Guest tdeutsch Posted February 1, 2006 Report Share Posted February 1, 2006 I have a couple general questions about old tube receivers. Mine is an old (1966 or so) Lafayette 15 wpc model LR-400.I’m sure these questions will lead you to believe I know next to nothing about stereo equipment – and you would be right! But just by dumb luck I have my father-in-law’s old receiver (a 15wpc Lafayette LR-400 which he gave to me 10 or so years ago) and most recently he “remembered” to give me the “little speakers” that he bought at the same time – these turned out to be the pair of AR-4x that brought me to this site.Up until very recently, since I already had a “modern” stereo setup (Sherwood receiver and Pinnacle speakers) the Lafayette was relegated to the unheated basement workshop in our first house and the outdoor workshop/garage in our second house. I think this unit looks and sounds cool with its analog tuner dial, glowing tubes, warm sound and scratchy controls (which I’ve cleaned in recent years, so they are now a little less scratchy).Here comes my first question (finally!) Recently I have read online that old stereos have wax-covered paper capacitors that are, at best, way out of specification and ruining the sound or, at worst, bursting into little flaming candles and burning down my garage. I also read that most of the other little caps, even if they are covered in plastic, are probably paper caps masquerading as modern caps and should be replaced, along with any electrolytic caps if the unit hums at all (which mine does, at least a little). So, am I a fool if I buy all these caps, buy a decent soldering iron (I’ve never needed a decent one – mine came from BigLots I think) and commence to re-build this thing; or, am I a fool if I continue to power it up as is and just ignore the mild hum? This unit is probably worth $120 in A1 condition, although I would not sell it, so I’m not sure the end result would be worth the many hours this will take me. But maybe it would be?Question #2: I’ve also read that a location exposed to temperature swings and/or humidity was a poor choice for these old receivers. Should I find an indoor spot for the old Lafayette and find a solid state unit for outdoors – or is this more hobbyist voodoo? After all, it’s been playing in a non-climate-controlled environment for years with no perceptible deterioration in the sound. Also, how many homes in the 1960s had central air (I’m in the sticky Ohio valley)?Question #3: On the back of said receiver, there is a screw-terminal for ground. My FM antenna attaches there, according to the manual. The power supply plug for the receiver is a typical old 2-prong on skinny brown lamp cord. So, where’s the ground? The neutral power leg (the white wire) in the outlet box is shared with ground, but it just seems weird to label this terminal “ground” when it isn’t really. Would it be safer or provide better FM reception if I actually attached this terminal to earth ground as well? I think I’m sensing the answer will be “NO! and STEP AWAY from the stereo, dude!” but I’ve always been curious about this and so thought I’d ask.Thanks! I appreciate the wealth of experience and opinions shared around here! Link to comment Share on other sites More sharing options...
soundminded Posted February 2, 2006 Report Share Posted February 2, 2006 I'm sure there will be others who disagree with me here but coming from the "don't fix it if it ain't broke" school of life and the "don't monkey around with what you don't understand" school as well, I say leave well enough alone. There are many possible causes for a slight hum, a bad power supply electrolytic capacitor not being a likely one (a failure there would probably produce a much larger very objectionable hum.) This receiver was a low end budget item from a not too well regarded manufacturer (but a great distributor) and is likely not worth much on the market even in the best possible restored condition. Restoration would be a major pain in the rump requiring researching all of the parts (sometims the information on the capacitors themselves is difficult or impossible to read, schematics difficult to obtain, and replacement parts expensive and hard or impossible to find requiring jury rigging adaptations) so it is IMO a big undertaking which should be reserved for outstanding examples of old equipment by those who know how to go about it. Storage of electronics in "poor" environments is not necessarily bad. It is only bad if it gets wet and then should be dried thoroughly before being operated. (If electronic equipment gets very wet, it can be dried in a very low temperature oven to drive off residual moisture.) It will usually not be affected by storage in very cold or dry conditions and it will experience much higher temperatures in operation than in most storage. Clean off any dust or mold which may have accumulated and use a deoxidizer like "tweak" to clean potentiometers, switches, and jacks to restore their ability to make good electrical contact and it should be OK. Be sure tubes are firmly seated and cleaned as well.The ground screw on the back is NOT for an FM antenna. There should be screw terminals for that purpose. In that era they were invariably for 300 ohm balanced twin lead but you can connect them to an inexpensive transformer if you have a 75 ohm coax lead in for FM. In that era most receivers had a pair of clearly marked antenna terminals, some had a ferrite loopstick antenna installed which could be disconnected for connection of a better one. The ground terminal is for a phonograph which has a seperate ground lead needing to be grounded to the preamplifier stage to eliminate hum. Some turntables like AR's (I think) carried the chassis ground through one of the signal wire grounds and didn't have or need a separate ground terminal. Keep all phonograph coax wires and other signal wires away from power cords if possible and that should reduce hum. It is not necessary to use an earth ground nor a safety ground since the unit was UL listed without one.Good Luck>I have a couple general questions about old tube receivers.>Mine is an old (1966 or so) Lafayette 15 wpc model LR-400.>I’m sure these questions will lead you to believe I know next>to nothing about stereo equipment – and you would be right!>But just by dumb luck I have my father-in-law’s old receiver>(a 15wpc Lafayette LR-400 which he gave to me 10 or so years>ago) and most recently he “remembered” to give me the “little>speakers” that he bought at the same time – these turned out>to be the pair of AR-4x that brought me to this site.>>Up until very recently, since I already had a “modern” stereo>setup (Sherwood receiver and Pinnacle speakers) the Lafayette>was relegated to the unheated basement workshop in our first>house and the outdoor workshop/garage in our second house. I>think this unit looks and sounds cool with its analog tuner>dial, glowing tubes, warm sound and scratchy controls (which>I’ve cleaned in recent years, so they are now a little less>scratchy).>>Here comes my first question (finally!) Recently I have read>online that old stereos have wax-covered paper capacitors that>are, at best, way out of specification and ruining the sound>or, at worst, bursting into little flaming candles and burning>down my garage. I also read that most of the other little>caps, even if they are covered in plastic, are probably paper>caps masquerading as modern caps and should be replaced, along>with any electrolytic caps if the unit hums at all (which mine>does, at least a little). So, am I a fool if I buy all these>caps, buy a decent soldering iron (I’ve never needed a decent>one – mine came from BigLots I think) and commence to re-build>this thing; or, am I a fool if I continue to power it up as is>and just ignore the mild hum? This unit is probably worth $120>in A1 condition, although I would not sell it, so I’m not sure>the end result would be worth the many hours this will take>me. But maybe it would be?>>Question #2: I’ve also read that a location exposed to>temperature swings and/or humidity was a poor choice for these>old receivers. Should I find an indoor spot for the old>Lafayette and find a solid state unit for outdoors – or is>this more hobbyist voodoo? After all, it’s been playing in a>non-climate-controlled environment for years with no>perceptible deterioration in the sound. Also, how many homes>in the 1960s had central air (I’m in the sticky Ohio valley)?>>Question #3: On the back of said receiver, there is a>screw-terminal for ground. My FM antenna attaches there,>according to the manual. The power supply plug for the>receiver is a typical old 2-prong on skinny brown lamp cord.>So, where’s the ground? The neutral power leg (the white wire)>in the outlet box is shared with ground, but it just seems>weird to label this terminal “ground” when it isn’t really.>Would it be safer or provide better FM reception if I actually>attached this terminal to earth ground as well? I think I’m>sensing the answer will be “NO! and STEP AWAY from the stereo,>dude!” but I’ve always been curious about this and so thought>I’d ask.>>Thanks! I appreciate the wealth of experience and opinions>shared around here!> Link to comment Share on other sites More sharing options...
Guest tdeutsch Posted February 3, 2006 Report Share Posted February 3, 2006 The users manual on my low-end budget Lafayette receiver (which I like anyway!) plainly illustrates connecting a dipole FM antenna lead to two screws -- one marked FM and the other marked ground. I thought this was weird too -- that's why I asked! There are three screws grouped together -- one marked FM, the second marked Ground and the third marked AM. I have seen old receivers with two screws marked FM -- mine has only one.I'm sure you are right about the phonograph being attached to the ground screw. So, no one attaches an earth grounding wire to the screw marked "ground"?Doesn't a proper ground have something to do with reducing hum? Link to comment Share on other sites More sharing options...
rrcrain Posted February 3, 2006 Report Share Posted February 3, 2006 Every piece of equipment is different. To date, I've seen and heard of more problems when stereo equipment is grounded than if it's left ungrounded. Some people I know have had to resort to using a 3 to 2 prong adapter to lift a ground to remove hum. Link to comment Share on other sites More sharing options...
soundminded Posted February 3, 2006 Report Share Posted February 3, 2006 If you are satisfied with FM reception the way you have your antenna connected, that's all that matters. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.