Gemini table hum
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New member Username: DrumsuckSt. johns, Newfoundland Canada Post Number: 6 Registered: May-04 | My new Gemini XL500II arrived the day before yesterday and I got it fitted with a Grado Black right away. It sounds great connected to my HK 3380 with a set of Monster 300MKii's, but I have two questions: 1. there is an audible hum produced whenever the unit is turned on, even when the platter is not spinning and the tone arm is in rest position. how do i remedy this? it's not a ground wire problem. 2. should i upgrade to the monster 400 series? will it make a difference? please give me some feedback. |
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J. Vigne Unregistered guest | Cables won't solve this problem. How do you know it's not a ground problem? Ground problems are what create hum. Have you lifted the ground to see what happens? How do you have it grounded? |
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New member Username: DrumsuckSt. johns, Newfoundland Canada Post Number: 7 Registered: May-04 | i know the cables won't make a difference to the noise... i should have asked that question in a seperate thread. I was just wondering if the 400 series sounds much different than the 300. As for the hum problem... it is grounded to the receiver with a ground wire supplied with the 'table. Also, the turntable has it's own 3-prong plug which is plugged directly into my surge protector. Any ideas? |
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New member Username: DrumsuckSt. johns, Newfoundland Canada Post Number: 8 Registered: May-04 | also, removing the ground wire creates a much louder more distorted hum than that which is already there. |
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J. Vigne Unregistered guest | Try a ground lift plug at the three pin AC plug. Any hardware store has them, they simply turn a three pin plug into a two pin plug. Should cost about $0.59. If it reduces the hum slightly do what they tell you not to do and cut the wider blade on the cheater plug down so you can turn it around backwards in the outlet. If that doesn't solve the problem, is there a ground strap on the back of the cartridge? Are the table and the reciever plugged into the same AC outlet? Who sold and installed the cartridge? Have you called them with this question? |
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J. Vigne Unregistered guest | I don't know that particular HK. Are you grounding to a ground terminal on the amp or to a screw on the chasis? If it's a screw you may have to scrape away some paint to get a good ground. |
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Gold Member Username: John_aPost Number: 1248 Registered: Dec-03 | Brad, You could also try making your own connection from the mains ground (aka "earth") to the amp/receiver case/chassis, and making sure the ground wire from the turntable is in good electrical contact with that. Some modern electronics boxes have plastic cases, bolted on with metal bolts that still make no electrical contact with the true ground. I have a Nokia unit like that. |
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J. Vigne Unregistered guest | John A.'s idea is fine as long as everything is grounded in the same place. It occurs to me that you have different ground potentials between the reciever and the table as it sits right now. If you decide to ground to the electrical box you first have to determine whether the electrical box is grounded properly. To do that you need to go to Radio Shack and get an outlet tester. This is assumimg you have a three wire outlet that you are plugging everything into, if it is two wire ALL BETS ARE OFF. This tester will tell you whether you have a good ground and if the plug is wired to the correct polarity. If you can't find it at R.S. any good hardware store should have a similar device. If you have determined your ground connection at the plug is correct you can then, with the power to the outlet turned OFF, loosen the center screw on the wall plate and ground both pieces to that screw. It connects to the metal plate of the outlet box and will give as good a ground connection as possible without running a dedicated ground wire to earth. |
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New member Username: DrumsuckSt. johns, Newfoundland Canada Post Number: 9 Registered: May-04 | whew... lots of replies, thanks... let's see, first the HK I'm using (3380) has a phono ground terminal and that's what the ground wire is connected to. the turntable and receiver are both plugged into the same surge protector (an RCA home theatre one) and that is plugged into a 3-prong outlet. It wouldn't surprise me if this problem stemmed all the way back to the electrical supply in the house. I'm going to go out and look for a "ground lift". When I do this, should I plug the turntable into the A/C outlets on the back of the receiver? Or should it still go to the surge protector? By the way, I have tried plugging the turntable into the wall and bypassing the surge protector, and that makes no difference, nor does plugging the turntable and receiver into seperate wall sockets. |
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Gold Member Username: John_aPost Number: 1251 Registered: Dec-03 | Brad, Forget my suggestion; you can rely on the HK phono ground terminal, I am sure. I wonder if your turntable is located near a strong source of electromagetic field? Anything with a transformer, or rheostat (light dimmer switch etc). Fluorescent strip lights might also do it. If you suspect anything, just move the turntable away from the possible source and see if that has any effect. |
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New member Username: DrumsuckSt. johns, Newfoundland Canada Post Number: 10 Registered: May-04 | I bought and tried the ground lift 3- to 2-wire adapter and after plugging it into every possible outlet, I determined that that made no difference. Back to the drawing board... thanks for all the replies, guys. |
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Bronze Member Username: DrumsuckSt. johns, Newfoundland Canada Post Number: 11 Registered: May-04 | I just called Paul Frecker(www.paulfreckeraudio.com), who sold and installed my cartridge for me, and he says that the hum probably has a lot to do with the fact that the Grado cartridge is unsielded. So, we're trying to come up with a cartridge that is shielded and will perform as well as the Grado (within a reasonable price range.) That last clause will probably make things difficult. Suggestions? |
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MARK AUDIO4KICKS Unregistered guest | I have read a few reviews on different turntables, some of the reviewers mentioned there is an audible hum from some of the tables, its funny but it always seems to be the more expensive tables that have this problem, what he said was try to return it and hopefully the next one you get won`t have the problem, if it does it must be in the system somewhere, I PURCHASED A NUMARK TT-1600 TURNTABLE, IM USING A ROLLS OUTBOARD PHONO PREAMP AND A AUDIO TECHNICA CARTRIDGE INTO A ONKYO A/V RECIEVER, AND THERES NO HUM WHAT SO EVER, I QUESS I JUST GOT LUCKY. |
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Bronze Member Username: DrumsuckSt. johns, Newfoundland Canada Post Number: 28 Registered: May-04 | Audio Technica?? I thought you said you were getting a Grado! My table hum is something I've come to terms with. It's inaudbile when music is playing, and I can live with it between the tracks until I save up enough pennies for a Music Hall, or Thorens or something. I'm putting a Grado Prestige Gold on the table next week, hopefully, and I might wall-mount it sometime soon too. |
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mr.man Unregistered guest | micro screen mu-metal some epoxy and a sandwich of balsa wood takes care of the shielding issue... though really its the motor that should be shielded...and typically are. a decent substitution for the Grado (not as lush but just as nice for different reasons) would be the Ortofon OM5 or 10... (the ten if you're one of those guys who likes to upgrade their system periodically... the upgrade trail for the om 10 is schweet. |
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Bronze Member Username: DrumsuckSt. johns, Newfoundland Canada Post Number: 43 Registered: May-04 | thanks for the reply, but i have since sold the gemini turntable and am using my grado cartridge on an onkyo turntable, until i make a new purchase. am considering music hall mmf-5se, mmf-5, and rega p-3/grado gold/record clamp |
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davehopeyougetitright Unregistered guest | I have found that the grado's have hum. I have had the hum get louder as you move the arm closer to the motor. I have had also noise from the power supply of a unit on the shelf below. I have tried to sheild the motor but that did not work. I would try a sumiko. The one table that I had a grado work good on, is a Nottingham horizon turntable. |
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daujo Unregistered guest | I have a similar problem: I have a Thorens TD-166 MkII turntable I recently acquired, and a Denon AVR 1803 receiver. I just replaced the existing and old ADCOM cartridge with a Grado Green. I now have a humming sound that wasn't present with the old cartridge, and the music seems quieter and less powerful than before. Does this mean the problem is likely with the cartridge and not with the rest of my system? I have the ground wire attached to the designated ground on the receiver. The hum goes away when I touch the cartridge/arm. |
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Bronze Member Username: DrumsuckSt. johns, Newfoundland Canada Post Number: 60 Registered: May-04 | grados do hum with DC (i believe) motors. however, the grado signature hum wouldn't go away just by touching the arm or cartridge. it's my guess that you have a ground problem somewhere in the arm of your turntable. is your denon receiver equipped with a phono input/preamp? |
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J. Vigne Unregistered guest | Remove the ground to the amp and see if the problem goes away. Cartridges output different voltage levels, the Grado is lower output than the Adcom. It is still working correctly. |
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J. Vigne Unregistered guest | Some cartridges also have a ground strap that can be removed from the rear of the cartridge to eliminate hum. If removing the ground from the amp doesn't solve the problem, look on the rear of the Grado for a grounding strap. |
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daujo Unregistered guest | Thanks for the replies. The Denon receiver does have a phono input. I will try removing the ground to the amp. If that does not work, what does a grounding strap on a cartridge look like? I did not see anything on the rear of the cartridge, other than the four connections for the wires. |
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J. Vigne Unregistered guest | A grounding strap on a cartridge is a small metal tab that runs around from under the back edge of the cartridge body to loop over one of the ground pins on the back of the cartridge. It is there for situations where the ground potential between the cartridge and the amp are at two different levels. That is often why a hum comes and goes when you touch the tonearm. Normally Grado's don't use a grounding strap but check for one anyway just to be certain. |
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davehopeyougetitright Unregistered guest | The hum is from the cartridge. Have you ever heard the cartridge sound good? Assuming that you did all the proper ground checks. If there was a hum coming from the system it would always be there in most cases all the time even on other inputs. The ground problem is not in the tone arm because the hum would go away if you touched it. If you have cable tv connected to this system try diconnecting the coax cable. If your problem remains get another brand cartridge and try. If the other cartridge works that is the answer. |
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J. Vigne Unregistered guest | Dave, I would argue the hum is not from the cartridge, but, from the difference in ground potential between the cartridge and the rest of the system. This is quite unlikely to be a defect of the cartridge itself. The suggestion to try another cartridge ignores the fact that this cartridge has been chosen and should work with this table. If that solution were to be implemented, what would be your direction should the next cartridge also have a noise problem? There is a fix for the situation that shouldn't involve replacing a brand new cartridge. That is what we are trying to achieve here. |
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daujo Unregistered guest | After disconnecting the ground wire did not work, I solved the hum problem by (again) disconnecting all turntable and cartridge connections/wires and reconnecting. I probably had something loose/wrong somewhere. Thanks for all your suggestions. |
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Gold Member Username: KeggerWarren, MICHIGAN Post Number: 2419 Registered: Dec-03 | Just found this: "It has been said that Grado cartridges can hum when used with VPI or Rega turntables due to their unshielded motors" Have seen it talked about in other places as well! So it seems grados "can" make a hum on a turntable that does not have a shielded motor! |
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Silver Member Username: Joe_cOakwood, Ga Post Number: 158 Registered: Mar-05 | try an ortofon super 20 , i had a grado red on a project 1.2 and it hummed progressively louder as it got closer to the motor across the plate, when I put the original oyster back on no hum, so I called and was informed of the sheilding problem with grado's and bought an ortofon super om 20 and couldn't be happier, even the needle is better. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 3576 Registered: May-04 | "It has been said that Grado cartridges can hum when used with VPI or Rega turntables due to their unshielded motors" Kegger - I hope I didn't post that information. The Rega presents a problem because the motor is located at the center line of the table. Any table based on the Rega designs, of which there are many, will present the same problem with a Grado cartridge. The VPI's all have their motors mounted offset to the far left hand side of the table. I have never, in my memory, experienced a hum with a Grado mounted in a VPI. I use that combination now with no problems. VPI has changed motors since my table was made, but I don't recall a problem existing with their tables and would doubt that possiblity due to the placement of the motor. I would not try to dissuade anyone from buying an Ortofon MM cartridge as they are great value products, but the Grado's have a dollar for dollar sound that is in may ways the superior product to most moving magnet Ortofons. |
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Gold Member Username: KeggerWarren, MICHIGAN Post Number: 2421 Registered: Dec-03 | No Jan I did not get that from you. I recently picked up another table that has a grado cartridge that I was trying to figure which cartridge it is "all it says is grado with JG in the front, all black" and when I did a google search found many people complaining of the hum with a grado cartridge and an unshielded motor. Even found this on review sites where they have changed the cartridge and it's gone away. From what they say it's a known issue that a lot of people have with non shielded motors. Some have gone to the extent of taking there tables apart to shield the motor and fix the problem. So it sounds real to me. They even say it's not on every table and if you have a new table to take it back and try another table. --------------------------------------------------------------------------- Anyways so far my impressions of the grado cartridge is kinda like an older tube amp comparred to a newer one. More testing needed at this point. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 3578 Registered: May-04 | In years past Grado manufactured cartridges from $19.99 to $800.00. They have expanded the line upward in price and quality in the last few years. But Grado, as do many cartridge manufacturers, makes only a few cartridge bodies. The difference in what you hear is in the stylus and cantilever system. At the top of the line the cartridges were hand selected for response. This gave the Grados a very similar sound throughout the line but a distinct improvement as you went up in the line. The black body and stylus grip don't tell you where in the line up the cartridge you own was placed. In general the one comment that would not be made about a Grado is to call it bright. Like a tube and and a BBC speaker, the Grados did a wonderful midrange and the top and the bottom were where the improvements occurred according to price. Detail and dynamics improved with price. The desire to remove a motor and put shielding around the motor (a thin sheet of aluminum) to allow the use of a Grado is a testament to the sound Grado has established. They are not a cartridge for everyone as many will prefer the sound of a brighter cartridge. But Grado and Ortofon are virtually unique in their price range in the use of an induced magnet design instead of a more traditional moving magnet. This gives the two lines a distinct advantage on the detail and dynamics side of the equation without resorting to the brightness of many other manufacturer's products. So what's the new table? |
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Gold Member Username: KeggerWarren, MICHIGAN Post Number: 2422 Registered: Dec-03 | nothing special Jan just a Micro Seiki MB-14 Belt drive for $80, a backup!  |
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Silver Member Username: Joe_cOakwood, Ga Post Number: 167 Registered: Mar-05 | hope i did not offend with my opinion jan |
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Silver Member Username: Joe_cOakwood, Ga Post Number: 168 Registered: Mar-05 | hope i did not offend with my opinion jan i just found the ortofon to be actually not so bright as the grado red which I seem to enjoy more since my speakers are generally bright anyway, in other words it helped the sound of my particular system |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 3579 Registered: May-04 | I wasn't at all offended by your remarks. Both cartridge lines are very good and represent good value. They have similar strengths and the sound of a cartridge is merely a matter of taste. I have the Grado on my table now and have for many years, but previously I had Orotfons and found them to be an excellent choice overall. The best sound from Ortofon unfortunately comes in their excellent and somewhat pricey moving coils. |
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Silver Member Username: Joe_cOakwood, Ga Post Number: 174 Registered: Mar-05 | does foil around the motor really help?? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 3587 Registered: May-04 | A thin sheet of aluminum can sometimes be enough to minimize the hum on a Grado. Aluminum foil is not enough. It depends on the motor and its location on the table as to how effective this fix might be. It only costs a few pennies to try and about fifteen minutes to install. |
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