Sergelac wrote:
Back after ten years,
Yep! started that triwatt after having built a 18 watts and an Tramp and stopped for lack of interest i supposed. So after all these years tinkering with arduinos, programming, and astronomy, i'm ready to complete my triwatt.
So I did complete it but i must now seek for the help of some masters since i must confess I'm far from an expert in this domain.
1. In the schematic it seems that the wire coming from the impedance switch 16 ohms lug isn't connected to the secondary. I suppose it is only an omission, but the newer schematic is the same regarding this issue. And, is it normal that the presence circuit is only connected to the 16 ohms impedance lug ? Does it work with 8 or 4 ohms load ?
2. After having reversed the output transformer primary brown blue wires my amp is now much quieter. But even with the bias pot fully anticlockwise i got a reading of 150mv. In fact the pot doesn't seem do to anything regarding the bias???
Any idea ?
Thank for your help and sorry for my poor english.
And for posting a picture which hosting service do you used ?
Serge
Hey Serge,
Welcome back to the world of DIY amp building! It sounds like you're diving back in with some interesting projects.
Regarding your questions:
It seems like there might be an oversight in the schematic, as you suspected. The presence circuit should ideally be connected to all impedance lugs, not just the 16-ohm one. As for whether it works with 8 or 4 ohms load, it's best to consult with someone more experienced in amp design for specific guidance.
It's strange that the bias pot isn't having any effect on the bias readings, even when fully anticlockwise. It could be a wiring issue or a problem with the pot itself. I'd recommend seeking advice from experienced amp builders who might have encountered similar issues.
As for hosting services for posting pictures, you might want to check out HostNoc. They offer
cheap virtual private server solutions that could suit your needs.
Best of luck with your amp project, and don't worry about your English – you're doing just fine!
Cheers!