SX-626 re-cap, and a couple of questions

[tusntuk2]

What's the reasoning behind replacing Main Amp resistors but not the other signal boards? I always boost the power supply parts, I get that, and some resistor changes might lower the sound floor, but your BOM has only the Main Amp listed for general replacement.

 

[thismansaboy]

Why not do the tuner? Those caps are just as old.

Scared about not having the voodoo magic to re-align. Perhaps I've read it's not an issue as long as you don't do caps under 1uF?

When recapping, you should definitely include the tuner. Just stick to the original capacitance values. Returning the capacitance values to stock condition should not necessitate re-aligning the tuner.

Now I know! Thanks Doug!

I have a 626 in my current rotation, and it already has plenty of bass. I have bumped up input caps wjen I recap a KA-3500 to get more bass, but my little 626 already has more then plenty.

Stock, this 626 I'm mucking about with DOES have a surprising bass presence. It pairs well with larger speakers.

Hey great, thanks Doug! Sometimes I do try things, like my very first project - recapping a Pioneer SX-727. I got it for $25, new parts were about $20, and I figured that even if I totally screwed up and it burned on the bench, that the education was cheap! It started this wonderful hobby. Oh, the 727 turned out to be awesome, and a great education, to boot.

I am right here with you. The opportunity to become an electronics autodidact for relatively cheap is the fun part for me. Given my aptitudes, without AK advice, I'd be stuck, for sure.

 

[tusntuk2]

I'm also of the opinion (like others) that more bass in the smaller amp could be a marketing tool. A smaller amp would suggest smaller speakers, too, and back in the day the manufacturer would want to make the lower priced unit more competitive sound and sales-wise to the bigger rigs in order to appeal to more customers. Result - make it sound richer and fuller at lower volumes with smaller speakers. I run the 626 and a larger SX-727, and the 626 holds its own on the bottom end. Maybe too, that's part of the "warm" sound that these Pioneers seem to promote.

 

[dly66]

I have recapped several vintage receivers, included several that don't have any ICs in the FM tuner and MPX sections, or maybe just one, and keeping to the same capacitance values could not tell any loss in tuner performance, actually often the sound quality improved.

My SX-535 can be a bit bass heavy, recently picked up a cheap SX-636 from a fellow AKer, the issues that got it moved on just looking it over a couple things caught my eye replacing a few transistors and a few other things it is singing nicely now. Will recap it in the future but the 636 has a more balanced clean sound I actually like the sound of it much more than the 535. The SX-636 gets a lot of good reviews.

 

[dlucy]

My SX-535 can be a bit bass heavy, recently picked up a cheap SX-636 from a fellow AKer, the issues that got it moved on just looking it over a couple things caught my eye replacing a few transistors and a few other things it is singing nicely now. Will recap it in the future but the 636 has a more balanced clean sound I actually like the sound of it much more than the 535. The SX-636 gets a lot of good reviews.

I don’t think the SX-636 is cap-coupled output. So, no output caps to worry about.

 

[dly66]

I don’t think the SX-636 is cap-coupled output. So, no output caps to worry about.

No output caps on those two. Working on repairing an SX-1500TD so should get to see what a Pioneer cap coupled unit sounds like.

 

[RICK KING]

Any updates to the list? I'm going to rebuild my SX-626 when I finish my SA-9500 and a tube amp.
Thanks!