Here's a step up transformer box for low output moving coil phono cartridges. This box is set up to use Altec/Peerless 4722 or 4665 transformers. This box uses high quality Belton sockets, has gain switches to select the transformers full or center tapped primaries (main primaries in parallel for 4665's), and a three position switch for choosing how to ground the box: either to the left audio channel, floating in the middle position (so you use a separate ground wire attached from the ground lug to your phono pre), or with the left and right audio grounds and the box all attached together. Usually you don't need to worry to much about what the ground switch is doing, just wire the box how you like, and then put the ground switch in whichever position completely eliminates hum.

For this listing I'm also including a pair of beyerdynamic 1:15 mic input transformers that are mounted on an octal socket making them pin compatible with the 4722. These transformers are very nice, studio quality mic transformers that were used in lots of recording consoles from the 60's through the 90's. They have a nice sound and are very close in terms of ratio and performance to the 4722. If you already have your own 4722 transformers, please see my other auctions for just the empty box.

I also make a box specifically for these beyer transformers, internally hardwired without the sockets for a little bit less money. The reason I'm offering this box is so that if you want to try 4722 or other pin compatible transformers later, you can do so without requiring a second box.

These transformers are very popular with Denon DL-103 users, but with the two gain positions, they'll work with many MC cartridges. Of course I haven't tried them with a whole lot of models, but if you have a question about compatibility your cart, please let me know.

They have a 1:15 winding ratio, and are spec'ed for 200 to 45,000 ohms impedance ratio. This compares to the 4722's 1:18 ratio with a 150 to 50,000 ohm impedance. The result is these have a little bit less gain than a 4722, but it's a small enough difference (less than 2dB) that I'd say the two are electrically compatible. If your cartridge works well with a 4722 it should work well with these and vice versa. These also do have a 50 ohm center tap, which is selectable via the box's "hi/lo" gain switch. The "hi" position doubles the step up ratio from 15 to 30 times. 

The beyer primaries, being spec'ed for 200 rather than 150 ohms, actually have quite a bit higher inductance than a 4722, and as a result they have a little bit more extended low end, and actually have slightly less low frequency distortion than the 4722 (I've tested this on my old Amber distortion analyzer. I'm not sure my numbers are 100% accurate with this meter, but I can measure a difference for sure). This comports with most of the subjective descriptions I've gotten back from other people who've listened to both transformers, that the beyers have a bit more of a natural, clear sound, while the 4722's have a bit more transformer warmth.  Personally, the main thing I hear is just the very small difference in gain. Both transformers with definitely provide the full response, gain, and improvement in noise figure that are the main things you want from a step up box.

The included transformers are just soldered to a little PCB wafer that leads the transformer pins to the correct socket pins. The solder connections on the PCB aren't intended to withstand a lot of force, so I recommend you leave the transformers installed in the box until you're ready to try another transformer, and at that pint, be sure to grab by socket base and wiggle the transformer out gently.

The transformers you receive won't be the ones pictured here, but they'll be in the same condition and I'll be sure you get a pair with matching date codes.

I also have some slightly lower ratio transformers in 4722 compatible octal sockets, so you can also have a look at those if you like.

Again, feel free to contact me if you have any questions, and I'll do my best to help if I can!