Schematics and layout drawings.

[Willabe]

Guys posting a layout drawing DOES NOT replace posting a schematic of the amp or circuit.

If you want help, you really need to post a schematic, not just a layout drawing. Most times we don't need the layout drawing. Posting the schematic helps us help you. It's faster for us. If you want us to spend time helping you, you need to spend some time making it easier for us.

Looking at the schematic you can see the circuits flow from start to finish. The larger the amp, the harder and longer it takes to figure out what it is by trying to read the layout drawing.

And you analyze a circuit by looking at, studying the schematic, not by looking at the layout drawing. Layouts are for finding the parts in the chassis. Saves a repair person time when the chassis is on the bench. 

Most guitar/instrument amp companies never even released a layout drawing, they all released a schematic. That should tell you something. Fender is 1 of the few that also released a layout drawing. It's probably because Leo Fender was a radio repair man before he founded the Fender company.

If you don't have 1, you need to draw 1 yourself. It's easier to draw up a schematic, then it is to draw a layout. And if you don't know how, you need to learn, it's not that hard. I've seen guys draw a schematic on a napkin in a restaurant. 

And if you can't read a schematic, you really need to learn how to read a schematic. You can't be working with tube amps, either repairs or new builds without this simple learned skill.     

[Willabe]

ExpressPCB/ExpressSch

https://www.expresspcb.com/pcb-cad-software/

JSchem is 1 of many free schematic cad drawing tools on line.
Many guys have used this for years here.

PCB download link;

https://el34world.com/Forum/index.php?topic=590.0

And here's the down load link for Mac.

https://el34world.com/Forum/index.php?topic=22402.0

Edit; Added link at the top for ExpressPCB/ExpressSch

[bmccowan]

This is all great advice IMO.
ExpressSCH uses the same file structure and works pretty much the same. Doug also has links to it. I have used both and do not remember why I settled on ExpressSCH - something about exporting files maybe?
If starting with only a layout, I have to imagine the schematic in order to figure out what is going on. But I get lost. So I need to back the layout into a schematic. That is bassackwards as Willabe says.
If you want to learn to draw schematics in either of the two programs, a trick I used was to open up one of the existing schematics and start manipulating it. You will quickly learn how everything works. And you'll learn how to start from a similar schematic and "edit" it into your intended design. Doug offers up a lot of good advice on using the tools and has a library of symbols.

[shooter]

if you can't read a schematic, you really need to learn how to read a schematic.

yep, this is STEP 1.


I've been reading schematics since I was 14.  The schematics for my career typically were 6 volumes (books) covering 2 foot of bookshelf space per system.
when I landed here, I started with "A" in the schematics section and reviewed most every schematic Doug has on file.
then I had a good understanding of "design" in tube amps for guitars.


sadly we as a human race have relegated "reading" to the 'ol ways, we've advanced to cave-man drawings for learning n understanding the world around us

[rake]

Schematics give a logical flow of the signal path.
Layouts without schematics just gives everyone a headache!

[acheld]

You can hear the soul of an amp just by looking at the schematic.

I see sawdust and smell wood chips when I look at a layout.

Would rather hear it than see or smell it!

Uhh, aren't we preaching to the choir?

[Willabe]

Uhh, aren't we preaching to the choir?

No, they keep posting layouts in stead of a schematic for the amp. 

[bmccowan]

Willabe is recruiting new members for the choir.

[rake]

Willabe is recruiting new members for the choir.

I'm a tenor! 

[shooter]

my music teacher said she could see I had passion for music, but God didn't want her to lie to a 12 year old, so she suggested ANY career OTHER than music 
That's why I was reading schematics by 14 

[rake]

Somebody gotta play drums! 

[bmccowan]

my music teacher said she could see I had passion for music, but God didn't want her to lie to a 12 year old, so she suggested ANY career OTHER than music 
That's why I was reading schematics by 14 

HA! Similar here. "that's enough" was my music teacher's request. So I learned to install solar systems. And building/rebuilding amps gives me a great excuse to avoid practicing guitar.

[Joel]

Let me begin by stating that I'm no expert.  I've retained some level of expertise only because I have an interest in "old fashioned stuff" to quote a friend of mine.

I get the frustration from the experienced old hands, but let's take a step back.  As much as I hate to admit it, it's not the good old days anymore.  Modern teaching methods differ from the old ways.  Newer technology has pushed many old techniques to the side.  In the western world almost everything is repair-by-replacement.  Encapsulated circuits and disposable electronics rule.  Component level repairs are rare.  Hell, discrete componentry is rare!  I'm an old guy in a new persons Air Force (Royal Australian), and it's confronting knowing the new people coming through have no idea how to read a schematic, couldn't draw a logic table for an AND gate, or even identify common schematic symbology.  It's a different world.

And let's not forget, schematics are quite an abstraction.  It's a real skill being able to read a schematic and relate it to the real-world implementation.  Not everyone is wired that way.  My eldest daughter recently graduated university.  She double majored in Languages and Linguistics, and Korean.  Now, I can't even hear the fine details of pronunciation in most Asian languages, let alone reproduce them much to her amusement.  Likewise, she can't grasp the fine details of 4-wire vs 2-wire resistance measurements (like most of our new era technicians unfortunately).

There is one thing this aging dog has learned, tolerance and patience eventually win the day.  Even though it's difficult after the literal hundredth time!!!  The newbies to any craft need and crave mentorship.  It's a complicated world, and the only way to cut through the noise is tolerance and patience. 

[acheld]

The newbies to any craft need and crave mentorship.  It's a complicated world, and the only way to cut through the noise is tolerance and patience.

I happen to agree with most of what you're saying.  It really is a different world than when I was coming up!   

Lots of help on this forum is given to folks who are using (only) layouts.  And yes, it takes more work for us to do so. (I say us, but in reality I myself don't really have the patience for layout discussions.)  And most of the time no one is complaining too much.

But sometimes, the OP veers into circuit discussion that can't be reasonably had without a schematic.   It is the language of circuits! 

There is one thing this aging dog has learned, tolerance and patience eventually win the day.

Yep.  And part of that is patiently guiding the newbies toward reading and using schematics when it is required.

[mresistor]

A schematic is a roadmap.  A layout is how to fit it into a container.

[shooter]

It's a different world.

because

Modern teaching methods

no longer "teach"

I was in the advanced technology field for 32 years, working, close to 8 years "learning(tech schools, specialty classes, etal)" over that 32 years

probably had a dozen "next-gen" take interest and fall by the wayside before they made it through ohms law.
"students" are no longer learning for knowledge and understanding, they have the "gazing glass" for that, they learn "processes" to accomplish tasks.

I always wondered how civilization could go from the amazing to the dark-ages in 500 years, I'm now watching a sped up version unfold in real time.

[Willabe]

@ Joel, your not helping.

Nothing you wrote justifies not posting a schematic, not just a layout drawing.

Their being lazy and your giving them excuses to do that. They want without doing the work to get. 

[Willabe]

I happen to agree with most of what you're saying.  It really is a different world than when I was coming up!   

So what, doesn't matter what so ever about needing to post a schematic not just a layout drawing when asking for help.

Lots of help on this forum is given to folks who are using (only) layouts.  And yes, it takes more work for us to do so. (I say us, but in reality I myself don't really have the patience for layout discussions.)

I've been here ~15 years and have read almost every post since then. Never was that way, it's slowly changed over the years, posting a layout instead of a schematic.

And you say "I say us, but in reality I myself don't really have the patience for layout discussions." 

So don't defend the people who are posting just a layout drawing instead of a schematic. 

Their being lazy and your giving them reasons to do so.

It's not our job, no one gets paid here, to spend extra time trying to figure out their problem from their layout drawing.

They need to do their own work. They want help with the least amount of work on their part. But it's their problem. The least they can do is make it easier for us to help them.

And telling them that they need to post a schematic and learn how to draw and read them IS mentoring them. You want to do this? Then you need to learn how to do this.

[Platefire]

Amen!

[tubenit]

telling them that they need to post a schematic and learn how to draw and read them IS mentoring them.

Yep, it sure is!!     


With respect, Tubenit

[acheld]

So don't defend the people who are posting just a layout drawing instead of a schematic. 

Apologies Willabe.  I was trying to be nice while pointing out that schematics are necessary.  Obviously the "necessary" part of the message was not emphasized enough.   I am firmly in the "schematics are required" camp.

Along those lines, what sources are available for newbies to learn schematics?

I learned the basics when I was in college many decades ago, and then relearned by reading Merlin Blencowe's books.   Are there online programs that teach this and could be recommended?

[shooter]

pretty sure if you ask the gazing-glass something like;
"Tutorial on basic schematic reading and understanding"  you'll find a rabbit hole to explore 


it starts way before the schematic though, you need a working understanding of electronic components, both discrete and active, their
interaction" with each other.  Ohms law, probably Kirchhoff's law as well.


That said, at 14 I was able to "learn" the basics from reading and doing the Tandy 75 in 1, a book on "how to fix any Appliance" some guidance from Dad who was simply a tinker'er that could fix about anything! 

[jbrrrrr]

Just wanted to add that as a very, very green novice that has been making false starts with attempting to get a functional understanding of amplifier and audio related circuits for at least 20 years (and would formerly have been liable to be a "layout-only-help-requester") -

Having tools like LTSpice freely available (or CircuitLab, etc.) makes the learning process pretty interactive if reading it straight out of a book from 50 years ago isn't the most compelling for someone getting started.  It's not as if it's just hard to learn because it's not taught as commonly as it used to be.  There's plenty of resources for anyone motivated.

I'd be disappointed if I had started researching similarities between preamp topologies and was only able to find a bunch of DIYLC layouts.

I'm all for making it as easy as possible to get the freely-distributed assistance from more experienced techs, as well as preserving a communication format that makes it easy to see what's happening with the circuit, not how someone decided to run their heater wiring.

[Platefire]

  I really enjoyed learning amp schematics when I started tinkering with tube amps about in year 2000. It was a fun process to me. It took a while having very little previous electronic experience. Now I can use that skill on reading sch on lawn mowers, vehicles and when trouble shooting things around the house that is sometimes a very big help. The internet makes it so easy because everything you need to know is available if you are willing to search it out and study it. It seems like a big mountain to climb starting from scratch but it's like the old saying "A journey of a thousand miles starts with a single step"---so take that first step and keep on walking!!
 

[Willabe]

 

[johnnyreece]

Just to add to the available programs:  DIYLC isn't just for layouts.  They also have schematic symbols.  I do all my schematics there now.  The bonus is that Doug can use DIYLC for making boards. 

[pullshocks]

Just to add to the available programs:  DIYLC isn't just for layouts.  They also have schematic symbols.  I do all my schematics there now.  The bonus is that Doug can use DIYLC for making boards.

I decided to try doing a schematic in DIYLC.  One thing I like is being able to color code some of the connections. 

[74-335]

There are many pcb / circuit design tools out there.

Some years ago I used software (commercial) for work, Altium (Protel SE back in the day) which is now quite widely used in industry (industry standard).

Unfortunately it's also expensive, cumbersome, also focuses on multilayer smd pcb inline with modern manufacturing and componentry.

There used to be a free version for windows-based pc users, but since I've moved away from M$ OS'es many years ago, I am unsure if they still support it.

I Moved to KiCAD about 6 years ago when I re-engaged with my early professional skillset (out of necessity) and find it to be a reasonably robust and platform agnostic tool.

The only reason I mention this, is I'm not even 2/3 of my way to retirement, and I feel the world has moved on significantly, despite my familiarity with schematics, layouts, 3D rendering and FEA.

I would therefore suggest that anyone even remotely interested in electronics take a two-pronged attack at their upskilling.

1. The theory (i.e. books and wrote learning) is absolutely necessary and if one is "lazy", one can use the theory as a reference whilst acquiring the skillset to use the PCB design tools.

2. The practical (i.e. use of appropriate tools combined with learned knowledge) is only something that both amateurs and professionals alike develop as a skillset OVER TIME.

Nobody is perfect out of the box, and there are so many subtle nuances  regarding component placement, routing, layer separation etc. that it literally takes many professionals decades to become proficient.

So I won't be dismissive of someone who is a "layout" oriented person - HOWEVER - it is not an efficient path to learning circuit fundamentals, but rather a quick and dirty way to learn how to replace individual components for repair (and many times dare I say it, not even an adequate repair).

Layout AND schematic together is a powerful teaching tool, as it assists in visual communication on helping a user identify portions of circuits through visual cues - i.e. components on a board in a specific or familiar arrangement.

Just like AB763 is more or less the de-facto standard in this regard - simply due to the popularity of the product and the fact that Fender published schematics AND layout diagrams.

The reasoning was simple - easy to service.  nothing more than that. If a repair could be effected quickly with a minimum of diagnostics, then it made the product far more popular over time. It also reinforced a perception of longevity and reliability  - even if "reliable" is an oft misued term.

I do agree that for the purposes here on this forum, two things are absolutely mandatory for those who want to request assistance.

1. Schematic (accurate, and draw it yourself if you don't have access to what you're working on)
2. detailed CLEAR images of the actual board / product's innards that you are working on.

The requests made by those here who are the true champions of this board, make these simple requests in their post signature FOR A REASON.

So don't be disrespectful. If you come seeking help, the bare minimum you can do before asking, is to include the information that is required to help you resolve your problem.

Thanks to the champions - because we all learn from their contributions, regardless of whether members are active participants or casual observers.

[passaloutre]

LTSpice is free, available on many platforms, includes tube symbols, and easy to use. You don’t need to do any modeling to make it worth learning. I use it for all my schematic drawing now.