Rowe R88 continuous speaker noise

I'm trying to clean up the speaker noise in my R88. When I turn it on there is a loud pop on the speakers and then there is a continuous static sound coming from the speakers. I'ts loud enough to be annoying when sitting idle. You don't notice it as much when the record is playing but I think it's still there. Any Ideas?

Any help would be greatly appreciated.

Hello koeppen,

The pop on switching on is normal.
The static coming from the speakers is something else, if you remove the phono input is the static noise still there?
Is the mute plug connected and operational?
Is the static noise comming through on both channels?

Regards
Alan

Alan Hood
ami-man
UK

Adding to Alan's recommendations, listen to these hum samples: viewtopic.php?f=3&t=6428

If what you hear is actually a hum and it is of the 120Hz variety --stop using the amp and unplug it. There is a potentially serious and damaging problem.

If it is the lower 60hz it will indicate a shielding and muting problem.

Rob-NYC

Alan

I unplugged the mute switch and the static went away. When its plugged in and I switch it to serv. and off - the static noise remains the same. Also the static increases with an increase in volume control.

Rob, I tried the link and it said they no longer exist. I unplugged the mute switch and the sound went away. When plugged in the sound stay the same in all three modes -on-serv.- and off. It also increases in volume with and increase in the volume control on the back of the box.

It sounds as if you have some grounding issues if the noise goes away when unplugging the mute plug.
Make up a test volume control by doing the following:- Use a five pin connection like the one currently going to the volume control on the amplifier, link pins 1 & 5 together and take this to one side of a 10k log control, connect a cable into pin 3 and take this to the wiper of the control.

Please let us know if this rectifies the problem

Regards
Alan

Alan Hood
ami-man
UK

Alan,

I'm not familiar with the terminology. I also don't have any manuals. I can make a five pin connection like the one going to the volume control. Can you help me find the 10k log control and the wiper. Don't be to hard on me for my ignorance.

Thanks for the help!!

One more note: when I turn the power off on the back the noise is till coming through the speakers. I got this figured out. It was wired wrong on the main switch. Still have the static however>




You can see the black and red wires coming from the Volume Control on the front of the panel. Note the placement of the jumper.


This is the backside of the same panel


This is the plug into the volume control on the Amp

Does all this look correct?

Sorry about the expired link.

I've renewed it:

viewtopic.php?f=3&t=6428

Rob

It is the 60hz for sure.

Ok, and you've stated that it varies with the volume control. Make sure the Mono-Stereo switch is in the stereo position. Is the hum on both channels?

Remove the Pnono Cartridge" input on the amp.

If the hum goes away -check:

If you have a meter measure the ohm the readings of both channels of the cartridge at the plug that goes into the amp. IIIRC, Rowe uses the standard of red-to-green and Black-to-white. You should see several hundred ohms (about 400 each channel). Next, connect one lead from the meter to a metal part on the tone arm and measure from the pins on the plug to the metal on the arm assembly. There should be no reading --an open circuit.

One common cause of hum from Rowe tone arm circuits in the 1960's thru '80s was a ground loop caused by a small piece of copper attached to one ground pin on the cartridge -visible here: http://s1192.photobucket.com/user/Rob-N ... ort=2&o=74 causing a loop when one of the mounting screw heads touches the shell of the cartridge as seen here: http://s1192.photobucket.com/user/Rob-N ... ort=2&o=75

The resulting hum was often not noticeable in a noisy location, but on a "quiet" record (or no record ) when the AGC turns up the gain it becomes a bit annoying. In my experience, This was so common it was almost universal. I either put a tiny piece of tape on each side of the cartridge to insulate the shell from the screws or simply removed the copper strap.

Rob




-

Does anyone have an internal image or a wiring diagram for the main power supply. It's been rewired and I want to make sure that everything is wired correctly.

This should be covered in your service manual ?? However, if the three voltages read correctly with a dependable meter, your PS is fine. Ron Rich

OK, everything tests our on my main power Supply. I've tested everything that has been suggested. Rob here is the picture of my cartridge, it looks like a newer version. It wasn't in contact with the side wall. I insulated it to test for sure with no results.



Now one thing to note: when I disconnect the phono spkrs plug from the amp: the speakers turn off. I can still hear a slight hum that is barely audible. It sounds like it's still coming through the speakers. I've disconnected each speaker individually thinking that one of them may have a short or a grounding issue with no change in the hum.

To reiterate the humming increases with a volume increase. I'm still looking for a grounding issue while I wait to see if anyone has any ideas.

Thanks for any help!

You have me scratchin' my head with your "note"--
If you still hear "hum" with the speaker plug removed from the amp--and it varies in volume with the volume control you really have something weird going on there--try removing the amp's power cord--still hear it--still "controllable" with the volume control ?? ( I am thinking that you are hearing a lamp ballast, or some other transformer type noise--but "controllable" throws me !) Ron Rich