I was hoping you could help me hunt this done.
Im using a VTA ST70 tube amp with a simple "pot in box" for volume control. I want to use a Haggerman Bugle2 as phono stage with a Rega turntable.
The tube amp doesn't use an earth ground. The Rega uses the left channel shield as ground and uses a power supply. The Bugle grounds thru the rca as well and uses a switching power supply. All of this plugs into power conditioner (surge, emi etc)There is no earth ground in the system.
With the bugle2 plugged in with no music I am getting a low level 60 cycle hum. Its only noticeable with the music off and the pot turned past 12 oclock.
I tried to cut right to the crux of the matter and ran a wire from the ground lug on the Bugle2 into my basement and wrapped it around the GEC and a water pipe and the hum remained.
The tubes are about 2 feet next to the cartridge.
I tried to relocate the phono stage (which uses a switching power supply) elsewhere with no luck.
The main question I have is if I rule out a grounding issue since I ran a wire to my basement and the hum remained?
Perhaps the proximity of the amp to the phono stage/turntable is an issue?
Is the phono stage just noisy?
A nudge in the right direction would be much appreciated.
Thanks
Im using a VTA ST70 tube amp with a simple "pot in box" for volume control. I want to use a Haggerman Bugle2 as phono stage with a Rega turntable.
The tube amp doesn't use an earth ground. The Rega uses the left channel shield as ground and uses a power supply. The Bugle grounds thru the rca as well and uses a switching power supply. All of this plugs into power conditioner (surge, emi etc)There is no earth ground in the system.
With the bugle2 plugged in with no music I am getting a low level 60 cycle hum. Its only noticeable with the music off and the pot turned past 12 oclock.
I tried to cut right to the crux of the matter and ran a wire from the ground lug on the Bugle2 into my basement and wrapped it around the GEC and a water pipe and the hum remained.
The tubes are about 2 feet next to the cartridge.
I tried to relocate the phono stage (which uses a switching power supply) elsewhere with no luck.
The main question I have is if I rule out a grounding issue since I ran a wire to my basement and the hum remained?
Perhaps the proximity of the amp to the phono stage/turntable is an issue?
Is the phono stage just noisy?
A nudge in the right direction would be much appreciated.
Thanks
Hi. Your main question about running an Earth to the basement to get rid of hum, forget that, it's irrelevant, the Earth is not a sponge. Does the amplifier hum with the inputs shorted?
Is the phono amp using the power supply shown here? https://hagerman-audio-labs.myshopify.com/products/bugle2 I had a power supply that looked very much like that came with a piece of equipment and injected a lot of noise
Is the phono amp using the power supply shown here? https://hagerman-audio-labs.myshopify.com/products/bugle2 I had a power supply that looked very much like that came with a piece of equipment and injected a lot of noise
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The problem could be in your volume control box.
Are the grounds for the L and R channels connected together inside the box?
If so, separate them.
Maybe I need to find a phono stage that doesn't use the junky wall wart (same one in the link posted). Maybe If I can figure out what plug the thing uses I can wire some 9v to test.
However, I think I might be on the right track.... see im lazy and didn't want to move stuff around but I reluctantly picked up the TT and Phono stage and moved them off the table and down to the floor and the hum greatly dimished.
So I assume the cartridge is picking of interference?
Unfortunetly when I reorganized the stuff I still end up with the 60 cycle hum with the pot turned up 3/4 way. I cant get far enough away, because using my passive volume control I think I am limited to the 3' rca's I use.
I wonder how many more feet of cable I can get away with?
However, I think I might be on the right track.... see im lazy and didn't want to move stuff around but I reluctantly picked up the TT and Phono stage and moved them off the table and down to the floor and the hum greatly dimished.
So I assume the cartridge is picking of interference?
Unfortunetly when I reorganized the stuff I still end up with the 60 cycle hum with the pot turned up 3/4 way. I cant get far enough away, because using my passive volume control I think I am limited to the 3' rca's I use.
I wonder how many more feet of cable I can get away with?
> There is no earth ground in the system.
Why not??
Not necessarily a "dirt" ground, but a reference to the general 60Hz hum that pervades any room with electric wiring. While intended for another purpose (SAFETY!), the "ground" wire in the supply system is also our usual hum reference. Un-grounded low-level systems usually do hum.
Anyway you should have all touchable electric appliances (including amplifiers) connected to power "Ground" for SAFETY.
Especially in a basement!! Concrete conducts better than you do.
Which aligns with the fact that hum is less on the concrete. The concrete is very indirectly returned to power "Ground" and is likely to be the lowest-hum part of the room.
Why not??
Not necessarily a "dirt" ground, but a reference to the general 60Hz hum that pervades any room with electric wiring. While intended for another purpose (SAFETY!), the "ground" wire in the supply system is also our usual hum reference. Un-grounded low-level systems usually do hum.
Anyway you should have all touchable electric appliances (including amplifiers) connected to power "Ground" for SAFETY.
Especially in a basement!! Concrete conducts better than you do.
Which aligns with the fact that hum is less on the concrete. The concrete is very indirectly returned to power "Ground" and is likely to be the lowest-hum part of the room.
What is probably happening is that the amp power transformer is emitting an AC magnetic field and the cartridge is picking this up. Distance is the best solution, but orientation may help too.
'Ground' is not a magic sink for all hum, noise, interference. It is, however, an important part of electrical safety when properly installed according to your local electrical codes.
'Ground' is not a magic sink for all hum, noise, interference. It is, however, an important part of electrical safety when properly installed according to your local electrical codes.
My Rega hummed like nobody's business, even after I decoupled it from the RCA and added a dedicated ground (do not do this unless you're absolutely sure of what you're doing, those tiny wires are very difficult to solder).
When I took the tonearm over to my SP15, I was able to greatly reduce the hum by running a second ground wire from the turntable chassis to the phonostage ground. I'm not sure how you would go about doing that on a Rega, maybe try one of the screws on the motor box?
When I took the tonearm over to my SP15, I was able to greatly reduce the hum by running a second ground wire from the turntable chassis to the phonostage ground. I'm not sure how you would go about doing that on a Rega, maybe try one of the screws on the motor box?
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