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!!

Power Transformer

The volume and tone pot has each been made ready by soldering them together and adding the .0047uF capictor to the tone control. Also the input jack and the on/off/on boost switch is now connected.

The circuit board is pretty much complete, the pots, the on/off/on switch, and the input jack are prepped and now I'm prepping the Power Transformer at this point. I've read the book and re-read the book to help me understand all of the steps.

Another great thing to look at prior to doing this step is to watch Gabby of "sound garage tales" wire a power transformer. Here is a link to his videos - make sure you watch all 4 of them:
http://www.youtube.com/watch?v=hKu4HG2q-iQ&feature=related



I've twisted some of the wires together so they will stay sort of neat looking as they run to their connection point.

I placed the wires to be twisted together into a drill and slowly twisted the pair together. This makes a nice even twist.

You need to be careful because you do not want to over twist them - they could actually break.

The next step will be to mount the PT into the chassis and measure and cut the wires to length. Perahaps I'll do that tomorrow night or thursday.

Solder, Solder, Solder

The last shipment of parts arrived today - not including a cab and speaker. Those will be ordered later.

I finished dry mounting the components onto the board then I double checked them and cut the wires that will run under the board.

Here is a good tip I read some place: When mounting the resistors and caps place the values up so you can read them. This helps when double checking prior to soldering.

I soldered all the components. I didn't follow the instructions in the book exactly. The book suggests soldering the board without the leads that will go the tubes and to vol pot and input jack. The book suggests wiring the components and adding them to the board later. I did just the opposite. I soldered the leads to the board then placed the board inside the chassis, mounted the vol, tone pots, input jack and switches and then cut my lead wires to length.

Tomorrow I'll do the same with the leads that go to the tubes. Right now it's late and I'm tired. Here are a couple of shots of the soldered board sitting inside the chassis.

No work today

I didn't actully work on anything today, but I did order what should be the last of the electronic parts. All that is left is the cabinet and speaker. I'm going to go with a single 12" speaker which is different from what is in the book plans. The design originally called for one 10" and one 12" but the new kits that can be purchased uses just the 12"

I've dry mounted the components that I have. I will re-check before I solder (possibly thursday) and I need to plan out where connector wires will go and running connector wires under the board.

I want to have it all planned out before I solder.

One note for those who plan to build and not buy from a kit: It helps to be a detail person. Double check before ordering that you are ordering the right parts. Also, it may help to buy the chassis first. The mistake I made was ordering the tube sockets and not knowing what size hole was in the chassis plus their mounting specs. Also when ordering I didn't double check my quantities and I accidently ordered one 9 pin tube socket when I meant to buy two.