Pioneer SX-3700

Pioneer SX-3700 Front

From that slightly awkward time that lies between the fully analog and fully digital eras come the Pioneer SX-3700. It was 1980 and digital displays were just catching on and Pioneer sought to capitalize on the movement with its Fluroscan technology. The SX-3700 produces 45 watts per channel and incorporates a direct coupled amplifier design.

Pioneer SX-3700 Meter

There is a variant of the SX-3700 labelled the SX-820. Apparently it is a European version but has a black dial face and white Fluroscan. A couple other SX-3000 series receivers also had European variants in the SX-620, SX-720.

Pioneer SX-3700 Knob

The Fluroscan display shows the tuning for the AM or FM bands depending upon AM or FM selector button is pushed. The analog dial shows both FM and AM tuning as well. The power output meter is also a Fluroscan display. Pioneer utilized a 3 gang FM tuning capacitor and quartz servo lock technology to create a very good FM tuner section. The Fluroscan FM display is backed up by a quartz crystal oscillator that provides a stable time base so that the correct numbers will always be displayed for a given frequency selection. The display is also 5 digits as opposed to many other manufacturers that used only four digits. Pioneer referred to all of this as their P.D.Q. or Pioneer Digital/Quartz tuning technology.

Pioneer SX-3700 Inside

The SX-3700 was a mid range receiver and had bigger brothers in the SX-3800 and the SX-3900. But, those receivers had more complicated designs and are more difficult to work on than the SX-3700.

Pioneer SX-3700 Inputs

If you like the Fluroscan display then the SX-3700 (or SX-3800, SX-3900 depending upon your budget) might be the way to go. They do look very nice in the dark and are a good representation of the technological shift from analog to digital. They are also very good performers and can be found for a price that is within most budgets.

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35 thoughts on “Pioneer SX-3700

  1. If I remember correctly, Pioneer’s analog-tuned Fluoroscan receivers that had quartz lock (SX-3700, 3800, 3900) used a varactor to control the LO, acting as an additional ‘gang’ to those on the main tuning cap. Thus the SX-3700 and 3800 have 4 gangs, not 3 (and the SX-3900 has 5, meaning its tuner may be better than that of the TOTL SX-D7000!).

    Now if you’d only do the SX-D7000 next… ;-)

  2. Always awesome reviews! love old vintage stereos, They don’t make them like they used to definitely applies to stereo equipment. Thanks for bringing back memories of the cool stuff from back in the day. Someday hope to put together a vintage stereo system,

  3. Slight correction to the wording of the review. The review is written stating that the digital display only shows FM tuning, while the analog display showed both AM and FM. This isn’t entirely accurate. The digital shows both AM and FM as well.

  4. I recently sold my SX-3700 to a friend who needed a receiver powerful enough to drive a pair of Bose 901 series one speakers.He did not know much about stereos and I was concerned about it’s rating of only 45 wpc.Most of my receivers are over 100 wpc,so I did have something to which to compare power outputs.For only 45 wpc this thing had more than enough for the aforementioned application.My guess (educated from years of experience) is that it is comparable to others rated at 60 wpc.Powerful,superb tuner,and one of the most tubelike Pioneers I have owned( SX 780, 890,1250) .About to buy another one for less than $100,and it was just serviced and looks great!!

    1. Hi there,

      I like your comments and agree 100%. When you say most tube like and reference these SX 780, 890,1250, can you speak more to your tube like experiences with vintage hifi?

      I’m curious to hear your thoughts and ranking of such equipment.



  5. Gents, maybe you can help. Mine is fine except the quartz tuning no longer holds the frequency (FM). Is it possible to replace with new or make sense to just use it as an amp for other inputs?

  6. I just got this old receiver back from my father’s house in Tennessee. My grandpa bought this for me when I was 15 years old. I’m so excited brings back alot of memories. It’s still in excellent shape and works like a charm. I had forgotten how heavy it was lol. Cant wait to hook up my turntable and play all my old albums and 45s.

  7. got a pioneer sx-3700 receiver, been had it for about 20 years. just started back
    using it after about the last three years. cleaned it up with a product called
    deoxit and it sounds like new. they don’t make recievers like the vintage stuff
    any more.

  8. Was just given a SX 3700 from a coworker(been sitting in a closet for years)
    and it has minor problems, balance not working, tuner not accurate but i only need one station here in NOLA and its locking in if i play with it . Tons of power, got a couole Sony satellites so i’m gonna see if i can find a deal on a subwoofer. Yeah, it looks cool in the dark, power meters are a hoot.

  9. I just purchased a set of led replacements for all the lights on my 3700 that I bought new in 1980. It had been in a box for years. Patience and some soldering skills paid off big time. It looks great with all the lights burning. The flouroscan was going in and out. One blog suggested re soldering the contacts between the two boards there are about twenty of them. Did so and it worked like a charm. I think todays so called amp ratings are bs. because this amp pushes my CV AT-12s to window breaking limitsunlike another one I wont metion the brand that claimed 100 watts. I gave away my new stuff the sound is no comparison.

  10. I picked up mine for 10 bucks. everything works great. Such great sound. Not a scratch on the wood. Looks great all lit up at night..

    1. Wow! That’s an awesome find! I’m considering one from a local ad on FB for $125. Needs TLC from what the seller said. Prices have certainly gone up on these classic Pioneer receivers!

  11. Hello: sorry my english.. sound the Pioneer SX 3700 is better than the sx650?

    Is the sx 3700 built with stk or is it like the sx650 without STK?

    Greetings from Argentina.

    1. Yo creo que el SX-3700 tiene STKs mientras que el SX-650 no tiene ninguno. En cuestion de calidad, el SX-3700 es comparable al SX-750, un nivel arribita del SX-650. Pero los dos recibidores son muy buenos. Lo unico que no me gusta del SX-3700 es el display digital. Yo lo preferiria que fuera analogo como el resto de la linea. Pero que es del año 1980, fue cuando esta esa combinacion de analogo y digital.

  12. Ale; the quality of the sound is not that different but the 3700 is louder. La calidad del sonido es similar pero la del 3700 es mas fuerte sin distorcion.

  13. I am the original owner of a Pioneer SX-3700, was my pride an joy when I got it back in High School. it’s been sitting in my mother inlaw’s room for about 30 years, pretty much unused. I plugged it in a few weeks ago and it sounded great, except it couldn’t bring in any FM stations below about 100Mhz. After a few hours of playing, the fault relay started clicking. I took it to get it looked at, after re-soldering a few of the conections, everything is working fantastic. Hooked it up to some Advent Laureate towers, and man this system rocks! I mostly listen to FM, but I also hooked up an Audio Engine bluetooth connection to the Aux, so I can stream music. This old stuff sounds so good! I’m hooked! thinking about hooking up my old Yamaha NS-4s that I originally had as my system back in the 80s, but those are being used with my HT.
    I am curious how the sound of this compares to a Marantz 2230 or similar.

  14. I just found one in the trash. Needs some knobs, but it’s restorable. I have a few other parts Pioneers for the knobs. Glad I found it. Untested.

  15. I just received a SX 3700 and a pair of HPM 700 speakers as a house warming gift..Love it..could anyone tell me their thoughts on the speakers..also the receiver has a lot of dust..thoughts on cleaning the inside..

    1. I bought a can of compressed air and a can of electrical contact cleaner (both very cheap). Took off the outer shell, blew out as much dust as possible, then a heavy spray (draining onto newspaper) of the contact cleaner. Sounds much better and looks like new inside.

  16. yes , michael the hpm 700 should be a great speaker, i have aset of pioneer hpm 100’s and a pioneer sx 3700 receiver, the best way to clean your receiver is with a product called Deoxit, it is made by a company called caig. you can go on line there is an electronics company that carries this product, named ”Parts Express”.

    1. I saw one at a yard sale, I offered him all the cash in my wallet to buy as is without even plugging it in . I got it home fully expecting to find one channel out . Besides a little pot static at first with the balance knob I found no problems with my 3700. Its job now is to power 2 Electro voice ev 200s pa speakers that I can easily hear while playing my acoustic drums. Drums are freaking loud . Oh yeah how much in my wallet? 36 bucks.

  17. I have one that I bought new – the volume and balance controls got scratchy and intermittent so it sat on a shelf in my basement for about 20 years. I recently had a local pro clean it up (under $100) and now it pairs great with my L100s. I know the JBLs can handle more power than this puts out, but it will go much louder than I would consider necessary and it sounds great.

    1. Not sure about where to get an appraisal but a ‘new’ one sold on eBay last month for $527 + shipping. It didn’t have the original box with it though. My guess would be that ‘new in box’ would be around $700 but that’s just a guess. Maybe more.

    2. Depends on condition. A unit in great shape with absolutely no issues can go for between 375.00 and 500.00

  18. I just picked up one of these on ebay for $350.00. It’s near mint condition and looks beautiful. Sounds amazing too. Super happy with it. Wish I could swing the SX-3900. Next time. ; )

  19. Had a modern Yamaha 100wpc receiver I bought at Best Buy driving Polk Monitor 10bs. Very disappointed. I know those speakers aren’t very efficient, but it didn’t seem right. On a hunch I found a 3700 for sale and took a shot. $275, perfect condition. The speakers came to life and this 45wpc receiver lays waste to the Yamaha. Apparently all watts are not created equal. Owned a 3700 forty years ago. Paid off big time to go back to my roots.

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