[Sathimas]

Here he is:


And here the inside - as you see, I got almost no space ...
But I'll find something, I'm sure.

 

[heatmizer]

As a test. Unbolt the toroid and hang it over the side. then see if you still have hum. BTW, very nice looking

 

[headphonejunkie]

I know this may be a pain but I would try brading all your wires. The braid should help eliminate any stray EMF which could be inducing hum. If the toroid suggestion doesn't work that is.(by braid I mean twist them tightly)

 

[headphonejunkie]

You should twist your wires anyway since that could eliminate the hum from the toroid too. If there is any from the toroid. The toroid shouldn't pass any hum but untwisted wires can pick up hum very easily.I would try twisting the wires on the toroid first and see what happens.Then try your input wires if that doesn't work then the output, and volume, and selector switch wires next.

 

[headphonejunkie]

Untwisted wires can also pass EMF which would produce hum.

 

[headphonejunkie]

To take a quick guess I would bet it is related to the wiring between your inputs and selector switch. They should be routed a little better and twisted. Try to keep them away from the board like your headphone out is.

 

[Sathimas]

Well, keeping the wires away from the board is simply impossible.
About twisting ... the cables are too short and I would have to desolder them all to do that anyway.

Would help shielding them with aluminium foil?
Every shielded cable I ever opened had a layer of aluminium foil around the core.
Wrapping the calbes would be no problem.

 

[headphonejunkie]

I would try twisting the wires on the toroid. You can probably do that without desoldering anything. I would also try the input connectors. Foil might work but you can short circuit something. Be careful trying that.

 

[Sathimas]

The problem of short circuiting something came to my mind right after I wrote that,
but won't be a problem. I will wrap the free parts of the contacs with duct tape
and use the aluminium foil afterwards.
But thank you for the hint, electronics are dangerous.
(Although I managed to be hit by an electric shock only once

)

The problem with my case is, that some parts are hardly removable.
The torriod is glued to the bottom of the case and the screw will turn as a whole,
the bottom side isn't fixed in any way ...

I'll have a try later today or tomorrow, we'll see.
Since the amp is finally finished, listening is much more fun than modifying it

 

[headphonejunkie]

I hope it works but be careful. You have a lot of voltage coming in from your house.

 

[Sathimas]

I've got exactly 230Volts coming out of the wall, and I already had these running through me

You can be sure that I'll be careful now

But my thought was to mainly shield the signal cables, from the inputs to the switch.
Well, to be sure, I'll shield simply everything.

 

[headphonejunkie]

try a little at a time then test it. that way you don't have to do what is not necessary.

 

[kklee]

Quote:

Originally Posted by Sathimas /img/forum/go_quote.gif Would help shielding them with aluminium foil? Every shielded cable I ever opened had a layer of aluminium foil around the core. Wrapping the calbes would be no problem.

If the hum is being induced by the transformer (EMI), aluminum is useless as a magnetic shield. I can tell you from personal experience that you'll need something along the lines of magnetic shielding metal (mu metal, or the like) to quell transformer hum.

Aluminum shielding would still be good for blocking RFI, so it may still help. It just depends on what the source of tyhe noise is.

 

[konder8u]

Ditto on the Pana FM's - even for those you list for C7, C8, and C11. The great thing about the SOHA design is the only cap in the signal path is C2 and C14, and that's an orange drop/box cap. So, the Pana FM might be the best non-boutique choice, period.

According to the designers/first proto builders, T1 should be a toroid if it's in the case. If you mount it remotely in a different box or walwart, then whatever you want. Unfortunately, I've found the 30VCT uncommon enough that the toroid is the simplest choice anyway.

For the LED, if you're talking the tube light, be sure to use a T1 (3mm). That's different from the Millett. With a 3mm LED, though, you can push it up into the tube socket for a very direct effect.

 

[tomb]

Quote:

Originally Posted by konder8u /img/forum/go_quote.gif Ditto on the Pana FM's - even for those you list for C7, C8, and C11. The great thing about the SOHA design is the only cap in the signal path is C2 and C14, and that's an orange drop/box cap. So, the Pana FM might be the best non-boutique choice, period.

Agree with that completely - another Pana FM lover.

Quote:

According to the designers/first proto builders, T1 should be a toroid if it's in the case. If you mount it remotely in a different box or walwart, then whatever you want. Unfortunately, I've found the 30VCT uncommon enough that the toroid is the simplest choice anyway.

Except for a local dealer who was vacating his space and sold me about 50 FP30-400 Flat Packs at a song.

They fit the Jameco walwart case with room to spare - could even parallel two of them for more current if the Jisbos ever come along.

Quote:

For the LED, if you're talking the tube light, be sure to use a T1 (3mm). That's different from the Millett.

Not the MAX - it uses T1's, also. Quote:

With a 3mm LED, though, you can push it up into the tube socket for a very direct effect.