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. 

sdorfman58

Taking perspective of manufacturer. Based on the fact the Black Magic worked in another system, this proves the cable NOT defective. Based on my idea that at least handshake required for proper operation he'd have to modify your cable with power pin wired in order to make it work with all your setups. I can understand his not wanting to  cover cost of shipping and modifying cable, as far as I can see he is not responsible in any way. You purchased used cable without understanding this issue, I'd be talking to seller in this case, if they didn't notify you of this situation prior to purchase they are the responsible party.

There is no "Black Magic" about USB cables, they either have 2 or 4 internal wires. They can be easily tested with a multimeter for continuity.

There is no special resistance or impedence, only other possibility is earth, are the cable ends showing continuity?

If the cable doesn't work in anything and you can prove damage the seller should give you a refund. I think it's very unfair to cast aspersitions on the manufacturer.

Sns What other system did this cable work in? The Black Magic cable did not work in the other system. The Black Magic Ultra cable (another cable) worked in both systems, one and two. The Ultra also worked in my headphone system not the Black Magic. lordmelton  Again I am not asking for advice on how to rectify this situation I I am only telling how the manufacture handled the situation and to give possible     advice when troubleshooting a issue, as it was not even a thought that a USB cable could cause the the issue I was having with my dac.  As far as casting aspersions on the manufacture, take this information and form your own opinions. Of course the cable is not under warranty but offering a discount on a much more expensive cable and not even willing to test my cable at my expense is not the way I thought this would go. 

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?