Roender's FC-100 prototype and builder's thread

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#983
correct, PMI cap multipliers. I can take a tap from before the multiplier just by moving the crimp connector, and then compare, but I liked it so much like this I just left it.
I have another set of boards built for biamping, this will be for bass driver and will use a 30V transformer as I have one handy. I will raise the front end voltage by 2 volts as well.
When I build this one I will use 2 X 10000uF caps on each board.
Next project is an AYA II dac.
 
#989
wineds said:
Are the transformers locally wound? Where does the shunt assembly fit into the case?
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I'm surprised you dont recognise the transformers. They are 2 X 25V 160VA from Jaycars🙂 If you look at the photo with the case lid off, you will notice some aluminum brackets on the front panel. The shunts and transformer mount on these brackets, so they are very close to the front end.
Its surprising how much of a challenge it was to fit it all into such a big case. The cap multipliers take a lot of real estate, so in order to keep the power transformers away from amp boards and audio in/out, I stacked them.
I don't know if you have heard this amp, but its very good and I am listening to a lot more music since building it. I totally recommend it.
I want to biamp, but metal work really slows me down. When building this I snapped a tap in one of the holes. I bought a 18mm drill for the front panel and received a 20. Some of the capacitors were missed from the BOM. Every time I had a problem , it sat for months. It took me ages to match the transistors.
 
#998
AndrewT said:
Here is the ambiguous statement that could lead to a VERY DANGEROUS construction if implemented by a Beginner that did not realise what he/she was incorporating.
The least you can do is expand on what you said to make the "SAFETY" part appropriately important.
Or.
simply remove the potentially fatal advice.
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Looking for some info in this thread today, I realized that I had not followed up on this. In fact, I did end up connecting the output common to chassis. Zero hum, all safety requirements satisfied.

Sheldon
 
#999
Sheldon said:
Looking for some info in this thread today, I realized that I had not followed up on this. In fact, I did end up connecting the output common to chassis. Zero hum, all safety requirements satisfied.

Sheldon
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took me a while to find that post. #865 from 28th November 2013. And referring back to previous posts around 840 to 860.

And just to confirm. You have connected the Main Audio Ground (MAG) direct to Chassis to ensure that a mains fault finds a route back to PE to allow rapid rupturing of the Mains Fuse.
 
#1,000
AndrewT said:
took me a while to find that post. #865 from 28th November 2013. And referring back to previous posts around 840 to 860.

And just to confirm. You have connected the Main Audio Ground (MAG) direct to Chassis to ensure that a mains fault finds a route back to PE to allow rapid rupturing of the Mains Fuse.
Click to expand...


Yup.

And as an aside. In the past, I have occasionally used a bridge/resistor/capacitor ground lift. But I've learned that if I pay careful attention to proper grounding paths, I have been able to eliminate them in virtually all cases. So I don't give up now until I get to that point.

Sheldon
 
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