You need to list your entire system and any changes. Make sure you didn't plug your phone pre into a phono input on your preamp. |
Sounds like a ground has come off or broken somewhere.
Could be as easy as the ground from the tonearm to the
phono stage, or worse, a broken ground inside the arm-
tube.
It could maybe a bad tube in your Phono Box S or a tube
that is starting to go.
Also, you should always mute or turn the volume all the
way down before you do anything with a turntable. |
You can do a simple trick:
use tape to attach any wire to the base of tonearm and connect it to the ground pin of your preamp.
If problem disappears, than ground wire is relatively easy to replace compared to the signal wires. The ground wire usually connects outside of the armtube, than goes through the hole and than out to preamp. The only trick is not to loose proper horizontal bearing tension if it needs to be removed.
If you want to communicate further, you can e-mail me.
I repair various turntables daily and restore them to original fully operational condition. |
Thanks. I will try some of your suggestions. I was thinking it is a possible ground issue or a tube problem but wanted some others opinions. One of my tubes is looking rather black on the glass when I checked this morning. The other tube still clear. Sure would be easy if its a tube.
Only change I've made is running output to pc to transfer vinyl. Otherwise no other changes.problem wasn't there when I swapped output. Showed up later. Problem doesn't go away no matter the output either. I wouldn't think this has anything to with it. |
before starting make sure your pre is not set to phono
1. check the ground wire, make sure its attached and not broken. usually you get very bad hum if its not connected but it can be lesser symptoms
2. check your cartridge leads to make sure they are tight. what you are describing sounds more like microphonic pickup from loose connection
3. if the RCA cables are user swappable, swap them and see if the problem goes away. if they aren't swappable make sure they are connecting tightly
4. possible that its a tube but microphony isn't a usual sign of tube aging... they get dull sounding. If you have connected a new piece of gear to your preamp, it may be causing you electrical problems. See if the problem goes away with only the Project Tube Box S connected as a pre input. |
Ground wire foing from the 5.1 to the tube box s is fine. No kinks and looks like it was taken straight from the box. RCA cables are signal cable silver ref phono cables. All connections are tight. All power cables are tight. I will try swapping cables first then try the ground wire from tonearm. Hopefully I have some time when I get home from work.
Thanks again fellas |
If there are separate tubes for the two channels, checking that off the troubleshooting list is as easy as swapping the tubes. If the circuit uses one triode of each tube for each channel, you'll need to try replacing each tube w a known good. FWIW, it sounds to me like an intermittent electrical connection somewhere. Ground or signal. |
I know your phonostage has 3 different gain settings. Try the lowest one. Not sure if that's your problem, but it's very easy to check. |
1. Both speakers or one of the two?
2. I doubt this is purely a grounding problem, although the hum problem might be separately related to grounding. Again, is the hum in both speakers or only one? And is it really "hum", defined as 60Hz or 120Hz tone, or is it "buzz", which sounds higher in pitch and is really a mixture of frequencies?
3. My thought on the fact that sounds made when you handle your tonearm are transduced into the speakers is perhaps a microphonic tube. Most likely culprit is the first tube (input) of the phono section. That's typically a 12AX7, and it supplies much of the gain of your phono stage. Check that there is good acoustic isolation between your tt and your phono stage or preamplifier.
Like someone else said, I would also say that if the problem is in one channel, then you can check hypotheses by swapping tubes from one side to the other. |
Swapped the tubes out with a pair of reissued Mullards. Anyways mostly everything has gone away. When I tap the player I no longer hear it through my speaker, I cant hear the clamp being screwed...very slight hum when nothing is playing but only if I turn the volume up high.
Thanks again for all your help |
"very slight hum when nothing is playing but only if I turn the volume up high."
That's normal tube rush. Glad you solved the problem. |
Now you are down to following suspects:
1. tubes
2. cartridge |
Czarivey, Wouldn't you agree that the problem related to transduction of sounds into the speakers was shown to be a microphonic tube or tubes? Hum and noise are other bugaboos, but if the OP is now happy, then I would guess the hum and noise are minor issues, relatively. |
I would agree after I test the 'suspects'. swapping tubes or cleaning sockets inside the box or swapping cartridge. Not too many unknown left so far... |
Yes what was happening has now gone away. Sounds good once again.
Thanks again |
