Vintage Pioneer Fan in need of advice

K

kevinrobinso

New Member
Hey guys,

Forgive me if this post is in the wrong category here – I’m an occasional lurker and near-never poster. I’ve rolled through AK doing research in the past, and I’ve asked a few questions along the way, getting great advice and help (and have a met a few nice folks along the way). The fact of the matter, however, is that I’m a music fan, not a gear head, so while AK offers a profound technical resource, I’m much more likely to come read through the threads here than I am to post.

That said, here’s my problem – I hope you guys can come through with some good advice.

About four years ago I bought an SX939, on ebay if I recall correctly. I’ve loved this stereo for those years: it sounds fantastic, looks beautiful and performs like a vintage dream. Coupled with the four Advent Loudspeakers I have, I’ve heard things on my albums I’d never heard before. Sadly, it has the persistent problem of losing a channel at least once a year (the right one, for the most part). A helpful AKer that lives in my metro area has done some great work on it (this fellow is a skilled technician and an experienced Pioneer expert). About a month ago, almost on schedule, I lost the right channel again. I think I’m done dragging this unit around my city, trying to get it fixed. I’ve got some cash saved up (not much, a few hundred for a good unit) and would like to replace my stereo with something similar – another 939, or even a 1010 if I can track one down. But! I don’t know what to do with my current unit, or how much I trust the Craigslist/Ebay world, after my experience with this unit. I figure my current 939 must be worth something to someone that loves restoring these units or needs parts. Likewise, as someone that loves the look and fidelity of classic Pioneer units, but doesn’t have the talent, patience or knowledge to do a restoration myself, I want to find a unit that I can trust will bring me years of listening enjoyment.

What are your recommendations for where to find a comparable unit (and suggestions for what that unit might be, if not a 939 or 1010), and what to do about my current unit? Ideas on how to trade my unit + cash, and suggestions for businesses that deal in this sort of transaction? Recommendations for good stereo shops or folks you know that might have something like what I’m looking for, and/or might be interested in buying/selling/trading?

Thanks in advance, guys.
 
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I'm thinking that an SX-950 or SX-980 may be comparable with what you have, perhaps a step above. These put out 80WPC where I saw where yours puts out 75WPC.
 
Thanks for the quick replies, fellows!

I've looked at the other 900-series Pioneer - I can be talked into one of those, easily. I think part of what I like about the 939 is the blue flouroscan on the face, but also that it is of an earlier vintage.

Do you guys have any ideas/suggestions on what to do with my old unit, or where to look for/ how to go about securing a quality unit?
 
Before I went looking, I'd at least try and clean all the switches and pots. I'm thinking you have a dirty Tape monitor switch, AM/FM/Phono/Aux or a -20db switch. The push button function switches on the 939 / 1010 need cleaning regularly. These are the weak link in an otherwise outstanding receiver.

The other plus here is that you save time and gas, by doing it yourself. It's down for about 2 hours total. and you don't have to lug it in, tell someone what it's doing while getting a BLANK LOOK, and waiting 3-5 weeks just to get it cleaned, and a 50/50 chance it wasn't done right.

Now if you want another rig to either upgrade to or get something different, I don't have any recommendations. The 939 is a very good rig in it's own right.

But I'd still take a shot at cleaning it 1st.

Larry
 
larryderouin said:
Before I went looking, I'd at least try and clean all the switches and pots. I'm thinking you have a dirty Tape monitor switch, AM/FM/Phono/Aux or a -20db switch. The push button function switches on the 939 / 1010 need cleaning regularly. These are the weak link in an otherwise outstanding receiver.

The other plus here is that you save time and gas, by doing it yourself. It's down for about 2 hours total. and you don't have to lug it in, tell someone what it's doing while getting a BLANK LOOK, and waiting 3-5 weeks just to get it cleaned, and a 50/50 chance it wasn't done right.

Now if you want another rig to either upgrade to or get something different, I don't have any recommendations. The 939 is a very good rig in it's own right.

But I'd still take a shot at cleaning it 1st.

Larry
Click to expand...

I'm down for taking a crack at cleaning it - that's something that's been done along the way every time this happens. Would this be a common occurring - that is, needing an annual cleaning, and losing a channel as a result of needing that cleaning? I feel like needing to clean all the pots and switches is something that should only be happening once in a long while.
 
For me the fun of vintage electronics is that you can find unexpectedly good stuff unexpectedly cheap, but you've got to be open to options and expose yourself to opportunities to get more/different gear. If you go looking for a 939 or 1010 and you don't find one right away, you'll be bummed... but if you go to thrift stores, cruise craiglsist and ebay, hit garage and estate sales etc.. all with the goal of finding a cool, good old receiver, you're likely to be really happy.... find a sansui for a bargain on CL? sure, it's not a 939, but buy it and bring it home, you might like it? See a Kenwood or marantz at a garage sale, again, not the 939 you're looking for, but good stuff none the less. if the price is right, buy it and use it for a while, when the next one presents itself, you can always sell or trade..
 
El Pee said:
For me the fun of vintage electronics is that you can find unexpectedly good stuff unexpectedly cheap, but you've got to be open to options and expose yourself to opportunities to get more/different gear. If you go looking for a 939 or 1010 and you don't find one right away, you'll be bummed... but if you go to thrift stores, cruise craiglsist and ebay, hit garage and estate sales etc.. all with the goal of finding a cool, good old receiver, you're likely to be really happy.... find a sansui for a bargain on CL? sure, it's not a 939, but buy it and bring it home, you might like it? See a Kenwood or marantz at a garage sale, again, not the 939 you're looking for, but good stuff none the less. if the price is right, buy it and use it for a while, when the next one presents itself, you can always sell or trade..
Click to expand...

I like the part where I find unexpectedly good stuff at decent prices, I just don't like the part where I find stuff at a good price that doesn't work as it should. Honestly, I'm a music fan - the fun of vintage stereo equipment for me is that it looks fantastic and (when it works right) sounds AMAZING.

You make a good point, though El Pee, about buying a good unit and then swapping it for a better or different unit later. I guess my problem is that I'm not enough of an electrician to want to monkey around with the unit too much. Which makes me weary when buying online through ebay. I guess I was hoping someone here would know of a good place or website to trade this unit for something that's gonna work right the first time, every time.
 
However, keep in mind with vintage equipment, it's old. Those great Pioneer stereos are approaching 35 years old. That is why most people on here have more than one vintage receiver on hand.
 
kevinrobinso said:
I guess my problem is that I'm not enough of an electrician to want to monkey around with the unit too much. Which makes me weary when buying online through ebay. I guess I was hoping someone here would know of a good place or website to trade this unit for something that's gonna work right the first time, every time.
Click to expand...


Exactly, neither am I... I bought a receiver on ebay once... it wasn't a great experience. Now I only buy on CL or at a thrift store when I can inspect and hopefully audition the piece. You learn what looks good and what doesn't, I can't fix anything either, but I can open up and clean stuff pretty well, that usually does the trick... On CL I bought an old Scott tube amp for a good (not great) price... I still had to pay someone to refurbish it for me... sometimes that happens and you'll decide that it's worth it to you to pay to have something fixed so that it's perfect... chances are your 939 will cost more than new used receiver to fix... you gotta decide what it's worth to you.

As far as a good website to trade your receiver, I think you're on it... barter town is made for that sort of thing. You can also probably find a good one to buy there too... personally, I like the thrill of the hunt, I like lurking in second hand shops and garage sales, you never know what you'll find.

Either way you go, good luck and happy listening!
 
What has been repaired on your SX-939 in the past?
I wonder if it is being strained running the stacked Avents? I presume they're 8 ohm impedance speakers (each) and the SX-939 is rated at 100 watts at 4 ohms so while you should be safe you could be pushing it on the older gear.

For where to find something I would suggest you make the $25 leap and become a subscriber, that gives you access to the Barter Town forum where deals do abound. Knowing your location would be helpful as well.

Enjoy the music.
 
w1jim said:
What has been repaired on your SX-939 in the past?
I wonder if it is being strained running the stacked Avents? I presume they're 8 ohm impedance speakers (each) and the SX-939 is rated at 100 watts at 4 ohms so while you should be safe you could be pushing it on the older gear.

For where to find something I would suggest you make the $25 leap and become a subscriber, that gives you access to the Barter Town forum where deals do abound. Knowing your location would be helpful as well.

Enjoy the music.
Click to expand...

It's had a relay contact replaced, and all of the little colorful circle things that have the two wires that are soldered into the green boards replaced, as well as the metal pieces that look like refinery tanks. (Can you tell I don't know jack about stereos?) It's been professionally cleaned several times as well.

I'm in Chicago, for what it's worth.
 
Recapped - I'd keep it!
Face it, if you go the vintage route you'll end up with another old receiver that will need some love eventually.
I'd get yours repaired and look for a xx50 series Pioneer (SX-850 to SX-1250). Then keep the SX-939 as a spare.
But then again I'm talkin' like the junkie I am...
 
Recapped, I agree with Jim. Sounds like the Advents are a drag on the 939 if running stacked. Are they wired together, or separate to "A" and "B" connections on the back. Series vs. parallel. Just in case you don't know the difference, see drawing below.

Hopefully these are 8ohm'ers which hooked up separately will put you into 4ohm territory. If they are 4 oHm and hooked up separately you can't run them that way. too low of an impedance. Your risk of killing the amplifier just went up exponentially.

If you have them strung in series, and they are 4 ohm, then it's ok as the 939 is seeing 8oHms. Put them in parallel and it's seeing something like 2.2oHms. Not Good.

If they are 8oHm in series, then the amp sees 16oHm. OK. If paralleled 4oHm. Ok.


Any vintage amp is gonna need work. It depends on how much and when it's done. Either you have it done, or the previous owner has it done. If the previous owner did it, ask for paperwork. If no paperwork, be leery, unless you know what to look for inside. Like an old car, don't expect it to run 100% right off the other guys driveway.
Anyway you look at it, it's gotta be done.

The Refinery tank things are called Capacitors (think energy storage) and themulticolored things with two leads are resistors. Kink a hose and you resist the flow. Same thing only different values.

You might edit your profile to let us know where you are. Someone may be able to take a look at it for you if close enough.
EDIT: DRAWING CORRECTED
attachment.php

Larry
 
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The above picture #2 (series) is in error.

Here is how you wire in series. Though the image below shows individual drivers just consider each as one of your Advent boxes:

sp_wiring_series.gif
 
Regarding the Advents: They are hooked up separately, two pair into A and two pair into B. I've only been running a single pair since we moved in Dec and I set the unit back up. So, I have one pair on "A" and one pair on "B", and generally speaking I have both A and B buttons depressed. Clear as mud, right?

I think the old car analogy is apt, and I agree, you don't just get rid of a GTO. That said, I don't know how many times you can have the carburetor rebuilt before you need to look for a different ride. At some point, you're going to want to restore dash and do some work to fix up the transmission, you know?

I live in Chicago (agree about updating my profile - I just don't post that much here.) Honestly, I think I'm looking to trade this unit plus some $$ for something that's at least not going to drop it's right channel annually.
 
Thanks Jim: I saw your's and said WTF?? went back and looked at mine, and saw the lead between the + and - on the 2nd box. D'OH!! That's what i get for staying up all night.

OP:
I don't think the problem is with the 939 as much as it is with how the speakers are hooked up. If you insist on stacking speakers, then connect them so the gear driving them will see impedances in the range it was designed for.

TWO PAIR ON "A" AND "B"!?!?!?!?!!!!!!!!!!!!!!! No wonder the 939 is rebelling. I'm not familiar with the Advents. 4 or 8 oHm??? And backing off to one pair isn't helping as the damage has already been done.

Anyway you look at it the 939 has been overstressed!!! Paralleling 8oHm (2pair) on "A" and paralleling 8oHm (2 pair) on "B" with both "ON" at the same time runs into the 2ohm to sub 2ohm range of impedance. with 4oHm speakers being 1/2 that to less than 1oHm or DC.

You've been extremely lucky the only thing that's happened is that the one side drops off every once in a while.

Here's how to stack speakers and maintain a healthy impedance level. This was written by Dynaco for their "A" series speakers, but translates well to most any 8oHm speaker. Don't try it with a 4 ohm speaker as the impedances get too low for the amp.


http://www.audiokarma.org/forums/attachment.php?attachmentid=294062&d=1313822383
 
larryderouin said:
Thanks Jim: I saw your's and said WTF?? went back and looked at mine, and saw the lead between the + and - on the 2nd box. D'OH!! That's what i get for staying up all night.
Click to expand...
I see you've corrected it (try #3).
BTW, I believe that the Advents are 8 ohm speakers which would give a nominal load of 4 ohms. That being said 4 ohms may be taxing the older receiver and at differing frequencies could in fact dip well below that.
 
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