Another finished brianGT GC.

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troystg

troystg

Member
Joined 2004
Hey Waltson-

Beautiful. Love the leds in the knobs too.

Just throwing out a possibility....

Could the metal shaft for the volume be picking up EMI from the transformer coupling the hum to the Pot? Could you try replacing it with wood as an experiment?

But the project was very well executed.
 
W

waltson

Member
Joined 2004
Thanks to your kind words everybody.
This was my first time working with aluminium, and I only had tools for woodwork, so the quality and precision is not first class.

rabstg said:

Could the metal shaft for the volume be picking up EMI from the transformer coupling the hum to the Pot? Could you try replacing it with wood as an experiment?
Click to expand...

I tried removing the whole shaft, and it didn't change anything, so I guess that's not the case.
 
Coulomb

Coulomb

Member
Joined 2002
diyaudio.com/wiki/index.php?page=Active+Group+Buys
Actually, I think the Hum is because of a difference in ground potential. Your transformer clamp appears to be magnetically shorting the windings to ground. I do not see the prerequisite rubber spacer/insulator under the metal clamp.

Try unbolting the transformer and lifting it off the chassis temporarily, put the metal washer aside and see if that effects the Hum.

Regards

Anthony
 
W

waltson

Member
Joined 2004
Thanks again for your compliments!

The knobs and the case are all from scratch.

I made the knobs by first filling a 50mm tube with a plywood disk to make it solid, and then I just glued a piece of 3mm aluminium to the end of that with some epoxy. Then I sanded the exra aluminium off, and polished the knob.

The leds are 5mm by diameter, with a small 1.8mm tip in the end. I drilled a 2mm hole to the knob, and then drilled a 5mm hole from the plywood side so that the led could fit easily inside. Then i glued the led to the hole with epoxy, so that the tip is protruding little from the front of the knob. After the glue was dry, I just sanded the extra led off. I hope I made myself clear:)

About the hum: There are rubber spacers between both the trafo and the case, and the trafo and the clamp, so I guess that's not the case either...
 
W

waltson

Member
Joined 2004
G4ME said:
Do you have the exact model selector and pot that you are using, and the vendor that you got them from.

I got to Elma's corporate site , but couldn't find and local distributers.

Btw love the case, i am leaning towards similar design for my own.
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Thanks for the compliment!
I bought the selector from a local electronics store called Bebek. I don't know the exact model. I just asked for "an elma selector".:)
The Alps pot is from RSelectronics' local branch in Finland.
 
W

waltson

Member
Joined 2004
DIAR said:
Nice work :D

Have you concidered anodizing aluminium parts. It costs only 15-20 euros to do it. Check out yritystele.fi for firms that do it.

Where did you buy the aluminium. It's quite difficult to find a good aluminium dealer in Helsinki. :cannotbe:
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Thanks.
I was planning to get the parts anodized, but then the only place I found that said could do it for less than 50 euros was in Pori, so I just laquered the parts. Do you know any cheap places in Helsinki that could do it?

I worked in a metal workshop in Lahti last summer, so I got the aluminum from there. The only problem was that they only had a guillotine type of cutter there, so afterwards I had to trim all the edges by myself with a router, which wasn't very easy.
 
F

filholder

Member
Joined 2005
Got to say that is one superb looking peice of DIY mate.
How does it sound. Serious thinking about getting one of BrianGT kits but still uming and arhing about the inverted,non inverted issue.

One thing i would say is that it might be an idea to try some better quailty interconnect leads. You seem to be using some pretty bog standar one. I had issues with my NAD 352 humming, i used it for TV/console/Moviewatching etc so it is around a fair mess of mains leads. ANyway i got interestes at some of the various DIY lead suggested on TNT. Tried a few out. One thing i noticed if you built you own leads with decent cables is that the mains hum picked by near by mains leads just disapears.

Solved my problems, trying build some with heavily shield wire.

Fil
 
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