So messing around on the DYGs I measured the electrolytic 150uF shunt cap in the woofer leg to see what actual values are going on to enter into the sim. Both were actually closer than expected at 155uF. What surprised me was the ESR @120Hz is 0.47. Entering that value into my sim really messed with the FR/phase.
That sent me down the rabbit hole of try to find an alternative to get the ESR lower as it really would be better lower. Measuring lower value electrolytic caps (100, 50) showed they have even higher ESR. So even three 50’s in parallel had higher ESR than the 150 alone. Bypassing electrolytic with polys really didn’t help the situation, bunch of combinations explored.
So looking at trying to find 150uF of poly. Any experience with doing this affordably and not huge beer can size caps? I’ve found a 250V on ebay, definitely don’t need the ridiculous size of 400+V pieces. Figured I throw this out to the heard for possible options.
In the order I mentioned, I thought 33’s were the biggest, turns out I had two 47’s. So those, a 50 Dayton and a Jantzen 10…155uF. ESR is .29. Better than the electrolytic, but not as good as I’d hoped and a hell of a conglomerate.
I’ll give this another day. If nobody has a poly 150 to check, I’ll bite the bullet and buy something to try. That Wima looks like the cheapest candidate. It’s specs say 1.7mOhm, but doesn’t specify at what frequency. For some reason the data file won’t open on my phone.
Multiple caps will work too - Any film cap will have nicely low ESR. Yup, solid solution ! I really like the recommendation for Brad’s 150uf - killer inexpensive !!
