XLR to RCA to XLR

01-21-13: Rdeckard
Will these work if mixing consumer audio (-10dBV) and pro audio (+4dBu) gear? In other words, do they provide any level-matching?

The PI models will function in that situation, but they will only provide a very slight amount of attenuation (corresponding to their "insertion loss," which under the test conditions shown in the datasheet is 1.6 db typical, 2.0 db max).

Assuming that what you want to do is to reduce the signal level, what you would probably want is their model PC2-XR, which provides about 14 db of attenuation. A phone call to them would be a good idea, though, to confirm its suitability to your specific application.

Also, at a considerably higher price point Steve McCormack of SMc Audio offers a transformer-based product called Flex-Connect, which provides 12 db of attenuation, together with various other features. I have no specific knowledge of it, but I know that his VRE-1 preamplifier, which utilizes coupling transformers, has an exceptionally good reputation.

Regards,
-- Al

I now have Jensen transformers for the 107/2 and 102 KUBEs, plus a spare. I found that sound quality was better with XLR outputs from the transformers to the amps. Since my May '12 post, I've replaced the Proceed Amp 2 & 3 with Proceed HPA 2 & 3 (500 watts peer channel into 4 ohms).

Hi Al

Thanks for posting about SMc Audio's Flex-Connect. I believe they called it the Interocitor before. For mixing consumer and pro audio what about the Rane Balance Buddy 44x?

http://www.rane.com/pdf/bb44xdat.pdf

Not the prettiest looking piece of gear but could be available used at a decent price.

Thanks Tvad and Almarg for the info. I've since looked into it a bit more with regards to the input and output voltages I'm dealing with and I may be OK just using XLR to RCA cables with the shields floating at the RCA ends. If that doesn't yield the results I want, I will pick up some transformers.

Hi Jedinite,

Regarding the Rane BB44X, which I see sells at B&H for $279, based on a quick Google search I didn't find much that would shed light on the sound quality it would provide in a high-end home audio system.

Looking at the datasheet, though, a concern would be that while a statement is made that the unit provides "wide bandwidth," the only spec that is provided is that frequency response is 20 Hz to 20 kHz +/- 2 db. The 2 db tolerance is very uncomfortable, IMO, and the fact that no margin is indicated relative to the audible frequency range is as well. Without a margin of 5 times or more (i.e. 4 Hz to 100 kHz), and preferably even approaching a factor of 10, I would not feel comfortable that audibly significant phase shifts wouldn't occur within the 20 Hz to 20 kHz range.

In contrast, Steve McCormack's unit is specified as having a 3 db bandwidth of 0.5 Hz to 150 kHz, and the frequency response graph shown in the datasheet for the Jensen PC2XR shows it as being in a similar ballpark.

Also, some cautions that would apply if any of these level converters were used to step UP "consumer level" to "pro level":

First, using one of these devices in that direction will increase the impedance seen "looking back" from the destination device toward the signal source by a factor of about 16 (corresponding to the square of the nominally 4:1 turns ratio), and will decrease the load impedance seen by the signal source by that same factor of 16. That will result in impedance incompatibilities in many cases.

Second, at 20 Hz the unbalanced input of the Rane device will reach its overload point at only 1.68 volts, with the Jensen PC2XR being only slightly better in that respect. So, as might be expected, one would not want to use one of these transformers to step UP the outputs of unbalanced signal sources which provide the 2 volt kinds of levels that are typical these days, especially with digital sources. And chances are that other components in the signal path would overload as well, if that were done.

These two cautions do NOT apply to 1:1 transformers, such as the Jensen PI models, and do NOT apply to the 4:1 level converter devices when used as step-DOWN transformers, i.e., going FROM "pro levels" TO "consumer levels."

Regards,
-- Al