Jehosaphat
404 posts
Jan 04, 2013
8:39 PM
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This is (almost) the same sort of enquiry as Fred Gomez but that thread really makes my brain hurt..caps..
I do understand electricity and what it can do,in fact i have seen one guy killed by it.
In my twenties i was a Linesman and often in summer,hot dry day,standing on a wooden ladder you'd find your rubber gloves filling up with sweat..uncomfortable and hard to work in..so take the gloves off and work barehanded on the live(240 volt) lines.Absolutely verboten in the safety manual but rules are made etc.
Basically with the dry conditions you were isolated from earth so with due care it was doable.
Trouble is you'd also sweat yourself..the guy was killed because his overalls got wet and he leant back on a bare wire earth(neutral) cable while working on a live phase line..Zap..left a widow and two kids.
Anyways I digress.
Ok this is a (1960s')Radio record player type thing works perfectly(the record changer even has a 78 option),I am just wondering if I could connect a mike to the wires from the record player cartridge and have a usable signal to the Amp
Viola!
Like i said i understand electricity in a broad sense but definitely not at this level .
So mike to cartridge wires ,dangerous..stupid or just not feasible because of impedences or somesuch.Any harm in just trying it out?
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Greg Heumann
1925 posts
Jan 04, 2013
8:45 PM
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Actually phono pickups and microphones work on the same principles - either the needle or the mic's diaphragm move a magnet in a coil (dynamic) or stress a crystal - to produce a tiny electric current. I don't know enough about the signal levels from phono cartridges to know if you can just swap a mic element for one with good results, but I do know that they're both low enough power that you can't hurt anything by trying. Let us know!
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/Greg
Last Edited by on Jan 04, 2013 8:45 PM
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fred_gomez
34 posts
Jan 04, 2013
10:34 PM
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ok dont get mad. i had a solid state general electric record player. really cheap one early 70s. i had a decca guitar like hound dog taylors (stolen dont ask) with a metal pickguard. i lifted the tone arm cut the wires from the pickup, then i stripped the end of a guitar cable and twisted them on. no solder no black tape. it worked.
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Greg Heumann
1926 posts
Jan 05, 2013
9:06 AM
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Why would anyone be mad, Fred? In this case you worked with miniscule power sources and didn't endanger yourself. In the other thread that is not the case. What is scary is that you don't seem to think it is important to know the difference.
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/Greg
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jimbo-G
149 posts
Jan 05, 2013
9:28 AM
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Old valve record players can be more hassle than worth if your going to convert. Like Greg said the pick up is very similar, but the circuit has different filters. When the needle Is dragging along the Lp it picks up a lot of interference from dust, and stuff so they Icorperate negative feedback controls and sometimes the record will sound great through it but a Mic can sound weak.
The frequency produced from records also limits the circuit.
Don't know if any of that helped but its a wee bit of info anyhow.
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JD Hoskins
399 posts
Jan 05, 2013
10:16 AM
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The one and only thing I know about this is that my Masco's for instance, have a phono input that lacks that initial gain stage the mic inputs have. I believe it pretty much goes directly to the phase inverter. If this is typical, then you would need another gain stage to get good sound.
Last Edited by on Jan 05, 2013 10:16 AM
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Jehosaphat
405 posts
Jan 05, 2013
1:28 PM
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Ok cheers guys.
Seeing as it looks like i won't electroplate myself i'll give it a go and (hopefully ;-))report back
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