The Ceriatone DC30 Lives!!!
I received the few small part I needed to finish the Ceriatone DC30 last night, so after getting the kids to bed I fired up my soldering station and set to work. I thought it would be a simple matter of soldering the wires onto the half-power switch, soldering in the 68 ohm 10 watt power resistor and hooking up the B+ from the filter caps to the output transformer. It wasn’t quite that simple. I had left a bit too much of the leads from the 16/8/4 ohm taps on the output transformer to the impedance selector switch, so I had to redo those connections, and I wasn’t happy with the wiring from the impedance selector to the speaker polarity switch, so I redid that as as well. There were I a few other connections wanted to change as well, so I probably spent two hours finishing things up and another hour going over the layout and connections to make sure I had everything done right.
By this time it was around midnight and I should have gone to sleep. Did I? Nope, I put some tubes in and checked voltages. The 6.3V heaters were fine, as expected, but the B+ was a bit higher than I anticipated—about 360V rather than the 325V I thought I would see. Interestingly, switching the amp from full- to half-power dropped the B+ from 360V down to 350V. Still a bit high, I think, so I’m going to check with Nik to see what I should expect and then go back over everything with a second, third and fourth time.
And, of course, I couldn’t help myself… I had to plug in a guitar to see what would happen. I grabbed the Weddington and a guitar cable, plugged into the clean channel with all the controls set to 0 and slowly brought the volume and master volume up. Guess what, the amp came alive! I found out very quickly that the master volume had to be pulled out to be engaged; with it disengaged, the amp is damn loud, even with the channel volume barely cracked. The clean channel was clean, though it would get some hair if the channel volume was cranked, and the gain channel was, well, higher gain. It wasn’t Marshall crunch, but I could get some good Voxy gain tones even without spending too much time tweaking the settings. It was also after 1:00 am and my wife, patient though she is, didn’t want me to wake the kids—or the neighbors—with the amp dimed.
Now I can see why so many people on The Gear Page have commented that Matchless DC30s aren’t bedroom amps. This is a massively loud amplifier. The master and channel volumes helped keep it manageable for basement levels, but it’s too loud for late night practicing. I found that the master volume is touchy at lower settings, so I was using the channel volume to control the amp. Power scaling or an attenuator is definitely required to use this as a late night practice amp.
Problems? Aside from the higher than anticipated B+, it seems to be working. I did notice that when the master volume disengaged, or cranked, the amp hums a bit. This may be due to the high B+, or it may be due to how I routed some of the wires in the output stage. I’ll figure it out. Regardless, with the master turned down, the amp was fairly quiet though not silent.