Matchless Spitfire?

[beasleybodyshop]

Anyone build one? A friend gave me this old crate solid state amp. Came with an english G-12M in the cab, and the chassis looks big enough to use. I was thinking simple and sweet, maybe a Spitfire build. What spec PT/OT would I use? I have had good luck with classictone trafos.

lots of useful PCB components here. I think im going to rob the diodes for a SS recto option for the spitfire. Also spot 4 TI 4558 OP AMPS...good for tube screamers

[M Fowler]

https://tubeamparchive.com/viewtopic.ph ... s+spitfire

[beasleybodyshop]

Did you mismatch your Marshall iron for the 4K or whatever? I was a bit confused about all that jibba jabba.

[M Fowler]

I used Heyboer 18w Marshall type transformer set from Watt's so the OT is 8k with 4/8 R secondary and I used 4 ohm total impedance 212 cab plugged into the 4R jack.

I have gigged with this amp years ago and it cut through the mix though it's only 18w but did use a linear booster and distortion pedal on some rock songs to get what I needed. Crowd probably was just fine but I needed to feel and hear it

Received lots of positive comments regarding my amp sound using this version of a Matchless Spitfire. (Watt's version)

Note: At home the amp might seem too bright but in the mix of the band it was perfect so I keep the PI value stock (Watt's version 1k2)

[randalp3000]

Been wondering for awhile and since we're on the subject,

Should this amp have an AC15 OP trans instead of the 18W Marshall. I thought all the Matchless transformers were copies of Vox's.

These guys have the originals but they're not cheep.
http://westlabs.com/Frames.HTML under parts/transformers
I tried to talk to them on the phone about the primary impedance of the 15 watt and couldn't get a straight answer.

[Masco]

I know the original AC-15's had the 8k primary, but I've heard the Matchless(not sure if WestLabs OTs are the OEM or possibly one of them?) are mismatched 4k w/ mislabeled secondaries. Heard something about this, never got the straight poop though. Hope someone can shed some light.
I've done a few AC15 type builds w/ 18W Marshall sets that sounded good. The physical size is obviously different than original AC15 iron. Magnetic components and Heyboer have large size AC15 OTs, but neither are 8k.

[M Fowler]

You should be using the Westlabs transformers for correctness.

Bob Wood at TDS says they were the original builders of the Matchless transformers. They built me a custom 18w set for my 18w Marshall Tremolo build a few years back great product.

[niversen]

West Labs is just one guy out of his house. He's just on the other side of town from me. He's an older gentleman who, from what I can tell, used to know some of Michigan's bigger names in rock from the 70's and 80's. He's a nice guy but really quirky, so good luck on getting clear info from him on specs. As far as I understand, he bought up all of the Matchless transformers from whoever wound them back when Matchless went under temporarily. And he definitely asks a premium price for everything he sells.

[randalp3000]

I find it interseting that Mercury Magnetics says,

"We were the original production
supplier of transformers for the first generation of MATCHLESS."
http://www.mercurymagnetics.com/pages/mainframe.htm
http://www.mercurymagnetics.com/pages/mainframe.htm

and they have different models for the spitfire and lightning. I would think Matchless would have used the same transformers for both amps.
Also the West lab's are about $120 cheaper than MM.

[Masco]

West Labs is just one guy out of his house. He's just on the other side of town from me. He's an older gentleman who, from what I can tell, used to know some of Michigan's bigger names in rock from the 70's and 80's. He's a nice guy but really quirky, so good luck on getting clear info from him on specs. As far as I understand, he bought up all of the Matchless transformers from whoever wound them back when Matchless went under temporarily. And he definitely asks a premium price for everything he sells.

Yup, I have one of his West Filmore builds from the 70's . 200 Watts, the largest/heaviest transformers of all my amps. Just huge.

[beasleybodyshop]

Mark, I see two 30uf's and one 22uf solen in your filter cap section of your Spitfire build - the Watts layout shows two of each?

Is the 125ohm 5 watt cement jobbie the replacement for a choke?

I see you have two 25uf/25v electrolytics in the first stage - is one of those for that "fat boost" switch you have going on there?

Thanks for posting the pics Mark.

[beasleybodyshop]

Ah, I see what you did there, you moved that filter cap over close to the first stage.

Gotcha.

[M Fowler]

That was either my first or second build and a few years ago. Yeah that fat switch has 25uf/25v cap switch to ground.

Yup I moved the one filter cap.

[beasleybodyshop]

If I was going to use a choke which one would I use?


Or if I was going to use a resistor, what size would I use?

[M Fowler]

One schematic says ideal choke is Hammond 158M 10h 100mA 262R

The same guy says he used the 157L 14h 75mA 425R

I used a 1k/3w resistor