Those look very sleek!
Hmm, hum is not a nice thing, that's for sure.
I'm thinking of the proximity of the amp to the power supply. Being that close, there must be care taken to shut up any transfer of hum from the supply to the amp.
It is especially important that the signal wires are away from the transformer, shielded wire if possible, and well grounded. Star ground being essential as well. Of course, an iron plate between the amp and power supply sections would improve upon hum problems as well, but that's not always too easy to implement and isn't really necessary.
Is your input wire running beside the transformer?
Hmm, hum is not a nice thing, that's for sure.
I'm thinking of the proximity of the amp to the power supply. Being that close, there must be care taken to shut up any transfer of hum from the supply to the amp.
It is especially important that the signal wires are away from the transformer, shielded wire if possible, and well grounded. Star ground being essential as well. Of course, an iron plate between the amp and power supply sections would improve upon hum problems as well, but that's not always too easy to implement and isn't really necessary.
Is your input wire running beside the transformer?
Hi,
As it's rather tight in the box, signal wires (shielded) are quite near to the transformerwires and bridge. Here's a picture of the wiring inside.
As you can se, installing a shield plate is not so easy!
It's no big problem, but it would be nice to get it dead quiet in 'standby' mode. Any experiance with filters to cure this problem?
//Roger
As it's rather tight in the box, signal wires (shielded) are quite near to the transformerwires and bridge. Here's a picture of the wiring inside.
As you can se, installing a shield plate is not so easy!
It's no big problem, but it would be nice to get it dead quiet in 'standby' mode. Any experiance with filters to cure this problem?
//Roger
Attachments
Twist the cabling from the transformer to the bridge carrying oppposit phase.
Twist all signal carrying conductors with a ground wire, this will help if it is radiated hum you are picking up. You could also consider a mu-metal screenen around the toroid.
Also every cable pair you want to reduce intereference between cross att right angles.
I saw those recently on an ad on hifimagasinet btw... id you get the cases from conrad?
/ Micke
Twist all signal carrying conductors with a ground wire, this will help if it is radiated hum you are picking up. You could also consider a mu-metal screenen around the toroid.
Also every cable pair you want to reduce intereference between cross att right angles.
I saw those recently on an ad on hifimagasinet btw... id you get the cases from conrad?
/ Micke
That was rather incomplete of me to not mention wires at 90° angles and shared earth to signal grounds.
Definitely pass signal and DC power wires across the AC wires at right angles if possible when the wires must come near eachother. This reduces coupling to a minimum.
An earth-grounded signal/amp connection may cause a ground loop with other equipment that might be grounded. Do these gainclones hum when there is no input wire connected?
Definitely pass signal and DC power wires across the AC wires at right angles if possible when the wires must come near eachother. This reduces coupling to a minimum.
An earth-grounded signal/amp connection may cause a ground loop with other equipment that might be grounded. Do these gainclones hum when there is no input wire connected?
Tnx for all replys and advice!
Will try them out as possible with the current layout.
Micke: Cases are 'home made'. Originating from 24V battery chargers. Originaly black but (sorry don't know the english word) 'omeloxerade' (anodisized!?) to silver finish.
For sale, as I'm going to try another layout for the casing.
Have a stereo GC in similar lcases for everyday listening !
Scribble: Yes, grounded att mains. SG for power and signal!
Duo: Aparently easy to forget! I'm a ham radio operator/builder, so quite familiar with shielding/coupling/RF pickup etc, but taught this was more a problem for the radio frequency region!
Looking at other amps, the layouts mostly don'tn adress this or have I been looking at the wrong ones??
Maybe I'm making a chicken out off a............. !?
Sitting at listening distance you can't notice the hum only if you put your ear to the speaker.
Is there any hum in the GC's you've built ?
/Rog
Will try them out as possible with the current layout.
Micke: Cases are 'home made'. Originating from 24V battery chargers. Originaly black but (sorry don't know the english word) 'omeloxerade' (anodisized!?) to silver finish.
For sale, as I'm going to try another layout for the casing.
Have a stereo GC in similar lcases for everyday listening !
Scribble: Yes, grounded att mains. SG for power and signal!
Duo: Aparently easy to forget! I'm a ham radio operator/builder, so quite familiar with shielding/coupling/RF pickup etc, but taught this was more a problem for the radio frequency region!
Looking at other amps, the layouts mostly don'tn adress this or have I been looking at the wrong ones??
Maybe I'm making a chicken out off a............. !?
Sitting at listening distance you can't notice the hum only if you put your ear to the speaker.
Is there any hum in the GC's you've built ?
/Rog
Hej, Roger, radioamatör?
You should identify your grounding. Signal ground should meet the speaker ground, really "sniff" the cable. Then the speaker ground should go to smoothing caps and rectifier bridge. Do you have home brewed pcb's or is it BrianGT's?
A mono GC is totally hum free if you do it right.
You should identify your grounding. Signal ground should meet the speaker ground, really "sniff" the cable. Then the speaker ground should go to smoothing caps and rectifier bridge. Do you have home brewed pcb's or is it BrianGT's?
A mono GC is totally hum free if you do it right.
Hi PerAnders (PA) !
Yes a 'radiamatör' and main interest poweramps for RF.
Have been building power ampf for RF for almost 12 years now - gee...I'm getting old!
Latest project : http://hem.bredband.net/sm7uyj/
The boards are self made, but with similar layout as Brian's cards as you get a symetrical (component placement) nice looking card this way.
I'll try a different layout for my next project to get PSU and signal paths even shorter and more separated.
Will fire up the solder iron today and do some of the suggested advice!
Yes a 'radiamatör' and main interest poweramps for RF.
Have been building power ampf for RF for almost 12 years now - gee...I'm getting old!
Latest project : http://hem.bredband.net/sm7uyj/
The boards are self made, but with similar layout as Brian's cards as you get a symetrical (component placement) nice looking card this way.
I'll try a different layout for my next project to get PSU and signal paths even shorter and more separated.
Will fire up the solder iron today and do some of the suggested advice!
then try remove input cable as fas as from trans. 
If not work, simply just split PSU and Amp.
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