Graaf 13.5B Preamp Cooling

[Ali Tait]

Got round to getting more airflow into the pre by cutting a hole in the lid and fitting some mesh. Really didn't like how hot the lid was getting and I've seen other versions of the pre with louvres cut into the lid over the valves from the factory so decided to do similar.

Lid marked out-

https://i.imgur.com/BgtMBup.jpeg

Cut out and lightly sanded to give a key for the paint-

https://i.imgur.com/eXgVKEE.jpeg

Several coats of satin black later-

https://i.imgur.com/feY0LHQ.jpeg


Mesh painted and epoxyed into place-

https://i.imgur.com/GDIm6yn.jpeg

Finished article-

https://i.imgur.com/wWMtGrk.jpeg


Not perfect, but pretty good if I do say so myself. I'm happy with it.

They really didn't skimp on this thing, film caps everywhere, Elma selector switches, using extensions to minimise signal paths and a top quality stepper (bottom right). Not sure on the manufacturer, says made in Japan on it, anyone know?

https://i.imgur.com/NXnc0o6.jpeg

[Barry]

Excellent work there Ali. Well done!

[Macca]

You wouldn't know that wasn't always there, at least from the photo.

[Firebottle]

Looks great Ali, I thought Graaf were Italian.

[Ali Tait]

Thanks all, the case is now significantly cooler, no more medium rare components. :-)

Alan, yes Graaf were Italian. Love this thing, it sounds great.

[Qwin]

GRAAF Modena, Italy.

I briefly had the 5050 Tube Power Amp (50w stereo).
Nice sounding, great looks, but boy did it get hot, even hotter than my class A Sugden.
You couldn't hold your hand on the metal case work, for even a fraction of a second, not even the sides.

Nice work Ali, the mod looks in keeping with the units styling/period, reminds me a bit of the Audio Inovations casework.
Those Elma switches aren't the low end ones either.

[Ali Tait]

Thanks Ken, yes lots of good bits in this, Noble stepper too.