Attached you will find the power section of the HA3500 bass amp with the Fet powerstage.
Not so great, but it will do.
After some trouble to get it back to work it sounds very powerfull and clean.
Allthough, the heatsink becomes a bit to hot to my liking after 10 minutes of playing.
I do not have much experience with fet power stages and I wonder what the iddle current should, must be.
Adjusting the trimmer VR470 dosn't do much.
Any hints, very much appreciated.
Not so great, but it will do.
After some trouble to get it back to work it sounds very powerfull and clean.
Allthough, the heatsink becomes a bit to hot to my liking after 10 minutes of playing.
I do not have much experience with fet power stages and I wonder what the iddle current should, must be.
Adjusting the trimmer VR470 dosn't do much.
Any hints, very much appreciated.
Attachments
I design my own amps so no bias current setup for it.
Turn bias right down.
I connect to a speaker.
Apply a small sine wave and monitor output on a scope.
Turn amp on.
Turn bias pot slowly until crossover distortion goes.
While not perfect works fine for me and creates minimal heat.
Turn bias right down.
I connect to a speaker.
Apply a small sine wave and monitor output on a scope.
Turn amp on.
Turn bias pot slowly until crossover distortion goes.
While not perfect works fine for me and creates minimal heat.
Hello Mark, Fet's are IRFP 9240 and IRF 9240.
Hi Nigel, I have to do it. It's on the shelf right now. Will check it again probably at the end of the week.
Thanks for the "push" to keep on going.
It gave me a lot of problems initially and now it's the hot heatsink.
Sound is ok and with a lot of punch.
Thanks both of you.
Hi Nigel, I have to do it. It's on the shelf right now. Will check it again probably at the end of the week.
Thanks for the "push" to keep on going.
It gave me a lot of problems initially and now it's the hot heatsink.
Sound is ok and with a lot of punch.
Thanks both of you.