Home Cooking with Valves – Homemade Tube Pre-Amplifiers

Delicious lamb chops, fresh trout, a piece of good cheese and a glass of wine - how nice that you so easily can enjoy a wide variety of delicacies.
When it comes to your hi-fi system, unfortunately it’s not quite as easy - but it can be real fun.

Like with food you have the choice to visit a restaurant and let yourself be pampered by the chef - or you decide to do some home cooking yourself.

The following pages are all about cooking yourself, to stay within our culinary allegory.

It is not that complicated to prepare tube amplifiers. All the basic recipes have been well known for decades, and most of them are easy to follow. Your starting product is the tube - ideal for enjoying music. You can get tubes in many variations from direct heated triodes with pre-war mesh anodes up to powerful pentodes.

Especially triodes, of course, are very nice and simple. For poweramplifiers - you need high effenciency speakers, though -, but you can use them for preamplifiers as well. Looking at small-signal triodes, there are a lot of them around, stemming from the last 100 years.

You do not have to buy the pale artificial looking chicken from the supermarket - you can buy the real thing. And as far as ingredients and spices go (tantalum and carbon resistors, oilpaper and foil condensers, transformers and plate chokes) you’ll find plenty of delicious variations perfectly complementing your dishes.

Nevertheless, even the best ingredients can easily be spoilt, burnt or otherwise destroyed. Therefore, now some personal advice from an autodidactic amateur chef - tips, experience, and resources...

Our focus is the classical triode circuit. This is the way our grandparents cooked, sound and good. And this is the best way to test different flavors.

I limit myself to the mere basics. Of course you can always read a lot more about in-depth theory and practice.

Yet the basics are necessary to understand everything else. If you know the ropes, you can enjoy to taste all the different variations of vacuum tube amplifiers by your own.
But be careful: Do not touch the hot stove - high voltage!

And even when the oven is switched off, do not put your head in too soon - some of the high voltage capacitors remain charged for quite a long time.