META - Useful Information for Newbie DIYers (and others!)

GroupDIY Audio Forum

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Mark Burnley

Well-known member
Jun 3, 2004
Liverpool UK
META - Useful Information for Newbie DIYers (and others!)

This is a meta-thread, made to allow you to keep track of the posts concerning this single issue - I will continue re-editing this first post.

- All should be contained in this first post - which is re-edited regularily.

- Everyone is welcome to reply with comments and pointers to things they consider relevant. This will be copy/pasted into the first post, if the meta-keeper finds it relevant. (I deeply dislike censorship, but here it seems necessary for the sake of overview)

- On a regular basis, all posts but the first are deleted, and bumped up to the top.

Forum Links:
Why Green Pre rotary switch?- understanding why a rotary switch is used for gain setting rather than a pot.
SSL Servo Files- Dr Frankencopters epic account of modifying an SSL compressor using servo circuits. Forum post has useful description of why you'd use a servo circuit in an audio application.
Oh no.... another newbie!!! : )- some useful tips for a DIY beginner.
PRR's 24vdc supply.... 48v phantom- interesting thread with links for getting +48V from lower supply voltages.
Simple FET Compressor- ideas and links for simple FET compressor.
opamps on +24V PSU, How to...?- explanation and schematic showing voltage-divider biasing for op-amps off a single rail supply.
-20db Pad circuits? Various solutions?- explanation of designing pads, along with links.
Metalwork Tips 'n tricks on that tricky but essential DIY topic.
Newbie Question- DI box is going to be my first project  Great thread for DI ideas including Bo Hansens DI design  :thumb:
Universal Power Supply for your Projects! Nice design from Tekay
The B7 Class-A Discrete Op-Amp tk@halmi's B7 discrete op-amp design- a fine original DIY project from the DOA guy!
Steak Juice Dripped Into My Mackie! Not a Hammer Horror, but some useful (and entertaining!) advice for cleaning contaminated PCB's/equipment.
Mu Metal shielding Useful info and links for shielding your DIY equipment.
Jung Regulator and othet "Fancy" PSU's Improved "Jungian" voltage regulators. Direct link to article of "super regulator" in EDN:
Advice for newbies re: toroidal mains transformers Toroidal Transformer positioning advice from Thermionic.
Mastering Compressor Discussion as to which compressor should be the first DIY project to build- a tough decision  :?
PCB/Schematic Layout Software Discussions about who finds which package best.
PCB Making Kit Questions- some good info on DIY PCB's including exposure lamps etc.
Transformer Z?- Common transformer questions about voltage v. impedance ratios.
Bench Power Supplies- with a link to Ethans Split Variable Bench PSU. Vital DIY kit!
Good Basic Electronics Tutorials- Good step-by-step guide to basic principles. Op-amp section particularly good.
noob with a couple questions- typical intro to The Lab and DIY.
Op Amp Questions- FET Vs BJT when it comes to op-amps.
Questions re: Design of Neve BA283- great overview of the workings of the Neve BA283 circuit.
My first schematic- design of 990-style mic pre with good design insights.
Using a oscilloscope- includes link to PDF oscilloscope guide.
Web info on testing transformers...- some nice info on testing unknown transformers from pucho812.
Resistor wattage differences- So Watts the difference?


External Links:
Gyraf Audio DIY pages- many great DIY projects ready to build.
Rod Elliots Electronic Projects- lots of simple but useful building-block projects for audio use. Including the epic call to arms for all DIYers!!
Tubecad Homepage Lots of interesting tube/valve data and design information.
W. Marshall Leach Jr. Audio Electronics Maybe not entirely a newbie site, but I love it!
D. Self- Designing With Op Amps Designing with op Douglas Selfs inimitable style!
National Semicounductors Free Online Seminars If you've got an hour spare, some of these are well worth investigating, especially the op amp basics.
Ethan Winers Peak Meter Article Interesting article and constuction of peak reading meter.
All About Circuits erm, what more can I say?
Discover Circuits A good collection of schematics and links.
Svetlana How A Vacuum Tube Works The tube people tell you how they work!
Walt Jungs Homepage Great resource of Walt Jung articles. His "Op Amp Cookbook" is a personal favourite for no-nonsense design tips.
Picking Capacitors Fantastic article from Walter G. Jung and Richard Marsh.
Beginners' Guide to Potentiometers Rod Elliotts guidance through all manner of "pot" information.
The Bob Pease Page Excellent practical advice from my (second!) favourite Electronics Guru. His articles make fascinating reading- not always directly electronics related, but immensely thought provoking!
Signal Tracing Could be useful for fault finding? (shameless plug!  :oops: )
How to wire a mains power transformer- Handy chart.
John Klett on Ohms Law- Possibly the most important thing you'll ever learn...
dB Table- in PDF format. Keep one nearby, or get it tattooed!
DIY Mics using electret capsules- surprising quality for the price. Great beginners projects.
Harvey Gerst- "The Big Mic Thread"- a big thread on mics by Harvey Gerst. Good info.
Outboard Mic Preamps- what's the deal? by John Hardy- Console v. outboard mic pre's.
Filter Design In 30 Secs

Designing Gain and Offset in 30 Secs- two of many useful PDFs to download from TI.
Jeff Rowland Tech Papers- plus links to some of the most used Jensen PDFs.
Variable Dual Lab PSU Project- Another from Rod Elliotts great electronics resource.
Analog Devices "Analog Dialogue" e-magazine- An Devs extensive library of tech info.
Analog Tutorial- Rane Powerpoint presentation of Analog Engineering.
Iguana Labs- Beginners Tutorials- Another good set of beginners guides, with how-to-use meters and breadboards etc.
Etching Your Own PCB's PDF- Very good article on DIY PCB's.
Audioxpress "Audio Classroom" series of articles- Classic Norman Crowhurst and  Joseph Marshall articles. As quoted by NYD: "Crowhurst's "Voltage Amplifiers" chapter from that series is essential reading for anyone who wants to design a tube preamp. It's one of the clearest explanations of load lines I've seen." Praise indeed!
Lab Manuals- some PDF an MSWord downloads from a university course- good info on test equipment etc.
Rane Technical Library- Lots of useful PDF and HTML documents covering a range of pro audio/sound engineering topics.
Building Pads- Bring that level down to size. Plug 'n play guides.
Canfords dB Comparison table- Keep it on the bench.
Shure Audio Transformer Introduction- Basic audio transformer primer.
JBL Technical Library- Basic and not-so-basic info from JBL.
JBL Vintage Manual Downloads- the #1 UREI resource. Grab some manuals and examine the classics of yesteryear.


NEW- Online Calculators:
General Formula Calculations- Handy online calc.
V/R/I/P Calculations- All the basic calculations.
dB Calculator- Get to grips with dB conversions.


My Latest Favourites:
AIM-SPICE Simple to use SPICE program- hours of fun!
Altec Lansing Publications Awesome retro-tech information brought to my attention by NYDave. This is an especially handy PDF:
Standard Pads Pad design info and dBm voltages at different impedances etc.
Jack Ormans Lab Notebook Great stuff- dare you take the distortion challenge  :wink:
Standard Handbook of Video and Television Engineering Really great PDF chapters of this book- seemingly for free. Check out some of the articles lower down the page under the heading "New Chapters:Audio/Radio"
Datasheetarchive- Awesome datasheet resource.
The Sound Of Capacitors- Can you hear it? Steve Bench explains...
Valve Museum- You've gotta love this!
tubecollector- Useful info.

Please add anything you want to see here below!



Datasheet Archive (listed above) now allows you 60 searches in 24 hours (it was 50).
I don't know about you, but I've reached that limit, often.
TIP: go to UK Datasheet, and get 50 more!!
It looks like a mirror site.

Just an addition to gyraf's excellent pcb link: Move a brush in circles over the pcb instead of moving the etchant. The physical contact will speedup the process and helps to prohibit overetching... :idea:
Here is a method for avoiding fuse blowing when testing a faulty piece of gear

Right. This is an old guitar-amp fault test. Have you got a domestic lamp holder and a 15W light bulb? What you do is take the lamp holder and connect two pieces of wire to the screw terminals, as if you were going to make a lamp pendant. Connect one wire from the bulb to the Live terminal of the IEC connector and take the other wire coming from the bulb to the Live input terminal of the transformer. This way, the bulb is placed in series with the Live supply.

Then connect the Neutral wire as usual. Wire the primaries as before, and leave the secondaries disconnected but safe/insulated.

Okay, the theory behind this is that the bulb acts as a "variable load". It takes quite a bit of current to fully light a bulb compared to a transformer primary with an unloaded output. If there is a problem with the transformer- shorted primary winding, shorted secondary winding etc etc, when connected to the mains a larger-than-normal current will flow, thus blowing the fuse. With the bulb in series with the primary, the fuse doesn't blow (as long as the fuse is rated to run the bulb okay- 15W bulb @ 115V is just over 100mA) because the current passing through the transformer primary is enough to light the bulb, and the current is dissipated as heat/light in the bulb.

This can be a useful test with guitar amps which "keep popping fuses" because it allows you to see exactly how bad the "inrush current" is. If the bulb is glowing at full brightness, as if it's plugged directly into the mains, it means that there is a helluva short causing a large current to flow. If the bulb glows dimly, then the current flowing isn't so bad. If the bulb doesn't glow at all/is very dim then perhaps things are okay.

This may help check whether the fault lies within the transformer, or maybe a fuse fault. You may have "superfast" acting fuses, or some odd type that don't like your particular transformer at power-up! This is a cheap test before you shell out the loot for a new transformer.

If you are at all unsure what you're doing with this, don't do it. If you do, make sure all your connections are safe and well insulated. Keep the bulb and holder supported off the surface too.

Walt Jungs Homepage Great resource of Walt Jung articles. His "Op Amp Cookbook" is a personal favourite for no-nonsense design tips.

Notice that Walt Jung has moved. -> The link is also changed.

Delete this post when the moderator has corrected the URL. :grin:

BTW: I have started a link collection with a good link software. Your are free to add.
Standard EIA Decade Resistor Values Table

E3 50% tolerance (no longer used),
E6 20% tolerance (now seldom used),
E12 10% tolerance,
E24 5% tolerance (and usually 2% tolerance),
E48 2% tolerance (also for inventory cost control in place of E96),
E96 1% tolerance,
E192 0.5, 0.25, 0.1% and higher tolerances.
Here's some stuff on front panel making...

sonicmook56 worked hard on this one, thanks!
Some tips on engraving:
My favorite:
Picked up this book used and it's blown me away at the simple explanations of stuff we talk about all the time. It even has some of past and preset lab members names in it under articles I believe..


Signal tracing link above @ is dead.

Now hosted at Kev's DIY Factory: