Express Build Tips

[strato17]

I almost have all the parts for an Express build. Does anyone have a recommendations for assembly order? I was thinking about making the powersupply section first, then checking the voltages, then moving on.

What are some common errors or issues that arise when building the express, or any other amp? How can these be avoided?

I have been told the KF built his amps on the edge of instability: does "instability" mean excessive feedback or self oscillations?

Thanks for the help!

[Tubetwang]

i've only built one Liverpool and one Express and have an Allyn chassis for another eventual Express and am far from being an expert...

I do think that they are on the verge of instability but...i'm unstable myself...:roll:

They also cut real nice!!!
Fun to play with.

[Richie]

I'm sure everyone builds amps differently,or how they go about it..

Sometimes its easier to work where you always have the most room in the amp..

But the first thing is, get all the parts in a box i am going to use for the amp, and measure them.
Then drill or fit any holes you need or will use. Depending on some chassis, you may have to conter sink the board mounting holes,if you use those on the power supply board. Since these will fit under the transformer. So its hard to put them in if you stick your tranny on their first! I make my bottom plate first too, and drill those holes.
If you wait till you finish the amp to drill or mount it, you might get some drill shaving in the amp. Thats why i like to do any of the drilling stuff first..
Next. Mount the sockets, and wire the hearters. Then i set the pots, and solder in the buss bar. Much easier to do when the trannys are not on the chassis. You can position the amp so you can have a flat surface to work on.
Then i install the trannys, and wire those up,and the power cable.

The boards i load out of the amp, and solder on flying leads,then when i install the boards..i can just clip the wire to length and solder those into the tube sockets.

Its much easier to get to the power cable and all other wiring if the boards are not in the amp. The last thing i do, is wire up the pots and front panel, and the filter caps.. I usually set the caps in the night befer,and let them set up,if your using the silicone to stick them to the chassis.

Some little tricks ,like solder the ground wire to the lug..for the power board first.. its easier to have this wire ready, and then solder it to the board.

If you put the board in first with a flying ground lead..you don't have alot of room to get in that section,or ground lug with the iron,so its much harder this way.

The other things, are make sure your routing of wires is correct,meaning what crosses what. And thats about it..

I'm sure there is no right or wrong way, just whatever a person likes.
And most do wire the power section and then move on

[gearhead]

For the chassis that have a lip such as Allynmeys, I do the pots first. Just can't get to them otherwise.

Came up with a pot "jig" by drilling holes in a wood slat attached to the inside of the actual chassis to be used (tape and clamps). Drill from the front and the holes are exactly where you need them. Wedge it against the chassis overhang, so you can use the edge of the slat as a measure of the top of the chassis (for clearance).

Just be real slow and careful about taking the finished assembly out and installing in the chassis.

[guitarsnguns04]

great idea gearhead..I will try that. I like your approach to the build also Richie..I makes good sense and sounds like a nice sytem to build with.
Thanks for sharing.

[strato17]

Wow.... thanks everyone for the help!

For the chassis that have a lip such as Allynmeys, I do the pots first. Just can't get to them otherwise.

Came up with a pot "jig" by drilling holes in a wood slat attached to the inside of the actual chassis to be used (tape and clamps). Drill from the front and the holes are exactly where you need them. Wedge it against the chassis overhang, so you can use the edge of the slat as a measure of the top of the chassis (for clearance).

Just be real slow and careful about taking the finished assembly out and installing in the chassis.

So, I am a bit confused on the purpose of the jig.... Is it so you can have the pots in proper placement, while you measure the right amount of wire and wire them up, then remove them later?

[gearhead]

It's for the purpose of completely wiring and soldering all the pots and the bright switch (with wires/components) as one assembly on the jig. Remove from slat and install in chassis all at once. By making it from the actual chassis that the pots are going in, all wires and components directly soldered to the pots should be the correct length.

Undo the nuts on the frontside, and (using another slat as a brace) slowly ease one pot a little bit, then the next, etc. Go back and ease pot #1 out a little more, and so on, until it's removed.

[Tubetwang]

Gearhead's jig is clever...

Thanks for the tip!

[guitarsnguns04]

Gearhead...on the copper buss what are you soldering to on the bottom of the pots?

[Tubetwang]

Gearhead...on the copper buss what are you soldering to on the bottom of the pots?

i was wondering the same thing...

[gearhead]

Magic pixie dust.

LOL.

Actually am going to redo those. I had run a loop of twisted wired around the pot stem and soldered near the bottom of the pot to seal the loop. One end then runs up and around the buss and then to the pot lug.

Couldn't find my last set of pot buss lugs I got from Allyn, but just found another batch. Not as good as Allyns, or Rons, but they will do.

[sliberty]

Wiring jigs like this are a great idea. I use one for guitar pot wiring - I stole the idea from RS Guitarworks actually, as they deliver their kits on such a jig. It makes the wiring much easier since its not in the guitar (or amp in this case) and you end up with a really neat job.

[gearhead]

Holy moly, that's a great idea! Have a G&L strat pots/pickups upgrade set that has been sitting around because it's such a pain to do. I have an extra pickguard that will just do the job!

[guitarsnguns04]

I was hoping you were going to say that. I just got a set from Ron and thought maybe they went like that but I wasnt sure and I couldnt find any pics.I guess now I know..thanks.

[gearhead]

Actually, it depends on how long Rons are. The one's I used before were clarostat; fed the buss bar straight thru the end hole in the lug. It made the buss bar ride too low for my taste; below the level of the preamp board. Ended up adding a second one in about the same location as the one in the pics.

In other words even if I had the longer ones, would still do it that way.