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This amp was a labor of love, I have to say. I give special thanks to Anthony, of Reason Amps, Nik of Ceri@tone,TransformerDesignandSupply, Jeanne of BNP, as well as the people on this board, who helped me trouble shoot a problem with little hum.

I wanted a Spitfire, but didn't really want it in the Matchless style cabinet - I like the look of the Marshall 18w. Ceri@tone helped me with a chassis that fits the Spitfire innards into the 18w chassis config.

The cabinet came bare from Reason Amps just before they stopped selling them, and I covered it with Lizard Skin Tolex (ebay). The tubes are: GT Mullard 12ax7 for the preamp, GT Mullard Matched Phase Inverter 12ax7, two matched JJ EL84's.

There were only two hitches I encountered. The first was when I loaded my speaker, chassis, and went to install the tubes - the end bell of the BBQ Blue Dog AlNiCo was directly in the way of one of the EL84's. Short term solution was to remove the end bell, but that left maybe 1/4" between the tip of the tube and the magnet - not good.. Long term solution was to have a new baffle board made that centered the speaker between the two banks of tubes. Anthony came through once again, and I was on my way.

The second hitch was an annoying, nasty little hum. With some help from this forum that led me in the right direction, I located a ground buss that connected the filter caps to the screen resistor/cap. Breaking the link between them, and running the screen resistor to preamp ground solved that one.

The final touch was the faceplace. With a gold vent, cabinet string, and Marshall handle, I needed a gold plexi style faceplate. I found Jeanne at BNP, and she did a terrific job!

I love the sound of this amp! It sounds like a huge amp, only not so ear shatteringly loud (how loud can you get with 15w?). Band mates and fellow musicians have raved over the tone and dynamic response. For those small to mid-sized venues, this is my amp of choice.

Ok, here are the finished pics:


From the front:


From the back:


Top View:


Chassis:


Here's where I needed to separate the filter cap grounds from the screen resistor/cap:



I'm looking forward to tomorrow night when I get to gig with it again!

Looks very nice. Really neat wring job. Well done. Quite an interesting idea to cross the two - Matchless & Marshall. And a cut control - do you find it does what you want it to?
How did you design the cut control? How about clean headroom - Got some??

BTW, nice job on the Tolex! How many amps have you made now?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Henry;

Great looking build Bro! Bet she sounds good as she looks, too! Thanks for sharing that Beauty! Awhile back, I had a customer that wanted one of my Spitfire/18 Watt Hybrid Thunderbolt 9 Amps in an 18 Watt Style Cab. Trinity came through for me on the cab which was built to my specs. Stephen was great! Here's a few pics of Miss Salt n Pepper:









CR ><>

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WoodCross Amps

http://www.geocities.com/woodcrossamps/

Dang, those are both beautiful amps. I'm not worthy.

Bear

When I was younger, I worked as a wireman for a television transmitter manufacturer - miles of wire in those things!! I learned to be neat and tidy, as well as how to solder. The cut control was taken from a DC-30 schematic and works as I expected. I just roll the highs off a tiny bit, and it sounds sweeter to my damaged ears. I can do clean one of two ways - crank the master and turn the volume up a little, or *even better* control it with my TopHat Expressor by using the clean cut. The bypass (a true bypass) lets the amp sing on it's own merits, and the boost gooses the preamp into a nicely liquid distortion.



This was my second try at tolexing - the first was a 2x12 cabinet. This time, I did a lot of research before I attempted it. Good materials make a world of difference.

The Spifire was my second build. The first was a Mesa Boogie Mark I head, made some 25 yrs ago when I was too poor (yup, a working musician) to afford the real thing, but ambitious (read young) enough to tackle the challenge. I never finished the cosmetics, just left it a Frankenamp. I gigged with it for years, but it is no longer my taste in amps - although it does sound righteous when crank the master and skip past the first stage of gain (input 2).

Very sweet looking amp you've got there!

I try to gig with it whenever I can. The lower power acts as a sort of governor for the band, we can't get too loud because of me! I have been approached by players who want one. heh heh... Just curious, why did you offset the speaker? If I were satisfied with a V30 or the like, it wouldn't have been necessary to move mine, but the Blue Dog just sounded so nice - 3d bass and treble response, nicer than anything else I tried.

Nice job!

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PJM

http://www.diyguitarist.com

Crosstown,

How did you find locating the two transformers? Was it hard to find the right location for minimum interference? How did you do it on that small chassis and those Matchless transformers? How far from the PT is the OT located?

I'm guessing you have no interaction between the two, but I'd like to know. I just might do a similar build with a 15!

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Hi Stephen,

The PT was kept as far away from the preamp as possible, and close to the a/c input, while still leaving distance from the OT (about 3.5" from bobbin edge to bobbin edge), and still allowing ~1.5 between the OT and the PS. The amp is pretty darn silent, is all I can say. Quieter than my other guitarist's Fender Dual Professional...

Henry

When it's designed correctly and working properly, it's amazing how quiet the Spitfire can be.

_________________
PJM

http://www.diyguitarist.com

Why offset the speaker you ask?
1. Though it may look alot like a Standard 18 Watt Cab, it's smaller. 21"x18.5"x9" if I remember correctly.

2. One of the practical reasons that Fender did it in so many of their Tweeds was because they put both trannies on the same side of the chassis and the speaker offset balances it better.

3. The costomer may want to put a Big Alnico Speaker in there in the future. I learned the hard way that Alnico Blues, Alnico Blue Dogs, and especially Red Fangs have HUGE freakin Bells on the back of em.

CR ><>

_________________
WoodCross Amps

http://www.geocities.com/woodcrossamps/

Ah, I thought it looked on the smaller side. Very cool, though. It must have weighed a bit less with those dimensions. Haven't weighed mine yet, but I figure it to be ~40lb.



As it turned out, my PT is way on the other side of the middle, with the OT closer to the middle, so not quite balanced. By accident, I offset the handle 1/2" (measure twice, dummy!) towards the transformer, and it's nicely balanced. All things being equal, I would center the handle next time for purely cosmetic reasons.



Gee, exactly the same reason I did what I did! GMTA, or just common sense?

Henry