Buyer Beware
This is my first post on Audiogon Forum but I have been a audiophile for almost fifty years. I like to buy and sell used equipment because it gives a chance to try a much wider range of products. Recently I wanted to try different USB cables and in that process I purchased two products from Mad Scientist Audio. One was their Black Magic and the other was the Ultra version. Both were purchased used from different sellers. I own two systems and decided to keep both. In both systems I use a AMR DP-777SE dac. In the system using the standard Black Magic USB the system was not using the built in volume control. About 2 month after purchasing the cable I tried using the internal volume control in the dac and it only worked at full volume. Thinking the dac was faulty I sent it back to TMR (great company) for evaluation. They tested it for 2 weeks in every configuration possible and determined it was working as it should. When i got the unit back (after a cost of approx. $200) I determined that the problem was the Black Magic USB cable. I contacted Bob at Mad Scientist Audio by email multiple times and he replied that his cable is incompatible with 1 in 50 produces and mine must be the 1. I then tried it in two other systems and also had the same results. Either the volume control didn't work or I would get cracking noises. after many emails back and forth Bob would not exchange the cable for a working one and only offered to sell me a Ultra cable at a discount. I don't know what his profit margin or warranty policy is but I have never experienced this especially with a cable manufacture, I offered to send it back to him so that he could access the problem but in the end his last email read "Therefore I don't think it's worth you wasting anymore money trying to fix or exchange your cable." Very disappointing. The cable is now in the trash. I know that this is a small boutique manufacture but with the controversy regarding cable costs and if expensive cable are necessary I thought that buy telling my story maybe it would alleviate this situation with this company.
This what you stated, "In the system using the standard Black Magic USB the system was not using the built in volume control. About 2 month after purchasing the cable I tried using the internal volume control in the dac and it only worked at full volume."
From this it seems you did indeed use this cable when not using built in volume control and had no complaints. Now after 2 months you try using built in volume control and now only plays at full volume. What am I missing? |
@lordmelton - I agree with you but it seems the cable actually worked for two months and then when the OP decided to use his DAC’s internal volume control, the cable was not compatible with that set up for some reason. It is a used cable, it worked for two months, and it apparently works except in the case of using the internal VC with the OP’s DAC. I understand his calling Mad Scientist to discuss and try to troubleshoot the situation, and I appreciate that Mad Scentist offered a discount on another of their USB cable products but, beyond that, at some point you take risks in order to save money by buying used stuff. From a technical standpoint, I fail to understand how a USB cable would work with a DAC when it is set to zero attenuation and then fail to work when the DAC’s internal attenuation is engaged. Hasn’t the data transfer already been made by the time attenuation is applied? |
Well, that is true for the original Universal Serial Bus (USB 1.x) which had just two wires to carry data, one bit after another. That's where the Serial part of the name comes from, as opposed to multi-wire parallel connectors. The other two wires were to carry DC power at 5 Volts and up to 0.5 Amps for a maximum 2.5 Watts. USB cables with just two wires are used as power supply cables only - they cannot carry any data. Some idea of the dramatic evolutionary steps in USB is that the maximum power in the latest standard is almost 100 times more, delivering up to 5 Amps at 48 Volts for 240-Watts. There have been three more major generations of USB specifications. From Wikipedia USB - Wikipedia
So there is no such single thing as USB. It is no longer even Serial! There are now nine families of USB connectors. For example, the new "standard" USB-C connector has 24 pins and looks more like the purpose designed HDMI which is Parallel and eschews data packets. USB was never designed for error-free streaming.
Note the implications here. Audiophiles often believe that because files and messages can be transferred error-free, that implies streams are error-free. They aren't, but you do get your errors for free. |
