Turntable Dilema

[lesaus44]

Hello! This is my first post to this forum. I have found some useful information in the short time since I joined.

My issue: severe hum when cranking the volume up past 50% when playing LP's.
I have 2 solid oak, 24" wide, 44" tall audio cabinets (with glassed doors) side-by-side. Each has a top shelf 12" down from the top and these slide out on rollers (your first clue). A hole for wiring is directly behind the sliding shelf in each. These are heavy cabinets, plus, the bottom of each is loaded with LP's.
My turntable is on the left, my (heavy) McIntosh MA6100 integrated amp on the right (checks in at 90 watts rms/ch). Wiring from TT to preamp (out and back in) doesn't come close to other wires to speak of. Speakers are Monitor Audio Silver RX6 (strong bass), about a foot on either side of the cabinets, location not alterable due to room layout.
I replaced an old cartridge 6 years ago when this issue first surfaced and it resolved the problem. Issue raised its ugly ahead a few months ago - new cartridge (Ortofon Red 2M) didn't do it this time.
Borrowed grandson's turntable, put on top of right cabinet and the problem disappeared. So, not a feared preamp issue.
Bought new TT (Teac TN-400S) to replace 37-year-old Sony, installed Ortofon (1.8gm tracking), problem persisted. Put on top of right cabinet and...problem disappeared.
Except the cabinet tops are valuable real estate, so it can't stay there. I am thinking I don't have a patch cord issue, but rather, a vibration problem. The sliding shelf the TT is on is heavy solid oak, but, not firmly attached.
Pardon all the detail, but, hoping it will save questions.
So, my question is: What can I do with the sliding shelf, sort of attaching it with screws, to reduce the vibration? Granite slab? Dampers of some sort? Thick rubber pad? All of the above?
Also, the cheap patch cords are way too tight and I would like to replace them with something decent, 4-5' long, with 90-degree plugs on one end or purchased separately.
Thanks for your responses in advance. Not having experienced this problem before I thought it's time to consult the experts.

Ed

 

[lovinthehd]

How about some pics?

 

[TLS Guy]

Hello! This is my first post to this forum. I have found some useful information in the short time since I joined.

My issue: severe hum when cranking the volume up past 50% when playing LP's.
I have 2 solid oak, 24" wide, 44" tall audio cabinets (with glassed doors) side-by-side. Each has a top shelf 12" down from the top and these slide out on rollers (your first clue). A hole for wiring is directly behind the sliding shelf in each. These are heavy cabinets, plus, the bottom of each is loaded with LP's.
My turntable is on the left, my (heavy) McIntosh MA6100 integrated amp on the right (checks in at 90 watts rms/ch). Wiring from TT to preamp (out and back in) doesn't come close to other wires to speak of. Speakers are Monitor Audio Silver RX6 (strong bass), about a foot on either side of the cabinets, location not alterable due to room layout.
I replaced an old cartridge 6 years ago when this issue first surfaced and it resolved the problem. Issue raised its ugly ahead a few months ago - new cartridge (Ortofon Red 2M) didn't do it this time.
Borrowed grandson's turntable, put on top of right cabinet and the problem disappeared. So, not a feared preamp issue.
Bought new TT (Teac TN-400S) to replace 37-year-old Sony, installed Ortofon (1.8gm tracking), problem persisted. Put on top of right cabinet and...problem disappeared.
Except the cabinet tops are valuable real estate, so it can't stay there. I am thinking I don't have a patch cord issue, but rather, a vibration problem. The sliding shelf the TT is on is heavy solid oak, but, not firmly attached.
Pardon all the detail, but, hoping it will save questions.
So, my question is: What can I do with the sliding shelf, sort of attaching it with screws, to reduce the vibration? Granite slab? Dampers of some sort? Thick rubber pad? All of the above?
Also, the cheap patch cords are way too tight and I would like to replace them with something decent, 4-5' long, with 90-degree plugs on one end or purchased separately.
Thanks for your responses in advance. Not having experienced this problem before I thought it's time to consult the experts.

Ed

You have acoustic feedback. So your turntable is likely right over an antinode of a standing wave. This is a common problem with turntables. So you have to move your turntable or your speakers. You really have no other choice other than turning the bass way down.

 

[highfigh]

Hello! This is my first post to this forum. I have found some useful information in the short time since I joined.

My issue: severe hum when cranking the volume up past 50% when playing LP's.
I have 2 solid oak, 24" wide, 44" tall audio cabinets (with glassed doors) side-by-side. Each has a top shelf 12" down from the top and these slide out on rollers (your first clue). A hole for wiring is directly behind the sliding shelf in each. These are heavy cabinets, plus, the bottom of each is loaded with LP's.
My turntable is on the left, my (heavy) McIntosh MA6100 integrated amp on the right (checks in at 90 watts rms/ch). Wiring from TT to preamp (out and back in) doesn't come close to other wires to speak of. Speakers are Monitor Audio Silver RX6 (strong bass), about a foot on either side of the cabinets, location not alterable due to room layout.
I replaced an old cartridge 6 years ago when this issue first surfaced and it resolved the problem. Issue raised its ugly ahead a few months ago - new cartridge (Ortofon Red 2M) didn't do it this time.
Borrowed grandson's turntable, put on top of right cabinet and the problem disappeared. So, not a feared preamp issue.
Bought new TT (Teac TN-400S) to replace 37-year-old Sony, installed Ortofon (1.8gm tracking), problem persisted. Put on top of right cabinet and...problem disappeared.
Except the cabinet tops are valuable real estate, so it can't stay there. I am thinking I don't have a patch cord issue, but rather, a vibration problem. The sliding shelf the TT is on is heavy solid oak, but, not firmly attached.
Pardon all the detail, but, hoping it will save questions.
So, my question is: What can I do with the sliding shelf, sort of attaching it with screws, to reduce the vibration? Granite slab? Dampers of some sort? Thick rubber pad? All of the above?
Also, the cheap patch cords are way too tight and I would like to replace them with something decent, 4-5' long, with 90-degree plugs on one end or purchased separately.
Thanks for your responses in advance. Not having experienced this problem before I thought it's time to consult the experts.

Ed

I'm going to bet that your McIntosh's power transformer and/or other circuitry is too close to the cartridge and when you crank it, the 60Hz hum is setting up a feedback situation. Move the Mac and if it stops, my bet is likely correct. If it doesn't, move the turntable as TLS recommended and don't put it on top or too close to the Mac. Also, your speakers are very close to the turntable- if possible, move them farther apart.

 

[TLS Guy]

Question for OP. Does the hum stop when you lift the stylus off the record?

 

[cornemuse]

Weak ground tween TT & amp??

 

[lesaus44]

How about some pics?

Per your request:
Setup with TT moved to top of cabinet where issue is non-existent:

Drawer where TT has the hum issue:

Drawer slid open to show glides:

The drawer weighs in at 6.5#.

 

[lesaus44]

You have acoustic feedback. So your turntable is likely right over an antinode of a standing wave. This is a common problem with turntables. So you have to move your turntable or your speakers. You really have no other choice other than turning the bass way down.

There is definitely a vibration with the TT sitting on the drawer. I was hoping weighing it down might help stabilize it. I have an onyx chess board that weighs a LOT and isn't very thick - might try that first.
Turn the bass way down? Blasphemy!!

 

[lesaus44]

I'm going to bet that your McIntosh's power transformer and/or other circuitry is too close to the cartridge and when you crank it, the 60Hz hum is setting up a feedback situation. Move the Mac and if it stops, my bet is likely correct. If it doesn't, move the turntable as TLS recommended and don't put it on top or too close to the Mac. Also, your speakers are very close to the turntable- if possible, move them farther apart.

You may be onto something. However, whether on top of left or right cabinet, the hum is the same. So, maybe still too close? Will need longer patch cords and move TT off the cabinet entirely to see if that helps - only a test, as no other place than cabinet for TT or Mc, which is way too heavy to move, anyhow. Speakers are pretty much stuck where they are due to room layout.
Thanks.

 

[lesaus44]

Question for OP. Does the hum stop when you lift the stylus off the record?

With the arm up and the volume up over 50% there is still hum, just not the hum that overrides the playback signal from the TT when volume cranked up. Note that >50% volume is quite loud. I could turn off the loudness contour, but, why?

 

[lesaus44]

Weak ground tween TT & amp??

Ground is good. With old TT I even ran amp ground to house ground to see if that helped, and it didn't.

From all the responses I'm getting the feeling that I have 2 issues:
1) acoustic feedback
2) transformer feedback
Will putz around with various tests to see if I can apply above suggestions to my situation given the limitations.
Another question: will good patch cords make a difference? Using the cheap ones supplied with the TT and would need suggestions as to what to buy within reason ($50 max?)
Thanks to all.

Ed

 

[TLS Guy]

Ground is good. With old TT I even ran amp ground to house ground to see if that helped, and it didn't.

From all the responses I'm getting the feeling that I have 2 issues:
1) acoustic feedback
2) transformer feedback
Will putz around with various tests to see if I can apply above suggestions to my situation given the limitations.
Another question: will good patch cords make a difference? Using the cheap ones supplied with the TT and would need suggestions as to what to buy within reason ($50 max?)
Thanks to all.

Ed

Yes, you have two issues.

You have induced and or grounding loop hum, and you have acoustic feedback.

Turntable installations are difficult and hard to do well. Few are done properly and that is key to good results.

Now first grounding, and that coincides with induction issues. First of all it is not a good idea to extend turntable cables. This is because the output from a turntable cartridge is very small and the capacitance of the system increases with length and this is not good.

So the turntable should be as far away from the turntable as possible without extending the cable. If the cable needs extending further, then a turntable preamp should be installed at the turntable and the turntable converted to line voltage and plugged into a line level input.

The turntable should be grounded to the grounding screw on the amp.

Next your turntable and electronics are far too close to your speakers. The surface on which you turntable is placed should be far more robust solid an non resonant than anything I see in that picture.

Finally obsessional set up and adjustment of the turntable is mandatory.

You have work to do to get any useful results from your turntable.

 

[Swerd]

I agree with the others who said you probably have an acoustic feedback problem. Acoustic feedback is a mechanical vibration where sound from the speakers travels through the air or furniture and enters the turntable's tonearm, platter, or pick-up. Once in the pick-up it gets amplified and sent through the speakers again, and again.

The best way to deal with acoustic feedback, as TLS Guy mentioned above, is to move the turntable or the speakers, until you no longer get the noise. You already did that when you moved your new Teac turntable to the top of the cabinet and the severe hum disappeared.

Except the cabinet tops are valuable real estate, so it can't stay there. I am thinking I don't have a patch cord issue, but rather, a vibration problem. The sliding shelf the TT is on is heavy solid oak, but, not firmly attached.

You may not have a choice. As a test, try putting some material (newspapers, magazines, folded towels, etc.) between the sliding shelf and the turntable to dampen vibrations. If that makes a difference, you can keep that or look for a more permanent dampening material.

So, my question is: What can I do with the sliding shelf, sort of attaching it with screws, to reduce the vibration? Granite slab? Dampers of some sort? Thick rubber pad? All of the above?

Avoid things like screws or a granite slab, that would couple the shelf more securely to the cabinet. Look for vibration dampening materials such as a rubber pad. No need for it to be expensive.

Also, the cheap patch cords are way too tight and I would like to replace them with something decent, 4-5' long, with 90-degree plugs on one end or purchased separately.

By "way too tight" do you mean too short? 4-5 feet long is alright, but don't go longer. If there is enough slack in the cable, you probably don't need 90 degree plugs on one end. If you really need them, I don't see a reason why something like these couldn't be used for a phono connection.

Amazon.com: Cable Matters 2-Pack Right Angle RCA Adapter, 90 Degree RCA Adapter: Home Audio & Theater

Amazon.com: Cable Matters 2-Pack Right Angle RCA Adapter, 90 Degree RCA Adapter: Home Audio & Theater

www.amazon.com

Does the back panel of your turntable look like the photo below? It apparently has an internal phono pre-amp and a switch (labeled PHONO EQ) to allow you to use it (ON) or bypass it (THRU).

TLS Guy suggests you might also have induced hum from your integrated amp. If so, slide the PHONO EQ switch on the Teac to ON. You must also move the cable connection on the back of your integrated amp from the phono input RCA jack to any other unused RCA input. That will raise the signal in the cable between the turntable and the amp to a higher voltage that may make it less susceptible to hum.

If you use the McIntosh's built-in phono pre-amp, be sure the turntable is switched to THRU.

 

[lesaus44]

I agree with the others who said you probably have an acoustic feedback problem. Acoustic feedback is a mechanical vibration where sound from the speakers travels through the air or furniture and enters the turntable's tonearm, platter, or pick-up. Once in the pick-up it gets amplified and sent through the speakers again, and again.

The best way to deal with acoustic feedback, as TLS Guy mentioned above, is to move the turntable or the speakers, until you no longer get the noise. You already did that when you moved your new Teac turntable to the top of the cabinet and the severe hum disappeared.
You may not have a choice. As a test, try putting some material (newspapers, magazines, folded towels, etc.) between the sliding shelf and the turntable to dampen vibrations. If that makes a difference, you can keep that or look for a more permanent dampening material.
Avoid things like screws or a granite slab, that would couple the shelf more securely to the cabinet. Look for vibration dampening materials such as a rubber pad. No need for it to be expensive.
By "way too tight" do you mean too short? 4-5 feet long is alright, but don't go longer. If there is enough slack in the cable, you probably don't need 90 degree plugs on one end. If you really need them, I don't see a reason why something like these couldn't be used for a phono connection.

Amazon.com: Cable Matters 2-Pack Right Angle RCA Adapter, 90 Degree RCA Adapter: Home Audio & Theater

Amazon.com: Cable Matters 2-Pack Right Angle RCA Adapter, 90 Degree RCA Adapter: Home Audio & Theater

www.amazon.com

Does the back panel of your turntable look like the photo below? It apparently has an internal phono pre-amp and a switch (labeled PHONO EQ) to allow you to use it (ON) or bypass it (THRU).

TLS Guy suggests you might also have induced hum from your integrated amp. If so, slide the PHONO EQ switch on the Teac to ON. You must also move the cable connection on the back of your integrated amp from the phono input RCA jack to any other unused RCA input. That will raise the signal in the cable between the turntable and the amp to a higher voltage that may make it less susceptible to hum.

If you use the McIntosh's built-in phono pre-amp, be sure the turntable is switched to THRU.
View attachment 35770

Thanks, guys! I tried Swerd's preamp suggestion and it resolved the hum issue that a couple of you opined on - probably would have tried it eventually myself, but, using the internal phono preamp on the TT did the trick!!

That hum is all gone, except when I turn the volume up all the way and stop the platter. Then there is such a low hum that you have to put your ear up close to a speaker to even hear it. Turning the platter on raises it so little that it is still hardly discernable. Previously, the platter hum was unbearable - I thought it was a motor noise issue!

Another change was in turning the loudness contour off. I think I know what LP I turned it on for and forgot to turn it off . Walls don't rattle now and the cabinet vibrates a lot less at higher volumes. I have almost always had the preamp in the "flat" position.

I'll deal with the acoustic feedback next - not so urgent now. The patch cords are only 3', and it's 2' between the cabinet cord holes, leaving only a foot from the holes to preamp and TT panels - much too tight in an enclosure. So, need to order cables (probably 4') before trying TT inside the cabinet again.

Again, thanks to all of you for chiming in with your experiences and knowledge. I now know where to go for my serious audio issues that I can't resolve.

Ed