_mac

Correct - you can use any of those. As always, check the transistor pin-out configuration to ensure they are installed correctly. It's very odd indeed that you now have a reduced output level - it doesn't make sense. Are you 100% certain that every transistor in installed in the correct orientation? Likewise, it is odd that the crackling is still there. I'm assuming that you've replaced all of the small signal transistors on both the amp and preamp boards?

Element14, RS Components, Mouser and Digikey the way to go. Yes, those are the locations for the 2SC871 capacitors. re: TA or BU, this refers to how they are supplied - on cut tape (TA) or loose bulk (BU). They are the same electronically. The datasheets have useful info which explain this kind of thing. The G are no longer available. Personally, I'd avoid those IC capacitors. Something by Panasonic, Nichicon, Kemet, EPCOS would be my choice eg: https://au.element14.com/epcos/b41252a8228m000/cap-2200-f-63v-alu-elec-snap-in/dp/2468296?st=63V C817/818 need to be upsized as I mentioned above -go for 2200uf or 3300uf. You will need to check the diameter of the originals to ensure that whatever you choose will fit OK. Upsize the other power supply caps too (C002 to C005): C002 - 1500uf 63V to 2200uf 63V C003 and C005 - 500uf 35V to 1000uf 50V C004 - 220uf 50V to 470uf 50V The above will depend upon what you can find available. Going up a further step in voltage rating won't be an issue.

Grab the free schematic from hifiengine: https://www.hifiengine.com/manual_library/sansui/au-222.shtml C601/602 - install 1.5uf WIMA MKS2 or Panasonic stacked film capacitors or similar - you will need narrow lead spacing of 5mm to suit C609/610 - 10uf WIMA MKS2 if you are keen and can source them, otherwise I'd suggest Nichicon UKL low noise caps - you will need narrow lead spacing of 5mm to suit if you use the WIMA C707/708 - 3.3uf WIMA MKS2 or Panasonic stacked film capacitors or similar - you will need narrow lead spacing of 5mm to suit C709/710 - 10uf WIMA MKS2 if you are keen and can source them, otherwise I'd suggest Nichicon UKL low noise caps - you will need narrow lead spacing of 5mm to suit if you use the WIMA C801/802 - install 1uf WIMA MKS2 or Panasonic stacked film capacitors or similar - you will need narrow lead spacing of 5mm to suit C817/818 - output coupling caps - go for 2200uf or 3300uf 35V to 50V caps here Regarding the power supply filter caps, go larger where you can (generally one step up in capacitance, and either match or exceed the original voltage, but don't exceed 100V) as you might be able to get closer to the size of the originals. I'm pretty sure that some of the originals will have old-school lead pitch / spacings, and won't match the modern snap-in capacitor lead pitches. Some creative installation work and mods may be required (AKA drilling a tiny hole or two in the right place, having regard for the layout of the PCB traces to ensure you complete the circuit and don't short anything out in the process!)

The crackling sound is likely to be one or more of the small signal transistors - they are probably 2SC871s. BC550s are an appropriate substitute. Regarding the larger capacitors, you can also increase their size. Two are the output capacitors which are in the direct signal path, and the rest are power supply filter caps. Personally, I wouldn't go higher than 100V for any of these. Let me get back to you with some specifics.

This will make you appreciate the main rig all the more! It's like owning a fast car, then driving around in a Hyundai Getz for a few weeks, and jumping back into your fast car again.

In addition to the tweeter and two midrange drivers, there is a 8" down-firing woofer.

It is - the red banner below. It clearly says 'read before posting' and if this instruction is followed, these questions won't continue to be asked. There's also a private message sent to all new members explaining this.

Nah, they have a different sonic signature to the vintage Sansuis. They are a nice little amp, of course, but don't fit the bill here.

Yes, that's the downside of the desirable Sansuis - they do command reasonable dollars (unless you can find someone who doesn't realise what they are selling). You also should factor servicing and restoration costs into the equation - there are known age-related issues which should be addressed for reliability and sonic goodness.

I've used Aleene's Tacky Glue with all manner of foam and rubber surround replacements with great success. No dramas adhering either type of surround to metal and alloy speaker frames, and paper/poly/carbon fibre cones. The stuff is legendary in US vintage audio circles. https://www.craftonline.com.au/products/aleenes-aleenes-original-tacky-glue?istCompanyId=6239f585-e517-4055-88c7-7d5a95ff678b&istFeedId=90b82938-72d6-4f31-931a-d3d5864f55a9&istItemId=iwrmpallx&istBid=t&gclid=Cj0KCQjw6sHzBRCbARIsAF8FMpW-UlLI2UrlgCoNJJjBujy4OymaPtPSOayzuegmgsUp0rwjH15ddBwaAqTbEALw_wcB

If you can manage to grab a 517 or 717 (or 519/719) I can highly recommend that as an upgrade path. The 417 is a nice amp to be sure, but it's less sophisticated than the above, and roughly the equivalent of the slim form-factor AU-317 in the larger AU-517/717 chassis. It has one transformer vs two, and half the number of filter capacitors - it lacks the 'dual mono' style of construction found in the 517/717 and 519/719. You can see the empty locations in the chassis in the images below. A well-priced 417 is still a good amp though, but just make sure it is appropriately priced. AU-417: AU-517/717:

These would be interesting stats indeed... we've had four people at work order the RAV4 Hybrid recently with a quoted 6-9 month wait (the standard line), only to be told a few weeks after placing the order that there have been cancellations and they could receive the car in 2-3 months provided they weren't fussy on colour.

I reckon we're already experiencing a correction across a variety of 'collectable' markets, and the slide will continue. The demographic who have typically done the 'collecting' and pushed prices up are the ones who grew up with the collectables and have an emotional attachment to them. The younger generations often don't have the same emotional attachment (nor such deep pockets!) so demand and prices are falling (perhaps apart from ultra-rare items used by celebs and the like). IMHO something is only valuable or collectable because of what it 'means' to someone. If that meaning/context/relevance is lost over time and there is a narrower pool of potential owners, it stands to reason that the value drops.

Likewise, even if people are playing silly-buggers with their friends to generate notoriety, they'll need to act quickly to ensure they are not hit with a 'final value fee' for these supposed 'sales'.

To the OP, that's a 110V output, USA-spec stepdown transformer - it's not suitable for use with a Japanese market 100V device.