Vox AC30 head layout

[pdf64]

Hopefully it ended with a different cathode resistor on the el84s - 500 ohms won't work too well.

[fyl]

Maybe 500R works nicely when coupled with the vibrato section...

[Bruce / Mission Amps]

Right, that single cathode biasing resistor needs to be something more like 68 ohms.

[Alf]

And it used to be 47 ohm that's why there's probaby the mistake with the 500 ohm which should have read 50 ohm ! Just an 0 too many .

Somewhere between 47 and 68 ohm would be nice. With 47 ohm the tubes can get to over 200 degrees celcius ( on the outside ).


Alf

[Hardtailed]

And it used to be 47 ohm that's why there's probaby the mistake with the 500 ohm which should have read 50 ohm ! Just an 0 too many .

Somewhere between 47 and 68 ohm would be nice. With 47 ohm the tubes can get to over 200 degrees celcius ( on the outside ).


Alf

Yup
I built one recently and went with the traditional 50ohm there, I've never seen an amp dissipating so much heat on idle! But it sounds godly!
I left an opening in the front of the head cab for better ventilation (the back is completely exposed)

[jmaf]

Below is the layout with the EL84s in line. I move the OT a bit. I haven't ordered or decided on the trannies yet so this is only an estimate os size and a guess of mount type.

A bit off-topic here, can anyone please ID the software used by fabiomayo to do the layout drawing? I thought it was really neat. Thanks very much in advance and sorry for the topic detour.

[Leif H]

I'd be interested in hearing how it turned out, and if there were any issues with the build, noise, things getting too hot (an AC issue) I'm starting my build, I'm going to do the chassis in flat layout, like a head, and build the cabinet taller to accomodate an open (mesh) back for cooling and use the grill cloth as a face and vent the top as well.
I'm going 15 watt as my power supply is only good enough for that.

[Delayar]

Hi!

has anyone still got a hi-res image of the layout? I am revising the layout of my own AC30, so another layout may bve helpful.

Regards,
Markus

[bob p]

I recently emailed fabiomayo with a request for the high res drawings and never heard back from him. If anyone else has them, please let me know! TIA.