XLR to RCA Adapters
I do think that it's highly inaccurate to characterize line output transformers, as a group, as requiring a substantial or specific load on the secondary to acheive proper transient response. All of the line output transformers I have ever seen need some kind of load, but its not so much for transient response as for flat frequency response. |
All of the line output transformers I have ever seen need some kind of load, but its not so much for transient response as for flat frequency response.Proper transient response and flat frequency response of course go hand in hand, especially in the HF/ultrasonic region, where a poor quality transformer tends to resonate. But for a bit of perspective, I pulled out a John Hardy M-2 mic preamp and ran a couple of sweeps. This uses a Jensen JT-11-BMCF output transformer, and its response deviation between 150, 600, and 100K loads were all within +/- 0.1 dB of each other from 20Hz to 50KHz. Measuring the AP System One itself (Bruce Hofer's patented transformer output circuit) delivers virtually indistinguishable performance into all three loads (less than +/- 0.01 dB of each other) from 20Hz to 200KHz. Pretty good for a bit of iron, eh? |
Talk2me, several references to your amp that I've seen indicate that it has rca as well as xlr inputs. Is that not the case with your particular amp? In any event, the reason you didn't find an explicit answer as to the best way of interfacing rca outputs to xlr inputs is that there is no answer that is universally applicable and universally agreed upon. Relevant variables include cable length, component impedances, susceptibility to ground loop effects, rfi/emi environment, deep bass extension of the speakers, etc. In your case, I found a post somewhere indicating that the balanced input impedance of your amp is an unusually low 2,000 ohms. If so, that probably rules out the Jensen input transformer approach, and limits you to a choice between a Jensen output transformer, such as their model DM2-2RX (the "RX" version is the same as the "XX" version referred to in the data sheet, except that it has rca input connectors), or the adapters you are presently using, or adapter cables. As Mitch2 suggested, you should speak with a Jensen rep before finalizing a choice of one of their transformers. See section 2 of this paper for further information. Note that for all three of the methods that are illustrated the cable has symmetrical signal and return conductors (i.e., it is not a coaxial unbalanced cable). Regards, -- Al |
