Express inspired amp completed!

[Tinkerer]

Gurus,
it's done! I've completed my first, and by no means my last express inspired amp. This one is build for a good friend of mine, and I liked it so much that I'm now doing one for myself.

I'm guessing I was lucky as from the first time I powered it up without the lamp limiter, the voltages were spot on and all I had to do was bias the tubes. No hum and just the usual hiss from the CF resistors. Checked out perfect on the oscilloscope. I've used Marstram iron on this build, but I've bought Heyboer PT and Pacific OT from rj for mine. Not that there is anything wrong with Brian's iron, in fact it's awesome, but I wanted to use the 'original' iron in mine. I'm also using PS6 caps instead of the Jupiter caps in my amp to keep the original look.

I've used F&T filter caps, but mounted them to a turret board for ease of servicing, three above and three below. The rest is pretty much standard. It's not the neatest job in town, buy hey, it works and sounds incredible.

Thanks to all for your advice and help with my questions, I couldn't have done it without you, and this site for the wealth of information.

Tinkerer

[rbryerton]

Very nice! I like the idea of the filter caps on the turret board.

How does it sound?

Oh yeah, and how did you do the face-plates?

[M Fowler]

Nice job on your build. Neat wiring job on your amp.

I also like to deviate from the original design and use cap board or can caps. But I built my first three with the cap stack and lazy loop wiring. But changed that on my last two Rocket builds.

[UR12]

Nicely Executed. Congrats !!!

[Allynmey]

Nicely done!

[Tinkerer]

How does it sound? Truly amazing! The only amp I can compare it to in the way it responds to playing and guitar settings is Glenn's clip on you tube, and it does all of that properly. Playing through a quad box loaded with Weber 1225s with pre-Rola doping, it absolutely sings. Plenty of bottom end when the bass is pushed, singing mids and crystal clear highs with the guitar volume turned down. When dimed, nothing changes except the tube break up kicks in and it just gets raunchy for want of a better word! Another friend played it using his Les Paul loaded with Gibson '57s': his jaw dropped and he damn near creamed his jeans. He's used to playing through my JCM800, JTM45 and AB763 Black Face Twin (all home made), and this just leaves them all for dead. The Express is one incredible amplifier.

The face plates were easy. Nik emailed me the engineers drawing for the chassis (I used a Ceriatone chassis), which I then took to a local trophy shop who laser cut the plates to the drawing, then cut the lettering in from behind into gold backed plexi. Finally they sprayed black acrylic paint from behind to highlight the lettering. It was a little expensive due to the initial art work, the pair cost the equivalent of US$100, but subsequent ones will cost half that.

Thanks for the compliments guys. I was worried about posting pics after seeing some of your amps, and I didn't think mine stacked up against the quality of yours. And I have since changed the impedance knob to an Express type instead of the chicken head.

Tinkerer

[keithrick]

Congrats on a job well done.

[Bruciep07]

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The face plates were easy. Nik emailed me the engineers drawing for the chassis (I used a Ceriatone chassis), which I then took to a local trophy shop who laser cut the plates to the drawing, then cut the lettering in from behind into gold backed plexi. Finally they sprayed black acrylic paint from behind to highlight the lettering. It was a little expensive due to the initial art work, the pair cost the equivalent of US$100, but subsequent ones will cost half that.

Tinkerer

Did you see the plates RJ sells? I bought a cherry express style plate from him and it's very clean, only the face plate but thats all the originals had anyway. And less than half the cost of what you spent on the plexi ones... Nice build, I dig the turret cap stack...
Bruce

[KellyBass]

Very nice build! I'm definitely gonna have to borrow that turret board/cap idea for my next build.

I couldn't help but notice that some of your outside foil bands on some of your capacitors are oriented differently than mine. I wish I was clearer on this...does the band go on the ground/low impedance side or visa versa?...and just how critical is this?

[Tinkerer]

I saw the plates that rj sells and thought about them, but my friend originally wanted a Comet until I told him that I could build an Express. When he heard that he got very exited about the idea but didn't want an Express cabinet. The amp is being built into an early Marshall style of cab and he wanted a rear plate...pic of cab is posted, and I wish I could do this quality of work! This isn't the actual cab, but he has ordered the same design.

About the cap orientation. I've read conflicting stories about the orientation of caps, and the consensus of opinion is that with modern caps it doesn't matter, but if in doubt, contact the cap manufacturer. I read somewhere on a site about a Marshall built with Sozo caps, and that the band on the cap must point to the tubes, but when Sozo where asked, they claimed it didn't make a difference which way the caps were oriented.


Tinkerer