Audio Systems: Sound Issues, pioneer sx, amplifier section


Question
-------------------------Hi Kevin---thanks for the information! Hmm..Speakers, I got two larger ones (3 ft) with the receiver, tape deck and turntable. I'm not too sure what they are, they have metal circular thingies on them for legs, which are missing...The other two are a set of Wald, small size in a heavy wood cabinet...And the other two are pieces of crap I found on someones curb.....I'll disconnect the speakers and see if that makes a difference...I hope so! I just moved, although I packed it carefully in the car, so I hope nothing majorly bad happened inside of it..It would not surprise me at all if I had too many speakers attached to it, that kind of knowledge isn't my forte....Thank you again! :)

Rachel



Followup To
Question -
I am presently using a Pioneer Sx 636, with a Pioneer Pl150d, in addition to a Sanyo Rd5030. The components are hooked up to 6 speakers total and up until today I haven't had any problems with them. When I just put on a record, some of the sound shorted out and got really distorted and the only thing I can think of is that the receiver needs cleaning.(I purchased all the components, minus 4 speakers for 60 bucks at the Sal. Army, a great deal!) A friend of mine said that I could open the system up and spray it with contact cleaner, but I am concerned that I might make the problem worse. What do you think is the problem? I also was checking the speaker connections which seemed fine, as well as the outlet it is plugged into- since there have been a lot of thunderstorms in the past few days....Any help is appreciated, as I live in a rural area in which people aren't exactly knowledgeably about such things...Thank you! (Ps- the stereo is plugged into a cord with a circuit breaker, so lightening would not fry it----at least hopefully..)
Answer -
Dear Rachel,

Wow, this is some vintage stuff.

First, running six speakers off an amplifier designed to run four will cause the amplifier section of the receiver to overheat. And your Pioneer receiver only puts out 25 watts per channel, dinky by today's standards. Since receivers of your vintage (early '70s) did not offer thermal protection circuits, which would shut down the receiver if it overheated, it could be that the extra load represented by the extra two speakers caused it to seize up.

Second, you have a very old component that, since you got it at a thrift store, probably hasn't gotten the kid gloves treatment when being hauled around from loading dock to stockpile to display. My guess is that its treatment has been pretty rough, meaning that almost anything could have been jarred loose in the process. All it took was a couple of hours (or more) of playing for the thing to disengage entirely.

Unless your house took a fairly close lightning strike, it's doubtful that a thunderstorm is the culprit.

And, no, spraying the interior with contact cleaner is not the solution. Contact cleaner will work occasionally on the connections between components, but indiscriminately spraying it on the interior of the unit is going to coat it with guck--and unless you've cleaned it first, very dirty guck at that. Plus the coating will make anything fixable harder to fix.

The first solution is to disengage two of the speakers. Put one speaker *only* per speaker output. Unplug the unit for a day to let it cool down completely. Then turn it back on with *only* the "A" speakers on. If you get the same result, then go to the second solution.

The second solution is to open up the unit and very, very gently clean it out preferably by hand with a soft brush and a very low powered vacuum cleaner. Keep an eye out for loose wires. Wires should not be loose in audio components. Then find a friend to solder the wire back in place. It'll be pretty obvious where the break is.

If none of this works, I don't recommend taking it to a repair shop. They'll charge you an arm and a leg: more than the whole system is worth. If it turns out you need a new receiver, and don't want to go the thrift route again, let me know. There are some perfectly acceptable for well under $200.

Good luck. You're very brave to use components as old as these. Tell me, what kind of speakers are you using?

Kindest regards,

Kevin  

Answer
Dear Rachel,

Hmm...I'm not very surprised by your response. My guess is that you've cobbled together the speakers like you did the components--music must mean a lot to you. My guess also is that they're also very old, like the other components, and probably exhibit the characteristics of old speakers: large, very heavy, screw heads or clips for terminals, AND they're woefully inefficient. It's the last thing that worries me with your Pioneer receiver that only puts out 25 watts per channel.

Inefficient speakers require lots of power to drive, that is, to play at decent volumes. If you (1) put too many of them in the sound chain (and six was way too many--four may also be too many) and (2) you crank up the volume, your receiver is going to max out fairly quickly; and when old receivers max out, they just quit, usually frying or melting something in the process. I love old stuff (my first receiver was a Pioneer ca. 1974 with 35 watts a channel), but the science and technology of sound reproduction has advanced so profoundly over the last 30 years that you can get way better sound for a relatively small investment. (No, I'm not in the audio retail business.)

You probably went to the thrift store because you're on a limited budget: great idea. When you have $500 (a sum that's not even imaginable now, but in audio terms not much at all) you want to spend on audio/music, let me know, and I'll help you put a rig together that will have you dancing far into the night. A promise.

In the mean time enjoy your music. Have a great life.

Kindest regards,

Kevin