Phono stage hum

Well, my Grover phono cables arrived and did not solve my hum problem.  I did, however, track down the source of the hum.  Much to my embarrassment I had reversed the left and right ground wires on my cartridge.  I reversed them and the hum was gone.  OP might want to check this.

P.S. The Grover cables were a nice upgrade.

I too have a Thorens TD 160 (Mk I) that is now out of service but at one time was suffering from a hum problem. Somewhere I found instructions for a cure which involved altering the grounding scheme on the rudimentary power strip inside the plinth. It was a snap to perform and worked. So yes the problem probably is turntable specific. 

It seems I found the cure on either Vinyl Engine or more probably, on a vintage Thorens website. I will see if I can dig up the info but it did get rid of the hum...

Brock

Correction to my last.  The Ortofon arm is a TA 110.

Interesting problem in that it changes with the turntable used.  I have a Garrard 301 with Ortofon TA 1000 arm and Lyra Delos running to an original CAT SL-1.  It is dead silent at max volume except, of course, some normal tube hiss which is not audible at any reasonable listening level. I also have a VPI HW-19 MK IV with ET II arm and Van den Hul black beauty.  It hums.  Not as severe as OP's as it is not audible at reasonable listening levels more than a couple feet from the speakers.  It is, however, like an itch I have so far been able to scratch.

With the VPI rig I'm using 1ft long solid solver interconnects with cotton jacket.  They have no shield.  Thought this might be the problem so I substituted a 1 meter pair of Straightwire ICs wasn't using. The hum got worse, however, it varied in intensity as I moved the cables around (1 meter is a bigger antenna).   Ergo, it must be EMI.  Note, this is a low level hum as opposed to a buzz.  So it is not a ground loop. And, in any event, I've tried every ground combination I can think of and unplugged everything but the amp, preamp and turntable without success.

I've ordered a pair of Grover Huffman Empress ICs.  They are triple shielded and very low capacitance.  I'll post if they solve the problem.  

Your TT RCAs need replacing - bad ground.

I figured something interesting out - the hum is there even when the turn table power cord is unplugged.... but only if the TT RCAs are plugged into phono stage.

Strange that doesn’t happen with the other TT hooked up to the Manley.

As noted above, the hum is isolated to the Manley, not the other units. Both channels. The most likely common point between the two channels is the power supply in the Manley. It could be a cap in the power supply or a different defective component in the ps. But just as a test, try reversing the power input to the unit, if that is possible in the Chinook. Might also try plugging all the electronics into the same wall outlet.  Maybe relocate the Chinook farther away from the cartridge to see if the cart is picking up hum from the phono stage.

Call Manley tech support.  I had a SE version that developed a hum.  After various steps of troubleshooting they had me send it back.  They rotated one board 90 deg and solved the problem.

Does the Chinook run a  lot higher gain than the simaudio?
Is the gain adjustable on it?
Could account for some of the excess hum
Could be your expensive tt and wires are more sensitive to the gain difference than the cheaper tt ?

My older Teac tn300 never gave me any hum no matter what was in front or behind of it, My Nottingham on the other hand is a LOT more sensitive to things like cables, ac power lines, phono stage gain etc.

I would think you are right @otherones.
I guess chinook had some issues before according to google search. Might have to give them a call. I would try a cheater plug first tho.

Did you buy it new from a dealer?

My amp (parasound a21) has a ground lift option and the hum is still there when enabled.  Would testing a cheater plug do anything different?

I will confirm the TT rca solder joint to make sure it is ok - but if there was an issue wouldn’t it be present on the other phono stage (sim audio lp5.3)?

My next guess is TT itself is not grounded properly within TT chassis. I would check RCA solder joint and make sure it checks out.

Try using a cheater plug on the amp. This removes the ground connection and therefore the loop. 

Both TT tested in same spot and I have also tried moving the phono stage as far away as I could... same result 

Do you place two TT on the same spot?

I would move the phono amp away from the other equipment as far as you can and see what happens. 

I appreciate the tips but the hum didn't go away.
A few other notes:

• The hum is on both speakers
• The hum increases/decreases with volume
• The hum is 'mostly' drowned out with music playing but still audible and very audible in between tracks or during quiet parts of song
• Thorens turntable + Sim Audio LP5.3 (solid state phono stage)= No Hum
• Thorens turntable + Chinook (tube phono stage) = HUM
• Teac turntable + Chinook (tube phono stage) = No hum

It is sad b/c I really like the sound of the Chinook but will probably return it in a couple days b/c I won't be able to stand the hum.
If anyone has other troubleshooting ideas, I'd be grateful :)

Check all the ground wires inc the one on the chassis. Run a test wire from the Chinook ground lug to the chassis to see if it resolves it.