Thats what I'm thinking... that I'm not getting a strong enough signal out of my pre-amp.
Something like this may help: Henry Engineering Matchbox HD Unbalanced to Balanced Audio Interface Converter 744890350257 | eBay
This unit handles both directions. I assume you don't have the tools to troubleshoot to the component level (scope, meters, generator, etc.) and likely are not read to build an interface.
Going from pin 2 + to RCA tip and connecting 1 & 3 together and connecting to the shell should have worked.
I avoided the problem by building all of my amps and processors to take balanced I/O (or unbalanced if I needed that)
This unit handles both directions. I assume you don't have the tools to troubleshoot to the component level (scope, meters, generator, etc.) and likely are not read to build an interface.
Going from pin 2 + to RCA tip and connecting 1 & 3 together and connecting to the shell should have worked.
I avoided the problem by building all of my amps and processors to take balanced I/O (or unbalanced if I needed that)
Interesting beast. Looks like all the impressive-looking vacuum bulbs are actually power supply components (rectifier, series + shunt regs for a pair of supplies), only the two little ones in the front left are actually involved with the signal - maybe an actively loaded gain stage (the 12B4 has a suspicious µ of 6.5) buffered by a MOSFET or emitter follower. The circuit is almost certainly spectacularly inefficient. "We don't like electrolytics, so let's do a CLC with films and regulate away the ripple." Then again, efficiency probably is not a primary concern in stratospheric MSRP audio equipment...
Anyway, I'd double-check the wiring with the ol' multimeter and visually, maybe there's a bad ground connection or short somewhere. If in doubt, any old preamp (or integrated amp pre-out) with an RCA splitter cable should be able to stand in for the Epifania.
Yes, the signal is going to be kinda quiet at normal volumes, but not inaudible. It would still be nice to have some gain in the unbal/bal conversion, but I guess the tube amp isn't exactly low noise anyway. You're only using the DCX to feed a sub, where noise isn't that much of a concern, but when used as an actual crossover I'd definitely pay attention to these things, especially between the DCX and power amp. The unit has an input and output noise floor of -90 dBu each (for a maximum dynamic range of 112 dB, which actually is quite decent), and consumer power amps will take about 1.5 Vrms or roughly +6 dBu for full output, so you'd get about 96 dB of dynamic range tops, which is hardly spectacular if you value noise levels that are just about inaudible.
Place a multimeter on the output of Your gear (pre-amp ??) connected to the DCX. Measure the Voltage. If the peaks are higher than 300mV, You are above consumer level and signal should flow into the DCX. If You have a lower signal, then perhaps You need some amplification before. Is there a menu setting on the DCX for signal routing muting / selecting inputs ? Check that also.
Hey... Thanks for checking in.
My tech gave me every kind of adapter he had, including a box that switched phase and had an attenuater filter. Not sure what the filters did but I know it didn't work.
By the way, all appropriate adapters and phase shifter/filter worked as should when using the DAC outputs.
SO... I hope to get by techs place today or tomorrow. Will drop off the pre and have him do some measurements and diagnostics. Will get a handle on the outputs soon! Stay tuned and thanks for everyone's input thus far.
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