Tube amp....It's alive....and so am I!

[scott spencer]

Last October I finished my first electric guitar for my 16 year old son.
http://sawmillcreek.org/showthread.php?t=43739&highlight=guitar
We were encouraged enough by the sound that we thought it merited a tube amplifier, but the CFO (LOML) wouldn't "buy" into our enthusiasm . The cheap solution was to build one....a 3 watt, Class A "night light" from mostly salvaged parts. We used the chassis and power transformer from a 1939 Stromberg Carlson radio. This project has me way out of my element, but after several weeks of headscratching, several revisions to the schematic, and several feet of solder up in smoke, she finally glowed and sang to us tonight! Woo Hoo!

Every tube amp website I look at had huge WARNINGS about how the high voltages of these things can kill you if you don't know what you're doing. , so with one hand in my pocket, I poked and prodded and gained some confidence that this thing wasn't pouring juice in the wrong direction. All systems go so far, but there's still much work to be done. The plan is to clean up the layout, then stuff the whole thing in a box from a 1928 American Bosch radio. I'll post some pics once it's presentable.....right now I'm just happy that it works and that no one got fried to a crisp!

[Wes Bischel]

Scott,
The project sounds really cool! Your son will have one outstanding set-up.
Not sure if you are already using one, but a bit of advice I was given early on was to use an isolation transformer for testing and working on my radios. It isn't an excuse to be careless, but it does protect against some mistakes. Naturally this sounds like it's a day late and a dollar short.:rolleyes:
Please post pictures when it's done - inside and out!
Wes

[Tom Pritchard]

Nice going Scott! Your amp was a challenging project for someone with experience, and you got it running on your first try! Way to go! Funny thing about electronics, specially with tube amps, there's no way to put the smoke back in if you fry them!!!:p

Cullen will always treasure this project Scott. What a great gift to give him, and you had fun doing it!! A double win!!:D

[Jim Becker]

Wow...great follow-on project! Tubes really do the right thing with an electric guitar...from totally clean to completely raunchy, especially if you can do both master and post gain volumn controls. My Sundown is set-up that way and it's a wonderful thing!

[Tyler Howell]

Pictures!!!!:confused:
Nothing like some 12AU7s and a couple 6L6s to rock the house:cool: .
I'd be interested in web sites you used too:confused:

[Robert Mickley]

ooooohhhhh 6Lq6's Stack enough of them and you can have the loudest CB radio around err, so I've heard :rolleyes:

Gotta love high voltage toys

[scott spencer]

Thanks for the "plug" gang! There'll definitely be some pics forthcoming gents! I need to gussy her up a bit first...she's not much of a looker at this point! (there's a pic of the Bosch radio box that it's going into below...) Many thanks to Tom Pritchard and Ahmet Becene for answering countless questions. I'd probably have curly hair and Marty Feldman eyes if not for you guys!

The output tube is a fairly rare 6V6G (or so I'm told)....see the pic below. The pre is a 12AX7 that I plucked out of my Mom's intercom, but a 12AU7 is a direct plug in with lower gain...I've got one on hand and will plug it in out of curiosity. I might even add a 2nd gain stage....hhmmm. (getting greedy! :D)

QUESTION FOR YOU GUITAR PLAYERS:
This amp lacks reverb. Danelectro has some effects pedals for < $20...my son has the "Overdrive" and "Distortion" pedals, which he likes....which of their pedals is closest to reverb..."Echo" or "Chorus"? ...and what's a "Flange"?

Here ya go Tyler:
http://www.radiomuseum.org/tubes/tube_6v6g.html
http://ax84.com/
http://www.diyguitaramp.com/tech.html
http://www.drtube.com/
http://amptone.com/
http://schematicheaven.com/
http://www.aikenamps.com/StarGround.html
http://diycustomamps.com/index.htm
http://dobermanamps.com/newshop/index.php?main_page=down_for_maintenance&zenid=1fca6028f5846f2fe38559fa8031766e

http://i6.photobucket.com/albums/y203/hewood/Projects/boschampbox.jpg

[scott spencer]

Wow...great follow-on project! Tubes really do the right thing with an electric guitar...from totally clean to completely raunchy, especially if you can do both master and post gain volumn controls. My Sundown is set-up that way and it's a wonderful thing!

Hi Jim - I started out thinking about just using a volume knob to keep it simple, but quickly added a seperate gain, then eventually added bass, mid, and treble to the mix just to make sure I was thoroughly confused! :rolleyes:

[Al Willits]

Echo would prob be closer to reverb than Chorus imho, keep an eye out in some of the guitar web site forums or Crag's list, lots of them effects are going dirt cheap.
Maybe stop by your local music shop and see if they take trade in's or consignment, they'll prob have a lot of used effects.

A old player I used to know once said, "learn how to play it first kid, then plug it in"....effects are fun, but no replacement for knowing how to play...fwiw

Loks like your having fun...:D

Al...who hope's your nickname doesn't become Sparky....:)

[Dennis Peacock]

Pretty cool Scott and CONGRATS on not getting fried. :p :D Glad to see this go along with the guitar for your son. :cool: :cool:

[Jim Becker]

Hi Jim - I started out thinking about just using a volume knob to keep it simple, but quickly added a seperate gain, then eventually added bass, mid, and treble to the mix just to make sure I was thoroughly confused!
Worth it in the long run...that little amp will be a "studio wonder", providing a great range of sounds and at a volume level respectful of the home. It will be really great for recording, too. Put it in a big cardboard box with a mic, adjust the sound and turn on the recording device of your choice. Small digital multitrack machines have really gotten low in price...or record directly to your computer with some inexpensive multitrack software. Folks like Sweetwatersound.com have a bunch of options in that regard.

[Tyler Howell]

[quote=Al Willits]
A old player I used to know once said, "learn how to play it first kid, then plug it in"....
What Al said.

I do have to say I'm really impressed with this project father and son have completed:cool: . As and old sparky and gizmo builder that's quite an accomplishment, especially with used parts.
2nd on the caution aspect. More than one plate voltage got my attention over the years.:eek:

Thanks for the links.
There's is Fender twin reverb and a tube type Leslie sitting in storage needing a lot of attention;) .

[scott spencer]

Tyler - The funny thing for me is that I cut my teeth on vacuum tubes through exposure to high end audio amps and preamps. The objective in high end audio is to get the circuit as clear as possible over a very wide bandwidth, but with a guitar, the bandwidth is pretty narrow, distortion is a good thing, and heavy distortion is better! The first time we hooked up my son's little Behringer amp, I thought something was seriously wrong :eek: ...I would have had a cow if my audio system ever made that noise!

My closest "tube buddy" in the high end audio world was Kenny Stevens from Convergent Audio Technology who is "Mr. Clean" in that circle. He'd be appalled by my amp, but it really sheds light the stark contrast between the two industries. They really are completely different applications of the same basic technology and I now know that the end products are not very interchangeable in that regard....which of course is a silly question that asked early on. :rolleyes:

I did get zapped a little when turning on the currently unmounted standby switch. Yowser! :eek:

Regarding the father/son aspect...the story's even a little deeper. My father passed away in 2000. He used to tinker with old tube TV's and radio's, and had 3 old wooden table top radio's sitting around my Mom's house that we took home last year (Philco, Strom/Carlson, Bosch). At the time, I had no thoughts of building a guitar amp, but I thought the radio's were cool and that someday I might get some use out of them....little did I know that they'd be resurrected as a an amp for my son's homemade guitar. Dad would be delighted and there's definitely part of him in that amp....so it's a grandfather/father/son project in some regards... More than you prolly wanted to know, but hey...now you know! :D

[Tyler Howell]

I seem to recall a butt kicking Mc. amp pictured in one of your threads. Love that stuff.
I have a couple of 25W McIntosh monos in storage too:o . # escapes me at the moment.
The plan is to put them in a place worthy of their class and style in the new house:cool: :D .
Making sparks and music has been on a back burner since WW and management. No time for the (other) finer things in life.
Congrats again and thanks for the great story.

[Al Willits]

Rick, a "nice" tube amp was one that could sound really clean normally, and dirty when needed, depending to type of music you played, not so sure a dirty only amp would be a good thing unless you played a pretty narrow range of music, but to each their own.. :)

One of the nice things about multiple tube amps was you could wire them to run off different numbers of tubes, my Twin was wired that way and getting distortion out of it was as easy as flipping a switch, and cranking the master volume up.
Yet when in its normally position it played quite sweet.. imho
Lots of ways of wiring a amp, sounds like you have a good start.
Enjoy

I envy the fact your doing all your own stuff, with my amps and guitars 90% of the mods were done by a high school friend, who did that stuff for a living...call me coward.. :D

Al

[Brian Blackburn]

Nice amp Scott !
Be careful of the caps, they are the ones that will kill you.
The 12AU7 pre amp tube sounds kind of 50s rockabilly pushing 6L6s with a Strat. You can almost smell Memphis. I dont like the same combo with Humbuckers, it sounds thin and if you push it just gets thinner instead of brown.
With a little experimentation you will find different sounds even with tubes of the same number. Some brands sound good in the tone controls but not in the preamp. The same goes for output tubes.
Happy Jamming
Brian