1 Tube 1 Watt Guitar Amp - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Instruments and Amps Everything that makes music, Especially including instrument amps.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 10th June 2011, 05:25 AM   #1
diyAudio Member
Join Date: Jan 2011
Default 1 Tube 1 Watt Guitar Amp

I am interested in building a small 1 tube low power guitar amp, less than a watt is fine. I know there are numerous options, but I wanted to try an ECL82. OTs are easy to find and cheap but power trannies are not.

So here is what I want to try and need some advice. There are interesting options for outputting around 190V, one of which is the NeonNixie High voltage module (have a kit which takes 1/2 watt 12-14V and puts out 22ma @ 190V), which should do the trick. Has anyone used a small split output transformaer such as the MagneTek FS12-1000 (1watt 12.6 2watt 6.3) and build a power curcuit to drive that (or a similar) tube? Maybe another option is running it off a wall wart, but those are not usually too clean.

Once I have the power worked out I will get to the amp specs, but I think this would make for a small footprint practice amp (stomp box size) that would sound reasonable.

  Reply With Quote
Old 10th June 2011, 07:10 AM   #2
Doz is offline Doz  United Kingdom
diyAudio Member
Doz's Avatar
Join Date: Jul 2010
Location: Sat Down
I doubt your nixie-tube supply will put out enough current to drive the output stage.
I built an amplifier with an identical tube, and used two back to back mains transformers to obtain the HT. Not so easy in the USA, because you have 110V mains, but you could get two transformers : 110 to 6V then 6V to 110-0 110-0 (Universal "Primary"). You can then use the 6V winding for your heater, and wire the 110-0 110-0 for 220V and your HT. Done and dusted and change out of 20

I think you are thinking along similar lines with the magnetek transformer.

I used a Hammond "Universal" SE O/P transformer. The thing had to be cheap, and mine was made entirely from junque box parts.
"To err is human.. to make a real balls-up requires a computer"

Last edited by Doz; 10th June 2011 at 07:15 AM.
  Reply With Quote
Old 10th June 2011, 12:19 PM   #3
Cassiel is offline Cassiel  Libya
Account disabled at member's request
Join Date: Sep 2004
Location: Madrid
ECL82 is fine but you need more gain, one triode to drive the pentode won't be enough. Here are some ideas for the power supply:

JJS.at : Electronic Projects : Class A Subminiature Amp

freestompboxes.org • View topic - "Superfly" - submini tube version of Doug H's Firefly
  Reply With Quote
Old 10th June 2011, 12:38 PM   #4
Doz is offline Doz  United Kingdom
diyAudio Member
Doz's Avatar
Join Date: Jul 2010
Location: Sat Down
Originally Posted by Cassiel View Post
ECL82 is fine but you need more gain, one triode to drive the pentode won't be enough.
Very true, although running the first triode in "starvation" helps, and produces some "colourful" distortion
"To err is human.. to make a real balls-up requires a computer"
  Reply With Quote
Old 10th June 2011, 12:42 PM   #5
SY is offline SY  United States
On Hiatus
SY's Avatar
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 2
Have you considered using a three section compactron? I'm putting together a small practice/studio amp using a 6AF11, which has a nice 5W pentode, a high mu triode, and a medium mu triode in the same envelope (thanks to rsumperl who pointed me toward that tube).
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 10th June 2011, 01:44 PM   #6
diyAudio Member
Tom Bavis's Avatar
Join Date: Jun 2002
Location: Macedon NY
The 6AF11 and its equivalents (6BD11, 6AS11) had occurred to me as well - they have 15V versions too, but you'd probably want DC for heaters to avoid hum. A dual-primary 6V / 30+ VA transformer with ISOLATED primaries (not bi-filar wound, like some Signal parts) could be used, with one primary used as 120V secondary. Use a doubler to get 280VDC.
  Reply With Quote
Old 10th June 2011, 07:40 PM   #7
Fuling is offline Fuling  Sweden
diyAudio Member
Join Date: Aug 2001
Location: Sweden (Mora)
I made a just-for-fun guitar amp for my brother in law a few years ago: A single ECC81 mated with a 180V power supply, a tiny 7k:4R OPT and a 4" 8ohm speaker. One ECC81 section is good for 0,3W or so, loud enough for bedroom use. A switchable diode clipper after the gain stage increased the rock `n roll factor quite a bit.
  Reply With Quote
Old 10th June 2011, 08:29 PM   #8
M Gregg is offline M Gregg  England
diyAudio Member
Join Date: Jun 2010
Location: UK
I still find this interesting.

OK its not one tube the use of the EF86 I find interesting.


I have never seen an EF86 in SE mode though!

M. Gregg

Last edited by M Gregg; 10th June 2011 at 08:34 PM.
  Reply With Quote
Old 11th June 2011, 12:41 AM   #9
diyAudio Member
Join Date: Apr 2004
Location: Monroe Township, NJ
What's all the fuss and muss about? An inexpensive Triad N-68X isolation trafo feeding a Greinacher doubler takes care of the B+. A 117Z6 is perfect for this job, as it will provide the "sag" guitar pickers favor.
Eli D.
  Reply With Quote
Old 11th June 2011, 02:10 AM   #10
ChrisA is offline ChrisA  United States
diyAudio Member
Join Date: Jan 2008
You can run a micro-power guitar amp off a wall wwort power cube. The trick is to use an AC power cube. Get one that puts out at least an amp at 12VAC. Then inside the amp you have a 12V filament transformer wire "backwards" THat gives you 120VAC and when you rectify it the filtered DC comes out to maybe 160V. You might also use a 6.3V filament transformer and get a higher B+ voltage. This sytem will only give you single digial milliamps but for a 0.25W amp that is all you need.

One other very good power source for micro-power amps is batteries. It is good to not have to plug in to mains power but then you need a switch mode power supply
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
my 250 watt tube amp can be a 500 watt tube amp for less than 2 bucks plus tubes speakerfritz Tubes / Valves 17 24th October 2013 11:50 PM
Need help for Portable Guitar Amp Class D 5 Watt varisign Class D 1 14th September 2010 12:47 AM
1/2 watt tube guitar amp 9am53 Instruments and Amps 26 17th October 2007 04:20 PM
FS: Custom 18 Watt Tube Guitar Amp EL84s PRNDL Swap Meet 0 14th December 2006 04:19 PM

New To Site? Need Help?

All times are GMT. The time now is 06:27 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2