Marantz 2220B (Later '78?) Restoration Advice/Questions

[fromnowon]

Lots of great comments here and several have been very helpful to me. I still have my Marantz 2220B receiver which I bought in 1977 and placed in storage about 22-23 years ago. Short story, I recently took it out and lit it up to see if it still worked. It did but I hadn't bought new speakers yet so I via my AKG 240 headphones, I discovered that the output was scratchy and the left FM channel was not working. So I took the unit apart and did what everybody does: cleaned the pots, replaced the lamps and did a complete clean up of the entire unit inside and out. It looks brand new... no exaggeration. So I bought JBL Studio 630 speakers and found the left channel still worked and it still sounds fantastic after de-oxing the pots. Unbelievable. But since it is on its last legs, I bought a refurbishment kit on eBay I will be giving the unit a good listen for 4-6 months and inspect the parts in the kit before starting. The plan is to start with the relay and power assemblies and testing as I proceed from one section to the next. Two questions:

1. I noticed that several of the replacement caps are of a higher voltage. In fact, the 2 replacement relay caps in the kit are also now identical and at substantially higher voltage. I have been assured they are higher quality than the old caps but how does the higher voltage impact the performance? Are the other non-cap parts being replaced to accommodate this? Maybe my plan to test after each section is refurbished doesn't make sense and could even damage the unit.
2. Should I be expecting a noticeable improvement in sound quality after the refurbishment? Considering it still sounds excellent already, I've been advised to expect some minor improvement in clarity if that.

I appreciate everyone's thoughtfulness on this thread. I never thought I would refurbishing my Marantz or even soldering anything again.

Hi @Philvbo,

Good luck with your project! That's very cool that you still have your 2220B. (I wish I still had my 2235B that I bought right about that same time.)

- Replacement caps having a higher voltage is common and doesn't cause issues - in general, they might also be smaller than the originals (even with higher voltage ratings). I think it's safe to say that a higher voltage rating is a good thing as long as the caps can fit in the spots, and sometimes the original voltage caps are not available.

- Based on my experiences (I'm not an expert but have recapped / refurbished some Pioneers and a Marantz) you just might notice a significant difference. I sure have. It's been a blast and I imagine it being what these amps and receivers sounded like when they were new, maybe even better than that.

I'll bet you'll be really happy with it after refurbishing and you'll learn a lot in the process. There are some knowledgeable, helpful people here if you run into any questions.