0 Members and 2 Guests are viewing this topic. Read 2612 times.
I bought two Jerome Industry power supplies since there was a minimum order amount. I sent both to Wayne to get one modded and to get a power cord put on the other one. They just arrived yesterday. I thought he would have marked them on the case so I would know which was which, but they both looked the same. I figured this would be great opportunity to do a blind test. I hooked up the first one and was met with a fairly loud transformer hum. I hoped this was not the one that got modded. The difference in sound between this and the switch mode PS was that this one had more weight to the sound. I then hooked up the second one. This one had almost no hum, but the sound was not quite as good as the first one. It had almost the same amount of weight, but something was missing and I do not know what. I switched them both out one more time and the one with the hum still sounded a bit better. I opened them both and saw an extra cap in the one with the hum, so this was the one that had been modded. At least I felt better now, knowing that I did not waste my money. I heard a consistent difference without knowing which was which. About that time, I noticed that on the end of the plug there was a label indicating this one had been modded - doh. The difference between the switch mode and linear was that the linear had greater weight. The difference between the modded and unmodded PS was not night and day, but still noticable. I am really not sure what I heard that made it more appealing, but the difference was there. At this time, the only software mod was doing the FLAC to PCM conversion at the SB server and, on the Touch, the single output mod was the only one in effect.
As Mike noted, the power supply that had been modded had a BOLDER Cable Company labeled heatshrink covering the DC connector and the stock one had unlabled black heatshrink.Both power supplies will need a good 400 hours of constant use before the true sound of them will emerge. The main power supply filter caps and the reservoir cap have been changed and an additional bypass cap had been added. The sound of the power supply caps and how they are used will improve depending on exactly what caps are used.I never noticed any hum from either unit when it was on the bench. However these supplies are surplus and have been sitting around for some time. For $10.00 you should not expect every one to be perfect. It could be that some of the windings might have loosened up in shipping. You might want to contact Herbach to see if they would be willing to send you a replacement. If they do and you test it at home to find no hum, ship it out to me and I will mod that one for you at no charge.