diytube.com

I finally got my stereo poseidons working well, and it sounds great!

The only issue I am having is that when there is no input and the speakers are hooked up, it hums pretty badly. It was suggested to run a wire from my negative input on the jack to the star ground, but this did not fix the issue. Once there is an input signal, the amp sounds great and is very quiet. Any suggestions as to why it hums like this when there is no input?

Thanks everyone for all the help with this project, and I'll post links to the pics here in a little bit,

Blair

Hi Blair,

Hum is perfectly normal for an amp running with an unterminated input. You can either keep an input connected, or use an RCA plug that has its center conductor shorted to ground to terminate the input.

Congratulations on getting the amp up and working. Feel better now?

Hey Eric,

Thanks for all your help with this project. I ended up needing to go down to a 10H 150ohm choke, and may order another choke with a lower DCR. I'm about 10 volts under across the board. The lower DCR choke allowed the amp to really open up. Sounds more like 60 watts :) I'll post a link to the finished product here in a few minutes. Do these amps like to be driven with preamps? I was listening to it through my line stage and then through my friend's 6SN7 preamp, and it definitely sounds like it has more overhead with the preamp versus the line stage. Anyway, let me download the pics, and I'll post it.

Thanks again,

Blair

Blair,
Congrats on getting the amp done - I cannot wait to see photos !

Thanks Steve,

Check the Poseidon forum, and look at the topic Finally!!

Blair