Emergency

[vinyljunky]

Oh my god help lads just set up my new system two items which are loaners.Firstly I had the nva monoblocks wired to the icon audio pre then the goldnote CD player wired to the pre no probs playing music great.I have subsiquently wired in Alan's Firebottle 2 and now when the monoblocks are switched on there is a hum through the speakers any suggestions guys the links inside the fire bottle look like they are set up for mm:scratch:

[killie99]

sounds like you have a ground issue. Have you connected the ground wire from the turntable to the Firebottle? Is this the only 'extra' ground wire you have as I have seen people in the past connect ground wires which come some sets of phono leads, you shouldn't connect these other extra grounds. If it is the only ground wire, try disconnecting it from the Firebottle and see what happens to the hum.

[vinyljunky]

The deck is an rp6 seperate power supply no ground wire there is a ground wire off the Firebottle don't know if this should lie loose forgot to mention the rp6s seperate power supply was off as I have found the wall wart powering it is not working could this be the issue.:scratch:

[Stratmangler]

Oh my god help lads just set up my new system two items which are loaners.Firstly I had the nva monoblocks wired to the icon audio pre then the goldnote CD player wired to the pre no probs playing music great.I have subsiquently wired in Alan's Firebottle 2 and now when the monoblocks are switched on there is a hum through the speakers any suggestions guys the links inside the fire bottle look like they are set up for mm:scratch:

Ground loop?
Show us a photo with the way things are set up, and where the amplifying bits are plugged into the mains.

[vinyljunky]

Chris having bother uploading photos from my iPhone to the forum.The deck is wired to the input of the Firebottle the pre is wired to the output the monoblocks are wired to the output of the pre.:scratch:

[vinyljunky]

The pre is plugged into a mains block the firebottleis plugged into said mains block and the monoblocks are plugged into wall sockets

[lurcher]

I believe the NVA amps are class II devices, so the signal earth should not be connected to mains earth. That may or may not have some significance.

[Stratmangler]

I believe the NVA amps are class II devices, so the signal earth should not be connected to mains earth. That may or may not have some significance.

So the phono stage protective earth may be the same as the signal earth?

[lurcher]

Just to check (not sure from your post), is the hum there all the time, or only when the pre is switched to the firebottle input?

[Firebottle]

.. there is a ground wire off the Firebottle don't know if this should lie loose ...

Steven the short ground wire from the back of the power connector should be attached to the rear ground terminal (along with a ground lead from the TT if there is one).

:)

[vinyljunky]

Alan do you mean the ground lead on the back of the phono stage and attach this to the back of the power supply thanks:scratch:

[vinyljunky]

Is the small terminal with the Alan key head on the back of the power supply the one the ground lead has to go to if so I cannot unscrew this to attach the ground lead:scratch:

[vinyljunky]

The hum only comes on when the Firebottle is switched on.Guess there's been a nuclear holocaust and I'm the only one left on planet earth hmm interesting thought wish kera knightly could have survived as well:stalks:

[lurcher]

The hum only comes on when the Firebottle is switched on.Guess there's been a nuclear holocaust and I'm the only one left on planet earth hmm interesting thought wish kera knightly could have survived as well:stalks:


Assuming it only comes on when the FB is on, and the FB is selected as the source. I think Alan is most likely able to help as he knows the FB earthing. Not sure what "lead from power connector" means.

[vinyljunky]

The lead connecting the phono stage to the power supply has a ground lead coming off it not sure what this attaches too there is an Alan head screw on the back of the power supply but this does not screw out so you can attaché said ground lead so I'm at a bit of a loss :rolleyes:

[struth]

The lead connecting the phono stage to the power supply has a ground lead coming off it not sure what this attaches too there is an Alan head screw on the back of the power supply but this does not screw out so you can attaché said ground lead so I'm at a bit of a loss :rolleyes:

Has the tt got an earth point?

[vinyljunky]

There is an Alan head screw on the back of the power supply but it will not screw out so you cAn attach the ground wire:rolleyes:

[struth]

You normally have an earthing wire between turntable and phono pre amp Steven. what the screw has to do with I know not unless , if its a loaner it may have come off the last tt it was on. only alan could say for sure as I had the plus noth the new 2 version. I had an earth connected from my TT to the phono amp

[vinyljunky]

My rp6 has a tt psu which is a seperate power supply and speed control this has a built in earth.Unless the Firebottle still needs to be earthed to the deck but this should not be the case a real head scratcher the last time I scatched my head as much I had to go and see nitty Nora with her steel comb:D

[struth]

Phono stage should already be earthed through the plug as it has a metal case. as its a 2 box affair and the wire comes out of 1 of the boxes, have you tries touching the earth cable to the case of the other part of the phono stage to see if hum deminishes? it could be a lying earth link between the 2 parts. otherwise I would either wait for Alan to get back to you or you could try pm-ing him

I had a pro ject tt that had a speedbox but it also had an earth point at back of tt

[vinyljunky]

Cheers grant for your prompt replies your a top fella in answer to your question yes I have done this and the hum is still there I think I should pm Alan

[struth]

Probably best. I would double search the tt for an external earth point though. my project speedbox one was tucked away in a spot that was very difficult to see.

[struth]

Found this article where it says that there is no earth to the rp6, and it relies on cable shielding for a ground. perhaps not the best method imo. here is the discussion

http://audio-forum.gspaudio.co.uk/re...topic2239.html

[RichB]

Any joy Steve?

[Firebottle]

Steve, sorry to hear you haven't cracked it yet.
Do not try to undo the Allen headed screw on the back of the power supply, this is the dedicated Earth connection internally for the mains earth.

I may have been misleading you with the comment about a short wire coming from the back of the power connector, I have only fitted that to the second FB 2 :doh:

The screw terminal on the back of the preamp between the phono sockets is the earthing connection point for any lead from the TT.

All that should be required is to connect the power connector to the back of the preamp with the locking collar tight. If this has been overtightened it is possible that the
socket on the back of the preamp has twisted and two wires internally may be touching. This will cause a hum as the HT and heater earths are separate.

The location 'pip' at the top of the power socket should be aligned at the very top of the socket, as shown here:

http://i601.photobucket.com/albums/tt97/Paramotorpilot/Firebottle%202/FB%202%20rear.jpg

As you have had the bottom off to check the MM/MC links, do the same and it is easy to see the rear of the power socket. Check to see that the connections on pins 4 and 5 are not touching.

The power supply has a built in 'earth lift' resistor to help prevent earth loop problems.

:)

[vinyljunky]

Will check this out Alan will let you know if I get sorted.Rich keep checking the thread I'm bound to find a solution it's probably something obvious that I have overlooked:doh:

[vinyljunky]

Checked tonight have connect the earth wire on the back of the phono stage to the ground terminal now only got slight hum in the right speaker:scratch:

[vinyljunky]

The hum is now on even when I switch the Firebottle off but disappears when I switch the monoblocks off :mental:

[vinyljunky]

Hallelujah I've just had a religious experience it was a loose connection from the right monoblock to the back of the pre I now have music sweet music no hum:cool:

[brian2957]

Well done mate :)

[vinyljunky]

Cheers Brian how's me klotz getting on:D

[brian2957]

I've been following this thread with interest . There's nothing worse than a fault like this , and nothing better than the satisfaction of fixing it :)
Still waiting on the plugs Steven . As soon as I get them I'll get the cables built and sent to you mate . It can be a bit frustrating at times , but these plugs really are the best option for use with the Klotz MC5000 cable ( I've tried quite a few other plugs to date and the MS Audio plugs still come out on top ) :)

[vinyljunky]

Oh goody can't Wait could be the final piece of my jigsaw:cool:

[brian2957]

Yup , that's how I see these interconnects mate . :D

[r100]

man ! that's got to be the most distracting avatar I have ever had to look at :eek:

[walpurgis]

man ! that's got to be the most distracting avatar I have ever had to look at :lol:

It can't be as distracting as this, surely? :lol:

[r100]

Granted, yours is quite distracting as well :D

[Stratmangler]

The hum is now on even when I switch the Firebottle off but disappears when I switch the monoblocks off :mental:

No shit, Sherlock!

[r100]

:lol:

[clarkey555]

Glad you got it sorted Steve and I hope the religious experience has given you inner peace lol. :lol:

[RichB]

Hallelujah I've just had a religious experience it was a loose connection from the right monoblock to the back of the pre I now have music sweet music no hum:cool:

Happy days!

[DSJR]

Please forgive me for butting in, but is the preamp active (powered) or a passive design. You mentioned the pre being plugged onto the mains so alarm bells rang... I promise not to go into a lecture, but like the older Quad amps, the NVA amp circuit has a nice high sensitivity, so doesn't really need to be 'driven' by anything other than a good quality 47k (my preference but 10k does fine too ;)) pot or attenuator!

Anyway, glad you're sorted out hum wise. it would appear that the Rega RB earthing arrangement can upset some phono stages, but glad it doesn't with yours - whew! :respect:

[vinyljunky]

Dave the pre is passive so no probs yet just making sure I have synergy not 100% sure yet