Model 19 coil resistance

**les winter** · September 1st, 2015, 01:09 PM

I've built a pair of Model 19 style cabinets and populated with 416z and GPA 902 drivers. Previously I ran it bi-amplified. I'm going back to the original passive x/o scaled to 16 ohms. When it comes to the coils, I'm having difficulty getting the smaller values in iron core, as the originals were. Anyone know the iron core resistances? I'll use air core and tack on a series resistor.

thanks.
Les

GM · September 4th, 2015, 01:57 AM

Hmm, double the resistance, double the inductance.

GM

**les winter** · September 6th, 2015, 03:42 PM

Halve the caps. Thanks GM

**Alien_Shore** · September 7th, 2015, 02:58 PM

What appears to be an excerpt from an Altec engineering schematic for the model 19 crossover is posted in this thread.

Also, member RonSSS had done some measurements of his original N1201 crossover inductors. There were separate posts for inductance and resistance.

Depending on the impedance curve of the 416z's, you may or may not want to fully double the DCRs of L1 and L2 when adjusting for a 16-ohm woofer. The N1201 provides CD compensation and while it is a small effect, the resistance within the HF and MF circuits affect the voltages for the LF filter as well. It will be tricky to swap out drivers and retain the intended M19 voice.

**les winter** · September 11th, 2015, 03:25 PM

Thanks Mike.

**les winter** · September 12th, 2015, 02:39 PM

Anyone know what type of caps were used in the original M19 x/0?

**timoteus** · September 12th, 2015, 07:05 PM

Callins aluminum electrolytic in both pair of 19s I've rebuilt. Interesting factoid, Callins was asked to serve on the Board of Directors for LTV Ling Altec and declined because he didn't want to relocate.