Tonearm "buzz"

analog97 · « **on:** 28 Jan 2009, 12:48 am »

Dear all,

I have been working on trying to get rid of my hum/buzz for vinyl play via Cornet2. I did 2 things:

1. Took apart the Cornet2 and sanded off the ground contact area on the anodized back plate.
2. Installed a Goldring 1042.

Two things happened. First, the hum/buzz went way down!! I LOVE that!! However, the tonearm now buzzes when I touch it? That did not happen with my Denon 103/Piccolo combo. The buzz/hum disappears when my fingers are not in contact, so overall I'm happy, but just don't get it. Any thoughts from vinyl junkies?

Thanks

tubesforever · « **Reply #1 on:** 28 Jan 2009, 07:15 am »

Many cartridges are shielded however some are not. I am not sure if your Goldring is shielded or not. I run my RCA grounds individually from the recepticle to the board rather than jumper them. Part of the reason why is that if you use a shielded cartridge either the right or left ground wire will be the shield. I want that to hit the circuit board directly and not be fed back over to the other rca ground where it might loop.

Engineers might tell you I am just wasting wire, after all the board is common grounded. However my Cornet 2 is super quiet and it hummed when I was combining the rca grounds.

Also, make sure you take a ground wire from your tonearm to the table ground and that should go back to the earth ground on your Cornet 2. If there is a ground wire coming from the tonearm, check continuity to make sure the arm wand is actually grounding. Sometimes the internal arm ground wiring dislodges and does not make connection.

I hope this helps.

amandarae · « **Reply #2 on:** 28 Jan 2009, 10:28 pm »

Have you tried grounding the arm directly to the phono preamp ground?

Are the phono cables shielded?

Abe

analog97 · « **Reply #3 on:** 28 Jan 2009, 10:48 pm »

Quote

Have you tried grounding the arm directly to the phono preamp ground?

Are the phono cables shielded?

Abe

Abe,

Thanks for your interest and also Tubes....I have a VPI MK IV w/ heavy TNT platter, Cardas tonearm re-wired RB-300. The TT wire has a ground and yes, I put it on the Cornet2 ground lug. I can't answer Tubes question of shielding of the cartridge or tonearm wire. I can check continuity as I have a decent DMM. The Goldring is a good cartridge and the Cardas wire is supposed to be good as well. I will putz around some more with it, but you know...it's just more of that vinyl playback mystery!! Damn...you really gotta tweak EVERYTHING. My system sounds SOOO good, but if I could ever achieve that stone-cold silence of CD......Ahhhhh!! Would be perfect!!

amandarae · « **Reply #4 on:** 28 Jan 2009, 10:55 pm »

Quote from: analog97 on 28 Jan 2009, 10:48 pm

Quote
Have you tried grounding the arm directly to the phono preamp ground?

Are the phono cables shielded?

Abe

Abe,

Thanks for your interest and also Tubes....I have a VPI MK IV w/ heavy TNT platter, Cardas tonearm re-wired RB-300. The TT wire has a ground and yes, I put it on the Cornet2 ground lug. I can't answer Tubes question of shielding of the cartridge or tonearm wire. I can check continuity as I have a decent DMM. The Goldring is a good cartridge and the Cardas wire is supposed to be good as well. I will putz around some more with it, but you know...it's just more of that vinyl playback mystery!! Damn...you really gotta tweak EVERYTHING. My system sounds SOOO good, but if I could ever achieve that stone-cold silence of CD......Ahhhhh!! Would be perfect!!

Hmmm....have you tried disconnecting the cartridge wires, make sure the pins of the wires does not touch with each other, then see if by touching the arm tube the hum is still present?

regards,

Abe

Wayner · « **Reply #5 on:** 28 Jan 2009, 11:43 pm »

Buzz could be also from other "outside" sources, like a power amp or preamps' transformer. Could be a near by wall wart or something like that as well.

Wayner

analog97 · « **Reply #6 on:** 28 Jan 2009, 11:58 pm »

Abe,

The cartridge pins are OK. I just discovered that the buzz/hum goes WAY lower when I switch the Cornet2 to Mono. I mean WAY less humm/buzz. There must be a clue there, but I am clueless. Thanks also to Wayner!! There is no wall wart nearb and the amp is about 2 feet (center line to center line away).

Wayner · « **Reply #7 on:** 29 Jan 2009, 12:18 am »

Getting a buzz touching the tonearm is usually a sign of bad connection from shield to chassis ground, like the others have reported from their experiences. I'd just try a piece of wire for now. Connected to some metal (not painted) on the tone arm and then to the ground screw of the preamp. Does the Goldring have a replaceable stylus? If so, is it fully inserted into the cartridge body? That happened to me once........or twice......

Wayner

tubesforever · « **Reply #8 on:** 29 Jan 2009, 05:18 pm »

Hey Analog97,

if you look at the back pins of the cartridge, do you see any foil tabs wrapping around the ground pins on either side? This is how some cartridge companies will establish ground to the shield of the cartridge.

If not, does the cartridge have a conductive surface on the top mounting side of the cartridge to mate to the tonearm?

On some cartridges with a conductive top surface you need to make sure you have top surface to metal head shell connectivity and that the headshell is grounded to the tonearm. On your RB 300 it is a single cast aluminum tube so you just need to make sure there is aluminum to cartridge contact to get the shielding right. If the bottom mounting area is painted, this needs to come off. (Only if you have these top grounding cartridges and luckily they are not the norm.)

Most of the modern cartridges use that tab approach to ground the shielding to the ground pins.

I make sure on my gear that the RCA chassis grounds are floating to the casework/chassis and that each right and left ground has an individual wire back to the pcb. I just want to make sure the ground cannot loop before it hits the circuit.

If any of the cartridge clip solder joints are "cold" then you can also get a buzz. Same thing with the solder joints at the RCA of the tonearm wiring. Did you use the Incognito kit? It has excellent soldering and grounding. If not make sure you have a good clean connection of the grounding of the arm wand and tonearm IC to the ground pin of the Cornet.

I hope I am not leaving anything out....oh....make sure the ground post on your Hagerman has a clean thick straight wire back to the IEC earth ground post on the power cord connector. I use this as the star ground point on my Hagermans and they are silly quiet.

Don't we all just love grounds and grounding? I hope Jim H has time to write up an article on grounding from his perspective and experience.

analog97 · « **Reply #9 on:** 30 Jan 2009, 12:45 am »

Report:

I re-examined all cartridge connections, etc and then proceeded to check continuity of the tonearm wire (green) to the end clip. When I disconnected the tonearm ground ground from the Cornet2 the HUM WAS HUGE!!! Then, purely intuitively, I reduced the volume from the preamp and tried grounding the tonearm wire to various locations. AND THEN, I clipped it to the Cornet2 370BX tranny (on a bolt protruding thru the tranny). WOW!!!!!! The hum/buzz went down by about 90%!! Obviously, no measurements here. I believe I have solved the problem, albeit without understanding. It just appears that the transformer is grounded "better" than the Cornet2 ground lug. I am thrilled!!

For those of you with a better grasp of these elusive concepts, maybe you can explain why this happened. I know I don't want to take the time and risk of taking apart my Cornet2 to figure this out.

I maybe hearing the Cornet2 at its best for the first time. The Cornet2 gets my highest praise. This critter is simply phenomenal. Tonite I listen to at least 10 of my favorite MFSL's.....Many thanks to you guys for your help and encouragement.

hotrod · « **Reply #10 on:** 30 Jan 2009, 01:24 am »

Being new to this forum but having read every thread on the C2 made the assembly go pretty much without a hitch.(tube issue)
If you haven't already done so remove the tranny covers and you will find a grey ground wire connected to one of the lower tranny bolts.Run that wire down through both grommets and connect it to the ground lug on the C2,you may have to lengthen the wire so it will reach.
These grounding seem to be disscussed at great length and all seem to be rectified.
I just ordered the Clarinet board tonight.I'm not real knowledgable in electronics,but owning something that I can troubleshoot myself and do repairs as needed is the reason for purchasing Hag products.Ive had to many problems in the past finding Techs in my area who work(or I trust) on Tube equipment.

tubesforever · « **Reply #11 on:** 30 Jan 2009, 07:54 am »

Analog97 that is great news. I suspect that the tranny is not getting a clean ground to the star grounding point, which would then carry the ground to the board. Hotrod is exactly right. Make sure to grab the ground wire inside of the tranny cover. It is the one with the star washer. I had to cut mine and solder on a longer wire to get it to the star point.

I think this is all you need to do! What a great world!

Hotrod, you are gonna love every minute of this journey. The Clarinet is a real keeper. BTW I am now a huge afficianto of the JJ 12AU7 long plates. These are just 13.95 each at tubesandmore.com. I think these stack up pretty well with some of my NOS tubes. I think they have a gold pin version of this tube.

I was playing Ron Wasserman's "Solo" album tonight. He also has an album out called "Duet" and another called "Trio".

The Clarinet gets the bass lines so superbly natural it just takes my breath away. I have this recording on cd as well. The vinyl through the Cornet 2 feeding the Clarinet is so good the CD sounds dull in comparison.

Welcome to our diy madness. It is an E ticket ride to be sure!

Cheers!

Wayner · « **Reply #12 on:** 30 Jan 2009, 01:32 pm »

Good news that you took the initiative to go hunting. This is how we all learn. Here the problem is back to a pesky transformer. Not knowing which was grounded better (transformer case or shield ground plane of RCA jacks), but the potential to ground has now been homogenized. I'll assume that it is a core and coil transformer as opposed to a toroidal. Transformers are a den of nastiness. All kinds of electromagnetic fields (pulsating) emf, and you can even throw some RF in the mix.

For your permanent solution, did you run a ground wire from the trannie to the RCA jack ground plane?

Wayner

analog97 · « **Reply #13 on:** 30 Jan 2009, 02:02 pm »

Quote

For your permanent solution, did you run a ground wire from the trannie to the RCA jack ground plane?

Wayner Very Happy

Tubes and Wayner, Hotrod and Abe:

Looks like I made another mistake in my report. The significant decrease in humm/buzz I reported was in error. If you recall, I also reported that the hum was reduced by switching the mono/stereo switch to mono. This morning I switched it back to stereo and the hum came back. Drats!!!!! Why would this be?

I also looked at the Hammond 370BX tranny this morning. There is no easy way to do a permanent fix unless I take the entire Cornet2 apart. To get the tranny side caps off, it looks like the tranny chassis bolts have to come off and I have to take all those tranny electric supply wire clips off the PCB. That will be a PIA. I don't like down-time with my music! When I have enough time, I will do this when I reverse my LED wires (mine glows RED). Thanks again gents!

Wayner · « **Reply #14 on:** 30 Jan 2009, 02:05 pm »

Do we know what turntable you are using?

Wayner

analog97 · « **Reply #15 on:** 30 Jan 2009, 03:44 pm »

Quote

Do we know what turntable you are using?

Wayner

Wayner,

I have a VPI MK IV w/ heavy TNT platter, Cardas tonearm re-wired RB-300. I do not understand why the mono switch makes such a dramatic difference. Thanks.

Wayner · « **Reply #16 on:** 30 Jan 2009, 05:26 pm »

Because their signals are not combined. It sounds louder because it's coming from 2 sources and actually may have a harmonic component to it that is canceled out or reduced when the signal is combined.

Wayner

Wayner · « **Reply #17 on:** 30 Jan 2009, 07:01 pm »

When I was building ARMOD, I had the same problem (at least with the proto-type) that when I touched the arm, I would get buzz. Of course you realize that there is such incredible gain going on between the cartridge and the preamp that the capacitance (and electrical generation) of your body caused an electrical hum in the system. I later found out it was poor connection between the tonearm and the metal frame holding the tonearm. The new Armod has a wood frame so that problem has gone away. Remember that other metal parts in the system may collect RF, EMF and if not properly (as opposed to poorly) grounded, they can have an influence. That may mean that the metal pieces that may be in contact with the tonearm pivot may have just enough contact to shed off said voltages because they are collecting, yet not have a good enough ground to sink them.

I had a tonearm that had complete total continuity and still the left side would not produce music. Later to find out the interconnect cable had 1 strand barely touching in the center contact of an otherwise completely severed connection.

Wayner

WGH · « **Reply #18 on:** 30 Jan 2009, 08:11 pm »

How about another experiment?

Plug the turntable directly into the main pre-amp without the Cornet2 in the loop.
Re-connect the turntable ground to the main pre-amp.
Crank the volume.
Touch the tonearm.

If it still buzzes then you will know the Cornet2 is OK and the problem is with the turntable.

Wayne

amandarae · « **Reply #19 on:** 31 Jan 2009, 01:15 am »

WGH has a very good suggestion!

Do you have any other phono preamp than the Cornet 2? Have you tried that and see if you are getting the same result?

The way I look at it, if it is the power tranny, it does not matter if you are touching the tonearm or not, it will buzz/hum as soon as the phono preamp is on.

Keep us posted!

Abe