Pioneer SX-3500

Pioneer SX-3500

Serial No. BE3406226Y

Professional Restoration with full Recap and Audiophile Modifications.

MSRP $225, Circa 1980

Cost Adjusted for Inflation $860

$545


FMI HiFiHealthCare@Gmail.com


It was 1980 and the transition from the analog realm towards digital (tuners) was just around the corner when Pioneer introduced the SX-**00 line with “Flouroscan” display technology. The ‘coolness’ factor of those blue bars moving effortlessly to the music left many a entry HiFi enthusiasts dreaming of owning one to complement their lava lamps.


Coolness factor aside, the solid audio engineering that went into the circuitry design always hid a potential unrealized under “Mass Production” pressures. 

It was however, a solid performer in it’s category and time priced at about $850 2024 dollars.








The SX-3500 was rated at 20 watts per channel into 8 ohms however, during our final testing after all modifications, this example produced over 2 times that at over 42 Watts of clean output with Both channels driven simultaneously! This is an example of what you hear about with classic gear being “under rated”


 









One reason some people get into the Classic HiFi scene is their discovery of vinyl. The 3500 had a very good discrete complimentary low noise phono amplifier to begin with. 

We took the design up a notch by replacing the entry level audio capacitors that were incorporated originally with modern high grade “Gold Series” audio caps from Nichicon, bringing this piece up a notch sonically.

Particular attention was taken with the front end of the phono amplifier where we selected high accuracy Poly Stacked Film capacitors!

All transistors were upgraded to much higher performance KSA992’s and their compliment, this really supercharged a solid phono design into the best performer it can be.









The real power behind the punch of an amplifier is the large main filter capacitors. You will almost never see anyone replacing them on a 3500 (or many other models for that matter), why?...

Number 1, they are quite expensive and bench testing at 1khz will often show them within spec, but test them at 20hz and 15khz and you almost always see a different story. BESIDES, THEY ARE OVER 40 YEARS OLD!

Number 2, To gain access to them on this amp you need to do a complete teardown of the chassis to access the pads on the PCB in order to change them,…not a very easy job to do and very time consuming!

We do though…

 and if you go through that much effort why not upgrade the value by a couple thousand microfarads and use premium 

“Fine Gold” caps from Nichicon…Yeah, now that’s putting the tiger in the tank!








At this point in the restore, it is essential to address the #1 killer of output transistors in classic gear, poor heat conduction due to old dried out heat transfer compound.

To address, we remove the complete heatsink assembly along with the outputs and strip them down to the bare components and insulators and clean off all the old crusty failing heat sink compound and refresh it with a modern version of High Density, Non Curing Thermal paste to protect the device for decades to come.


 





The Tuner required alignment which was performed in accordance to the Pioneer Service Manual.

After alignment the tuner worked flawlessly and we have to agree with everything that classicreceivers.com has to say about the SX-3600 which has the same tuner as the 3500.









DC Offset was checked as per Pioneer Service Manual.

Quiescent current was low and was adjusted on both channels as per technical documentation.


Final testing concluded with Power output test.

Using an 8 ohm dummy load we easily achieved 42 watts of clean power out of this baby at 1khz, see scope picture for results. This exceeds the manufacturers specification by more than 100% showing what this under rated receiver can really do when at it’s peak operating condition!






This is the beauty of doing a restoration, you are not restricted by the Bean Counters trying to shave a few dollars off the retail and instead you have the freedom to make the original engineers proud that their design was able to be brought ‘next level’. The 1st 80% of good sound quality lies in the design, it is the component selection that can squeeze out the last 20%.

Speaking of “Restorations”, it is really sad to see some of the items being hawked under false pretenses.

If the work isn’t shown, it probably wasn’t done or at least not as described. In some cases you even see “Complete Recap” and they show pictures of the interior with all the original parts!

Although it is a significantly higher amount of work, we tear down pieces to the point of extracting controls such as potentiometers to refresh properly instead of the shortcut that many do trying to hit the device in-situ and often create a mess on adjacent components and PCB’s in the process not to mention often having insufficient access to entry points to make the refresh effective long term. After appropriate cleaning and lubricating (where appropriate) we finish the tracks and contacts with F5 or D100 as appropriate.





We are proud to show our work and attention to detail that will set apart our restorations from the pack. 

When a piece leaves our bench it not only meets the manufacturers specifications, it exceeds them. Our part selection is made with longevity and reliability in mind.

 

If you are looking to travel back in time here is your opportunity to step into a classic receiver that is back to like new condition operationally. 

This will be a conversation starter in your retro room and you can proudly boast how no one in the world has another quite like it!