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I started building my SIIIv6 today (Saturday, January 27) and thought I would document it from a different point of view. That is from the eyes of an almost beginner going through the build. I hope that I do not bore those who are more experienced and that this will be of use to those starting out. I will also be including the times it takes me to get through the steps as a general idea to those starting out that these things do take time.

By way of introduction, this is my second amp build. My first was a year ago when I built an sIII kit for my nephew. When I built that kit, I had to buy all of the tools, as I had never soldered before. By background, I have a mechanical engineering background.

Unfortunately, I do not have a digital camera, so this will be a verbal description.

Open up the box and take a look. Resist the urge to open all of the packages! This only makes it more difficult as soon as you need to find components.

Take the protected package containing the front and back panels (the very thin and long one) and carefully put it somewhere flat and safe. Remove the power cable and the control knobs and place them with the panels. This gives you more room and gets the parts safely out of the way.

Find the build manual and READ IT, then go away and come back tomorrow. Now READ THE MANUAL AGAIN, it is full of important information!

Find the appropriate bill of materials for your kit, the schematic, the layout and the voltage chart and make a few copies of each for future use.

Now get a clean sheet of paper and, leaving plenty of room between items, list all of the resistors on the BOM (bill of materials). Do the same on another piece of paper for the capacitors.

Prepare you work area. I put down an old wall size calendar (24â€

Checking the components against the bill of materials:

Now you can find the packet containing the resistors. Carefully open the package, remove the resistors and go through and identify them. I use the color code but check every one with my DVM. As you identify them (a magnifying glass is very helpful!), place them on your sheet of paper. As you find the correct number of the appropriate resistor, tape them to the paper and check them off the list on a copy of the BOM.

Note: The resistors that resemble sugar cubes are the 5 watt, the large, in my case, gray bodied resistors are the 2 watt or 1 watt, the brown bodies resistors are the ½ watt carbon resistors and the cream colored resistors are the ½ watt metal film resistors. (I hope!)

In my build, it took me a while to realize that for the 6 100K ohm ½ watt resistors I received 4 carbon and two metal film, so look at all of your parts!

Do the same for your capacitors, remember, electrolytic capacitors are the ones with one side marked with a + and / or a necked down area at one end.

TIME: This took me about 1 hour.

First item I build up: Input jack assemblies

The next thing I do is out of the suggested order given in the manual, but I find it helpful to me.

I build the INPUT JACK ASSEMBLIES now. I found them to be very time consuming and “fiddlyâ€

Tube socket and front panel install:

Next I installed the tube sockets, front control panel, pots and tag strips.

I cut a SMALL slit into the corner of the packet containing the screws and nuts so that I could work out just the parts I need at the time. (Carpeted floor and cat alert)

I installed the sockets for V1, V2 and V3. In my build, these had a self-contained tube retainer, make sure that the inner clip of the retainer is not caught between the socket retainer and the socket.
NOTE: I had to file the ends of the mounting tab of the two 3 terminal tag boards so that they would fit against the socket. Also to prevent a reoccurrence of an issue I had on the first build, I bent down the center tabs that are connected to ground. I also had to slightly bend the mounting tab on the tag strip that fits into the chassis corner.
COMMENT: I think that I’m going to install the input jacks and wire up the connections to V1 before any other socket wiring, it looks very tight in that corner of the chassis and I have large, somewhat clumsy hands!

Next I installed the sockets for the EL84’s and the rectifier.

Next I found the package containing the 6v6 and boost components and installed the 6v6 sockets.

Now comes the tag strip for the power transformer (PT)

Next find the package with the pots and lay them out to find which are which. On my build, the 500K audio taper (500k A) are marked on the back of the pot, the 250 k linear (250k L) are marked on the front of the pot on the connector tab strip. Break off or flatten out the locating tabs, the single tab on the side of the pot that point towards the front (shaft side).

Now carefully unwrap the front control panel from its protective covering and lay it against the front of the chassis.

I tape the ends of the panel to the chassis and completely wrap over the corners. I almost broke the panel on my first build by catching the edge on the table while moving the chassis for soldering and think this will prevent that from happening this time.

Lay the pots out in the correct order, remove the locking nuts and one of the two washers from the shaft and install the pots. I tighten the nuts with a 6â€

Back control panel install:

Again I taped the panel onto the chassis and wrapped the tape around the ends of the chassis. If you do this correctly, I think that the tape will be hidden by the cab so that you can leave it on permanently.

I trial fitted the impedance selector switch, the boost and tube selector switches and the power mains (attached to the end of the power cord) and saw that they all will get in the way of wiring the tube sockets, so I removed them for now and just installed the fuse holder.

Time: About 1 ¼ hours.

That’s it for tonight. Tomorrow I’ll populate the board and we’ll see what else.

Sorry for the lack of updates. Something came up Sunday, snowed 12" here yesterday and between work and shoveling I;m too tired to do wiring woth any confidence.

I'll be working on the board this weekend.

OK, I built up and populated the board and put the jumpers on the tube sockets and ran the heater wires. Doesn't sound like much, but it was over five hours to do.

The write up for this will be the next day or two.

Things are progressing nicely, except for having to re-do one of the resistor sets to the V1 socket! Went to pin three instead of pin two, boy it's tight in there.

Back of turret board build up:

To build up the turret board, I started on the backside.
I placed my work surface (a smooth approximately 6â€

Populating the board:

Next I wanted to populate the board. It looks like you’ve really accomplished something and, more importantly, gets a lot of loose components soldered into the assembly so that I can’t lose them!

I flipped the turret board over so that the turrets are facing up with the ground line at the top of the board. Now it looks the same as the layout drawing.

Now find the sheets of paper with the taped down identified resistors and caps, get out a magnifying glass and the DVM as I’m going to recheck every component value as I put it onto the board.

HINT: The SOZO caps are marked differently than the BOM and the layout, here’s a cross reference:

BOM / Layout value: SOZO marking:

.0047uf 422k
.01uf 600V 103k
.022uf 600V 223k
.68uf 684k

Hope this helps.

Before I started, I asked Stephen for some help is which way the SOZO’s are supposed to be oriented, if you wanted to go the extra mile. He sent me a great picture of an sIII board. I think he will be putting this up in the on-line build documentation.

Since I am right handed, I thought it would be better if I started on the left side of the board and worked my way to the right. That way I could steady my soldering hand on the board without disturbing any loose or previously components on the board.

If you look at the layout, the board has 9 groups of components laid out on it where each group is self-contained and has no components that connect to another group. Hope that makes sense. Anyways, I decided to populate and solder in the components in three batches, the first batch being the 6v6 components, the 100R 1W, 8K2 2W and 16uf 450V batch and the 6 resistor, 2 cap symmetrical looking batch. I installed these components after double checking each component and orienting the caps so that I could read the values easily for future repair / tweaking. After soldering these in, I took the magnifying glass and checked each joint.

As I checked each joint, I took a colored marker and marked the connection and component off on a copy of the layout.

The next section is 3 batches that go from what was just soldered in up to the 2 .022uf caps. Again orient the components so that the values are readable and check the joints after soldering.

The last batch consists of the remaining components, repeat with the details as above.

I now have a completed turret board.

HINT: Some of the turrets have a number of component leads going into them, I found that if after cutting the component leads to length, if you knock the burrs off with a file, that they are much easier to get into the turret.

Time: about 2 ½ hours

Tube socket jumpers:

As I mentioned above, I removed the mains connector, the impedance switch and the tube and boost switch’s from the chassis to give me more room to solder.

I wanted to fit the jumpers onto the tube sockets before hooking up the heater wires. The jumpers are closer to the tube socket and I think that it’s easier to do them first.

These are the pin 4 to pin 5 jumpers on V1, V2 and V3, the pin 3 to pin 8 jumper on V3, the pin 1 to pin 7 and the resistor on V2 and the 68k resistors from the tag strips to pin 2 and pin 7 of V1.

Looking at the room I had to work with, I decided that I wanted to connect the heater wire to pin 5 of V1, V2 and V3. Therefore when I soldered in the pin 4 to pin 5 jumpers I soldered the jumper to pin 4 to stabilize the jumper so that it will stay in place until I connect the heater wire and solder pin 5. On V2 I soldered pin 1 and pin 7 leaving pin 6 until later. On V1 I soldered the resistors to pin 2 and pin 7.

HINT: When connecting wires to the tube sockets, try to get the wire going straight down to the pin when looking at the socket from above. This minimizes the possibility of having a wire from one pin accidentally contacting another pin causing a short (and smoke and fireworks).

The area around V1 is tight, I soldered the TMB input resistors to pin 3 by accident and it took ½ an hour to correct this. Pin 2 now has a lot of solder on it, I tried fitting the tube into the socket and it inserted completely, so I think I’m OK.

Time: about 1 hour

Heater wiring:

HINT: To make things easier, I took 2 different colored markers, one “darkâ€

Misc. connections:

At this time I also connected the 1k5 resistors to pins 5 and 6 of V6 and V7 (the 6v6 sockets) soldering pin 5. I also connected the 500pf and .0047pf caps to the normal channel pots and the 100k resistor to the TMB channel volume pot.

Time: about ¼ hour

The update will be later this week.

I spent Saturday shoveling snow. Snow off of the driveway, snow off of the deck, pulled snow off of the roof of the house, repeat shoveling off the deck, shovel snow off of the roof of the garage --- again. You get the idea.

Today (Sunday), measured up and soldered on the flying leads (leads from the board to the pots and tube sockets, power tube socket to socket jumpers, final install of the input jacks, some pot to pot leads and bolted in the transformers.

Good progress, should be getting real close by next weekend.

Wiring the flying leads:

I’m not sure where I got the term from, but that’s what I call the lead jumpers that go from the turret board to the pots and tube sockets.

NOTE: When going through the wire you’re given for the kit, you will find a red and black wire that are about 18â€

Wiring the power tube jumper leads:

While I was cutting wire, I wired the pot-to-pot jumpers (3 leads) for the TMB channel and the single pot-to-pot jumper on the normal channel.

Next I wired the power tube socket jumpers. These are the jumpers from pin 6 of V7 to pin 6 of V6 to pin 9 of V5 to pin 9 of V4.

HINT: On these jumpers I placed sections of heat shrink tubing on the lead terminations on V7, V5 and V4 to isolate the connections and prevent any pin-to-pin contact. I did NOT shrink the tubing, so far there seems to be enough of a friction fit that I do not want to shrink the tubing unless I have to. This will allow easier rework in the future.
I did not put heat shrink on pin 4 of V6 because it will get another connection from the turret board.

I now wired the jumpers from the tube select switch to pin 8 of V7 to pin 8 of V6. I did not connect the lead to the switch and again I put short sections of heat shrink tubing on the pin connections. I then wired the jumpers from the tube select switch to pin 3 of V5 to pin 3 of V4, again using short sections of heat shrink tubing.

Installing the input jacks:

I thought that it’s now the right time to install the input jacks.

I took the pre-assembled jacks and trimmed the co-ax wire ends for connecting to the tag strips at V1. Remember, this end of the co-ax has the ground wire cut back and is NOT connected at the V1 end. I also soldered the ground connector onto the ground lead before installing the jacks so that I had more room to solder.

NOTE: I bought some extra ground connectors because I wanted to be able to completely remove each input jack assembly individually if I ever needed to work on it or repair them.

I took the input jack assembly with the longer leads to install for the TMB channel. There is not a lot of room for making these connections, space is tight. Remember, the leads for the TMB channel goes to the tag strip with the resistors that connect to pin 2 of V1.

HINT: To solder, I tipped the chassis up on its narrow end and against my chest to get room and light into the corner for soldering. It worked for me.

I repeated the above for the normal channel with these leads going to the tag strip with the resistors that go to pin 7 of V1.

I forgot the times!

Times:

Wiring the flying leads and power tube jumpers: 3 ½ hours

Install input jacks: 1 hour

Bolting in the transformers and cap can holder:

I decided to bolt in the transformers to see how they fit. I’m using the custom Trinity set.

The power transformer is a very tight fit. To get the transformer in make sure that the wires are not crossed, they have to smoothly and snugly conform to the side of the transformer. I also tipped the transformer to get one side of the wires through the chassis to get some extra space to work the other side through. Take your time, do not rush or force the transformer through the chassis opening, you do not want to mess up the insulation on the transformer wires.

Oh, to mount the power transformer I removed the nuts from the through bolts holding the stack together, fitted the transformer into the chassis and then bolted it back together through the chassis. Careful you do not knock the laminations loose. They are sort of stuck together from the shellac / coating but I’d be careful.

NOTE: The green and black wire side of the transformer goes to the pot side of the chassis.

Time: ½ hour

UPDATE: Final build note posts will be later this week.

AMP IS UP AND RUNNING GREAT!

Wiring up the Power Transformer, Cap Can and Output Transformer:

Correction to the “wiring the power tube jumper lead: section:
Paragraph 2 should read

Now I wired the power tube socket jumpers. These are the jumpers from pin 4 of V7 to pin 4 of V6 to pin 9 of V5 to pin 9 of V4.

I had written pin 6 of V7 and V6

Now onto wiring the PT and Cap Can, take your time and follow the layout.

I started by trimming the PT 220V lead (black and red) lead to about 3 inches long, heat shrink tube seal the end of the lead and tape it down with electricians tape.

I did the same to the brown and white and the blue and white leads from the OT.

I trimmed the two solid green leads on the PT and soldered them to the tag strip to connect to the heater lines. To make sure that there was no possibility of shorting out the connections, I left a vacant lug on the tag strip between heater wire / PT connections.

I trimmed the two solid red leads on the PT and soldered them to pin 1 and pin 7 of the rectifier socket.

I trimmed the black and white lead on the PT and soldered it to the power switch along with a jumper to the light.

NOTE: For all wiring between the mains plug, fuse plug, light housing and the power and standby switches I used the trimmed off wires from the transformers, there was enough length for me to do this on my build.

I trimmed the red and yellow and the green and yellow leads from the PT, soldered on the supplied ground lugs along with making up the cap can ground jumper and soldering that to the ground lug of the cap can.

I trimmed the solid yellow lead on the PT and soldered it to pin 5 and trimmed the white lead from the PT and soldered it to pin 4 of the rectifier tube socket.

Check all of your connections to the rectifier tube socket, I checked this twice and still soldered the white lead to pin 6!

Wire pin 3 of the rectifier socket to the standby switch and run the jumper from the other lug of the standby switch to the correct terminal of the cap can but do not solder this connection until the board is installed as there is a lead from the board that goes to this lug.

Once the rectifier socket is wired I now installed the mains connector and the fuse jack. I did this now so that I had plenty of room to solder the connections on the rectifier tube socket.

Make sure that the mains connections are made as shown on the layout and make sure that the ground connection is made with the same gauge wire as the transformer leads. Solder a ground lug onto the ground jumper and connect to the grounding lug that you locate next to the mains connector. When installing the mains I had to use the longer brass screws to get enough length.

For the OT you can run the blue lead to pin 3 of V7 and the brown lead to pin 3 of V6. When doing this make sure that you leave enough slack that the leads will lie flat under the board when installed. Also, while doing this run the jumper wires from pin3 of V7 to pin7 of V5 and run the jumper wires from pin 3 of V6 to pin 7 of V4. Again when I did this I used a short section of heat shrink tube to capture both wires going to pin 3 of both V7 and V6 and another short section of heat shrink to cover the connections to pin 7 of V5 and V4.

NOTE: As I stated above, do not shrink the heat shrink tubing onto the connections, you need to get to these to take your voltage readings and to correct wiring if required.

Everything is now completed except installing the turret board and the output jacks, impedance selector.

Time: about 2 ½ hours