Spitfire amp

[M Fowler]

Anyone built one of Ken Watts Matchless Spitfire amps. I bought a chassis off of Ebay store to build something. Well like an idiot I decided to build the Spitfire! I should have just bought his kit instead but I have still saved money, since I had most of the stuff needed already.

I have to remind Ken W. that I need the transfomer wiring diagram for the 7000018 Heyboer PT 18W Marshall style

And 7000118 Heyboer OT 18W Marshall style.

Or does anyone out there have a schematic for these transformers?

Mark

[FYL]

Here's what I've got:

[M Fowler]

FYL

Thanks very much I knew there had to be some one out there with the info. Ken is normally very good at getting back to me but he must be out.

Mark

[M Fowler]

Well the tranny schematic isn't exactly the same but close enough. I have amassed a collection of layouts and schematics for the Spitfire and all are slightly different.

I am using the second layout.

[M Fowler]

OK I liked the sound of my spitfire; however, the MV wasn't working so I looked at other 18 watt amps as well as different spitfire schematics and layouts. I decided to move the wires to the middle wiper and the third pin, and viola the amp is singing nicely. Why do you think the layout has these wires like they do? Under the spitfire.pdf above.

Mark

[Structo]

Not sure, but yours looks nice.

Are you sure the Master pot you are using is not reverse tapered?

Like to see a finished picture.


Btw did you paint the control panel?

Why are the pot indexing holes showing? Just curious as why those would be there or maybe the knobs aren't big enough to hide them?

[M Fowler]

I started by buying a chassis from Turretboard.com off ebay and that is the way it comes all painted and controls marked, fully drilled very nice chassis.

Then I got a hair up my butt to build Ken Watts version of the spitfire. I could have just got one of his kits but oh well. I still saved money since I had most of the parts.

You don't even notice the pot locating holes I don't think. I ended up puting it in a Gabkit cab I had originally built for my Ceriatone Express but moved that chassis to a cherry cab I built. I run it into a 212 with celestion vintage 30s. The more I play this amp the more I like it.

Mark

[M Fowler]

No it is not a reverse taper pot.

I just put it back together today, but I could pull the chassis out again and take some pictures if you want.

Mark

[mcrracer]

What is the value of the choke? I have searched all over the place no luck yet. Thanks

[M Fowler]

mcrracer

This amp doesn't use a choke, there is a 1k 3w resistor and 22k 3w resistor between the 33uf filter caps. See the layout called Spitfire.pdf

It uses 18watt marshall style Heyboer tranny set.

Mark

[mcrracer]

I see that. Actually, I was going by the schematic.

[M Fowler]

The Rocket uses the Hammond 158L but I am not sure what rating would be appropriate for the Spitfire.

Mark

[M Fowler]

Looks some where between 90-100 ohms resistance on the inductor, just guessing.

Mark

[M Fowler]

Well I was asked to provide some build pictures so I took the chassis out of cab and snapped some pictures.

Mark

[Cygnus X1]

Very clean build, Mark!
How would you compare the volume of it to a 5E3 Tweed?

Either my 5e3 is too loud, or my Spitfire clone too quiet.
But the Spitfire is a cool tone. Just no volume to it.
I must have something screwed up on the grounding.

Did you ever get the MV to work?
I gave up, and put in a second input jack.