How to supply amp with power?

[walkerjhart]

Hello,

I’m building my first tube amp and I need some help. The schematic (I will upload it), says that the circuit requires a 300v “B+” power supply. As you can see from the image it implements two 12AX7 tubes. I’m fairly new to building circuits, and I’ve only really worked with the 9v batteries in the kits I’ve built-300v seems like a ton compared to that. I have no idea how to attain this voltage level (with a transformer?), and I would be incredibly thankful if you guys helped me out, because I’ve already put about $100 into building this thing. Preferably this would be something that I could buy rather than build, but any help would be greatly appreciated. Also, feel free to recommend another voltage for the power source if you think that 300v is too little or too much (etc…)

Thanks very much in advance guys.

[attachment=104]12ax7_schematics.gif[/attachment]

[Robin]

You are building a preamp? 300Vdc is typical in a tube amp and yes, that would be the B+ (high voltage) tap from a power transformer. But you will also need some form of rectifier (tube or solid state) and a heater (filament) circuit (6.3v)to make the tubes work. And if you intend to build a complete amp, you’ll need a power section.
Check out: http://www.valvewizard.co.uk/
There is info there that addresses all these topics. Also, Dave Hunter’s book “The Guitar Amp Handbook” explains how a tube amp works in very user friendly terms. Study the Two Stroke schematic found in the Wiki section of the TAN site. It is a very basic tube amp design that illustrates the various parts of a tube amp and how they connect to each other.

[walkerjhart]

Thanks for the help-will check those links out.

[Andy]

I second Robins recommendations. If you check out our Books page, there are some great resources Dave Hunters book is great for starters and has a fantastic starter amp build detailed. If you are set on building your own circuit, I’d start with Marantz’s book. The Merlin Blencowe books are also awesome, but they are separated into one for we’re and one for preamps.

http://www.amazon.com/dp/0615291805?tag=oliandott-20&camp=213381&creative=390973&linkCode=as4&creativeASIN=0615291805&adid=10Q7FKJHP124ZG94G4W1&&ref-refURL=http%3A%2F%2Fwww.tubeampnetwork.com%2Ftan-recommends

The circuit you posted has some interesting choices that we don’t usually see in a preamp. Typically we see two 12AX7s in series, like you have. But a cathode follower on the second stage is a bit odd. For a guitar amp.

What kind of application are you building for?

What

[Andy]

I second Robins recommendations. If you check out our Books page, there are some great resources Dave Hunters book is great for starters and has a fantastic starter amp build detailed. If you are set on building your own circuit, I’d start with Marantz’s book. The Merlin Blencowe books are also awesome, but they are separated into one for we’re and one for preamps.

http://www.amazon.com/dp/0615291805?tag=oliandott-20&camp=213381&creative=390973&linkCode=as4&creativeASIN=0615291805&adid=10Q7FKJHP124ZG94G4W1&&ref-refURL=http%3A%2F%2Fwww.tubeampnetwork.com%2Ftan-recommends

The circuit you posted has some interesting choices that we don’t usually see in a preamp. Typically we see two 12AX7s in series, like you have. But a cathode follower on the second stage is a bit odd. For a guitar amp.

What kind of application are you building for?

What

[Author]

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