build experiences

How many builds do you get under your belt before you really felt like you understand the ins and outs of building an amp? I've got a few builds under my belt but the last couple just didnt go that great. I have one amp at an amp tech and another that I'm contemplating pulling the board out and starting over. I've learned a good bit each time but it almost seems like the more I learn the more issues my builds have. I started with a couple pedals, then a Mod102 amp then a 2204 from mojotone that all worked well. I scrapped the 2204 and cannibalized it to build a plexi based on the valvestorm layouts and it had a few issues but I was able to work it out. These last two really took my confidence down.

I have a few books that Ive been reading and each time I re read sections it makes more sense but I still have a long long way to go before I can fully understand half of what I'm reading. I'm going to build a Rat clone and a 5f1 before revisiting the amp I screwed up.

So I guess my questions are

how many builds did you do before you felt comfortable or that you had a basic understanding of the amp(i.e. knowing what each section is, what it's doing exactly, the symptoms of a faulty part, etc)

Whats a cost effective way to get in the practice? I pretty much have a ton of caps, resistors etc but chassis and transformers are killing me.

Any recommendations, tips, tricks to get a better understanding.

IMO it's one thing to be able to look at an amp and trace the signal flow or draw a schematic. My engineering background and a few books and builds made that pretty easy fairly early. I've built several channel switchers with both relays and LDRs and did a lot of my own design/layout with those as well.

But it is a whole nuther thing to be a great troubleshooter. And sometimes I tend to get way too cute with builds. I just recently rebuilt an amp for like the third time and only now does it actually sound good.

Started as a mini-Major (2xKT88 ultralinear) thing but sounded like shit. Changed the PI because using the Major PI+driver was a dumb idea to begin with when using only 2xKT88. Still sounded like shit. Ripped out the board and made it a 2xKT88 ultralinear Wizard MCII and only now does sound decent.

I also think it's OK to shelve something for a while and come back to it after you've learned more. I've done that a couple of times and when I revisted the amp years later thought; "WTF was I thinking!"

I looked at pics from my first 2204 and it's a miracle that it didnt explode let alone actually worked. The plexi I just finished looked right and really well put together but it's a bit screwed up. So its tabled for a bit. I have a 5f1 kit I'm going to do today so I can go along with rob robinette's site and try to learn more and then have a little amp I can mod and use pedals with. What's weird is I get frustrated to the point of giving up then I will get a second wind.

This hobby is a bit addictive and it's nice to give me something to do besides playing guitar

ClintN667":36q85mn8 said:

This hobby is a bit addictive and it's nice to give me something to do besides playing guitar

Click to expand...

Ha, whenever I have a problem build I think almost opposite. I could have been playing guitar!

Troubleshooting is not one in the same as designing. I know great engineers that can design to cutting edge limits that couldn’t troubleshoot themselves out of a paper bag in the lab. I also know of those in the opposite that are excellent hands on techs and engineers, but don’t have the experience needed to design on the bleeding edge.

As was mentioned before I have my technician degrees and my masters in EE both to lean on for amplifier design and troubleshooting both. It doesn’t come without trial and error and it does help to have some more experienced engineers or techs to lean on throughout the process to gain more experience. It’s really hard to self teach these circuits at times because problems can be hard and individual.

Don’t beat yourself down - it happens to us all. I’m rebuilding a new bias probe because the screens don’t operate in the range they stated. It took me even half an afternoon to determine it was the displays and not a plethora of other problems that needed narrowing down.

You’ll get there. Don’t look at failures as failures, look at them as learning experiences. No engineer or amp builder ever got to where they are now without trial and error along the way.

Hopefully I can add something constructive to this conversation......

how many builds did you do before you felt comfortable or that you had a basic understanding of the amp(i.e. knowing what each section is, what it's doing exactly, the symptoms of a faulty part, etc)

Click to expand...

There are 2 parts to this.
Depending on background and education, we can have a very clear understanding of all the sections of an amp and how they work, but understanding the symptoms of failed parts etc., and troubleshooting is a whole different game. The expertise in troubleshooting can only come with experience.
All skilled trades include an apprenticeship. The reason being that, while you can get technical knowledge from books / school, you need to actually spend time in the field DOING THE WORK before you can master the craft. It takes time to feel comfortable doing this stuff.
I can totally relate to the info posted earlier about having builds not work or sound like shit. I have a few amp chassis in my shop right now that have had 3 or 4 different circuits in them, but it didn't work out for whatever reason. They go back on the shelf, and I come back to them later.
I also understand how it can be so euphoric when you fire up a build for the first time and it sounds great, but I also know how depressing it is when all you get is noise, loud hum, or god forbid nothing at all... It happens to all of us. Hang in there and stick with it!

Whats a cost effective way to get in the practice? I pretty much have a ton of caps, resistors etc but chassis and transformers are killing me.

Click to expand...

Other than rebuilding different circuits into the same chassis, not much you can do here. Sometimes you can find unfinished Ceriatone or Mojo kits for low $$ on the buy and sell. The other thing to look for is lesser known amp brands with good components selling for cheap. For example, I bought a Roccaforte amp recently for less than what the parts would have cost. It had Mercury Magnetic's iron, high quality aluminum chassis, pots, and switches, and the amp was built on a turret board so it could easily be re-worked into whatever I wanted.
If you know what to look for, there are deals out there...

Any recommendations, tips, tricks to get a better understanding.

Click to expand...

I love this website:
https://www.ampbooks.com/
I use the calculators all the time, and the tutorials tab and the classic circuits tab are pure gold. The walk through of the SLO100 circuit is mind-blowingly cool!
If you haven't downloaded the Duncan tone stack calculator, you need to get that ASAP as well:
http://www.duncanamps.com/tsc/

Hope that helps

I got a pretty decent understanding after my first build, I did a lot of research ahead of time. Also I have an software, and hardware engineering background so that helped immensely.

After I got 4-5 builds complete I realized I wanted to continue to learn, and experiment with different circuits. I realized quickly that is was going to get very costly to just keep building. So I bought up a bunch of Randal MTS gear. This way I could build/rebuild circuits on MTS modules. I eventually outgrew the capability MTS, and wen't back to building full heads.

Basically what I do now is build, and sell/trade (not for profit) it at some point to fund the next build. I also have a few builds around that I can rebuild at anytime.
Also I'll do mods, or builds for others.

thanks guys. I work in Research and Development for a chemlab while my educational background as well as half my work history is in Information Technology. I am hoping to go back to school for EE since a lot of what I do has to do with PLC systems so building as a hobby has overlapped a bit in my career. Ive already got most of my stuff ready to go to the local college (credits transferred, Orientation, etc) Just need to schedule classes. My job function and hours are getting ready to switch while having to set up a Lab Infomation Management System so I will hopefully have a bit more time on my hands as well as a little bit of income to help me with the hobby.

It is frustrating and depressing sometimes but I really do enjoy it. Its like as soon as I feel like "screw it! I give up..." a few minutes later Im tinkering again. I have the Merlin Blencowe book and Dave Hunters Guitar Amp Handbook that has really been useful but as I said earlier each time I go back and reread sections its a bit clearer. I got a Champ kit yesterday to kinda reset a bit and get a confidence boost but while populating the board I noticed that one of the Turrets was missing. So I guess that one is going to be a few more days out. Another thing I enjoy about this is it gives me something to do when I need to put down the guitar for a bit. My guitar teacher has me working on Racer X's Scarified(the chorus part) and it's kicking my ass even at the slowest speeds but after taking a break and tinkering for a few I was able to pick up a few BPM and play it a bit more clearer so thats a win-win.

I also gotta say I have a new found respect for guys who do this for a living.

Playing Paul Gilbert material is usually a humbling experience. I need to revisit Viking Kong, I "shelved that one for a few years" just like those problem amps.

How many builds? This will be dependent on the persons basic skill set. I built a Dumble clone my first build 10 years ago and it is still running great. Most would suggest starting easy. thats not how I roll

In the last year I have been trying to find the lowest cost alternative to continue building amps. Since I already have a few full amp heads which have FX loops I started building handwired preamps from scratch. First one I did I took the Ceriatone YETI layout and built the whole circuit up to the FX loop out(just before it hits the phase inverter) using a $30 chassis from amazon and a $35 Antek torroidal trannie. I cut my own boards from G10 garolite from Mcmaster Carr. Check bulk pricing when ordering parts. Sometimes its cheaper to buy 100 resistors than 10.
Since finishing the Yeti preamp with great results I have built the AFD35, BE DELUXE (3 channel Friedman), Fortin Meshuggah, Jose modded 4 hole Marshall and on my workbench atm I am working on another Jose style Marshall with added 12ax7 boost and MV footswitchable and a Dumbleator FX loop on the rear panel for the heck of it. Anyways these can be built for <$200 in parts if you have the skill.

Lastly, you could build as many amps paint by numbers as you want and never learn a damn thing of how they work and what components do what. I only really started digesting all the info once I took the time to trace out schematics and compare them to other amps to see the differences.
Having build problems like you are experiencing can be daunting but they also offer the best opportunity to learn from. If you arent sure where to start when it comes to tracking down the problem ask some of the guys here at the forum and I'm sure they'd love to help you out

Todd

SpiderWars":20itzyx2 said:

Playing Paul Gilbert material is usually a humbling experience. I need to revisit Viking Kong, I "shelved that one for a few years" just like those problem amps.

Click to expand...

Man the thing is, I was using a tab and my guitar teacher is pretty well versed in guys like Paul, Yngwie, etc he looked at what I was using a re did the tab for me. I'm basically doing the "chorus" from Scarified and it was kicking my ass hard. Still does but at least I can play it all the way through at about 80% speed.

Also I built a 5f1 over the weekend and everything worked off the bat. I know thats kinda low hanging fruit but I wanted to get 1 build that worked to get me motivated again. Im going to try to either troubleshoot my Plexi or pull out the PCB and add a turret board. I have a turret board 90% finished so maybe one will work out.

It depends if you’re painting by numbers or trying to understand each part of the design. If you are sending an amp to a tech that you built you are throwing away a prime opportunity to learn by troubleshooting. I got my start when I bought an amp that didn’t work. I learned more fixing that amp than putting together any kit.

scottosan":2agqh9ag said:

It depends if you’re painting by numbers or trying to understand each part of the design. If you are sending an amp to a tech that you built you are throwing away a prime opportunity to learn by troubleshooting. I got my start when I bought an amp that didn’t work. I learned more fixing that amp than putting together any kit.

Click to expand...

+1

I’m troubleshooting my build as we speak. I found the problem to be a relay that is intermittent - thermal resistance causing the latch state not to latch as the relay warms up. Ordered some 9V relays to replace my 12V relays. 12.75V wasn’t enough headroom to account for thermal degradation. Live and learn. I’ve never messed with relay designs before so learning as I go.

scottosan":3hhedd6i said:

It depends if you’re painting by numbers or trying to understand each part of the design. If you are sending an amp to a tech that you built you are throwing away a prime opportunity to learn by troubleshooting. I got my start when I bought an amp that didn’t work. I learned more fixing that amp than putting together any kit.

Click to expand...

100% truth

scottosan":2oibz009 said:

It depends if you’re painting by numbers or trying to understand each part of the design. If you are sending an amp to a tech that you built you are throwing away a prime opportunity to learn by troubleshooting. I got my start when I bought an amp that didn’t work. I learned more fixing that amp than putting together any kit.

Click to expand...

The amp I sent to the tech was after troubleshooting with the guy who designed it. I tried everything I knew to check but I was tapped out. I just finished my Plexi this past week and I'm really happy with it. I made a lot of screw ups with this one but was able to sort most of it out on my own. Now I'm going to use it as kind of my baseline amp to try stuff out. I am installing a PPIMV hopefully Monday whenever my Pots show up. It does feel really good when you figure out an issue.

I think I just have to make sure Im not biting off more than I can chew with projects. The next one Im working on is another 2204 with Burgers PCB. Then once its up and running trying a few mods.

The amp that is sitting with a tech is still there so on one hand it makes me feel better that he is having as much trouble as I did then on the other hand it has me scratching my head on what I could have possibly screwed up so bad.

glpg80":2u9iojt0 said:

I’m troubleshooting my build as we speak. I found the problem to be a relay that is intermittent - thermal resistance causing the latch state not to latch as the relay warms up. Ordered some 9V relays to replace my 12V relays. 12.75V wasn’t enough headroom to account for thermal degradation. Live and learn. I’ve never messed with relay designs before so learning as I go.

Click to expand...

Hmm. 12v should allways be fine for 12v relays.

The problem people run into with switching many times is getting the LED and/or Resistor correct in the foot switch. Also the kind of LED matters, sticking with basic red will give you the correct results for most of the basic switching circuits .

You can do the series LED like Friedman does. This works great because the relay coil acts as the current limiter to the LED (provided you use the same omron relays), so no resister needed. In this case you have to parallel another LED if you use two relays. This is why you see an internal LED in the butterslax footswitch.

Or you can do the parallel to the footswitch LED. This is the balancing act because you have to get the series resistor correct. Too low, and the rely will stay latched when you disengage the switch.

CNutz":2v1e03q6 said:

glpg80":2v1e03q6 said:

I’m troubleshooting my build as we speak. I found the problem to be a relay that is intermittent - thermal resistance causing the latch state not to latch as the relay warms up. Ordered some 9V relays to replace my 12V relays. 12.75V wasn’t enough headroom to account for thermal degradation. Live and learn. I’ve never messed with relay designs before so learning as I go.

Click to expand...

Hmm. 12v should allways be fine for 12v relays.

The problem people run into with switching many times is getting the LED and/or Resistor correct in the foot switch. Also the kind of LED matters, sticking with basic red will give you the correct results for most of the basic switching circuits .

You can do the series LED like Friedman does. This works great because the relay coil acts as the current limiter to the LED (provided you use the same omron relays), so no resister needed. In this case you have to parallel another LED if you use two relays. This is why you see an internal LED in the butterslax footswitch.

Or you can do the parallel to the footswitch LED. This is the balancing act because you have to get the series resistor correct. Too low, and the rely will stay latched when you disengage the switch.

Click to expand...

I figured it out and buttoned it up - DC from the LED was causing the relay to refuse to unlatch. Calculated a shunt pull-up resistor and it works like a charm. Essentially it provides a path for current to the LED while also pulling the relay coil up to 12V quicker and helping to reduce coil bounce. It was an odd problem to have, but fun to find and fix

glpg80":1o437p0x said:

I figured it out and buttoned it up - DC from the LED was causing the relay to refuse to unlatch. Calculated a shunt pull-up resistor and it works like a charm. Essentially it provides a path for current to the LED while also pulling the relay coil up to 12V quicker and helping to reduce coil bounce. It was an odd problem to have, but fun to find and fix

Click to expand...

Yeah, you can do it that way. But just putting a larger series resistor with the LED does the trick by limiting current to the point where the LED still lights, but not enough for the relay to stay latched. That is the traditional way. People get into trouble because they will use an online calculator to calculate the resistor needed for current limiting of the LED, but that does not account for current limiting needed to unlatch the relay. You can up the LED series resister by quite a lot, and not sacrifice the usable brightness of the LED.