So, it might be absolute nonsense and I've been taken for a ride, but I was curious enough to want to put a bid on this;
It's a Woden Output Transformer, probably one of the first they ever made for vox as the date code puts it in October '62, and the earliest found is from August that year. I'm really excited about it because I do believe there's something in the transformer sound, and really the Output transformer is the only thing in an AC30 signal path that can't be perfectly duplicated with modern equivalents, because you're never quite sure how they were wound inside.
At some point it's been painted black, the last owner tried to clean it up. It's got separate primary halves, for some reason - you need to connect two red wires together to make a centre tap.
It arrived earlier, I've got as far as wiring it into my AC30 sat on a coffee table, with a Jensen P12Q serving as a sacrificial test subject in case some terrible malfunction blew the speaker. It works, next step is getting some stand-up bell covers so I can mount it on the chassis and give it a proper test with some old Alnico speakers.
Comments
Odd though.
Changing the primary impedance is a useful tool to change the sound, My other AC30 is a 1x12 running at half power with the original output transformer, which means the two remaining EL84s want to see around 8k, but are seeing 4k unless I plug a 16 ohm speaker into the 8 ohm tap. Doing so does make it a bit louder and more bassy, but I also love the sound of an 8 ohm speaker with it too, it's a little quieter, a bit cleaner and tighter, more immediate and the bass has a nice growl without ever getting woofy. I think some of the smaller Matchless amps deliberately ran the same impedance mismatch to get the same effect.
If I can find a suitable AC transformer, I'll run a few volts into the secondary and see if I can work out a rough primary impedance for this woden, I've read they're often on the high side of 4k.
Bandcamp
Spotify, Apple et al
Tomorrow evening I'll take it to practice and put some proper current through it.
Bandcamp
Spotify, Apple et al
The stock transformer on the Custom Classic series is a bit odd. It's got smaller laminations but a taller stack of them, and it doesn't sound bad really, just a strange blend of being a tad gutless while also not letting the amp focus in on the mids when pushed. Replacement OTs I've got for ones I've modded before (I've had a MM Woden clone, and one made by Trans-Amp in Chesterfield) have had a better roar to them and more punch.
It's impossible to talk about the sound of an OT without sounding like you are so superstitious an audiophile that you probably believe in witchcraft but ah well.
Bandcamp
Spotify, Apple et al
Fucking hell, yes.
Bandcamp
Spotify, Apple et al
I can't be arsed with full fat AC30s because frankly they're too heavy and too loud when you get them in the sweet spot where everything gets exciting. But playing through a great one is one of my all time favourite experiences - there's nothing like it
Bandcamp
Spotify, Apple et al
Bandcamp
Spotify, Apple et al
The first thing I noticed with this Woden was that the treble was less in your face - I turned back the cut knob; on all the modern AC30's I've ever had, the cut's lived at about 3 o'clock to stop things getting harsh with distortion pedals. I turned it back to about 1 to get the top to open up, and while those upper harmonics came back they still weren't harsh.
Other than that, it's just thicker overall. More midrange gets through, and the bass had this really lovely compression where it was full but not boomy. I found myself rolling the bass knob back from 2 o'clock to about noon.
It's hard to get scientific about it, because the differences made me set the knobs differently and also subtly play differently. But I'm really happy with the way the voice of the amp's changed
Bandcamp
Spotify, Apple et al