Looking for Matchless Spitfire Porn

[bob p]

I'm looking for Matchless Spitfire Porn, specifically a PTP a circuit layout.

When I say PTP I mean a true PTP layout using direct wiring and perhaps terminal strips, not a turret or eyelet board layout.

pictures are surprisingly hard to find, and a layout drawing seems to be nonexistent.

anyone?

[Justin Thomas]

Would you take a PTP Spitfire built into an old Stromberg-Carlson PA? I can get pics of that... I think it has a few "Chuck H. Tweaks" too... nothing more than a couple resistors and a cap or two.

Or did you want a real Matchless Spitfire?

Justin

[bob p]

While I'd definitely prefer to get a look at a real Matchless Spitfire, I'd love a chance to look at any good PTP layout. Pictures have been surprisingly hard to find. There are lots of Spitfire clone builds out there but most of them seem to be board-based. If you did a PTP build then I'd surely like to see it. It'd be great if someone had a PTP layout diagram in their files.

FYI there's thread on TGP about showing off your amp guts -- it has to be 30-50 pages long. It's old enough that many of the photos are no longer showing up.

What struck me as odd in that TGP thread was that people were praising the anal-retentive looking Hiwatts as the ultimate in good amplifier design and bashing Matchless amps as being "sloppy looking." I couldn't find images of a Spitfire, only the more complicated Matchless amps. Personally, I thought that the Matchless amps were classic works of art.

This EL84 amp is one of those back burner projects that I'm trying to get done. I had originally intended to build myself a little PTP EL84 amp by converting an old Heathkit chassis but the Beatles pushed me into a case of modder's remorse as I mentioned in the Please Please Me thread.

Looking over the parts boxes I found that I've got enough parts to build a Spitfire, and it's looking like I'm going to have to do a scratch build because I don't want to tear apart that little tube HiFi amp.

[Justin Thomas]

Bob,

I'll see if I have my pictures handy. I wouldn't say my "layout" is "good," exactly... I take my Spitfire build as proof that some "laws" are flexible in amp construction. I was forced to follow the layout of the chassis, so it"s not very tidy. Most of my builds would be "extremely sloppy" by HiWatt standards... but they're more like the organs I used.

I think HiWatts are beautiful, and Matchless are too. HiWatts are neat, but I consider Matchless to be more inspired by the "military" look. The density they achieve in a tiny space surprises me, but I know their main concern was ruggedness, not necessarily "neatness" or "ease of repair." Matchless went for bulletproof, and followed the people who'd know best...

Justin

[bob p]

I tend to think of turret board construction as being the military type of build, built for ease of service in the field with all of the components spread out and easily accessible, while I look at true PTP designs as being what the military was trying to get away from by creating the turret board scheme.

We all know how easy it is to work on eyelet board and turret board builds -- they're built for ease of service. But they're not very compact. To me it seems that eyelet board and turret boards purposefully trade away compactness for ease of service. Like this Spitfire clone. It's a beautifully simple board layout but the turret board paradigm spreads things out enough to make the easily accessible that it really makes the amp a lot bigger than it needs to be.



Contrast that with true PTP wiring as was developed in the 20s and 30s and you can get complicated amplifiers that are a lot more compact. This sort of compactness reached it's zenith in the 50s-60s with some of the HiFi stereo amps, where it was ncessary to cram complicated circuits into as tight a space as possible. These amps ended up being tremendously tight, which made working on them difficult. The Matchless amps I've seen remind me of that.

That kind of construction is a true work of art. Unlike a Hiwatt design that uses the shortest possible circuit path from Point A to Point B by stressing wires taut, some of the old classics will use bundles of wires routed together along long circuitous paths, laced together with waxed twine using a running knot called a "telephone hitch." Now we use cable ties and the artistic part of the build seems to have been lost.

It looks like some people are trying to keep the old wiring methods alive:

Navy Electricity and Electronics Training Series (NEETS), Module 3, 2-41 through 2-53 - RF Cafe

[bob p]

I wouldn't say my "layout" is "good," exactly... I take my Spitfire build as proof that some "laws" are flexible in amp construction.

Laws are nothing more than someone else's opinion of how you should behave. They're meant to be broken.

[J M Fahey]

Laws are nothing more than someone else's opinion of how you should behave. They're meant to be broken.

CITIZEN BOB!!!!!!

You!!! ... yes, you!!!! serial number 428763228 !!!!!!!!!!!

STAY WHERE YOU ARE !!!!!

Don´t touch that keyboard or try to turn computer off!!!!

Thought Police SWAT teams will be getting through door, window and roof in 10 - 9 - 8 - ........ !!!!!

[Justin Thomas]

CITIZEN BOB!!!!!!

You!!! ... yes, you!!!! serial number 428763228 !!!!!!!!!!!

STAY WHERE YOU ARE !!!!!

Don´t touch that keyboard or try to turn computer off!!!!

Thought Police SWAT teams will be getting through door, window and roof in 10 - 9 - 8 - ........ !!!!!

It's funny because it's tru- oh, wait... it <IS> true! And that's not funny at all!
Juan, you should really stop picking on us Americans for our short-sighted-ness... And here I thought the referenced serial number was a Matchless Spitfire.

Justin

[Justin Thomas]

True PTP Ugly Spitfire Porn!

Hey Bob,

My buddy sent me some pics of the Spitfire I built and he bought. Some of the component values may not be "Spitfire-Perfect," but I built a straight Spitfire clone to start and then did some "Chuck H mods" to it; the schematics for those are floating around somewhere, I think under "Spitfire With Cheese." I didn't change the layout when tweaking, just values. Enjoy, and be nice - it was my first build! (Not that I've worked on getting better...) The fourth pic is the Stromberg-Carlson PA schem that came under the lid, so that's the transformers and rectifier tube I used. The can cap is new, I think a 20/20/20/20@450V CEDist.

I think I should mention: The full guts shot, the vertical one, the preamp tube is the 12AX7 that is between the can cap terminals and the speaker jack. I tried to make the preamp tube the socket right by the input jack, but having to run the PI circuitry from back to front to get to the EL84s made hum and noise. I just switched the positions of the PI and preamp tubes (like the original PA) and the noise issues were gone. So I've got a long run of shielded input cable going past the filter caps and near a speaker jack, and then the signal gets routed back toward the front of the amp where the controls are... Go figure, I wouldn't have thought that would work given all the "rules" about layout I have "learned..." :P

Justin

[bob p]

Thanks for posting that, Justin. The police came, just like Juan said they would, and they won't let me look at porn right now, not even amp porn. They say that I have to finish my aversion training first.

[Justin Thomas]

Wow. My amp-building skills haven't improved at all as far as neatness goes! Oh well, at least the owners like the way they sound. That was my first build. Still working on #4.

Justin

[nosaj]

Wow. My amp-building skills haven't improved at all as far as neatness goes! Oh well, at least the owners like the way they sound. That was my first build. Still working on #4.

Justin

I think it looks just fine being point to point, True point to point only looks bad if you don't understand what is going on. Very similar to an early RCA amp I had minus the 12 guage buss bar.


nosaj

[Justin Thomas]

Thanks Jason! I'm comparing my work to that 1951 Siemens projector I got for $20. Or that Viking mic pre... The real art pieces. Or even a genuine Matchless... Holy cow.

Justin