OLA crossover change in mid 70's

[Pete B]

The white dot inductor is only used in the decrease position, if you want yes it is better to change it.

[Brad1234]

On 12/4/2022 at 5:20 PM, Brad1234 said:

Hi Pete, I had not even thought of converting the Rev1 xover to a Rev 2 with just changing the 16 to 8uF cap and changing the red dot to 0.45 mH inductor, is that all it takes?  Is the Rev 2 xover better, I guess it probably is since it is a newer design. I was just planning to restore like with like between each pair, but if the newer xover is superior, I can convert my pre-1974 pair to new xover. 

Does the white dot inductor 0.2 mH need to change to a 0.065 mH as well to fully match Rev 2 xover?  I think you said that inductor is only needed in the decrease position, which is not really ever used. But while I am elbow deep in the cabinet I might as well replace it too?

Hi Pete, I have an inductor question, when shopping for them how close do I need to get to the DCR rating for ohms?  I think within .20 ohms of target?  Most of the inductors are around .45 ohms and the xover schematic calls for 0.25 ohms.
 

Also the red dot 0.8 mH inductor calls for 2.3 ohms, which I cant find. Would I add a resistor to reach that 2.3 ohm level?  Sorry for all of the questions, I am still learning about inductors. I am going to try converting one of my pre1974 advents sets to newer crossover and just replace the red dot inductor on my other pair to compare them. 

[Pete B]

If you decided to build the 16/8/3 then the DCR is lower, you have to tell us what you decided to do.

[Brad1234]

Hi Pete, I decided to build the 16/8/3 newer revision xover for both of my OLA's, it just seemed to complicated trying to replace that 0.8 red dot inductor. I will just have to swap a 16 for an 8 uF cap on the pair I already recapped. The DCR on the new 0.45mH inductor you recommended from partsexpress is around 0.45 ohm, which should be ok?  I really appreciate all of yall's help on my questions!

[Doug G.]

I hope everybody understands I have absolutely nothing against configuring each speaker to the latest revision Advent used, as advocated by Pete, I'm just kind of funny about keeping things original and, if I don't really hear any difference,,,

 

Doug

[Brad1234]

Hey Doug, I am usually on the same page about keeping things original, but that red dot inductor is a weird value and I couldn't find what I thought was a suitable replacement for it. Also, I agree with Pete about the Advent increase setting on the switch making the tweeter overly harsh on the original xover design, so anything to tone the tweeter down works for me!!

[Brad1234]

Update:  just installed the new .45 mH inductor in place of red dot and swapped the 16 for an 8uf cap, so it's officially updated to post 1974 xover and man what a difference in sound!!  The mids and highs are soooo much clearer and balanced, and the tweeters are not harsh like they used to be. I don't have a tool to test the old inductor to see if it was burned out or not, but very happy with Pete's suggestion to convert the xover to newer version. Thanks Pete!