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tannoy man
02-08-2010, 20:58
A question for Marco and and anyone else with Tannoys really.
Have you tried earthing the driver chassis?, mine have been run like this for over five years and the improvement is worth any effort.

Paul

Rare Bird
02-08-2010, 21:20
I spoke to Spendorman probably last year about this...

DSJR
02-08-2010, 21:29
Why would you do this? if there was real benefit, then the -ve terminal would be directly connected to the chassis and not insulated wouldn't it? Most -ve lines are connected to earth at the amp end I believe :scratch:

Barry
02-08-2010, 22:16
Why would you do this? If there was real benefit, then the -ve terminal would be directly connected to the chassis and not insulated wouldn't it? Most -ve lines are connected to earth at the amp end I believe :scratch:

Not eveyone will connect their speaker terminals to the coresponding coloured terminal on the amplifier. Those particularly concerned about absolute polarity and use a polarity-inverting power amplifier may well transpose the speaker connections to correct this. In this situation earthing the (black) speaker terminal would short out the amp.

On the face of it, it doesn't make much sense and would appear to be a fad. As far as I know Tannoy are the only speaker manufacturer to offer this facility; one would assume that they think it can be of benefit and why. Perhaps if Paul can explain in what way improvement is gained, then maybe some technical explanation might be possible.

Regards

hifi_dave
02-08-2010, 22:45
I've earthed several Tannoy's with the appropriate terminal and heard no difference at all. After all, it is only earthing a cast alloy chassis. Perhaps, if there is a lot of RF interference around, it might make a difference...:scratch:

dcarol
03-08-2010, 07:16
I have seen loudspeakers where the chassis is grounded via a ground terminal to 'mains earth' and not to the amplifier -ve terminal. Never did hear it without.

Don't Wilson Benech do something like that?

tannoy man
03-08-2010, 16:33
I have taken an earth from the driver to my Isotek Substation and it sounds better, I dont know why it just does. I also put my television digibox in standby mode and switch off anything that might corrupt the mains, halogen and flouresent lamps. computers and even my CD player and Dac when my TD 124 is in use, the cumulative effect is not subtle.

Barry
03-08-2010, 23:22
I have taken an earth from the driver to my Isotek Substation and it sounds better, I don't know why it just does. I also put my television digibox in standby mode and switch off anything that might corrupt the mains, halogen and fluorescent lamps. Computers and even my CD player and Dac when my TD 124 is in use, the cumulative effect is not subtle.

Paul, can you please describe how it sounds better? Steve (Toy) has made an excellent post, wherein he describes how the latest version of his Mark Grant cables sound with different styles of phono plug.

If you find the need to switch off halogen and fluorescent lamps (these presumably are plugged into wall sockets), this would suggest to me that your Isotek Substation is not doing a very good job.

Regards

DSJR
04-08-2010, 09:33
It worries me when systems seem so sensitive like a knife-edge to the tiniest things with mains, wire dressing (as long as cables afren't snagged) and other obsessive artifacts. I appreciate that Tannoys have a certain presence and clarity, but the best balanced systems I've heard during my long career don't seem anything like as sensitive.

tannoy man
04-08-2010, 16:55
Instruments sound more real and isolated, backgrounds darker, crescendos clearer and everything seems to have made a more analogue transition from the master.a simple analagy would be my sons recent purchace of The Beatles Help on direct metal mastered vinyl, compared to my original it sounds hard and unrefined.
The Substation was added to my system some time ago and was/is very beneficial to my goal of a totally dramatic but unfatiging sound.
Dave, its not a fussy system, it sounds fantastic all the time, but if im listening critically the benefits are easy to hear.
cheers gents

Reid Malenfant
04-08-2010, 17:40
<snip> If you find the need to switch off halogen and fluorescent lamps (these presumably are plugged into wall sockets), this would suggest to me that your Isotek Substation is not doing a very good job.
The Isotek is simply a filter & while it may only be dealing with mains frequencies it will actually have to have a much higher passband to allow for the rapid current pulses demanded by modern amplifiers. No filter is perfect & one that has less garbage to deal with will obviously have a cleaner output than if it has a lot to contend with. Just my take on things, but in this case it really does come down to 'garbage in, garbage out' :doh:

<snip> its not a fussy system, it sounds fantastic all the time, but if im listening critically the benefits are easy to hear.
I find that makes a lot of sense :) Kill the interference at source, rather than try to deal with it.

Barry
06-08-2010, 19:38
The Isotek is simply a filter & while it may only be dealing with mains frequencies it will actually have to have a much higher passband to allow for the rapid current pulses demanded by modern amplifiers. No filter is perfect & one that has less garbage to deal with will obviously have a cleaner output than if it has a lot to contend with. Just my take on things, but in this case it really does come down to 'garbage in, garbage out'.

The efficacy of a filter does not depend on the amplitude of signal unless, that is, the amplitude is so large that the inductors become saturated - and if that happens you have a very serious problem!

The Schaffner filter fitted to my Olsen distribution board is a four-section LC low-pass design presenting 70dB attenuation at 1MHz. The only variation to this performance will be due to changes in the effective source impedance and load. The former is pretty constant (~0.2 Ohm), the latter will depend on the current drawn by the load.

I still maintain that if the Isotek Substation needs suspected noise-creation devices to be unplugged from the mains for it to work properly, it's not fit for purpose! If all unused (and possibly noise producing) items are unplugged, what is the point of using the filter at all?

Regards

Barry
06-08-2010, 19:56
Instruments sound more real and isolated, backgrounds darker, crescendos clearer and everything seems to have made a more analogue transition from the master. A simple analagy would be my son's recent purchase of The Beatles Help on direct metal mastered vinyl, compared to my original it sounds hard and unrefined.
The Substation was added to my system some time ago and was/is very beneficial to my goal of a totally dramatic but unfatiging sound.
Dave, its not a fussy system, it sounds fantastic all the time, but if im listening critically the benefits are easy to hear.
cheers gents

I suspect that you might be suffering from RFI being picked up by your speaker cables and entering your power amplifier via the output. If this is occuring then your Isotek Substation will be of no help.

It is possible that in earthing your speaker basket and magnets and running this earth wire back to your Substation with the wire running parallel to the speaker cables, the low capacitance created by the physical proximity of these wires might permit a path to earth for the RFI, before it can get into your amplifier.

A way to test this hypothesis would be to disconnect the earth wire at the speaker end but leave it in place parallel to the speaker cable. If very little change is noticed then this would support my idea. The next step might be to experiment with shielded speaker cables.

Regards

Reid Malenfant
06-08-2010, 20:09
I still maintain that if the Isotek Substation needs suspected noise-creation devices to be unplugged from the mains for it to work properly, it's not fit for purpose! If all unused (and possibly noise producing) items are unplugged, what is the point of using the filter at all?

Regards
I do tend to agree with you Barry ;) However a good deal of us have probably experienced the improvement in sound quality after a certain time of night when most people would have gone to bed & switched stuff off. As you know, nothing is perfect & minimising the crud that you produce on the mains yourself has got to be beneficial.

Don't forget we are talking about a passive circuit here, the only modification it can do is attempt to remove garbage (though i know you know this so i'll keep it short) & it can only do so much. A regenerator can improve things without a doubt, but with a passive circuit keeping local mains noise to a minimum has got to be advantageous.

Not ideal but better than nothing in other words. Frankly i'm not impressed with the prices of these things i'll admit, we are talking a few chokes & capacitors & a box at the end of the day...

Bests to you :) Hope you have a good weekend!

hifinutt
04-01-2020, 17:16
just resurecting this thread , wondering how you earth tannoy speakers ? if anyone has tried it recently ?

and reading the review on gato amps , i guess its a big no no to use it with earthed tannoys

. Also, in order to optimise PSU performance, the DIA-250S’s left channel is
inverted, and its red speaker terminal connected to the right channel’s grounded
black speaker output. As a result, you must avoid any earthed speaker types. P

https://www.gato-audio.com/pub/media/content/reviews/DIA-250S_20190924_UK_hifinews.pdf

spendorman
04-01-2020, 19:34
My view, for the amps safety, probably better not to earth the chassis. If coil burnt out and shorted to chassis, output of amp would be shorted to earth.

For personal safety, I suppose it's better if metal that can be touched is earthed. Especially if it's likely to become live with an insulation failure and the amp has a large output voltage swing. I used to work with British Standards on electrical appliances, but that was decades ago. Things have probably changed a bit since then.

I can't really see how earthing the speaker chassis would make any appreciable audible difference.

hornucopia
09-06-2020, 13:29
Ocellia Callliopes have an earth wire-not mine though.

Pegwill
09-06-2020, 18:02
I remember reading sometime back that in an article by Russ Andrews he suggests that the basket of woofers ( and probably midrange) should be earthed. I also seem to remember that they were connected to an earth spike in the garden. I also remember that someone proposed the same thing, I think Frank Avaline though i’m not 100% sure though. It was something I was always going to try, but have never got round to it. I never did test to see if the basket and the negative connection were actually connected. Would be interested to hear if you experiment and your findings.

Regards

Heinz R
13-11-2022, 20:56
To refresh the thread, I have restored the xover 1091 of my 1993 Tannoy Canterbury to its original condition. This series did not have an earth wire yet. So I added one because I'm curious.
It is now exactly as in this photo of a Canterbury SE below in the link. And of course a connection in the plastic part where the driver connections are has bin done with a fifth socket in the middle.. I connected simple wires from the ground of the DC chassis to the ground terminal of my Quad 34. The effect is more than a little.

I'm not a guy who uses expensive power leads or RCA cables, I don't believe in voodoo capacitors wound by moonlight either. That's why I find the effect of earthing all the more evident. Some of the "shrill" tones that I had projected onto the characteristics of the HF horn have disappeared. Strings in classical music are now much more natural. A graininess in the sound has disappeared that I only now realise what was negatively present without the earth wire. The sound image is much more detailed and deeper.

I am not a technician, so I don't know if this significantly better listening impression can be transferred to other speakers. Perhaps the DC Tannoy tweeter benefits more than other speakers from the fact that "supposedly" the large chassis acts like an antenna and captures unwanted electromagnetic frequencies. And because the HF diaphragm is connected to the whole driver, it might be more disturbed than a small independent tweeter. But this is just my speculation.
However, it is a significant effect. A word of warning, I accidentally came up very shortly with the earth wire to the amp + connections. There were a spark and a loud popping noise from the speakers. Nothing is broken so far and I cannot measure any voltage difference between the earth cable and the + connection.

https://positive-feedback.com/jeffsplace/wp-content/uploads/2014/01/Canterbury-driver-connections.jpg