DIY Guitar tube amp, diversion #3427

[Z-TARD]

Heres some pics of my latest project, if nothing else just to prove that I do make progress on at least a few of my projects... It's a home built tube amplifier built from plans for the Hi Octane amplifier found on AX84.com. This is my first real electronics project, and amazingly it came out pretty good. It puts out about 5 watts of power, and is still amazingly loud. I was hoping for something a little quieter than this for using in the house. Tube amps never sound so good as when the gain knobs and master volume are CRANKED to "11". I can take this one to about 4 or 5 before it gets too loud for indoors Accordingly, my next build will probably be something in the 1 watt or below range. Anyhoo, pics:

 

 

No tube amp thread is complete without pictures of the heater filaments glowing!

Picture of my current setup, located in the garage of course. The cardboard box just visable in the background is acting as a speaker baffle for a Maddison 12" speaker, and acting badly at that. The final version will have either 2 or 4 12" speakers enclosed in a wooden box. Now all I need to do is go get a bunch of stomp boxes for effects.

[mario_82_ZXT]

That looks great!

 

Even though it is rated at 5 watts, tube amps are generally more efficient (and normally require more efficient speakers), and that's probably why it feels so loud. I love tubes, I fell in love with them listening to a tube radio in Mexico when I was a little kid.

 

I'm currently rebuilding said radio (it's a desk top unit) that was my grandfathers. I also plan on building the following:

 

http://www.s5electronics.com/l16stereo.html

(16 watt tube amp, but modified with everything except the tube sockets and transistors mounted upside down, allowing the tubes to stick out the farthest through the enclosure like your tube amp).

 

It's going to need one of these:

http://www.s5electronics.com/lpre.html

So that I can use my vintage turntables (old directdrive Kenwood and a fully programmable Fischer).

 

And I'm thinking about one of these to complete the package:

http://www.s5electronics.com/ltone.html

 

Their old 8W unit gets amazing reviews, and considering the price of new, and even vintage units, I rather build my own.

 

Now to get the money to do it...

 

Any sound samples?

Mario

[Z-TARD]

No sound samples yet unfortunately. I'm still working on the tone of the amp, replacing various resistors and capacitors to alter the tonal characteristics. I added a small 10k trim pot in place of one of the gain stage resistors that lets me change the distortion from pre amp driven like a lot of newer amps (Soldano, 5150, etc) to more of a power amp driven distortion like older Marshall amps. The overall tone though is still quite heavy in the mid range and upper frequencies, to the point of being almost annoying. I think I may end up swapping the output transformer for a better unit, as I went the cheap route and got a universal model that may not be up to the task of driving several large speakers. I know that the amp is capable of sounding absolutely huge with the right components, but right now it pretty much sounds like a practice amp. When I get to a point where I'm happy with the tone of it, I'll try to get some sound clips posted up.

 

Check this site out for some more amp designs. http://www.ax84.com/?pg=coreprojects

 

It's mostly oriented towards building guitar amps, but under the core projects section on their site there are quite a few pre amp and power amp designs that can be mixed and matched to do pretty much any audio stuff you need. My next amp will probably be based on one of their lower watt power amps combined with a similar pre amp to the Hi Octane I just built. They also have an online forum a lot like this one, but devoted to building amps. Lots of knowlege on that site as well.

 

Mike

[tfreer85]

Very cool stuff guys couple of websites I hadn't been to before. I was (before going back to school) researching a pre-amp and DIY speakers for my house. I've now downscaled and am looking to do a dual input chip amp for computers speakers. lot of reading on diyaudio.com Nice project though Z-tard came out really clean looking

 

Tyson

[Cruez]

I need to send this thread to a buddy of mine.. He is big into guitar stuff. He actually produces the "Hoochee Mama" pedal. (I coat them)

[e_racer1999]

sweet!

 

another guy in san diego that digs guitars and Zs

[Z-TARD]

Getting closer to making it sound he way I want. Found out that the tinny sound came mostly from trying to push 100 watt speakers with a 5 watt amplifier. I hooked it up to a vintage Jensen 12", probably rated for about 15 to 25 watts and the sound quality improved quite a bit. I also upgraded the output transformer to a larger unit designed specifically for single ended amps like this one, which improved the bottom end response even more. the new transformer is easily twice the size of the old unit. It's so bass heavy now that I may have to go back into it and undo some of the mods I did earlier to add bottom end.

 

Overall, it's getting very close to the sound I want, which is somewhere between a cranked Marshall 69 plexi and a Peavey 5150. Once I get some stomp boxes for it (analog delay, chorus, etc.) and get a cabinet built around it I should be ready to do some sound clips. I suppose Youtube is probably the easiest option for hosting video/sound files?

 

Mike