Damaging inputs?

[Prospero750]

Hey audio-geniuses. I have an sx-750. I bought it on a nostalgia fueled impulse a few weeks ago not realizing it would spark a whole new hobby. It was my first foray into audio. The folks on this site have already been very helpful and patient with my questions. Thank you for that. I've a few more.

I picked up a speaker from a serious audiophile today. And he voiced some concern regarding using modern inputs (cd players, pandora music etc) with my vintage receiver. Are there any precautions I should take when hooking up modern inputs to an old receiver? Is there damage or excessive wear occuring using modern inputs? I hear a lot of people using them with CD players so I'm guessing I'm safe, but who knows?

The mic port on the front, can it be used as an aux port for streamed music from an iphone? Am I just violating everything that is sacred and holy by even considering doing such a thing?

I've acquired a pioneer pl-115d turntable. I'd like to replace the cartridge. Any recommendations? Also, there seems to be a wobble with this table. I'll follow some instructions I saw in another post regarding cleaning and greasing. Hopefully it's not fatally damaged. Any other suggestions or things to watch for?

It took me a few weeks to realize the score that I'd made when I saw this tuner for $36 at Goodwill. Now that I know, I've become pretty attached to it. Are there any capacitors or other components I should test and possibly replace to prevent a catastrophic failure? With initial poking around I didn't see anything that looked obviously new so I'm assuming everything is original.

I'd like to re-veneer the receiver and the turntable (if the wobble can be remedied). If anybody has experience with that and knows things to watch out for I'd love any input you have. Sorry for all the questions! That was longer winded than I expected!

 

[whoaru99]

I picked up a speaker from a serious audiophile today. And he voiced some concern regarding using modern inputs (cd players, pandora music etc) with my vintage receiver. Are there any precautions I should take when hooking up modern inputs to an old receiver? Is there damage or excessive wear occuring using modern inputs?

Non-issue.

Usually this is centered around the input sensitivity specification that is frequently misunderstood. Input sensitivity is the minimum required to facilitate the rated output of the amp/receiver; not the maximum permissible input.

 

[markthefixer]

I can't let THAT stand. I take issue. There ARE overload levels.

The mic port on the front, can it be used as an aux port for streamed music from an iphone?
Am I just violating everything that is sacred and holy by even considering doing such a thing?

a 2.000v ipod output put into a 5mV (0.005v) mic input WILL cause overload. At least the parts are common parts that
'can be sourced and replaced easily. When the MIC jack is plugged into, the AUX inputs are ignored and the mic amp output fed
to that switch position. Thus the mic amp output can be inferred as 150mV. The MIC amp is a 2sa725 and 2sc1344 transistors.


for reference, a PHONO input is 0.0025v or 2.5mV with a phono input OVERLOAD of 0.200 volts or 200mV.
The phono preamp is an op-amp, no telling just what damage will occur, or where to get the replacement parts.
Plus the phono equalization will distort things even more.
an aux or tape input is 150mV.

So the best analogy is that you are trying to sip from a fire hose. That usually ends up badly.

 

[jeffpaletz]

Use the Aux input to connect CD players or other devices similar to that. I've used the aux input for CD players for many years and they sound great. If you need another line level input you can also use the Tape In input as well. Do not use the mic inputs for anything other than a microphone. Likewise only use the phono inputs for connecting a turntable.

 

[Prospero750]

I can't let THAT stand. I take issue. There ARE overload levels.

Thanks, that's what I was afraid of. Is the best option then attaching to one of the tape play inputs, or the aux input?

Can I also ask you, are there electronic components in this which, should they fail would lead to significant damage. I'm hoping maybe I can check them out and see if they are getting out of tolerance and replace them to prevent any big problems down the road. I'm newish to electronics work and not up to a full recap job, but I could certainly handle a few with meticulous caution. Or is recapping kinda of an all or nothing situation?

 

[kevzep]

Thanks, that's what I was afraid of. Is the best option then attaching to one of the tape play inputs, or the aux input?

Can I also ask you, are there electronic components in this which, should they fail would lead to significant damage. I'm hoping maybe I can check them out and see if they are getting out of tolerance and replace them to prevent any big problems down the road. I'm newish to electronics work and not up to a full recap job, but I could certainly handle a few with meticulous caution. Or is recapping kinda of an all or nothing situation?

Mark is of course right, there are indeed overload levels, but plugging a CD player into an AUX, TAPE or TUNER input is never going to overload the input.

 

[zebulon1]

The best route and easiest is to purchase a Bluetooth receiver with the two channel output. You can stream from your phone or computer. The newest ones sound really good and go for around $40. I also use the old iPod and docks that throttle the output to a safe line level. Perfect for plugging into the back of the vintage sets.

I think you mentioned a tuner? Best to leave it alone. If you really want to bring back some reliability you could restore the power supply. That's all I would do.