Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: Fresh_Start on March 25, 2008, 09:20:18 am
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Please let me know by PM if any of the links stop working or if other sites should be included. - Chip
Start here first - Hoffman Amplifiers Library of Information
All members need to read the info on the library pages. Many questions can be answered in the library and it's on line 24/7 with no waiting.
This is the forum search S E A R C H
How to trace out a circuit problem (http://www.el34world.com/Forum/index.php?topic=5.0) by Doug Hoffman in the Archives
Tube Amp Debugging Page (http://www.geofex.com/ampdbug/ampdebug.htm) from GeoFEX by R. G. Keen
Forum Info
Also, please look in the ARCHIVES (http://www.el34world.com/Forum/index.php?board=11.0).
FAQs (http://www.el34world.com/Forum/index.php?topic=475.0) from the Archives
Forum thread on Estimating an Amp's Wattage (http://www.el34world.com/Forum/index.php?topic=2291.0)
SCHEMATICS
EL34World Schematic library (http://www.el34world.com/charts/Schematics1.php)
Schematics & Layouts section of this forum (http://www.el34world.com/Forum/index.php?board=12.0) which are editable!
The Fender Amp Field Guide (http://www.ampwares.com/ffg/) includes speaker & cabinet info as well as schematics
Steve Aloha's schematic links (http://www.blueguitar.org/schems.htm)
Prowess Miscellaneous Schematics (http://www.prowessamplifiers.com/schematics/misc/) including Soldano, Harmony, Laney & others
You can fine tons of good info on Marshalls and other amp manufacturers as well at Dr. Tube (http://www.drtube.com/guitamp.htm)
Tube Data Sites
Frank's Tube Data Search (http://www.mif.pg.gda.pl/homepages/frank/vs.html)
Duncan's Tube Search (http://tdsl.duncanamps.com/tubesearch.php)
GENERAL REFERENCES:
How_Vacuum_Tubes_Work.htm (http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm)
Tubes for Dummies (http://www.diystompboxes.com/pedals/tubedummy.html) explains the jargon for basic tube circuits
Basic Electronics Concepts (http://www.facstaff.bucknell.edu/mastascu/eLessonsHTML/TOC_BasicConcepts.html)
Musical Note Frequencies (http://www.vaughns-1-pagers.com/music/musical-note-frequencies.htm)
Exploring Electrical Engineering (http://www.facstaff.bucknell.edu/mastascu/eLessonsHTML/EEIndex.html)
Electronics for Physicists (http://www.angelfire.com/planet/funwithtransistors/Book_Contents.html) (might not be as intimidating as the title suggests... )
Excellent Glossary of Amp terms (http://www.aikenamps.com/AmpTerms.html) from Randall Aiken.
Aiken's Technical Notes (http://www.aikenamps.com/TechInfo_2.htm) are a great reference.
So are Paul Ruby's notes (http://www.paulrubyamps.com/info.html)
There's a great introductory document on the basic theory needed to understand tube amps over on AX84.com: P1 Theory Document (http://www.ax84.com/p1/P1_Theory_Document.zip)
Jack Darr's Electric Guitar Amplifier Handbook (http://www.diyguitarist.com/Misc/J_Darr.htm) is a more indepth theory document.
How To Screw Around With Your Tube Loadline (http://diyparadise.com/tubeloadline/tubeloadlines.html)
The Valve Wizard's site (http://www.freewebs.com/valvewizard/) offers some useful theory discussions
Great source for old books on vacuum tube electronics: Pete Millett's site (http://www.pmillett.com/technical_books_online.htm).
Basic theory:
Radiotron Designer's Handbook (http://www.el34world.com/charts/Books/RDH3.pdf) (3rd edition) - 15+ mb
Radiotron Designer's Handbook (http://www.el34world.com/charts/Books/RDH4.pdf) (4th edition) - 24+ mb
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A "new" general reference (Feb 2010): P1-Extreme Theory Document (http://www.thermionic.info/misc/p1-ex-theory.pdf)
USEFUL REFERENCE BOOKS:
Please check "DVD's/Books" below for references which Doug Hoffman sells
Pentode Press (http://www.pentodepress.com/index.html) for Richard Kuehnel's books on poweramps, preamps, the 5F6-A, tutorials, etc.
Kevin O'Connor's The Ultimate Tone (http://www.londonpower.com/catalog/index.php?cPath=3&osCsid=b33b73267aaf6ec0a16fcab321961be2) series and other books (also available at AES).
OTHER FORUMS:
AX84 (http://www.ax84.com/) an ongoing series of single-ended amp projects with great documentation and support
Please note that you must register first to enter any of the next three forums:
http://www.ppwatt.com (http://www.ppwatt.com) for push-pull amp designs
http://www.sewatt.com/forum (http://www.sewatt.com/forum) for single-ended amp designs,
http://www.18watt.com/ (http://www.18watt.com/) *down temporarily*
AMPAGE forum (http://music-electronics-forum.com/home.php)
For D'Lite info: http://ampgarage.com/forum (http://ampgarage.com/forum)
or the Brown Note D'Lite forum (http://www.brownnote.net/forum/viewforum.php?f=8&sid=97d7817b5a9cf3ddd4dedbf2d98a0220)
How could I forget The Fender Discussion Page (http://www.fenderforum.com/)?
Sacrilege perhaps, but here's a Solid State Guitar Amplifier forum (http://www.ssguitar.com/index.php?PHPSESSID=bb2e544d0de5311e0560ae766299b669;). There's a downloadable book on solid state guitars in the first sticky thread under "Amplifier Discussion" which looks pretty good to this FNG in terms of things solid state.
OTHER MISCELLANEOUS LINKS:
Pentode Press site (http://www.pentodepress.com/index.html) has links to books, etc. plus some neat calculators there too.
Duncan's free software - the Tone Stack Calculator is great. I still haven't figured out how to use the PSU power supply simulator but it's there:
http://www.duncanamps.com/software.html (http://www.duncanamps.com/software.html)
Some good info on TONE STACKS:
http://amps.zugster.net/articles/tone-stacks (http://amps.zugster.net/articles/tone-stacks)
editable schematics of tone stacks courtesy of:
Tubenit (http://www.el34world.com/Forum/index.php?topic=732.0)
Duncan Amps tone stack discussion (http://www.duncanamps.com/technical/tonestack.html)
Here's another wealth of info: http://www.audiophool.cjb.net/Techno.html (http://www.audiophool.cjb.net/Techno.html)
This site has some useful information about how different sections of the typical Fender amp works and how to modify those.
Tone Lizard Odds & Mods (http://www.tone-lizard.com/Mods_and_Odds.htm). Here's his home page as well:
http://www.tone-lizard.com/ (http://www.tone-lizard.com/)
Blue Guitar: articles (http://www.blueguitar.org/articles.htm)
Here's a couple more informative sites from Sluckey:
Viva Analog http://www.lynx.bc.ca/~jc/index.html (http://www.lynx.bc.ca/~jc/index.html)
Navy Electricity and Electronics Training Series
http://www.hnsa.org/doc/neets/mod10.pdf (http://www.hnsa.org/doc/neets/mod10.pdf)
Sluckey's homepage has great info on his builds:
http://home.comcast.net/~seluckey/amps/index.htm (http://home.comcast.net/~seluckey/amps/index.htm)
Here are a few other bookmarks that may be helpful:
http://www.geofex.com/gtramps.htm (http://www.geofex.com/gtramps.htm)
http://www.geofex.com/tubeampfaq/taffram.htm (http://www.geofex.com/tubeampfaq/taffram.htm)
OSCILLOSCOPES:
The (Incomplete) Idiot's Guide to Oscilloscopes (http://www.tone-lizard.com/Oscilloscopes.htm) courtesy of the Tone Lizard
Basic tutorial (http://www.doctronics.co.uk/scope.htm#setting) for setting up and using an oscilloscope. Also Using An Oscilloscope (http://www.doctronics.co.uk/scope.htm)
AMPAGE thread (http://music-electronics-forum.com/t3186/) on oscilloscopes - reply #4 has links to four or five other useful threads.
Last but perhaps not least, some help with
SOLDERING:
Soldering tutorial (http://www.geofex.com/Article_Folders/how_to_solder.htm)
Soldering 101 (http://www.kingbass.com/soldering101.html)
Better Soldering (http://www.astro.umd.edu/~harris/docs/WellerSoldering.pdf) from Weller
NASA soldering standards (http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/613%20Terminals.html)
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CABS: BUILDING, TOLEX, ETC.
Silvatone – an excellent example of cabinet and tolexing
http://www.silvatone.bravepages.com/18%20Watt%20Lite%20II/Build.htm (http://www.silvatone.bravepages.com/18%20Watt%20Lite%20II/Build.htm)
Tutorial on covering a marshal box
http://www.thegearpage.net/board/showthread.php?t=70200 (http://www.thegearpage.net/board/showthread.php?t=70200)
Casey's Tolex Tutorial
http://s238.photobucket.com/albums/ff243/Casey4s/The%20Tolex%20Tutorial-Tolexing%20a%20Cabinet/ (http://s238.photobucket.com/albums/ff243/Casey4s/The%20Tolex%20Tutorial-Tolexing%20a%20Cabinet/)
http://s238.photobucket.com/albums/ff243/Casey4s/The%20Tolex%20Tutorial-Tolexing%20a%20Corner/ (http://s238.photobucket.com/albums/ff243/Casey4s/The%20Tolex%20Tutorial-Tolexing%20a%20Corner/)
http://s238.photobucket.com/albums/ff243/Casey4s/The%20Tolex%20Tutorial-Tolexing%20Curved%20Areas/ (http://s238.photobucket.com/albums/ff243/Casey4s/The%20Tolex%20Tutorial-Tolexing%20Curved%20Areas/)
Soldano building amps
Go-Kustom TV - Soldano Kustom Amplification (http://www.youtube.com/watch?v=Oz1Z16JIaaM#)
CALCULATORS, MEASUREMENTS AND CONVERSION CHARTS
From the nice folks at AX84, here's a really helpful paper entitled Basic Math for Tube Amp Geeks (http://www.rru.com/~meo/math.pdf)
Pentode Press Amplifier Calculators (http://www.ampbooks.com/home/amplifier-calculators/cathode-capacitor/) includes gain by frequency for a preamp stage, "tube specific calculators" which draw load lines for you (appeals to me!), and lots of other interesting tools.
Fraction/Decimal Conversion Chart (http://www.seoconsultants.com/charts/inches-decimal/#conversion)
Doug's capacitor code chart (http://www.el34world.com/charts/Charts.htm)
Capacitor Microfarad/Picofarad/Nanofarad conversion chart (http://www.lonewolfblues.com/techcapconv.html)
Doug's resistor calculators (http://www.el34world.com/charts/resistor/RESISTOR.htm) (4-band and 5-band)
R-C Filter Calculator (http://www.muzique.com/schem/filter.htm)
L-C Tuned Resonant Frequency Calculator (http://www.chemeng.ed.ac.uk/people/jack/radio/software/lc-calc.html)
Frequencies of Musical Notes for Guitar & Piano attached
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Another neat resource including tutorials on soldering, parts selection, etc. Obviously with an effects pedal slant, but lots of useful info:
DIY Stompboxes FAQs (http://www.diystompboxes.com/wiki/index.php?title=DIY_FAQ)
and PLEASE let me know if any of the other links go dead...
Chip
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There is a section in Doug's Library that I didn't find for a while but is very helpful:
Hoffman Board Manufacturing Instructions (http://www.el34world.com/boardmaker/BOARD0.htm)
There is nothing wrong with Gabriel's approach to making a board & mounting the components. This simply shows you Doug's method, plus his schematic/layout drawings make more sense if you walk through the instructions while looking at the drawing.
Chip
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HOW TO BIAS YOUR AMP
This topic comes up so often, I thought it would be helpful to have a collection of links:
Here's a great explanation of How to BIAS your amp (http://www.duncanamps.com/technical/lvbias.html)
Of course, there's also a section in Hoffman's Library (http://www.el34world.com/charts/fenderservice5.htm)
Also, Doug now offers kits to make his bias checker.
Just scroll down to the bottom of this page HERE (http://www.hoffmanamps.com/MyStore/perlshop.cgi?action=template&thispage=Tools&ORDER_ID=169730590).
Link to new assembly instructions is there too.
Hope this helps,
Chip