Newbie Amp Builder - Need Some Beginner Tips

[joel_ostrom]

Hey Folks,

I apologize if this kind of thread gets posted a lot, but its difficult to search the threads for exactly what i'm looking for.

Anyways, i'm a gearhead looking to dabble in some amp building, but i could use some info on some basic amp building knowledge.

Could anybody direct me to a good info base for understanding and reading amplifier schematics?

How do i determine a chassis/eyelet board layout from reading the schematic?

My first attempt will probably be to use the recipe given in Dave Hunters book "Tube Amplifiers for Guitarists". (A Princeton 8 Watt clone).

But i'm already looking to the future, and what i'd like to try is to clone my present amp, my Fender Blues Jr. - I'd like to come up with a good layout and do a decent PTP setup. I have a schematic that i downloaded online, but making sense of the schematic is another story.

Any help you guys can offer is greatly appreciated.
Cheers!
Joel

[angelodp]

Why not build a Tweed Deluxe kit to get your feet wet. Mission makes a great kit and you would learn a lot from that experience. RJ, here, puts together great packages and the Rocket has been well documented.
Also, there is an encyclopedia and a half of info here, so do take advantage of the search function.

Cheers Ange

[xtian]

As a beginner, I found the best projects for me were those that were thoroughly tested and supported by a large user base. The designs at ax84.com fit the bill nicely.

[Structo]

Check out Garage Talk.

https://tubeamparchive.com/viewtopic.php?t=9023

[azatplayer]

My first build was a clone of an amp i owned. I got it very very close tonally and to look at, basically copied what was in front of me, i think was a pretty easy approach.
The reason i cloned it, was cos a had imported it for a friend, who when it had landed, bailed on the deal, i was stuck with it. Had to recoup my loss, but thought why not clone?
It started an obsession i dont see ending anytime soon... be careful!

[surfsup]

Joel, what is it you want to accomplish by building an amp?

Do you want to build your *dream* amp you saw on youtube?
Do you want to learn how to build/construct/repair amps?
Do you want to design amps?

These are each different things I believe require a different answer. I recently started as well, and want to learn the design which is quite a bit to tackle.

If you want to just build an amp that you would like to have, for less money, and the "thrill" (used loosely) of building your own amp, I would suggest not wasting money on a kit and just do it (but spend a LOT of time up front understanding the circuit and looking at other builds/schemos first to minimize mistakes). Why not buy a kit? If you can relax, take your time, and methodically figure it out, once you build *your* amp, your kit amp will likely not get played much. You will also need a bunch of stuff besides the kit: soldering iron, solder, needle nose, wire snips, wire strippers, gator clips, DMM, drill/drillpress, various drillbits, step bits/holepunches, metal file(s), shrinktubing, zipties, centerpunches, cad software, etc etc. So you will wish you had that $250-300 you spent on the kit to spend on the tools to build your actual amp that you want to build instead. Otherwise just go out to the ATM, max out the daily withdrawl and hit the strip club. That's going to be more fun and about the same amount of money.

If you want to learn to build amps and want to get started right away, the kit is the way to go. Why? If you source your own parts, it will probably take you longer to find and order all the parts than it would to order a kit AND build it. You will also pay shipping through 5+ sources (tubes, trannies, sockets, pots/switches, wire, fuseholder, IEC, cord, passives, G10 board, etc etc etc). I've ordered stuff for a bunch of amps and the least amount of suppliers I can get stuff from is 5. So I order 3-4 amps worth now to save on shipping. You will also get stuff wrong, component is too big, voltage rating too low, etc. Then more shipping, more waiting, more frustration. So the kit keeps your first experience "in check" so you don't "wreck yourself". Even though about 1/10th of the way into the build, after having stripped 1000 wire ends, pre-tinned 900 of them because 100 were too short or long, pre-wired 75 passives, stared at 243 jpegs of tone stack pots to evaluate your work if it was done correctly, sat on the toilet with your HTC Evo and googled "resistor color code chart" to maximize time at the bench, checked and rechecked Wiki's "diode" explanation to make sure your diodes are facing the right way 30 times before soldering....if at this point you start to cry internally because your wife is sitting near you and you wish to not shame the male race, contemplating if all this hassle was worth the effort, don't worry, that's normal!

If you want to design amps, take it from me, get a couple good books, and read read read read read read read read. Read the previous two paragraphs above, again. Then ask yourself how much spare time and money do you have to figure all this stuff out and is it really what you wanna do? Do you have the space? If you don't have a workbench, organizational drawers, good lighting, etc. you are taking it all in/out of cardboard boxes stuffed in a hall closet to work in the middle of the night because your 18month old will destroy all your stuff and your wife likes to eat dinner on the diningroom table without an errant resistor getting caught up in a forkfull of spaghetti (don't ask me why I know about these things) then this is probably going to be a 12 on the 1-10 scale of frustration and fun. But hey, some people love it.

[Weathered]

Surfsup, EXCELLENT post.

Someone, when I was starting to build, told me "don't think it will be any less expensive to just buy the amp in the first place." I started building because I enjoy learning about these things, and it has been a long process. With a lot of frustration along the way.

If you want to build your dream amp, it may take 3-4 builds before that to really get your feet underneath you. If you want to build an arsenal of amps at all different wattages, all tuned how you want them to be tuned, then building might be the route to go.

As far as resources, Dave Hunter's book is a very good start. There are a lot of resources on the internet that will explain things very well. Go to AX84 and read the theory docs tied to the P1 project. 2 sets of books for advanced theory are Richard Keuhnel's and Merlin Blencowe's books - both get more into the mechanics of exactly how an amp does what it does. The more you learn ahead of time, the better your chance of success will be on your first build and all subsequent builds as well.

[Jack Hester]

Take a browse through this tutorial:

http://phillokit.com/basic_electronics/ ... onics.html

It will refresh what you know, and teach what you don't about tubes. Good site.

Jack

[kevster]

This is a great thread. This might end up a good sticky for newbies like me...

[joel_ostrom]

thanks for the tips and the info guys, really appreciate it.

I guess my interest is just about wanting to have something that i can call "my own". I enjoy personalizing my equipment to the nth degree. I've built 2 guitars for myself, in the process of building another (piecing together, that is).

I also want to learn about the amp building process. I'm nowhere near being able to design my own amp, but maybe someday down the road.

I'd rather not buy a kit, mostly because for me there's a lot to be said for doing something from scratch/from the ground up without an exact step by step guide. I don't mind acquiring my parts from various sources. I've found a great one (Watt's Tube Audio online) that seems to have about 90% of the components i need for my project. There's a local shop in town that's an electronics distributor that'll most likely have a lot of littler things that i need (solder, wire etc.).

I already own a lot of the tools i need for a project like this, mostly because of all the work i've done on guitars in the past.

I'm looking forward to getting started on this one.
Thanks again for the links to some good reading.

Cheers

~Joel~

[sliberty]

Let me address one of your specific questions. It is a question I remember having at the beginning as well. The question about determining layouts.

Layouts are a critical part of building amps. Many layout choices can have a significant impact on the sound of the amp. I had a hard time understanding this in the beginning, because it always seemed to me that once you connected a wire to a component, the rest didn't matter, but it does. When wires cross each other, or run near other components, or are too long, etc., some of the electrical characteristics, like capacitance, can be impacted. You can end up with noise, poor tone, oscillations, etc. So when in doubt, get help with your layout. The odds are someone has drawn one for any common amp.

Fender, back in the 50's and 60's, often published not only a schematic, but also a layout. This layout was pretty detailed, and showed exactly how the eyelet board should be done, as well as most of how the chassis should be done. [The funny thing is that their amps are a little less prone to layout sensativity than many other amps, so we actually might have gotten along with out them, but it is really nice that they exist.]

The guys on this forum also often provide detailed layouts, which has proven invaluable. Trainwreck amps are DEFINTELY prone to problems if the layout is not just right.

For amps that do not include a published layout, it is common to develop a board layout that closely follows the signal path. By that I mean that at one end of the board, you would have the components that connect to the input jack and first tube stage. And as you move progressively through the schematic to the tone stack, the next tube stage, the phase inverter, and finally the power tubes, your layout would progress towards the other end of the eyelet board. This approach is helpful in relation to the chassis layout as well. In other words, the tubes are usually also laid out in the order of the signal path. This results in the wires that go from the board to the tubes having a shorter and more direct path, with minimal crossing of other wires.

Take a look at the schematic and layout for a simpla Fender amp, like a 5e3 Deluxe, and note that right to left progression I was describing. You'll start to get the idea.

Good luck!

Steve

[Jack Hester]

My layout(s) tend to look just like a schematic on the turret board. Granted, I may use considerably more turrets than the norm. But, I don't need a drawing to follow the signal path.

Jack

[xtian]

My layout(s) tend to look just like a schematic on the turret board.

Nice layout! Can we see more?

[sixstringer]

Check out Tube Amp Network (http://www.tubeampnetwork.com), it's main focus is supporting the building of the simple, cathode biased design from Dave Hunter's "The Tube Amp Handbook". It's a great amp too. There an affordable kit for the design there and a number of beginning (and advanced) builders have posted build photos and offer help and advice.

(I hope it's ok to mention another website here, if not, please remove this post and accept my apologizes)

[gary sanders]

Just be careful.I got hit with 450 volts on my first build,from a faulty meter,and could have been killed.Its interesting and fun but dangerous.I have the most respect for plate and screen wiring now