Tube amp schematics 101, etc: NEW NEWER UPDATE: Biasing tutorial!

[Fiddy]

And one more with a labeled PT for us rookies, but of a Blackface champ...  

[atomicmassunit]

Hey guys, new to the board.  I work as an amp tech, so if you need any help with any of this stuff, let me know.

[rugby style]

Another question for the veterans - The schematic for the amp I'm working on specifically lists 1W and 2W resistors near the filter caps, but no wattage is specified in other areas.  Can I assume 1/2 watt where not specified?

On an electronics component site I found the following, relating to replacing older carbon resistors with newer metal oxide versions:

Wattage: Available at 1 Watt and 2 Watt. Replace your 1/2W carbon comp with 1W metal oxide..

So I guess it's not really an exact science, and going larger when in doubt is safe?

[rugby style]

My schematic doesn't, but I found another revision online, which does indeed spec 1/2w unless otherwise noted.  Thanks for your help!

[knathan]

Brad- this is an awesome thread/ tutorial...will come in quite handy when I begin my first attempt

[billaftermath]

I have been trying to figure all of this kind of stuff out. Just finished school for the year, so I am gonna focus on doing this for a bit.

[Keegan]

Is a standby switch just a kill switch for the high voltage from the transformer so that the tubes have time to heat up before any high voltage is applied? I wanted to add one to my Blackheart since I never use the 3w/5w switch.

[misterMagoo]

This thread is awesome!!! It's really helping me with the mods I'm doing to my AC30!

Here is another link that may be very useful:
http://www.freewebs.com/valvewizard/" onclick="window.open(this.href);return false;

[Sanibel]

Thanks for all of this information - it's fantastic!

[RaDana]

I was just curious, if you wanted to lower the wattage of your amp, you would apply Kirchoff's Law (V=I/R), no? Lets say you had a large transformer and wanted to step down--a 50w amp to run at 30w or a 100w to run at 50w--all you would need is a large resistance such as a large (series) of resister(s) following the transformer, yes? I understand voltage as what pushes the current through the circuit, so would this then in effect act as a yoke to prevent the amp from running untethered and destroying itself?

Hope I made my thought-process clear ....

[RaDana]

If it helps anyone else whose a visual learner, I found some videos that look pretty helpful.

http://www.youtube.com/user/glprecycledsound/videos" onclick="window.open(this.href);return false;

Plus when you look at the videos you can find similar videos on the right side bar.