Second Express Pics

[Ron Worley]

Here are some shots of my second Express, it's a 120 / 240V selectable version using a custom version of the normal Toneslut PT from the great folks at Heyboer.

Since it's going to live in the UK, it needed to be 240V to be practical - playing a Wreck through a noisy stepdown transformer probably wouldn't sound too great. I had to make it 120V capable too so that I could test it here in the US, hence the switchable PT.

I used a standard Marshall voltage selector and wired the 220 and 230 positions together for use with 240V to avoid confusion. This PT had the primaries in a second hole out of the opposite bell of the tranny (I think like some of KF's PT's had....), these wires went to the Power switch and the Voltage selector- which made the area around the Impedance switch a little crowded.

I used a 250V MOV, and had to do some work to make the pilot light work- I sawed the back off a standard Wreck 120V light, took the guts out and inserted a 6.3V bulb in there with some attached leads that went out the holes in the end cap of the light onto the little metal crimp connectors like normal. A little super glue, and it worked like a champ- in fact it's much brighter than the normal LED.

I ran the braided leads back to V5's heater connections, and raised the NFB lead in a hump over those wires to make sure that no noise got sucked into the NFB circuit.

Hopefully this one passes your review!

Ron

[Ron Worley]

More...

[Lonely Raven]

Wow, it looks practially vintage, Ron! Good stuff!

[castor]

Real a fantastic work, Ron!
Any difference in sound respect to your first build?

castor

[Ron Worley]

Castor-

This one seems to be slightly higher gain and more unstable when cranked all the way up. With the amp on 10, I could get very nice singing sustain with the guitar pot as low as 4 or 5. All the way up required me to face away from the amp and go as far as my 25 foot cord would let me. I think I know now why Glen K. uses a 50 footer!!

It's using reissue Tung Sol 12AX7s, with V3 being matched for the PI. The EL34s are NOS Seimens.... very nice. Point is that I bet that a nice NOS Phillips / Amperex / Bugle Boy / Mullard in V1 would help it a bunch. It's for a friend, so I will let him voice it with what he likes.. and wants to pay for....

RLW

[guitarsnguns04]

Ron...looks great. Very nice work.

Could you explain the jumpers on the impedance switch to me. I want to know why it is jumpered,what lugs jumper to which and is it necessary to do. I didnt jumper mine in my build and used a lorlin switch just like the one picture.Thanks in advance and sorry to highjack but that first pic is haunting me.

[Ron Worley]

This is an area that I am going to improve in the build guide, because I've been asked the same question at least 15 times.

The reason that KF used jumpers to an additional gang of lugs was to make sure that the switch could handle the high power of the speaker signal (as I am told by Allyn, I think...). To make sure, he wired a jumper to each of the three impedance inputs and the output.

The Stackpole / Electroswitch is the one I know- I've never used a Lorlin, so can't speak to it (even though I spec'd it in the BOM- Stackpoles are rare as hell).

The switch has a ring of 12 lugs around the back by the silver back plate. these are 4 groups of 3 that go to an output lug just behind the first lug of each gang. Here's a picture that should help:

Ron

[Ron Worley]

This is an area that I am going to improve in the build guide, because I've been asked the same question at least 15 times.

The reason that KF used jumpers to an additional gang of lugs was to make sure that the switch could handle the high power of the speaker signal (as I am told by Allyn, I think...). To make sure, he wired a jumper to each of the three impedance inputs and the output.

The Stackpole / Electroswitch is the one I know- I've never used a Lorlin, so can't speak to it (even though I spec'd it in the BOM- Stackpoles are rare as hell).

The switch has a ring of 12 lugs around the back by the silver back plate. these are 4 groups of 3 that go to an output lug just behind the first lug of each gang. Here's a picture that should help:

Ron

[jaysg]

...had to do some work to make the pilot light work- I sawed the back off a standard Wreck 120V light, took the guts out...

Wish you'd asked about this before going through all that work. The 120V lamp is probably a neon bulb in series with a resistor. All you needed to do for 240, was add another resistor. 5K comes to mind, but I could be off there.

[guitarsnguns04]

what about a regular 120v light with one leg from incoming wall power and ground the other side of the light? Would it induce ground hum or not..the chassis is esentially a ground right?

[Ron Worley]

A few pics of the finished amp. I can say unequivocally that I hate polyurethane and am never going to use it on an amp again.... it just sucks.

Ron

[Noel Grassy]

Wow, that one turned out great despite all the hoops you motated through!

I'd imagine there's fewer TrainWrecks in Britain & the Continent than there are in the US. Your friend's one lucky SOB. That's so cool of you to kick down something so mighty.



















Last Christmas, someone thought they were doing me a favor..........

[IMG:600:450]http://i145.photobucket.com/albums/r222 ... _o_pot.jpg[/img]
I jest!

[guitarsnguns04]

Sweet work Ron. Is that one of your drawer cabs?


NoelGrassy...what the street value of something like that? lmao

[Ron Worley]

Yeah, it's one of the drawer cabs- it was more of a factor of time than anything else. I want to do my own cabs eventually, but this was a time crunch.....

NG, that's either a lot of guacamole, of some serious bud....

RLW

[strato17]

Very nice work, Ron!! Looks pretty similar to mine... I wonder why?

We need to get together and jam sometime soon!