Really really really bad problem i have, Someone please help

[warwickhunt]

[quote name='StevieD_FenderP2009' post='690322' date='Dec 21 2009, 01:32 AM']£600's worth of equipment and i can't even use it properly... ~ARGH~[/quote]

Do you 'have' to put all of your kit in one rack? You could put the amp in one case (2U/3U) and then put the rest of the kit (tuner/receivers) in a 2nd 2U unit; they'd stack together and for rehearsals you could just take the amp and a cable rather than wireless. Just a thought but how about doing away with the rack tuner and getting a stomp box tuner? Just trying to save you a nervous breakdown.

[BigRedX]

Have you worked through all the suggestions in my last two posts? Have you bought and fitted Humfrees?

Your problem is 99% an earth loop caused because the earth between two pieces of equipment is being connected both via the signal cable and the equipment chassis. You need to break one of these earth paths either by isolating the casing of the equipment completely from the rack and the other equipment in there or by using a earth lift cable.

You need to work through the problem logically. Simply rebuilding and rewiring the rack without the additional measures I've outlined is not going to make the issue go away.

Fit everything into the rack exactly how you want it, but don't fit any signal cables yet. Route all your mains and other power cables to one side of the rack (the side furthest from where the majority of the signal cables will go. Use cable ties and clips to keep everything tidy and where you want it.

Wire it up the way you had it originally - each receiver going to an input of the tuner and the tuner feeding the amp and power up. It will be buzzing as usual. Do each of the following in turn and report back with the results.

1. Disconnect one of the receivers from the tuner.

2. Remake all the signal connections and disconnect the other receiver from the tuner.

3. Disconnect both receivers from the tuner and connect to bass directly to the tuner.

4. Disconnect the tuner and connect one of the receivers directly to the amp.

5. The same as #4 both with the other receiver connected directly to the amp.

6. Just with the bass connected directly to the amp, all other signal cables removed.

Report back with which of these give you buzz and which don't.

You need to do this with everything fixed properly in the rack exactly how you want it and all the bolts tightened up securely. The only thing you are changing is which signal cables are plugged in and what they are connecting. When you remove a signal cable unplug it at both ends and remove it completely. If you simply unplug one end there is a chance that the loose plug could be touching something in the rack and making an electrical connection.

[BigRedX]

warwickhunt, there's no reason why this shouldn't work without buzzing, it just requires some time and logical process to find where the loop is occurring and then take the correct steps to remove the problem. Removing the amp from the rack defeats the object of having the amp converted to be rack-mounting in the first place. I don't know if there are any stomp-box tuners that have two inputs which is what is needed to make this setup work. Also there's a lot of benefit in having everything permanently fitted in one rack with only the speakers to connect in order to set up, once it's been done properly!

I'm pretty certain that the rack-mounting conversion of the amp is what is causing the problem, as it has resulted in a hard electrical connection between the signal and mains earths, when normally they would be isolated at signal levels. Personally I would get the amp looked at by a reputable tech to make sure that the conversion has been done safely from an electrical PoV and properly from an audio signal aspect.

Edited December 21, 2009 by BigRedX

[warwickhunt]

[quote name='BigRedX' post='690446' date='Dec 21 2009, 10:27 AM']warwickhunt, there's no reason why this shouldn't work without buzzing, it just requires some time and logical process to find where the loop is occurring and then take the correct steps to remove the problem.[/quote]

Totally agree with you mate, I was just throwing an alternative solution into the mix, though as you say logically isolating the components will eventually solve the problem; saying that regardless of anything else I'd be having the amp conversion professionally checked out.

I should point out that I wasn't advocating 'de-racking' the amp, it could still be rackmounted but separately from the other kit. As you say a couple of extra connections to make when setting up and for one box ease of use, not the best way forward.

[StevieD_FenderP2009]

Hi there
BigRedX - I;ve got 5 packets of Humfrees on order (just so i have loads of spares as well as at some point i'm going to buy a DBX160 Compressor and change to a 5 or 6u rack)
Also, i've taken the steps of disconnecting it then putting the recievers into the amp one by one, and even tried bass to tuner to head and still the buzz was there when i tried it. So im now waiting for the humfrees to arrive and i'm also going in to the music shop tomorrow (as they have an audio product repair center next door) so they can take a look at it. Hoping this won't cost to much

Warwickhunt - I would go back to using stomp box tuners etc but as BigRedX pointed out, no stomp boxes have the dual inputs, plus, i love having all my stuff racked together. Looks neater, much easier to use (well, not in my case cos i'm stupid) and i've splashed out on the rack equipment so i'd rather not have to change back. If worst comes to worst and i get told i can't use my amp head in the rack mount, i'll put it back in the wooden sleeve, look out for the proper rack version/save up for a newer AH600-12 Trace Elliot rack head then sell the current one. I shall have to see, as said, if worst comes to worst i'll do that
Ps, Warwickhunt, what happened to the large array of Warwicks you had? didnt you have like, 10 at one point?

Cheers for all your help guys

[BigRedX]

StevieD,

Just to clarify, with everything in the rack as you want it and fitted properly you get buzz with every combination listed in my post #27?

Even with just the bass connected directly to the amp and NO OTHER signal leads connected?

You have also made sure that the power and signal leads are as far apart as possible as I also suggested?

Remember that the Humfrees only isolate the units from the rack mounting frame. You may still get hum if the metalwork of one unit is touching the metalwork of another, which is why I said in an earlier post you may have to fit some insulating material between the units in the rack to prevent their metal parts touching.

Edited December 21, 2009 by BigRedX

[warwickhunt]

[quote name='StevieD_FenderP2009' post='690686' date='Dec 21 2009, 03:00 PM']Warwickhunt, what happened to the large array of Warwicks you had? didnt you have like, 10 at one point?[/quote]

10... and then some! I realised that I was turning into a Warwick collector rather than a Warwick player, so most of them found new homes (I retained 3 though one is up for sale).

[StevieD_FenderP2009]

BigRedX - Buzzes in every configuration apart from when i plug my bass directly into the head and then run the head to the cab. It's only buzzing when the other equipment is plugged into the head. I've followed all your instructions and now i'm just waiting on the humfrees. I know they only isolate it but i shall have to see what the results are after i've fitted them to everything. I cable tied all my power cables to one side of the case as well as moving the plugs across to the other side that the majority of the signal cables were on, then cable tied the signal cables and clipped them to the opposite side.

Warwickhunt - More than 10? Dude you must of either had alot of money or you were very lucky to pick them up on the cheap. I played a Warwick 1987 Thumb NT4 through a Trace Elliot AH1000-12 at thr LIM Show last year and it was so nice, i will end up buying one when i've got the Fender Steve Harris and Rickenfaker I want/currently have being built. What you got for sale?

[BigRedX]

OK it sounds like your almost there. From your last post, it's the amp that's the problem.

You need to isolate the metal case of the amp completely from the rack and any other equipment in there. Start by fitting the Humfrees when they arrive. You also need to make sure that the metal parts of the amp and it's fittings aren't touching the metal parts of any of the other equipment. This includes the rack ears, and the top/bottom of the amp touching the bottom/top of any other equipment in the rack. In each case the amp needs to be separated from the other equipment by some insulating material. However depending on how the mains earth of the tuner works you may still need to connect the amp and tuner with an earth lift cable, as you will still have an earth loop between the signal cable and the mains earths of the two pieces of equipment.

Personally I would still get the amp looked at and sorted out by a reputable amp tech, because IMO the problem has arisen from the rack conversion not having been done in an electrically proper way.

[warwickhunt]

[quote name='StevieD_FenderP2009' post='691043' date='Dec 21 2009, 09:49 PM']More than 10? Dude you must of either had alot of money or you were very lucky to pick them up on the cheap.[/quote]

20+ years of saving and collecting... oh it also helps having a proper day job and spawning no ankle-biters!

[quote name='StevieD_FenderP2009' post='691043' date='Dec 21 2009, 09:49 PM']What you got for sale?[/quote]

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Good luck getting this sorted, I think with [size=7][color="#FF0000"]X [/color][/size]'s help you should have it cracked soon.

[umph]

[quote name='StevieD_FenderP2009' post='682763' date='Dec 13 2009, 02:49 AM']Hi there guys.
I've got all my kit rackmounted which consists of:

Trace Elliot GP12 Series 6 Head (mounted with a rack shelf)
2 AKG WMSPro40 Wireless Recievers
Korg DTR2000 RackTuner
Also, it's all plugged into a 6 way extention (with surge protection) socket thats been put onto a 1u rack piece

Basically, i've got it all built in but there's this f***ing horrible buzzing noise coming from my head when it's all hooked up. I've tried all different cables etc but still the buzzing is there. and this buzz is awful, it's so loud it actually rumbles my cab

the way i've got it connected is:

Bass guitar 1 + 2 loaded with AKG Bugs on different frequencies -> Recievers -> inputs 1 and 2 on the back of the Korg Tuner seperately -> single output connected to the Active input on my Trace Elliot head (as both basses are active) -> output on back of head to Marshall JCM800 Cab

I'll be honest when I say it's really upset me cos I am so proud of how i've worked to get all this equipment

I don't know if there is an earthing problem as it started to happen when everything was fully bolted into place. Please note all the "rackears" from each component are metal so they could be interacting and causing a problem, also, the casing on the Trace head is metal and the casing on the wireless recievers is metal so could earthing/insulating be the problem?
If so, how can i fix this?

Everything is mounted into one of these 4u rackcases - [url="http://cgi.ebay.co.uk/ABS-4U-19-RACKMOUNT-FLIGHT-ROAD-TRANSPORT-RACK-CASE_W0QQitemZ370216164827QQcmdZViewItemQQptZUK_Musical_Instruments_Rack_Cases_MJ?hash=item56329a5ddb"]http://cgi.ebay.co.uk/ABS-4U-19-RACKMOUNT-...=item56329a5ddb[/url]
That is the exact case by the way

Please please help! i'm desperate, Especially as i'm meant to be playing a big make or break gig for a management company in a few weeks time

Thanks so much
Stevie Dewar[/quote]

ey up its an earthloop caused by the wireless, i hope you've sorted your problem

[Dread Bass]

Three cheers for BigRedX, so helpful as always.

[StevieD_FenderP2009]

[quote name='warwickhunt' post='691402' date='Dec 22 2009, 12:14 PM']20+ years of saving and collecting... oh it also helps having a proper day job and spawning no ankle-biters!



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Good luck getting this sorted, I think with [size=7][color="#FF0000"]X [/color][/size]'s help you should have it cracked soon. [/quote]

Warwickhunt - Haha, i suppose that does help. God help my bank account the day i start working full time and have my own place... I think i'll have to have a limit put on my account. I really do want a Thumb NT4 at some point though. Well, i will have to wait a few years =D

BigRedX - Thank you so much for all your help in this. You've helped me determine the problem and everything. I'm going to put a sheet of insulating tape stuff on the bottom of the amp head chassis and fit the humfrees when they arrive. One question though, if i wrap electrical tape (or whatever that black tape is, sure it's electrical tape...) around all the rack ears, will this have the same affect as it would basically be cutting off the connection between the rack case and the equipment. Also, do the humfrees stop the bolt touching the rack ears all together or will there still be a chance that the bolt will connect with the inside of the rack ear?