XLR Low-Z out into 1/4” unbalanced Hi-Z matching transformer

Hey all,

Next week I’m going to use an RCA 44BX into an old Concord transistorized 220 mono reel to reel (yes it has the built in speaker!). The input on the reel to reel was designed for hi-z crystal mics, so will this work to match impedance? http://www.americanmusical.com/Item--i-AUD-CP8201

Also, if I decide I need more gain, & first go into an external preamp, what should I use? That Audio-technica adapter has an input impedance of 250 ohms, and an output impedance of 50K ohms. For the output of an external mic preamp (line level output) would I need a transformer with an input impedance of 20K, and output around 50K?

Thanks!

MrMegaEli said:

Hey all,

Next week I’m going to use an RCA 44BX into an old Concord transistorized 220 mono reel to reel (yes it has the built in speaker!). The input on the reel to reel was designed for hi-z crystal mics, so will this work to match impedance? http://www.americanmusical.com/Item--i-AUD-CP8201

Click to expand...

Yes.

Also, if I decide I need more gain, & first go into an external preamp, what should I use? That Audio-technica adapter has an input impedance of 250 ohms, and an output impedance of 50K ohms. For the output of an external mic preamp (line level output) would I need a transformer with an input impedance of 20K, and output around 50K?

Click to expand...

You shouldn't need a transformer there. Transformers are required if there's very little energy to start with - that's the case with a ribbon mic - and the impedances are widely different, or if there's an absolute need to balance/unbalance the signals.
In the case of connecting a preamp to the input of your R2R, the preamp has enough energy to drive the input; you just have to check the compatibility of its output with an unbalanced connection. Most preamps have floating outputs that can be connected to unbal equipment, or a dedicated unbal output. Just check the preamp's manual.