tube amp transformers...

[triskadecaepyon]

Is there a certain transformer you have to have for a tube amp?  On the schematics and diagrams it doesn't really show what it is.  Can you use one from a solid state?

[gtrmac]

Tube amps use a high voltage power transformer which is necessary to supply the plate voltage to the tubes. It is a very different situation than a solid state amp. You also need a transformer to match the impedence of the output tubes to the speaker load.

www.18watt.com is a forum dealing with building a Marshall 18 watt tube amp. You can see some schematics there that show the voltages for these circuits. Do a lot of research before you jump into a tube amp project and a kit can be a good idea. I've built two but I am well aware of the safety issues involved in working on high voltage tube circuits.

[triskadecaepyon]

if they only list it as "Tube amp transformer", what should I look for?

[mlabbee]

I'm not trying to be a smart-ass, but if you don't have any idea how to find the right transformer, particularly the power transformer, you probably should not be trying to build one of these yet.  It doesn't take much of a screw-up to make one of these things deadly!

At the very least, you should be starting with a project that gives you all of the information you need, especially information like what size/kind of transformer to use.

That said, there are typically two to three transformers in an amp (some use less, but they are very complicated).  There are one or two power transformers - these convert the power from the wall socket to the power needed to heat the filaments (usually 6.3 or 12.6 volts, at a fairly high current) and the power to plates on the tubes (this is all over the map - from 12 volts to 400 or more and much lower current)  These can be two separate transformers or a single transformer with two secondaries.

The last transformer goes between your power stage (this is audio amplification power, not power power) and your speakers - it gives the tubes a big load while allowing them to drive a small load (the speakers are typically 8 ohm, whereas the primary side of the output transformer can be anywhere from 1k to 25k ohms and up).

Again, you really shouldn't be playing around with these things unless you understand exactly what they are doing and how to set them up.  A good starting point is a book called The Ultimate Tone, which is available at tubesandmore.com - a very useful guide to understanding amps and tube circuits.  Once you have a better understanding of how the amps work, it should be easier for you to figure out what kind of transformer you need for your project.

[mlabbee]

Hey - just found this posted below!  Check it out - good explanation of transformers: http://www.eleinmec.com/article.asp?27

[The Tone God]

I have to add my concerns too. If you are asking these types of questions then I don't think your prepared to build a tube amp...yet. You need to do alot of reading and research for both the safety of yourself and to increase your possible rate of success.

This forum is directed towards effects. Head over to forums like Ampage that are dedicated to tube amps. You'll get a better chance of getting your questions answered in detail.

Andrew

[Mark Hammer]

I'm not trying to be a smart-ass, but if you don't have any idea how to find the right transformer, particularly the power transformer, you probably should not be trying to build one of these yet. It doesn't take much of a screw-up to make one of these things deadly!

Well put.

Where transformers are really only an incidental part of solid state stuff, the assorted transformers required for tube amps are often an integral aspect of why this one sounds this way and another sounds that way.  They are also the generally most expensive part of making a tube amp.

You are best advised to scoot over to the Amp forum at Ampage and ask the question there.  There are some truly talented and well-informed amp folks there, with a vast storehouse of knowledge.  The question will get you some reaosnable replies here, but it will delver untold riches if asked there.  Of course, if the question is about pedals, this is the place to be.

[Regan]

Not to be down on ampage, but I think your way better off going to ax84 and reading up there for awhile, then buy a kit from Chris the main man there. A tube amp is so far away from effects its not funny-doesn't look hard, and it isn't, but there is some safety issues you should know first and you should know basic tube theory first.
Regan

[smashinator]

I asked basically this same question over at //www.ax84.com, only I was asking how to figure out what transformer(s) to use for a Supro.  The answer I got was "check out the datasheets for the tubes, they'll tell you what kind of load the tube is expecting."  

So!  check out the datasheets for the tubes you're using, and that should tell you what kind of load the tube is expecting.  :lol:

Also, like everyone else said, you should probably build a P1 or 18 watter in order to get the hang of tube amp building and learn how to not kill yourself.  You can always rip it apart later for parts, if you discover you don't want it (doesn't sound like that happens real often, though).