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Non-inductive Resistors
Posted: Mon Mar 16, 2020 9:10 pm
by Bryan Cox
Anyone else notice that non-inductive resistors are hard to come by on Parts Express? I was able to find one of the two I need in the non-inductive flavor but not of the other. The only other option is low-inductance. Which begs the question: what is the difference in sound and functionality between the two?
Re: Non-inductive Resistors
Posted: Mon Mar 16, 2020 9:19 pm
by Bill Fitzmaurice
All wire wound resistors have some inductance. Those labeled as non-inductive just have the lowest available. Inductance in series with a driver rolls off high frequencies, but since the only resistor that we place in series is 4 ohms even if it has moderate inductance it won't have much effect, especially as the piezos we use it with are capacitive loads, which are far less affected by series inductance than the resistive/inductive loads that compression drivers present.
Re: Non-inductive Resistors
Posted: Mon Mar 16, 2020 9:57 pm
by Bryan Cox
Bill Fitzmaurice wrote: ↑Mon Mar 16, 2020 9:19 pm
All wire wound resistors have some inductance. Those labeled as non-inductive just have the lowest available. Inductance in series with a driver rolls off high frequencies, but since the only resistor that we place in series is 4 ohms even if it has moderate inductance it won't have much effect, especially as the piezos we use it with are capacitive loads, which are far less affected by series inductance than the resistive/inductive loads that compression drivers present.
Thanks for the information, Bill. I'll go with the low-inductance wirewound resistors then. Easier to get and a tad cheaper than the ones at Mouser.
Re: Non-inductive Resistors
Posted: Mon Mar 23, 2020 11:19 am
by Seth
Bryan, you wouldn't have been looking for a 4 ohm 10-20 watt resistor would you? Gotta link to what you ended up getting?
Re: Non-inductive Resistors
Posted: Tue Mar 24, 2020 12:38 am
by Bryan Cox
These are what I've found. The first is out of stock. The second appears to be PE brand (know nothing about the quality). And the last is what Mouser has to offer (didn't check all of them for inductance). Hope it helps, man.
https://www.parts-express.com/dayton-au ... tor--004-4
https://www.parts-express.com/4-ohm-20w ... gKURfD_BwE
https://www.mouser.com/Passive-Componen ... 1z0wo4tSGT
Re: Non-inductive Resistors
Posted: Tue Mar 24, 2020 12:41 pm
by Seth
Thank you Bryan. I'm sure you saw the other thread, I went with a 4.3 ohm. I didn't see the 4 ohm PE brand one when I searched their site. I probably would have taken that route had I seen the option.
By your reply, I'm guessing you haven't pulled the trigger yet. I'm doing a pair of shorty SLAP's to go with the T39. Drivers and Crossover components are on their way.
Re: Non-inductive Resistors
Posted: Tue Mar 24, 2020 3:32 pm
by Bryan Cox
SethRocksYou wrote: ↑Tue Mar 24, 2020 12:41 pm
Thank you Bryan. I'm sure you saw the other thread, I went with a 4.3 ohm. I didn't see the 4 ohm PE brand one when I searched their site. I probably would have taken that route had I seen the option.
By your reply, I'm guessing you haven't pulled the trigger yet. I'm doing a pair of shorty SLAP's to go with the T39. Drivers and Crossover components are on their way.
Yeah that PE resistor only came up in a Google search but not on their site. I have not pulled the trigger yet. Kids are doing school from home so my free time is almost totally gone. If they go back to school and I have time left I'll probably begin. But it's starting to look like they may finish out the school year at home.
Re: Non-inductive Resistors
Posted: Tue Mar 24, 2020 6:10 pm
by Seth
Bryan Cox wrote: ↑Tue Mar 24, 2020 3:32 pm
SethRocksYou wrote: ↑Tue Mar 24, 2020 12:41 pm
Thank you Bryan. I'm sure you saw the other thread, I went with a 4.3 ohm. I didn't see the 4 ohm PE brand one when I searched their site. I probably would have taken that route had I seen the option.
By your reply, I'm guessing you haven't pulled the trigger yet. I'm doing a pair of shorty SLAP's to go with the T39. Drivers and Crossover components are on their way.
Yeah that PE resistor only came up in a Google search but not on their site. I have not pulled the trigger yet. Kids are doing school from home so my free time is almost totally gone. If they go back to school and I have time left I'll probably begin. But it's starting to look like they may finish out the school year at home.
Time to teach them how to add and subtract fractions... in the garage. LOL
Re: Non-inductive Resistors
Posted: Tue Mar 24, 2020 7:31 pm
by Bryan Cox
SethRocksYou wrote: ↑Tue Mar 24, 2020 6:10 pm
Time to teach them how to add and subtract fractions... in the garage. LOL
Dude, the order of operations is kicking my daughter's butt right now. If I threw in fractions, LCD, and simplification, I think her brain would melt.
