Early pics of my Express build.

[leadfootdriver]

I tried to do a Wizard Multi Star Grounding. Those F&T caps were small enough that I was able to pack everything on the boards.

The grounding is chained together with each cap as a star point. You can pick out the eyelet where the bond to the chassis will be. I have isolation washers for the jacks.

I fused the PT, as well as the rectifier out. I mounted some MOV's for the OT on the bias board.

I'll paint the chassis before I do the final wiring. Plus, I need to buy my transformers still. I'm accepting PayPal donations at leadfootdriver@comcast.net.

Let me know if you see any potential problems so I can take care of it now!

*EDIT 3/14/21*
It seems like a lot of my original pics from Photobucket have vanished for whatever reason. Here are a few now on Flickr..

This 1st pic is the most current pic with a PEC Bias Pot and Flyback Diodes intact.. I have a 10k resistor on the input Grid of V1..

[Colossal]

Looks great so far! I like the way you implemented the bright switch. Will be interested to hear your thoughts on it's functionality.

What kind of orange drops did you use? They look like SBE 716P. I'm probably going to use them in my Liverpool and Express builds.

Well done.

[Colossal]

p.s. I like how you fused both legs of the PT secondaries. Cheap insurance and good practice.

[leadfootdriver]

Looks great so far! I like the way you implemented the bright switch. Will be interested to hear your thoughts on it's functionality.

What kind of orange drops did you use? They look like SBE 716P. I'm probably going to use them in my Liverpool and Express builds.

Well done.

Yeah, I went with the Sprague's. I tried the Malory 150's in my little test amp, but felt that they were looser on the bottom, and blurry on the highs compared to the OD's. The 716's were just a little bit more than the 715's, so why not?

[Colossal]

Yeah, I went with the Sprague's. I tried the Malory 150's in my little test amp, but felt that they were looser on the bottom, and blurry on the highs compared to the OD's. The 716's were just a little bit more than the 715's, so why not?

I'm not too keen on Mallory 150Ms. A little muddy to my ear compared to Sozos. I've got some metallized polypropylene caps in my test Liverpool and the clarity is phenomenal, the low end tight, no smear like with polyester caps. Don't get me wrong, I love the sound of Sozo polyester in a Marshall but I was aiming for separation. 715 and 716P are polypropylene film foil. The 716Ps have the copper leads. I'll look forward to giving them a shot. Let me know what you think of the tone.

[Colossal]

What are the tantalum caps for up on your bias board? Delocalizing your bias voltages?

[leadfootdriver]

What are the tantalum caps for up on your bias board? Delocalizing your bias voltages?

Those are MOV's. Apparently running MOV's on your OT primaries is better than running the diode string on the power tubes.

http://www.premierguitar.com/Magazine/I ... _Pt_3.aspx

These only have a capacitance of 40pf, so it shouldn't change the tone.

http://www.mouser.com/ProductDetail/Vis ... l36Q%3d%3d

[Colossal]

Those are MOV's. Apparently running MOV's on your OT primaries is better than running the diode string on the power tubes.

http://www.premierguitar.com/Magazine/I ... _Pt_3.aspx

Ah, interesting. They looked like little tantalum caps in the photo and I couldn't zoom down to them to clarify. Thanks for linking the article. I'll give it a read.

[M Fowler]

http://www.premierguitar.com/Search.asp ... &sa=Search

[leadfootdriver]

I redid the power board, so I don't need to worry about baking my caps with that honker resistor...

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1164.jpg[/img]

[RJ Guitars]

I am liking the looks of this build, particularly the innovation on the board layout. I've got a PCB based Express inspired build in the works with a similar idea but different implementation on the power supply filter caps... I'll be curious how yours sounds. Nice idea and nice work so far!

rj

[leadfootdriver]

I am liking the looks of this build, particularly the innovation on the board layout. I've got a PCB based Express inspired build in the works with a similar idea but different implementation on the power supply filter caps... I'll be curious how yours sounds. Nice idea and nice work so far!

rj

Trannys on order. Won't be long.

[cbass]

nice looking build

[leadfootdriver]

Finished. Now i need a cab. It's way to late to play it, but it seems to be working fine. V1 is real sensitive to long plate tubes, so I put a SINO era chinese tube in there, and that stopped the microphonics. I can tell this amp will be LOUD.

I bought a pack of bolts that were just a bit to long, so I put nuts on them so they wouldn't bottom out in my standoffs'. They look like crown nuts from a far. I'll grab the right set tomorrow.

I went with a 10mm LED for the pilot light. I ran a 220R off one leg of the heater for about 13 mv's of current. It's plenty bright without being annoying.

Thanks to all that made this possible. There's no way I could have figured this out on my own!

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1207.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1204.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1199.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1198.jpg[/img]

[IMG767]http://i258.photobucket.com/albums/hh26 ... G_1195.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1194.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1193.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1192.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1190.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1183.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1182.jpg[/img]

[IMG768]http://i258.photobucket.com/albums/hh26 ... G_1181.jpg[/img]

[Cliff Schecht]

The Express IS loud! I run mine at 4 Ohms into an 8 Ohm 1x12 closed back cab pretty much at all times to tame the volume a bit. KF actually recommended this somewhere as an easy way to cut the volume down a bit. Since I use high power, high efficiency speakers and don't rely on speaker breakup for my sound, this trick works really well to keep things more manageable volume-wise without killing my tone. As with any amp, as you turn down the volume it helps to boost the EQ a bit.

Some amps don't like a mismatch because it increases the flyback voltages from the output transformer become very large (Marshall's with a high OT primary impedance can be really bad about this, we're talking thousands of Volts potentially!) but the Express has those diodes on the power tube sockets to protect against just this. Some people don't like the sound of doing this so much but I suspect they are using lower wattage speakers that sound best when pushed.