Few more pics

Here are a few more pictures

It is Finished!

I finished the last bit of soldering tonight!

Here are some pics

The next steps are to double and triple check all of my connections for both the correct wiring and to check the solder joints. A cold solder joint has a dull appearance. All of the solder connections should be shiny.

As for plugging in and fireing up. Well there are some safety concerns. First amps, even small ones like this produces lethal voltages. Some safety precautions are in order.

I need to make a circuit in the power cord to check for problems. Here is a quote from the Aikens Amp web site, "make a fixture with a light bulb in a socket that is in series with one side of the AC line - if the amp has a major short, the light bulb will light up instead of blowing the fuse or vaporizing your new power transformer."

In fact, go to the web site and read their whole safety page found here: http://www.aikenamps.com/SafetyTips.html

It has some great advice that could save your life.

I have to go out of town this week, so I won't get to fire this puppy up for at least a week - I need to buy the stuff to make the safety curcuit. It shouldn't be long now!!

Tools for the build

I thought I'd take a minute and list some basic tools needed for this job for those who are considering this build or any amp build. Keep in mind this is my first build so I'm not an expert.

• Wire cutter & stripper.
• Small screw driver - phillips and standard depending on what type of mounting hardware you buy.
• A small set of needle nose pliers - I have a set of small tools I bought at sears a long time ago and I think they still sell them. See the picture below. The long needle nose ones have been extremely helpful in bending cap/resistor wires.
• Drill - The main thing for this amp was that I had to drill a hole for the ohm switch. For the twisting of the wires it is helpful, but you can build a small amp like this without it. If you build an amp with a bigger chassis and longer wire runs then it would definately help.
• Soldering iron - a variable temp iron. Why variable temp? For the light electronic parts you don't want to burn them up with a high watt iron, but when making ground connections to the chassis you need a hotter iron. If you have two irons already then this doesn't matter. I picked up this soldering iron for around $50 + shipping here: http://www.howardelectronics.com/xytronic/379.html and this place has it for $40 + shipping http://www.assemblyoutfitters.com/shop/item.aspx?itemid=2163 It also helps to have a tip with a fine point because some of the connections are small.
  

Off the top of my head that's a basic list. Here are some pics

Chassis work

I finished drilling the new hole in the chassis for the ohm selector switch. Here is a picture of the new switch mounted and also the wiring I did last night of the fuse, lamp, and power switch.

Begining assembly

After cutting the power transformer's wire to length I found that it is easier to strip the wire and tin the leads with the pt out of the chassis. That's what I worked on last night. After tinning the leads I soldered the fuse wire, lamp, power switch, and the first 2 leads to the power tube - the 6.3v.

Coming from the pt the two green wires go to the lamp and then on to the power tube socket numbers 2 and 7. These wires supply the need 6.3 volts.

The black wire from the pt goes to the fuse. The other side of the fuse will be a black wire from the cord that plugs into the wall.

For the power switch I made an optional change that is not mentioned in the book. This option comes from the updated notes by Dave Hunter. I replaced the on/off power switch with an on/off/on switch and I wired the pt's blue wire in the up/on position which will supply 125 volts and the down/on position will supply 120 volts to the amp. According to hunter the extra 5v will not hurt the amp and will actually give a slightly different sound. I'm all about versitility.

The last thing I worked on was a resister between lug 5 & 6 on the power tube socket - I almost missed that. This is actually the hardest fitting resister I've had to do yet because the distance is smaller than the resistor itself. I suggest not cutting the wires until after bending them in place and making a good mechanical connection. This would have been easier making this connection with the tube socket out of the chassis. I soldered them while in the chassis - do it before you put it in the chassis and before wiring any other wires to the socket.

I'm still working on drilling a hole in the chassis - I need to buy a bigger drill bit and I hope to go to sears or ace today and get that.

No pictures of last nights work which is probably fine since I just cannot seem to get any really good pics from that camera. I will take and post some as I make a little more progess.

EDIT: Output Transformer

In my last post I mentioned drilling the chassis in order to place an impedance switch in the circuit.

I could skip the switch and wire either the white or the yellow wire directly to the input jack. If I did this I would only get the following:

White wire: one 6L6 = 8ohms speaker
Yellow wire: one 6V6 = 8ohms
one 6L6 = 4ohms

There is also an optional green wire that you can read about in the book.

Power Tran & Output Tran

The Power Transformer wires have been measured and cut to length and so has the Output Transformer wires. I'm going to have to drill into the chassis for an impedance switch for the speakers.

This switch will allow me to run one of these set ups: one 6L6 power tube = 8ohms
one 6L6 = 4ohms
one 6V6 = 4ohms
one 6V6 = 8ohms

I've already purchased a 6L6 and I plan to run it into an 8ohm speaker, but in the future I may try and go with a 6V6 into an 8ohm speaker as this will give a tweed Champ or Princeton like sound.

My next step is to cut a hole in the chassis to allow that switch to fit and then I can finally begin assembly and solder... Not too far away from powering up!!