Phono turntable question - static noise

Factual Questions
21

Small update: I got the CD player playing and it sounds good. I think I had a bum CD in it the first time.

So, in my mind, this rules out the speakers, the speaker wires, and (possibly) the receiver as culprits.

More weirdness: The AM band of the tuner works fine, the FM gives only static. There is an FM antenna attached, but the unit is in the basement and possibly not receiving a strong enough signal.

mmm

22

Random intermittent static makes me think dried out electrolytic capacitors. Old capacitors are a very common problem in vintage electronics.

23

I know these are common issues in receivers and often replaced - do turntables have capacitors too?

mmm

24

Most electronic devices have electrolytic caps. They are very commonly used for bulk filtering in power supplies. Electrolytic caps might also be used in the turntable’s audio section.

25

I would think that would lead to humming, not static.
In my experience, switches and pots (or anything with a contact or wiper) tend to be the generators of static.

26
  1. Have you used this cartridge/preamp combo before or was the preamp from some other use? If you have used this combo in the past and it sounded good than ignore the rest of this post.
  2. Is the preamp specifically a phono preamp? If not, it likely does not have the RIAA equalization needed for a phono cartridge. (It seems odd that a phono preamp doesn’t have a dedicated ground terminal.)
  3. Even if it is a phono preamp it’s possible you have moving magnet cartridge and a moving coil preamp or vice versa. Are there any settings on the preamp for cartridge type?
27

You say you have a separate preamp for the turntable. The CD input seems to be working okay. Have you tried connecting the turntable preamp into other inputs? The CD one for instance.
It is possible that just one input on the amp is messed up.

28

Given it is a Shure cartridge it will be moving magnet. These are the higher output design. And the most common. If there was a moving coil cartridge we would be talking a whole step up in price and expectation.

I doubt there are any audio electronics in the turntable. Just direct connections from cartridge to output.

Electrolytic capacitors are a favourite problem, but will usually affect the channels differently. Usually.
But they can sound scratchy noisy and lacking any bass.

Changing inputs on the amplifier can help chase down bad contacts both on connectors and internal switches. Depending upon on the environment even internal switches can get into trouble. I once cleaned the residue of a few decades of cigar smoke from inside an amp. Fixed the crackly and bad sound instantly. Yuck.

29

UPDATE:

I connected the phono inputs (from the pre-amp) to the receiver’s CD input and achieved the same unsatisfactory sound from the turntable.

I cleaned all the connections with alcohol and Q-tips, no improvement.

I listened to another (different) CD from the CD deck and it sounds good.

I calibrated and balanced the tone arm (I know this wouldn’t affect the sound but I thought I’d share).

To attempt to further describe the sound I get when I play a record: I would call it static rather than a buzz or a hum. And the music is at a much lower volume than the tuner or the CD player produces.

At this point my suspects are: turntable, pre-amp, cartridge.

My gut tells me pre-amp, mostly because of the low volume (make sense?). It was very cheap, the cheapest one I could find. I think it worked ok many years ago, but I honestly am not sure about even that.

mmm

30

Dumb question. Does the pre amp have a battery? Is it dead?

31

No, it plugs into an electrical outlet.

There is no indicator light to show power is on. However, I plugged the phono cords directly into the receiver - bypassing the pre-amp - and got zero sound, which indicates the pre-amp is doing something.

mmm

32

Do you have a make and model number for the preamp?

33

Does the turntable have a built-in RIAA preamp? What is the model number for the turntable?

34

Imgur

35

Nope. Pioneer PL-115D.

mmm

36

Is it just me or do the RCA plugs (on the cable, not on the box) on at least the input side still look a bit … uh … rode hard and put away wet?

37

Missed the edit window.

if you twist any of the cable connections to that preamp, does it have any effect on the noise you’re hearing?

If so, then I’d probably either replace that cable or, at least, hit the plugs with either 0000 steel wool and some solvent or a pencil eraser and try to clean them up, inside and out.

Make 'em pretty.

38

I found a pic of the RCA AH500 on eBay. It had a grounded power plug. I assume this one does, too? If the AH500 is connecting the shields of the RCA connectors to ground, and the RCA connectors on the stereo preamp are connected to ground through the stereo’s power cord, it might cause a ground loop.

39

Yeah, but those are connected to the turntable, not a lot I can do about that other than cleaning them.

The other set are new, replaced them today.

mmm

40

Yes, the AH500 has a grounded power plug, but after that I’m afraid I’m not following you.

Anyway, if this is the case, how would I correct it?

mmm