Hi all,
This is Andrea from AAElectronics (https://www.aaelectronicspcb.com/). After a lot of request, I've started design for a PCB for Vox AC30 style amps, with the aim to make it flexible enough to accommodate seevral variants (e.g., EF86 channel, Normal, the AC15 version or additional mods). I'll attach the layout, PCB, and schematic for reference.
Would love to get your input on my design, and whether you'd like to see/add something to the PCB/schematic.
Have a great weekend!
Andrea
AA Electronics
Last edited by frusciante89 on Sun Dec 01, 2024 11:41 am, edited 1 time in total.
First thing that pops into my mind is the cathode resistor, R67. AC30s are biased too hot for me, and this is a likely component swap, so make it easy to do--that would be a great place to add a couple turrets. And your component looks to be 1w...should be 5w or higher for safety, and a cement resistor is the most common choice, so you'll need a larger footprint.
I build and repair tube amps. http://amps.monkeymatic.com
+1 on Xtian's comment. Two smaller 100R resistors in parallel for 50R would be typical if space is an issue (and wanting stock bias, although it's really hot), or ideally something large that can dissipate some heat. 56 to 68R, even 82R would be suitable to not run the tubes at 138% of max dissipation.
On your schematic C6 and C10 are reversed. Bright channel is 500p and Normal is 0.047uF (47n).
Thanks guys! Great suggestions! Do you feel that adding the tube rectification option will be a feature ppl might be interested in?
Also, I have seldom use Vox, so I'm under the impression the Top Boost is the holy grail, and the amp that this PCB should target. Any other variations on the circuit that you think might make sense to add?
Thanks in advance
I'm trying to view the images in post #1 and none of them are legible on my 4k display. What am I doing wrong?
Based upon the feedback that others have offered, I'm assuming that the images were legible at the time of their posts, but I also see that the first post was updated in december and now the images aren't legible. Can anyone help?
Hi guys! Quick update: finally finished this PCB and produced the first prototypes. I called it "The FOX30". It allows to build a 1:1 replica of the AC30, including the Top Boost mod, in a single compact platform (362 mmx 77mm)
You can check some pics below. It's now available on my website for anyone interested: https://www.aaelectronicspcb.com/produc ... ac30-style
You can consult all documentation (schematic and layout) for free
Nice Board! Good idea too.
I added a rotary switch on my AC30 build with three 25W Dale resistors mounted on the chassis. The switch can then add them in series to get different bias settings.
I think it was 100 ohm, 50 ohm and 25 ohm. Sometimes I want the Hot bias sound and other times I like it Cold!
