Semi OT: Decent Tube Amp

[Somicide]

Any suggestions on a nice 50-100W Tube amp to build?  Combo or head, either is good, i just wanna tackle a nice big project (and don't worry about voltages, trust me, we just got done with electronics in physics, i saw my teacher get electrocuted a few times; one hand in the back pocket at allllll times...) and this seemed fitting, seeings how we start gigging next month at clubs and bars.

[Alpha579]

have a look round schematic heaven:
//www.schematicheaven.com
See if anything tickles ur fancy...

[Somicide]

I found them earlier, sweet little site.  
Now, can anyone explain to me what the difference between Pre and Power Amps are?  do i need both?  I've only worked with combo amps, so im a little in the dark.  thanks!

[Alpha579]

This is my understanding of it (may not be a very good one, but here goes...)
Preamps boost the voltage alot, and this is where alot of distortion comes into play with the use of master volume controls.
Power amps drive more current to drive the speaker, and the overdrive heard in this stage is generally regarded as desirable, but without an attenuator, you need to crank it up very loud...

[Somicide]

ok, that helps a lot!  thanks, if anyone else wants to throw out bits of info, i'll gobble 'em up like a starved duck!

[Alpha579]

just to add to my last post, both combo amps and heads contain power and pre-amps. And im pretty sure you need both...

[Somicide]

thats what i was thinking
so... theortically, if it was all biased right... I could mix and match Pre and Powers?

not that i intend to, im just asking.  i think i can build soon now.  THANK YOU, I LOVE YOU.  If ever i get famous, the first thing I'll say to the crowd'll be "I owe so much to diystompboxers..."  or something.

[Athin]

yes you CAN mix pre and power amps. All you need is to have a master volume pot in the power amp, so as to get the overall volume just right. Also you might want to look @ the ax84.com page, real nice amps, but no to powerful. The thing is that now I use an amp in an amp thing.    It's a 2-5 W tube amp with a small output trannie [so it sarturates easily] and a 20-100W SS amp which gives you only the power. Works and sounds neat.
now, biasing is what you do to make the power tubes work right. there are a lot of FAQ's about that, so lust look on the net.

[Vincent Volta]

Hey,
the preamp is where the signal is boosted to a level that can easily drive a power amp. Its also where you have the distortion, eq., effects( if any) and gain stages. Next comes the power amp which manages a higher voltage and is capable to drive a speaker and blow your ears.
To understand the diff, pedals are a lot like small preamps. In fact if you were to build a solid state project you could use a pedal circuit as a preamp. Tube amps are more expensive to build, and use transformers and other stuff not present in SS amps. I would suggest you build a transistor amp first, it would be done quicker and will be more reliable as a diy project.
Just remember the golden rule, the preamp goes first and then the pwr amp, last the speaker... see Rod Elliotts page for some insight on transistor amps, and Ampage for tube ones. Good luck!

[gtrmac]

Check out //www.18watt.com

I built an 18 watt Marshall clone and it is a sweet sounding amp. With a 4X12 cabinet you'll sound like Angus Young (who was reputed to use an 18 watter in the studio sometimes).

Anyway, the good thing about this project is that you can get good transformers and a chassis from GDS amps through the website.

Beware of high DC voltage! It's nothing to joke about.

[Somicide]

sorry for my seemingly careless attitude, i wrote all those at about 4 am.  I get hyper and use weird analogies (starved duck?).  So yea, i dont intend to mock DC voltage, i respect electricity to much to be snobbish to it now.