Building a DIY Tube Preamp

[MattAnonymous]

I have a Peavey Deuce 120 Watt amp with 4 6L6 Power tubes, but a SS preamp.  I want to build my own tubed preamp.  How are preamps rated (in watts?)?  What size should I use?  The link below is to one off of geofex.com.  Can I use this one? http://www.geofex.com/FX_images/alembpre.gif

Also, how do I read the pins on a tube?

[Aharon]

(Make sure you know what you are doing before you attempt any tube project and are familiar with the safety precautions and dangers involved,if any doubts exist DO NOT ATTEMPT).
Most tube sockets are numbered and you can download a datasheet for the tube fron Duncan Amps or other sites.
The tubes only go into the socket one way so there's no room for mistakes that way.
Some ceramic sockets have no numbers but if you are looking at the tube or socket's bottom with the key towards you the numbers are 1 to 7/8/9 etc in a clockwise fashion.
Aharon

[Peter Snowberg]

Preamps are generally rated in terms of the number of dB of gain they provide and the input & output impedances they possess. Every 6dB means the signal strength is doubled. If you have an amp with 12dB of gain, that means the signal strength is doubled and then doubled again so the final strength is 4 times the input strength. 20dB is pretty common for guitar use (at least the ability to dial in 20dB is).

That Alembic preamp is really just the first two stages of a Fender amp. That's a VERY good one to use .  Read up on the dangers of high voltage if you haven't already worked with it, and be careful. I almost got killed by not giving a Fender amp my full and undivided attention while I worked on it as it was running.

To get lots of great tube info (including pinouts).... download the TDSL Personal Edition from http://www.duncanamps.com/software.html and while you're there also get the PSU designer and the Tone Stack Calculator. All are WONDERFUL! If you ever need backup software, Duncan is the first place to go too.

Watch out with tube pin-outs. It's best to look at the internal connections through the glass and get familiar with what they are on the schematics to imprint this stuff on your brain. The pinouts in TDSL are as viewed from the bottom of the tube. They go clockwise from the index (either a tab or a missing pin).

Finally... A great resource for amp building is http://www.ax84.com. This of it as the amp incarnation of this forum.

Have fun and welcome to tubedom!
-Peter

[DaveTV]

I've found a lot of good information and schematics on this site:

http://www.dogstar.dantimax.dk/tubestuf/index.htm

The designs are very straightforward and Fred does a nice job explaining what each part does, including basic tube theory. I learned quite a lot about general amp design from his Real McTube section.

[toneman]

Hey, U might try--
//www.paia.com
the folks @ PAiA have been producing tube
preamp kits 4 many many years.
i've been re-moding my StackInABox(SIAB).
Additionally, there's the TubeMicPreamp & the TubeHead.
i've added a compressor and headphone amp 2 the SIAB.
allows *loud* headphone practicing.
the "speaker sims" aren't that hot.
U can just get the manual and pcb also.
easy way 2 start your tubes!!
staytubed!
tone

[bobbletrox]

Ruby Tuby Preamp