Grounding problems with my Aikido/F4
Few days ago I discovered this very useful thread about grounding.
I do hope that among the many competent members that have written on this thread, someone can give me a helping hand.
I have mounted Aikido (JBs stereoboard) an NPs F4 (cviller PCB)
in the same chassis. Aikido is powered from BAS PCB.
F4 is Dual mono. I use a shield wire from RCA in to Aikido in, but only connected to ground in on Aikido. From Aikido out I use the shield from both ground out on Aikido to the ground track on each F4.
Even if they are mounted in the same case, I can listen to the two stages separately on headphones. Listening on each this way from a CD player, there are no hum or buzz.
If I connect Aikido and F4 together and listen from the same CD player through my headphones, I get hum and buzz in both channels, but if I disconnect the CD player from my isolated RCA input, the hum and buzz are absent.
My way of connecting is like what is shown in thread
# 72 (Berhard) witch is very simular to what digi01 describe in post # 66.
How do I break my ground loop (what I think it is)
Eivind Stillingen
Few days ago I discovered this very useful thread about grounding.
I do hope that among the many competent members that have written on this thread, someone can give me a helping hand.
I have mounted Aikido (JBs stereoboard) an NPs F4 (cviller PCB)
in the same chassis. Aikido is powered from BAS PCB.
F4 is Dual mono. I use a shield wire from RCA in to Aikido in, but only connected to ground in on Aikido. From Aikido out I use the shield from both ground out on Aikido to the ground track on each F4.
Even if they are mounted in the same case, I can listen to the two stages separately on headphones. Listening on each this way from a CD player, there are no hum or buzz.
If I connect Aikido and F4 together and listen from the same CD player through my headphones, I get hum and buzz in both channels, but if I disconnect the CD player from my isolated RCA input, the hum and buzz are absent.
My way of connecting is like what is shown in thread
# 72 (Berhard) witch is very simular to what digi01 describe in post # 66.
How do I break my ground loop (what I think it is)
Eivind Stillingen
could you temporarily and safely disconnect the chassis to Audio Ground disconnecting network?
You must work very carefully while the exposed conductive parts are NOT connected to Safety Earth.
Does this eliminate or reduce the hum/buzz problem?
What happens if one lead from the CD player is connected and the other input left floating?
You must work very carefully while the exposed conductive parts are NOT connected to Safety Earth.
Does this eliminate or reduce the hum/buzz problem?
What happens if one lead from the CD player is connected and the other input left floating?
Hi Eivind,
1. Connect the mains earth safety ground to the chassis near where it enters the chassis.
2. Connect the power supply common to this same point.
3. Connect the Aikido ground to this same point.
4. Connect the F4 ground to this same point.
5. Connect the input signal shield to this same point.
Dave
1. Connect the mains earth safety ground to the chassis near where it enters the chassis.
2. Connect the power supply common to this same point.
3. Connect the Aikido ground to this same point.
4. Connect the F4 ground to this same point.
5. Connect the input signal shield to this same point.
Dave
understanding grounding
This is the best advice that I have found
http://www.passdiy.com/pdf/articles/ground-loops.pdf
This is the best advice that I have found
http://www.passdiy.com/pdf/articles/ground-loops.pdf
Aikido/F4 grounding problems
David
So far no changes. Hum and fuzz(ripple) increase when I connect to a CD player.
With no connection to The RCA input it is mostly ripple I can hear in my phones.
I will try to change cables from Aikido to F4. Now I use a singel conductor shielded wire, and the shield act as the ground wire
A two conductor shielded wire (only connected to the ground wire in one end ??) will hopefully prevent ripple to interrupt in to the
ground wire. Or should I not connect the shield at all??
Eivind Stillingen
David
So far no changes. Hum and fuzz(ripple) increase when I connect to a CD player.
With no connection to The RCA input it is mostly ripple I can hear in my phones.
I will try to change cables from Aikido to F4. Now I use a singel conductor shielded wire, and the shield act as the ground wire
A two conductor shielded wire (only connected to the ground wire in one end ??) will hopefully prevent ripple to interrupt in to the
ground wire. Or should I not connect the shield at all??
Eivind Stillingen
Re: Grounding problems with my Aikido/F4
Hi Eivind,
We do not have a schematic of your system so I must assume it is exactly as in #72. Are there any differences? How about the optional ground break circuit?
When listening to the output of the first stage, is the output (signal and ground) of the first stage connected or disconnected to the input of the second stage ?
When listening to the second stage, how is the input signal connected? I assume the signal wire between the stages is disconnected from the first stage. How about the ground?
Can you tap into the output of the first stage with the second stage still connected? Is there hum there?
If you disconnect the ground wire between the first and second stages and then measure the resistance between the ground on the first stage and the ground on the second stage, what do you get? With the CD player connected and with the CD player disconnected.
Dave
Hi Eivind,
We do not have a schematic of your system so I must assume it is exactly as in #72. Are there any differences? How about the optional ground break circuit?
When listening to the output of the first stage, is the output (signal and ground) of the first stage connected or disconnected to the input of the second stage ?
When listening to the second stage, how is the input signal connected? I assume the signal wire between the stages is disconnected from the first stage. How about the ground?
Can you tap into the output of the first stage with the second stage still connected? Is there hum there?
If you disconnect the ground wire between the first and second stages and then measure the resistance between the ground on the first stage and the ground on the second stage, what do you get? With the CD player connected and with the CD player disconnected.
Dave
OK, lets take it more in details:
From my original monting I have done some minor changes.
This is what I “have” so far:
I have established three (3) busses, all of them separated from the chassis.
To buss A (right channel):
· Loudspeaker ground from F4, right channel.
· Common powersupply (0 V) from F4 power PCB board, right channel.
· Negative loudspeaker outlet, right channel.
To buss B (left channel)
· Same as buss A, but left channel.
To buss C:
· Aikido ground (the star point on the pcb).
· Inground from F4, both right and left channel (??? Se note).
· Powerground from BAS powersupply for Aikido.
· Ground from RCA in-socket, both right and left channel. Sockets are isolated from chassis.
To one point with contact with the chassis:
· From buss A
· From buss B
· From buss C
· Earth from main power socket.
All ground wires are 1,5 mm2 or thicker. Ground break circuit not motaged.
Note: Some information that might influence (??) on the results: On “cvillers” F4 PCB: Signal ground in, signal ground out (loudspeaker) and powerground (0 V) are connected together in one common point. It is from this one point I take one wire to buss A (and B). I have called this wire “loudspeaker ground from F4”. That is the reason that I am a little confused about and doubt if it is necessary to take a separate wire to in-ground from F4 to buss C.
David
Before I do those tests you ask me to do, I will change the connection from Aikido to F4 with a two conductor shielded cable
and try:
1. With signal connection only from Aikido to F4.
2. Same As 1, but with the second conductor connected to ground in on F4 and to buss C in the other end.
Eivind Stillingen
From my original monting I have done some minor changes.
This is what I “have” so far:
I have established three (3) busses, all of them separated from the chassis.
To buss A (right channel):
· Loudspeaker ground from F4, right channel.
· Common powersupply (0 V) from F4 power PCB board, right channel.
· Negative loudspeaker outlet, right channel.
To buss B (left channel)
· Same as buss A, but left channel.
To buss C:
· Aikido ground (the star point on the pcb).
· Inground from F4, both right and left channel (??? Se note).
· Powerground from BAS powersupply for Aikido.
· Ground from RCA in-socket, both right and left channel. Sockets are isolated from chassis.
To one point with contact with the chassis:
· From buss A
· From buss B
· From buss C
· Earth from main power socket.
All ground wires are 1,5 mm2 or thicker. Ground break circuit not motaged.
Note: Some information that might influence (??) on the results: On “cvillers” F4 PCB: Signal ground in, signal ground out (loudspeaker) and powerground (0 V) are connected together in one common point. It is from this one point I take one wire to buss A (and B). I have called this wire “loudspeaker ground from F4”. That is the reason that I am a little confused about and doubt if it is necessary to take a separate wire to in-ground from F4 to buss C.
David
Before I do those tests you ask me to do, I will change the connection from Aikido to F4 with a two conductor shielded cable
and try:
1. With signal connection only from Aikido to F4.
2. Same As 1, but with the second conductor connected to ground in on F4 and to buss C in the other end.
Eivind Stillingen
Hi Eivind,
Andrew is correct, you don't need the connection from Buss A and Buss B to the chassis because you have both of those busses connected to Buss C, which is in turn connected to the chassis.
Alternately, you could have all three busses connected to the chassis and eliminate the wires from Buss C to Buss A and Buss B. I prefer the other way.
One other thing - you don't say anything about a volume control. Do you have one, and if so, how is it connected?
Dave
Andrew is correct, you don't need the connection from Buss A and Buss B to the chassis because you have both of those busses connected to Buss C, which is in turn connected to the chassis.
Alternately, you could have all three busses connected to the chassis and eliminate the wires from Buss C to Buss A and Buss B. I prefer the other way.
One other thing - you don't say anything about a volume control. Do you have one, and if so, how is it connected?
Dave
Aikido/F4 grounding problems
First of all, thank you to those of you that still stay together with me with good adwises to somethings that easily could ends up as a “never ending story”.
This is what I have done today. May be it is a good idea to take a look at post # 154: the situation before my latest changes.
From both A and B busses I have mounted a disconnecting network(22 ohm//100nF//reverse diodes). This circuit goes to chassis (one point).
Results listening through my headphones:
· With no CD player to input RCA : A low but disturbing fuzz/ripple (??).
· With the CD player connected to input RCA: A increasing amount of fuzz/ripple and hum.
Having done changes from my original wiring I was curious to do the same test I have done earlier:
· A: I disconnected Aikido and F4. Connected a CD player to F4 in (a isolated RCA socket mounted close to the F4 PCB). No other changes. All power units working as usual. Listening trough loudspeaker outlets. Result: Beautiful music. Dead silent background. Nothing disturbing.
· B: Still with the Aikido and F4 disconnected, the CD player was now connected to
Aikido RCA in. Headphones was connected to Aikido out. Ground to headphones was taken from buss C. All power units working as usual.
Result: A very, very small amount of hum. No fuzz/ripple. I could very well lived with this results, the hum did not disturb.
· C: Same as B but, with Aikido and F4 connected again as original.
Results: Same as B.
THIS IS VERY CONFUSING. UNITS WORK FINE STANDING ALONE, BUT TOGETHER????
So far I have NOT tried to connect buss A, B and C as ONE point only to chassis. The question goes to “my experts” out there before I try out that solution. Is it a good idea??
NB. I have no pot as volume connected to Aikido.
Andrew: Any reason for moving the discionnecting network from buss C to A and B??
Eivind Stillingen
First of all, thank you to those of you that still stay together with me with good adwises to somethings that easily could ends up as a “never ending story”.
This is what I have done today. May be it is a good idea to take a look at post # 154: the situation before my latest changes.
From both A and B busses I have mounted a disconnecting network(22 ohm//100nF//reverse diodes). This circuit goes to chassis (one point).
Results listening through my headphones:
· With no CD player to input RCA : A low but disturbing fuzz/ripple (??).
· With the CD player connected to input RCA: A increasing amount of fuzz/ripple and hum.
Having done changes from my original wiring I was curious to do the same test I have done earlier:
· A: I disconnected Aikido and F4. Connected a CD player to F4 in (a isolated RCA socket mounted close to the F4 PCB). No other changes. All power units working as usual. Listening trough loudspeaker outlets. Result: Beautiful music. Dead silent background. Nothing disturbing.
· B: Still with the Aikido and F4 disconnected, the CD player was now connected to
Aikido RCA in. Headphones was connected to Aikido out. Ground to headphones was taken from buss C. All power units working as usual.
Result: A very, very small amount of hum. No fuzz/ripple. I could very well lived with this results, the hum did not disturb.
· C: Same as B but, with Aikido and F4 connected again as original.
Results: Same as B.
THIS IS VERY CONFUSING. UNITS WORK FINE STANDING ALONE, BUT TOGETHER????
So far I have NOT tried to connect buss A, B and C as ONE point only to chassis. The question goes to “my experts” out there before I try out that solution. Is it a good idea??
NB. I have no pot as volume connected to Aikido.
Andrew: Any reason for moving the discionnecting network from buss C to A and B??
Eivind Stillingen
Hi Eivind,
Since both the Aikido and the F4 work separately when the ground between the Aikido and F4 is removed , but not together when the ground between the Aikido and the F4 is connected, I suspect that the problem is with the ground connection between the Aikido buss and the F4 busses.
Try this:
1. Remove all disconnecting networks.
2. Remove the grounds between the Aikido and the F4s.
3. Remove the RCA input ground from the Aikido buss (both channels)
4. Mesure the resistasnce between three busses in both channels to make sure that there is no connection - sneak back path. If there is a connection between the busses, find it and remove it.
5. Connect a wire from each ground buss to the common star at the chassis.
6. Connect the RCA input ground to the common star at the chassis (both channels).
Dave
Since both the Aikido and the F4 work separately when the ground between the Aikido and F4 is removed , but not together when the ground between the Aikido and the F4 is connected, I suspect that the problem is with the ground connection between the Aikido buss and the F4 busses.
Try this:
1. Remove all disconnecting networks.
2. Remove the grounds between the Aikido and the F4s.
3. Remove the RCA input ground from the Aikido buss (both channels)
4. Mesure the resistasnce between three busses in both channels to make sure that there is no connection - sneak back path. If there is a connection between the busses, find it and remove it.
5. Connect a wire from each ground buss to the common star at the chassis.
6. Connect the RCA input ground to the common star at the chassis (both channels).
Dave