Install cooling fan guitar amp

The Power Transformer and Output Transformer are attached to the other side of the chassis. Another option for someone that has some electronic experience is the wonderful Fender 5E3 Deluxe amplifier. It has two power tubes in a push-pull configuration and is loud enough for many gigs.

I went from being a lousy solderer and having a casual knowledge of electronics I couldn't even calculate the value of 3 parallel resistors and having no idea how tubes worked to really understanding electronic amplification and tube theory and my soldering skills are now top notch after building an amp or two.

Researching that first build motivated my learning and I have really enjoyed the entire process--and then of course there's the end result--having a nice self-built tube guitar amplifier to play through. Opening a tube amp kit and seeing all those little parts can be overwhelming so I recommend you do an inventory of the big parts like transformers, chassis, switches, tube sockets, etc. Getting all those little resistors and caps in place on the board will make your amp project seem much more manageable and it will help you identify missing components or circuit board layout problems.

It sucks to come close to completing an amp and then realize you're short a capacitor and have to wait for delivery.

I also recommend you study factory built examples of the amp you plan to build so you know what your amp should look like. Also go to the tdpri. If you have not been trained to work with high voltage then have an amp technician service your amp. Never touch the amplifier chassis with one hand while probing with the other hand because a lethal shock can run between your arms through your heart.

Use just one hand when working on a powered amp. Learn how to drain the filter capacitors. See more tube amplifier safety info here. Assemble the circuit board with longer than needed lead wires.

Install the tube sockets and pilot light into the chassis. Match the tube socket pin orientation to your layout diagram. Install the power transformer into the chassis. Use grommets in the chassis holes where wires pass through. Wire the heater circuit with regard to heater wire phase. Install jacks, pots, fuse, power, standby and ground switches and as much of their wiring as possible. Trim the circuit board wires to length and solder their connections.

Complete the Amplifier Startup Procedure. Finish the amp, install faceplate, knobs and insert the chassis into the cab. Create a Voltage Chart. Create an Amplifier Tube Chart. How to determine the outer foil lead and orient your non-polarized capacitors. You need a good quality soldering iron with a clean, pre-tinned tip to successfully solder eyelets and turrets.

Frequent tip steam cleanings using a damp sponge will make soldering easy and keep your solder joints looking good. I just dab a little flux on the joint using a thin artist paint brush or you can use a refillable flux pen.

You want good solder joints because chasing a cold solder joint can be a colossal pain in the butt. Weller soldering irons are also well liked. I have run into turrets that still have some sort of lubrication on them that can make soldering very difficult.

If using flux on a turret doesn't make it easy to solder then you may need to wipe them down with rubbing alcohol to get them clean. When soldering turrets keep in mind they are pretty good heat sinks so you need to use a larger iron tip and preheat the turrets. I use a big fat chisel tip with turrets. Just apply iron heat to the turret for a second or two before making contact with the component leads.

You need the keep the iron tip in contact with the turret and all the component leads to get a good, shiny solder joint. This will keep you from frying components as you wait for the turret to get hot enough to bond with the solder. Speaking of frying components, it's a good idea to use heat sink clamps on component leads--especially capacitor leads--to protect the component during soldering.

Even just an alligator clip on the component lead between the soldering iron and component body will protect it from over heating. This is a pretty good soldering training video. Part 2 is about soldering turrets. I like to use 22 gauge solid core wire for everything except 20 gauge for heaters but even 22 gauge is adequate for heater wiring. Solid core wire allows for better lead dress because the wire will stay where you put it but some feel it can cause microphonics.

I haven't had that problem. Start your build with the circuit board itself , either eyelet, turret, B9A development board or even perf board.

Making your own eyelet or turret board is surprisingly easy with the right board making tools. Doug Hoffman sells a variety of tube amp circuit boards using either eyelets or turrets and you can buy them empty or with components soldered in. He also has an online program for creating a circuit board design then he'll make it for you. I like to measure and record the resistance value of all resistors just before I place them on the circuit board. I write the measured values on a printed copy of the amp layout diagram.

It can be impossible to measure some resistors once they are in circuit and it's a very common mistake to install a K resistor instead of the required ohm.

Measuring the resistors just before installation can save you from hours of frustrated troubleshooting. Also, knowing the exact resistance value can come in handy when measuring bias and troubleshooting. Install the components to populate the board but don't start soldering until the components and lead wires are all in place and you're sure they are placed correctly.

If you have access to an oscilloscope you can easily determine the outside foil lead and orient your non-polarized capacitors for least noise. I recommend securing the big filter capacitors so they don't hang by their leads. You can use a mild glue remember, someone will need to change these out someday or drill two holes in the circuit board and wrap a tie-wrap around the board and caps. Put the tie-wrap on before soldering the leads to keep from stressing the leads. Ensure the negative terminals of the big electrolytic filter capacitors are connected to ground because they may explode and damage the output transformer if installed backwards.

The exception to this rule are the filter capacitors in a fixed bias circuit. Most filter caps have an 'indention' on their positive end and arrows pointing to the negative end. You may need to install the circuit board hold-down bolts or standoffs before covering them up with components. I like to use carbon film resistors in classic circuits in place of carbon composition these days because carbon film create much less resistor "hiss" shot noise.

They are a nice compromise between classic carbon composition and ultra quiet metal film resistors. If you want your circuit board to look s and '60s period correct then you will need to use carbon composition resistors. I recommend metal film resistors for the input V1 grid leak and V1 grid stopper resistors for minimal resistor hiss injection into the first gain stage.

I don't recommend metal film for anything beyond the input stage for classic tube amps because they seem to sound a little too sterile compared to carbon comp and carbon film. Having said that, for the quietest amp you should use metal film everywhere except for the 3 watt and greater power or "voltage dropping" resistors and screen resistors where metal oxide should be used.

I like to use higher watt rating resistors to reduce hiss. Higher rated resistors will also increase amp longevity. One of the more difficult aspects of building your first tube amp is figuring out all the different types of capacitors used in them.

For capacitors in the signal path of classic amps I like to use Mallory polyester film capacitors now made by Cornell Dubilier CDE.

The Mallory and P Orange Drop caps are very close in tone and construction to the "mustard" caps made in the s and '60s. Polypropylene signal caps are also an option and tend to be more robust than polyester. For cathode bypass caps these electrolytics are my favorites. For small, Marshall sized 0. Classic amps used axial caps. For pF value caps typically used as bright caps and tone stack treble caps I like to use silver mica caps.

For tremolo circuits I go with what Fender used, ceramic disc caps. I don't like to use ceramic discs in the signal path because they tend to be microphonic due to their large, flat and thin structure.

Nice straight component leads look good but they stress the component during expansion and contraction every time the amplifier warms and cools during a power cycle.

Adding some bend to your component leads is the way the military and NASA demanded their circuit boards be built. You need some bend in your component leads to allow for expansion and contraction during amplifier heat cycles.

This lead bend adds strain relief and keeps the component above the circuit board. Parallel Mounting. Parts shall be mounted parallel to, and in contact with, their mounting surface. Slight angularity is permissible. One watt and greater resistors should be mounted above the mounting surface for cooling.

Lead Lengths. That's a really nice job, two questions: Could you fit the fan on the inside? Are these things then badly designed in the first place, or just "cheap"? Reply 11 years ago on Introduction. I would NOT install the fan inside the chassis, there is way to much power in there to mess around!

To say amps are badly designed? I say Yes and No, Tube amp circuits get Hot it is a fact, amp manufactures suggest placing a fan on your amp to keep it cool? I have had power trans, caps, and other parts burn up because of heat. With the fan cooling the trans, and circulating air in the cabinet, I have Not had a problem in years! Fitting the fan inside was a space consideration, I don't quite get the "there is way to much power in there to mess around!

Do tube-amps sometimes come with fans, is yours one that just didn't? The fan is cooling the power trans. There is No tube combo amplifier with a built in fan?

Rack power amps have them built in like a computer does. Nothing like this is available. Patent Pend. Yes you are correct, the peavey classic 50 has a cooling fan built in, this was designed for the application and is UL tested and listed.

Thanks I knew if something like this was already out there the experts here at instructables would find it and let me know?

Reply 9 years ago on Introduction. Umm, I doubt anyone can completely know about electricity and guitar tube amplification, I think a basic understanding would be good enough.

I did Not mean completely, my point is if you don't understand electricity within a tube amplifier, DON"T attempt to make this instructable! Just buy a fan made for a car and you'll be a lot better off. DYohn Moderator - Posts: 10, Joined: April 22, Location: Arizona, United States. I've used them frequently in car audio. I suggest to wire a relay that is switched off your remote-on power to run the fans. Thanks for the correction. Joined: March 28, Joined: December 23, Type S Member - Posts: Joined: April 16, Location: Canada.

Ketel22 Silver - Posts: