Australian Valve Amps
A growing collection of circuits, pictures, data, history, observations, oddities, tips, tricks, traps, and links; concentrating on Australian and New Zealand valve amplifiers for band use, guitar, bass, accordion, harp, keys, and PA.
From the Great to the Ghastly,
from the Gory to the Gold.
* * * http://ozvalveamps.org * * *Estd. July 2004 | Last site update: 2017/08/04
Note: this site does not cover valve Hi-Fi amps except incidentally,
nor physics-free speaker cables, kozmic capacitors, or the like.
Marketeers take note: Nor does it sell or advertise anything.
Read the Disclaimer at least once.
Plain hand-coded HTML, no cookies, popups, frames, or Java.
Photos have Rollovers, as do Links (stop cursor over to see).
Time: EAST/Zulu/CUT+10hrs Dateform: d/m/y (and yymmdd)
Found an old amp?
Don't plug it in!
Read Caps first, then Mains.
RIP Roly Roper, 1949-2016
Friends of ozvalveamps.org
Sadly, Roly Roper, creator of this wonderful repository of wisdom has 'shuffled off this mortal coil' early on Saturday morning, 20/02/2016, peacefully with his faithful companion Bev at his side. He had been diagnosed with lung cancer last year, it had spread, and he had a bad reaction to a hopeful new drug.
He has been an inspiration to me since my twenties (I'm 65), and has probably distilled more of his character and knowledge into a website than anyone. If we collectively contribute to it to keep it current, it is probably as close to 'living forever' as we dare hope.
There will be no funeral, and in a month or so a wake will be arranged. It would be a good opportunity for a few GearHeads to get together, even better if a 'show&tell' of some AVA100* 'Lamington' builds, or other projects inspired by ozvalveamps.org could happen.
Please see the AGGH forum thread for original announcement and for discussions.
27/07/2015 - Maintenance of AVA has been transferred to Stephen Bruce, as Roly's health prevents him from continuing. Over the next few months I will be applying the pending updates. Please be patient. Only this index page and the submission details have been updated so far.
All previous News Briefs are in the archive.
“The music business is a cruel and shallow money trench, a long plastic hallway where thieves and pimps run free, and good men die like dogs. There's also a negative side.” - Hunter S. Thompson
Introduction, Conventions - how these pages came about; and unit conventions used.
Valve amplifiers operate at high voltages that can kill or seriously injure.
If you are at all unsure of your skills please seek skilled assistance, or leave it to a competent technician.
A list of valve amp tech's
AC v DC electric shocks - body effects.
Professional valve tweeking.
|New Amp Material:|
|2017||Valve Techs, Moody,|
|2016||Links, Vadis, Valve Techs,|
|Archive||New articles Top or press your “Home” key|
Broadly the amps here represent three eras;
- the early era, pre-war to the 50's, typified by a small, cubic, single-speaker unit, such as the Amplivox to the Maton AM-3,
- the middle era of the 60's typified by Goldentone and Fender Twin look-alike combos, and lastly,
- the monolithic era of the 70's typified by towering Strauss and Trent stacks and brutal heads.
Even some of the more significant imported, and early solid state era amps are included.
Generally the models are arranged under each brandname from most to least powerful, then within that, less featured to more featured... generally. It's a bit arbitary. The latest contributions are (mostly) placed at the top of each section.
Look out for our mystery amps and see if you can add any information.
(p = picture, c = circuit, )
For more complete valve data sources please see Links page.
If your amp should be in this archive please see How to Submit.
Build your own valve guitar amp and save heaps.
- Modular mix-n-match designs,
- newbie friendly to advanced,
- co-operatively user-builder developed.
A design for a DIY valve guitar amp that is cheap and easy to build using available parts, and is expandable with a full range of popular options, for gigging and recording.
A picture gallery of valve amplifiers in use.
Well, that was the original idea, but instead it has grown into a collection of musical berzurkitude of the strange, weird, and wonderful ... but mostly just weird.
“A rock show is just like cooking in a busy kitchen - hot, loud, smells funny . . .
. . . you always get burned, and someone invariably complains” - Dan Kelly
Essays, discussions, considerations, opinionated raves...
|August 2015||Let's anticpate lots of ...|
Software reviews of FTP Commander and LT-Spice IV,
Speaker Cabinets including the Fane cabinet book,
Studio multi-headphone amp repair,
Pioneer/MiTAC 6120 Notebook recovery,
Resistor values - why?, Output stage overdrive “choking” - a consideration
|Nov 2010||Hum induction mechanism within valves by Tim Robbins|
|Jan 2010||Farfisa (revisited - reproducing a missing power supply)|
|Dec 2009||Microphonics in valves, Pot tapers|
Solid-State Amp Repair - how to
“Electric Guitar Amplifier Handbook” 1965-73 by Jack Darr
|Archive||Up to New Amp Listings Top or press your “Home” key|
Why valves and not later technologies?
Not infatuated, just pragmatic.
The stages of a typical valve guitar amplifier, from input to output. (large page, 26 circuits, 5 photos)
A walk-through tour of common period guitar amp practice.
Bringing the mains into the amplifier. No need to die for your art.
Heaters, wiring, and hum. Bright and quiet is good.
Internal signal grounding arrangements. Many amps can be noise-improved.
Pots or “volume controls”. Some characteristics.
Tonestacks, how they work, and some popular ones considered. Endless tinkering fun.
Stability problems in valve guitar amplifiers. Symptoms and what they mean.
Standby switching, why, and what's the best way? Some cherished guitarists myth exploded.
How to build stomp switches that are tough, neat, and road-worthy. A good first project.
Some reverb lines compared electrically. Operation in detail. Put the “boing” back in your amp.
Reverbs, tremolos, and other add-in's. Fit missing features.
Tremolo LFO filter for speaker “pumping” on older amps. A simple and effective solution.
Pickups - magnetic and piezo, as a signal source. The character of your amp signal source.
Variable Damping, current feedback, and “Damping Factor”. Sort the gems from the hype.
Applying 100-volt PA line transformers as valve output transformers, including examples.
New build or repair, this is the answer to a prayer.
Output stage “choking” under overdrive. Cause and possible solutions.
Data on larger transformers from A&R Sonar and Ferguson, power and output.
Some popular period tranny info.
Mains filters, theory, construction. Reduce “noises off” in performance and recording.
Decoding factory and date codes on old valves. Find where and when was it made.
Valve abuse, some failure modes illustrated.
Voltage regulator tubes data, applications, and some other gas tubes. These still turn up.Cabinets - speaker enclosures, including the Fane cabinet book. 18/4/12
Resistors - why the strange values? Colours; and how they relate to your fretboard.
Hum mechanisms within valves - Tim Robbins investigates the causes.
Mixing and modulation theory - tremolo, vibrato, ring mixers, Leslie's.
Formants - how do all those frequencies go down one wire?
Not really tone but sonics, beer, cabinets, drivers, output stages. And sheep.
Do you break out in a cold sweat if somebody mentions maths? A phrasebook for tourists.
Vibrators in old battery operated gear. ID, operation, repair.
Generators and DIY stage power. Shows in the Bush.
Tape-loop echo units. Keeping them going.
Scope soldering irons, and some soldering and desoldering tips.
Valve-based test equipment - VTVM's, Oscillators, and CRO's
History and some really old valves (slow page, lotsa big pix).
What I really think of “High Fidelity”.
Silicon Chip 12AX7 preamp - why, and who for? Failed to exceed my already low expectations.
Plugpacks/wallwarts for musicians. Selection, and repair tips - FAQ.
A/B/C/D Switch/Fx selector - more than just an A/B box. A couple of design ideas for tinkerers.
Found an old amp? Don't just plug it in! Read this first.
How to fix (almost) anything.
Faultfinding in valve amps.
Solid-State Amp Repair - output stage arrangements and repair techniques.
Electrolytic caps - How to bring up an old amp without fireworks.
Microphonics in valves. Some causes and cures.
Transformer Testing - Basic testing of power and output transformers.
Overheating transformer - fault diagnosis.
6DQ6 substitution in Goldies, Playmasters, Matons, etc.
“Electric Guitar Amplifier Handbook” 1965-73 by Jack Darr
XLR cable capers.
Gibson G-70 combo resurrection (S.S.).
Roland Cube-40 investigation (S.S.).
Farfisa Transicord Deluxe electronic piano accordion.
Power supplies for Transicord, Deluxe, and Compact.
Leem Pro 4-Channel mixer.
E-Mu Proteus/1 rack-mounting flagstone.
Roland D-50 Synth common socket fault.
The Superboard - the shortcomings of instruments. Calibration and standards.
MiTAC 6120 Notebook recovery. Blow by blow with Windows.
Soft toy repair - put the cackle back in your Kooka.
Sony TA-1010 stereo amp (S.S.) - repair and mod.
Electric fence energiser repair.
Small but useful construction projects.
Circuit collecton - a random collection of circuits for non-ANZ amps and stomps that the ANZ service tech might encounter, with comments. Many of the stomps are buildable.
Don't forget to connect the speaker before switching on!
Posters and other ways to promote your band.
(what the Melbourne Hot-Rod Show 2006 organisers should have read before putting the dates and prices on their web site. ;)
Related chords for all major and minor keys; working out songs.
Transposing instruments, or why the brass is in “B-flat”.
Some of those moments when things go wrong on stage.
More moments when things go wrong (2).
More wrong (3) - greyplanet reviews the motherf**king death set.
New Years Eve 2001.
Electro-Quackery “Looks great, but whatsit do?”
The Worlds Biggest Guitar Amp
Sony BMG virused their music CD's? Yep. Read all about it on my omnibus blog. (Now archived on the WayBack Machine.)
Review of the Countdown Spectacular at the Rod Laver Arena 9/9/06.
“I hate to advocate drugs, alcohol, violence, or insanity to anyone,
but they've always worked for me”. Hunter S. Thompson
Bibliography - a list of books that people have found useful when working with valves.
Table of frequencies for musical notes.
Project numbering systems used by Australian electronics magazines. EA, SC, ETI, AEM, HE
A glossary of PA, lighting and stage terms.
ZIP files FAQ - The what, why and how of using ZIP files.
Software reviews - for electronics workshop and website, mostly free.
Can't find it here? Selected links to valve data, circuits, circuit theory, and related material; with reviews.
Spread the word about AVA with this small poster you can print out for your favorite music shop or musicians hangout, cafe, laundrette, web shop, etc.
Put one on your fridge door for your mates.
ANZAmps Yahoo! group (requires simple free registration).
A single thread mainly frequented by amp techs and builders, and technically-inclined musicians.
Aussie Guitar Gear Heads forum (requires simple free registration).
Multiple threads on general equipment matters of interest to the serious guitarist.
Solid State Guitar Amp Forum (requires simple free registration).
Multiple threads primarily concerned with solid-state amplifers but also covers valve/tube and hybrid amps, mainly of American or British origin.
Vale - the halt, the sick, and the lame, and obituaries.
The Fine Print:
While every care is taken to keep this compilation as accurate as possible, by its nature the information is presented “as-is” without warranty of any sort. It is intended only to provide assistance to those struggling with repairing an amplifier who have no other information. You should keep in mind that any information here may be wrong or misleading. Corrections are most welcome.
I hate pop-ups, spam, marketing calls, junk mail, door knocking, trojan mailing list or address-book hacking or mis-use - AVA doesn't have a mailing list.
E-mails received may be quoted or used on this site and may be edited.
All contributions will be credited to the e-mail name unless otherwise requested.
Contributor e-mail addresses will not be published except by specific request.
Specific requests for information I can't directly supply may be forwarded with your e-mail address for direct reply to, an editor, contributor, or ANZamp forum.
I love to get your e-mails, but I am a technician, not a trader.
I do not buy or sell amps or parts nor provide valuations.
Established July 2004
Site URL (2010- ) - http://www.ozvalveamps.org/ - thanks to Andrew Krespanis
Mirror URL -
Whole site Copyright © 2004 - 2013 R.Roper.