Phase Linear X20 Crossover

Apr 26, 2011
Central Ohio
I have a living room with almost all P/L electronics. "The worlds first WOPL 400II" that Lee did a few years ago is in there along with a 3300 preamp and 5100 tuner. Until last weekend I was running ESS 1A's. I got a little carried away this weekend and took out the Heil diaphragms.

've got a pair of JBL 4412's that replaced the ESS's and added a JBL B380 subwoofer that's been sitting disconnected for a couple years. The sub is running on 1 channel of a full blown 700B. The only non P/L item is the electronic crossover which is a BGW Model 20. I installed several of the BGW's in clubs in the 80's. They're versatile and high quality.

I was in the process of installing the BGW and the sub when a musician friend at work mentioned a local music shop had a P/L electronic crossover for $40. It's the pro X20. I don't need it but I had to have it. I have the manuals for pro gear so I wasn't to concerned if it needed some work.

In the pics below there are several blue electrolytic caps in series to make a non polar. The question of the day is what is a good 50uf non polar, or is there such a thing? Also the opamps are NEC4741 which is apparently an improved quad 741 intended for audio filter circuits such as a crossover. They're in sockets so replacement would be easy. I'm open to suggestions for an upgrade. The outputs of the crossover uses one section of the opamp as a unity gain buffer if that matters.




Staff member
May 15, 2011
Sterling, MA
Old 'Arn Enthusiast
Hi Don
4741's are very poor audio op amps by todays standards. If the pinout is wonki, then I would recommend you use the brown dog adapters to get some Burr Brown devices in there instead.