I have read various posts on this forum & others re earthing for electrical safety, grounding for RFI, and signal (audio) ground etc! I do know a bit about electrics as I do building and car electronics, and built computers. I hope you will take some time to read my post below and give any firm solutions!
I have been in contact with Denon customer service who passed it on to their office in Germany, who then gave a reply. This reply though proved that they did not understand a thing and they contradicted themselves! I am getting nowhere with them as they don't know that they don't know!
This is the original problem that I sent to Denon;
I have the three F-109 units (amp/tuner, CD, Network player) which are all
interconnected for total system control for power off & system remote as
per Denons instructions. The units are all double insulated dessign (so no earth for electrical saftey).
My problem is that I can (occasionally) get a small static charge when I touch
them. I know that the units are not electrically earthed as "double
insulated", & are therefore "floating" in relation to true
earth which is 0v. Therefore you get static when you touch them as you are now
"grounding" (equalising the potential) the units! I have measured
with a digital multi-meter a voltage of around 90AC when connecting one probe
to the hi-fi (in standby mode) & the other to a good ground (radiator in
the room or the earth in the mains spike & RFI filter block extension which
the hi-fi is connected to). This are normal expected values.
Normally to stop this occurring you "ground" the metalwork which then
makes it relative to earth or 0v!
So I undid a back casework screw on the Amp/Tuner & attached a 2.5mm dia
cable which I then connected to the earth on my mains filter extension block. I
also connected a wire from the Network player to the same screw on the Amp, and
another wire from the CD to the same screw on the amp. Now all of the three
units are at the same potential, and all now measured 0AC voltage as all now
earthed, so no potential difference! Great!. No, not quite, as now I noticed a
faint electronic component buzz (unit in standby & buzz does not transmit
into speakers when operational). After much disconnecting of wires etc I traced
it down to coming from the back power side of the Amp unit! I removed the earth
connection & the buzzing stops! All three units can still be connected, but
as soon as I connect to "Ground" is comes back! I re-did the test
using different earthing points etc to eliminate bad earth etc., & still
the same result!
Also I noticed doing continuity checks that the CD Player and the Network
Player cases are isolated from their PCB boards and the signal - ground of the
co-ax out. But the amp case seems to be connected to the signal - ground of the
co-ax via the PCB board!
I know that the above is a bit long & technical but I would like to be able
to "ground" the F-109 hi-fi to get rid of static, but without the
Amp/tuner buzzing! Also I am trying to get as much RFI grounded (so far not
picking anything up through the speakers or the new F-109 system) as my
neighbour is an amateur radio nut (radio ham), and has a nice transmitter
aerial in his garden!!
I got a silly email back from them and sent them further info answering their email! I can not even re-send/reply or even open the "report" on their website!
This is further
I am
fully aware of what ESD is (voltage potential difference between two objects)
and I reiterate that when I connect a multimeter between the radiator in the
room (or other good earth) and any of the three cases that I get an AC voltage
reading of 90V. This is because the three units ARE NOT connected to EARTH!! If
they were then the reading would be 0V as that is “Earth”. If I already had a
direct connection through the Hi-Fi to “Earth” as you state that “There
is already a proper earthen point to the ground.” Then I would not be getting a
reading of 90ACV between the cases and an existing common earth!
The three unit cases ARE NOT directly connected together! Again if you connect
a multimeter between any combination of the three cases, you will find that
there is ONLY direct continuity between the Network player and the Amp/tuner
cases, even with ALL cables connected! Also there is about 3.16ACV difference
between the cases themselves, connecting the multimeter between one case and
the next, with or without all the cables connected!
What
“cinch” inputs?? You have co-ax RCA (phono style) for the digital signals, and
then a 3.5mm mini jack for the remote control system interconnects!
The
FM?DAB antenna IS NOT grounded! There is no need as it is internal (loft
mount), in fact in a normal domestic situation I have never seen an antenna
connected to earth! If I use your supplied antenna it would still not be
connected to Earth! Even if I disconnect the antenna from the Amp/Tuner and
reconnect my made up Earth lead to a good earth and the Amp (therefore only one
earth point and NO loops), I still get the buzz! If the antenna was causing
problems I would be getting noise etc on the Tuner through the speakers! I am
NOT getting any noise from the Tuner, in fact I am getting max strength (no.8)
on all my FM and DAB stations without any noise/interference!! I have never had
any noise in my antenna systems!
As
for ground loops, all units are double insulated (no earth), with only one
power connection as the CD player is daisy chained off the Amp, and the Network
player is daisy chained off the CD player. Even with the antenna disconnected
(therefore nothing external) the buzz appears!
All I
want to do is to have the cases at “ground” (0V), so no difference between the
cases and “earth”, and no difference between the cases themselves (best way to
stop ESD, etc), and without what sounds like an electronic component getting
agitated on the power side of the Amp! The noise DOES NOT transmit to the
speakers! It is a buzzing sound coming from the Amp/Tuner unit only, and coming
from the rear “power” side of the case. P.S I am having trouble getting to grips with your forum posting format as the other forums that I post on (cars) are a bit easier and have built in auto spell check etc. Many thanks if you can understand and help!!!.
I have been in contact with Denon customer service who passed it on to their office in Germany, who then gave a reply. This reply though proved that they did not understand a thing and they contradicted themselves! I am getting nowhere with them as they don't know that they don't know!
This is the original problem that I sent to Denon;
I have the three F-109 units (amp/tuner, CD, Network player) which are all
interconnected for total system control for power off & system remote as
per Denons instructions. The units are all double insulated dessign (so no earth for electrical saftey).
My problem is that I can (occasionally) get a small static charge when I touch
them. I know that the units are not electrically earthed as "double
insulated", & are therefore "floating" in relation to true
earth which is 0v. Therefore you get static when you touch them as you are now
"grounding" (equalising the potential) the units! I have measured
with a digital multi-meter a voltage of around 90AC when connecting one probe
to the hi-fi (in standby mode) & the other to a good ground (radiator in
the room or the earth in the mains spike & RFI filter block extension which
the hi-fi is connected to). This are normal expected values.
Normally to stop this occurring you "ground" the metalwork which then
makes it relative to earth or 0v!
So I undid a back casework screw on the Amp/Tuner & attached a 2.5mm dia
cable which I then connected to the earth on my mains filter extension block. I
also connected a wire from the Network player to the same screw on the Amp, and
another wire from the CD to the same screw on the amp. Now all of the three
units are at the same potential, and all now measured 0AC voltage as all now
earthed, so no potential difference! Great!. No, not quite, as now I noticed a
faint electronic component buzz (unit in standby & buzz does not transmit
into speakers when operational). After much disconnecting of wires etc I traced
it down to coming from the back power side of the Amp unit! I removed the earth
connection & the buzzing stops! All three units can still be connected, but
as soon as I connect to "Ground" is comes back! I re-did the test
using different earthing points etc to eliminate bad earth etc., & still
the same result!
Also I noticed doing continuity checks that the CD Player and the Network
Player cases are isolated from their PCB boards and the signal - ground of the
co-ax out. But the amp case seems to be connected to the signal - ground of the
co-ax via the PCB board!
I know that the above is a bit long & technical but I would like to be able
to "ground" the F-109 hi-fi to get rid of static, but without the
Amp/tuner buzzing! Also I am trying to get as much RFI grounded (so far not
picking anything up through the speakers or the new F-109 system) as my
neighbour is an amateur radio nut (radio ham), and has a nice transmitter
aerial in his garden!!
I got a silly email back from them and sent them further info answering their email! I can not even re-send/reply or even open the "report" on their website!
This is further
I am
fully aware of what ESD is (voltage potential difference between two objects)
and I reiterate that when I connect a multimeter between the radiator in the
room (or other good earth) and any of the three cases that I get an AC voltage
reading of 90V. This is because the three units ARE NOT connected to EARTH!! If
they were then the reading would be 0V as that is “Earth”. If I already had a
direct connection through the Hi-Fi to “Earth” as you state that “There
is already a proper earthen point to the ground.” Then I would not be getting a
reading of 90ACV between the cases and an existing common earth!
The three unit cases ARE NOT directly connected together! Again if you connect
a multimeter between any combination of the three cases, you will find that
there is ONLY direct continuity between the Network player and the Amp/tuner
cases, even with ALL cables connected! Also there is about 3.16ACV difference
between the cases themselves, connecting the multimeter between one case and
the next, with or without all the cables connected!
What
“cinch” inputs?? You have co-ax RCA (phono style) for the digital signals, and
then a 3.5mm mini jack for the remote control system interconnects!
The
FM?DAB antenna IS NOT grounded! There is no need as it is internal (loft
mount), in fact in a normal domestic situation I have never seen an antenna
connected to earth! If I use your supplied antenna it would still not be
connected to Earth! Even if I disconnect the antenna from the Amp/Tuner and
reconnect my made up Earth lead to a good earth and the Amp (therefore only one
earth point and NO loops), I still get the buzz! If the antenna was causing
problems I would be getting noise etc on the Tuner through the speakers! I am
NOT getting any noise from the Tuner, in fact I am getting max strength (no.8)
on all my FM and DAB stations without any noise/interference!! I have never had
any noise in my antenna systems!
As
for ground loops, all units are double insulated (no earth), with only one
power connection as the CD player is daisy chained off the Amp, and the Network
player is daisy chained off the CD player. Even with the antenna disconnected
(therefore nothing external) the buzz appears!
All I
want to do is to have the cases at “ground” (0V), so no difference between the
cases and “earth”, and no difference between the cases themselves (best way to
stop ESD, etc), and without what sounds like an electronic component getting
agitated on the power side of the Amp! The noise DOES NOT transmit to the
speakers! It is a buzzing sound coming from the Amp/Tuner unit only, and coming
from the rear “power” side of the case. P.S I am having trouble getting to grips with your forum posting format as the other forums that I post on (cars) are a bit easier and have built in auto spell check etc. Many thanks if you can understand and help!!!.
ray:
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