My first amp build (18W)

[pickdropper]

I started this half a year ago, but life is busy so it took me a while to chip away at it.  I went with a Mojotone kit for this build, but there's definitely a Hoffman board in my future.  I like the idea of being able to choose all my own parts.

I took a LONG time wiring this one since it was my first.  Twisting up the heater wires was a royal pain.  That was my least favorite part of it, but it came out OK.  Here is a pic with it partially wired.




It's mostly wired here:



Here it's getting tested.  I didn't build a dim bulb tester for this.  I ended up using a Variac to slowly bring it up and check the voltages.




All done.  I decided to call it "Stonehenge" as it looks like a small half stack that's in danger of being crushed by a Dwarf.   






I am going to have to add some sort of power scaling.  It has a great clean tone at lower levels, but I need to really crank it to get it crunchy.  Scaling it down will help when I have it at home.  I've borrowed a Hot Plate from a friend for now, but I think an internal solution would be better.

This thing has just a ton of low end.  With the 75Hz greenback and a sealed cab, there is quite a resonance at the low A (110 Hz).  Opening up the cab should help, but I may have to change to a 55Hz speaker or drop the value of the cathode bypass cap (or put in a switch for different options).

There is also a slight low level hum, so I'll take some chopsticks to the heater wiring at some point (although it won't move much).  It's not a ton of hum.  At normal playing levels, it's about 50dBA directly at the speaker and about 38dBA at the playing position so it isn't audible at all when playing.  Actually, I don't notice it even when I'm not playing, but I notice its absence when I turn the amp off.  It's not terrible, but I'll probably try and optimize it.  I've not built one of these before so I don't have a frame of reference, but I assume it can be improved.

Overall, it was a lot of fun.  I can see myself building a bunch more amps.  Finding a place to put them might be an issue, however.

[sluckey]

Really nice looking amp!    I'd never guess this was your first. Keep it up.

[EL34]

Looks good

[shooter]

 
That is a great build!

there's definitely a Hoffman board in my future

I just did my 1st designed board, kinda fun rolling your own!

again, great build!

[lkrasner]

I took a LONG time wiring this one since it was my first.  Twisting up the heater wires was a royal pain.  That was my least favorite part of it, but it came out OK.  Here is a pic with it partially wired.

Single best trick I ever learned for working with electronics is drill twisting wires. just stick the ends of the wires to be twisted in the chuck of a power drill, hold them taught with your other hand, and pull the trigger. Works perfectly for this kind of thing, and it's so easy!

That is a beautiful build. hard to believe it's a first timer. Nice work!

[pickdropper]

I took a LONG time wiring this one since it was my first.  Twisting up the heater wires was a royal pain.  That was my least favorite part of it, but it came out OK.  Here is a pic with it partially wired.

Single best trick I ever learned for working with electronics is drill twisting wires. just stick the ends of the wires to be twisted in the chuck of a power drill, hold them taught with your other hand, and pull the trigger. Works perfectly for this kind of thing, and it's so easy!

I actually did use a drill to twist the heater wires.  Without it, I never would've been able to get the twist that tight.  The difficult part for me was the interleaving of the wires as they met at each tube stage.  It was uphill sledding the whole way for me, but it did seem to work out OK in the end.

Thanks for all the kind words, guys.  I've built hundreds of pedals over the years, but it was nice to branch out and build an amp.  The only downside is that it takes a lot more space to store amps.  I'll figure out it, though.   

[billcreller]

That's outstanding !! Great attention to detail !

[kagliostro]

Very Cool 

K

[supro66]

I built three so far
it is like eating a potato chip
you can"t eat just one 

[pickdropper]

I built three so far
it is like eating a potato chip
you can"t eat just one 

I suspect this is a very accurate statement.  Already deciding what is next.

[TNblueshawk]

I built three so far
it is like eating a potato chip
you can"t eat just one 

I suspect this is a very accurate statement.  Already deciding what is next.

Dave, if I may....
 
How about this one 
http://home.comcast.net/~seluckey/amps/VAC15/ac15.htm
http://el34world.com/Forum/index.php?topic=16874.0;topicseen
 
I just need the iron (choke on back order) and I'm ready to roll.......
 
Oh, I've got a slight hum on mine but it really doesn't bother me. That or I'm too lazy to pull it so I tell myself it doesn't really bother me.
 
 

[zendragon63]

Wowser, if ANY of my builds looked that spiffy, I would change occupations. You, pickdropper, have the patience of Job. And it shows. The VVR 'scaling' thing works pretty well with the 18 watt--recommended. Regards

dennis

[mresistor]

That's a GREAT looking 18 watt. :-)  Very nice work.   

[MakerDP]

I took a LONG time wiring this one since it was my first.  Twisting up the heater wires was a royal pain.  That was my least favorite part of it, but it came out OK.

No need to twist the heater wires. Just keep them flat and parallel to each other and any other wires crossing at 90-degree angles.

Build looks awesome by the way. 

[supro66]

It took me a year to build my first Supro 6420 and the cabinet
the Supro head and speaker is what I build the original Supro is below
I made the head to fit in the speaker if you want to go combo
The second Green Fender tweed 5e3 is on the floor I built and the other 3rd  Supro is on top