Saturday, 11 June 2011
Crack and Speedball Up and Running!
Finally put the replacement parts into the C4S board this morning. See the photos below. The rebuild itself was very quick, only 5 components to solder and 3 wires to reconnect. After doing a few visual checks to make sure everything was in order, I fired her up. And yes, it worked! No problems this time. Equal volume on both sides, and all LED lighting up as they should. Now this amp has been fixed, I now have four fully working headphone amps; the Crack, TU882R, Ear+ and the MiniMax Millet. I'd have to say that the sound stage is a lot more compressed then what I remembered last time I was listening to this amp. I am using the stock tubes supplied by Bottlehead, which is a Philips ECG 6080WC and (I think) a Sylvania 12AU7.
An initial observation about the floor noise of the Crack. There is a hum, but given it is AC filaments, it could be from that source, but it could also be from the B+, who knows. I would have to say that it is not as loud or obvious as the hum on the Elekit, but this is just anecdotal observation, as the last time I listened to the Elekit was a few weeks ago. Again, the Ear+ doesn't have this problem, but that is DC filaments. Could it be from the B+? The Crack has CRCRC filtering. The Ear has CRC for the output tube, and an additional RC stage for the driver tube. The Elekit has cap input, followed by a FET, which I can only presume is acting as some kind of series regulator.
Well, moving house very soon, and all of this needs to be packed up and transported. However, the beauty of the headphone amp and system, is that they are so portable, and can be one of the last things packed, and the first items unpacked. I think in the coming months, I'd have a good opportunity to start some comparisons between the three amps.