033 impedance graph

[scroogemcdov]

Could anyone provide me with the 033 tweeter impedance graph?

[Earl K]

I don't have the 033's AC impedance for you but what is it that you are trying to accomplish ??

If it's replacing the 033 with a substitute then here are some important prerequisites :

(1) Choose a tweeter that's advertised as 6 ohms ( the JBL 033 having such a low dcr of 3.6 to 4.4 R means it'll be about 6 ohms AC ).

(2) Find a tweeter ( if you can ) with an Fs of around 1800hz ( as high as 2000hz >> to as low as 1000hz ) .
- The N110a has an LCR impedance correction circuit centered around 1800hz ( which is a dead give-away as to your existing tweeters Fs ).
- They are parts "L4" + "C5" seen in the schematic of the network. Altering the value of C5 will allow you to apply this LCR to your new tweeter ( if the Fs of the replacement tweet is not 1800hz ).

(3) Get a tweeter with a rated sensitivity of around 91 to 93db ( that will allow you to turn it down some with that variable LPad ) .
- 6 ohm tweeters will always be a bit more sensitive than their 8 ohm brethren.

(4 ) Buy whatever diaphragm type "floats your boat" .

Solen Tweeters would be my first place to shop ( due to selection ).

JBL L100A Tech Sheet

[scroogemcdov]

Thanks for the reply, I would like to replace the 033s with ScanSpeak Revelator D2905/9900-00 1" tweeters (which are also carried by Solen). Do you think that is a good replacement? They are 6ohms and have a dcr of 4.7ohms. The only problem is the Fs which is 500hz. The graph is provided at the link to them.

Also, since the Scans are more efficient, would a series resistor need to be inserted? And if so, do you know to what value?

I don't have the 033's AC impedance for you but what is it that you are trying to accomplish ??

If it's replacing the 033 with a substitute then here are some important prerequisites :

(1) Choose a tweeter that's advertised as 6 ohms ( the JBL 033 having such a low dcr of 3.6 to 4.4 R means it'll be about 6 ohms AC ).

(2) Find a tweeter ( if you can ) with an Fs of around 1800hz ( as high as 2000hz >> to as low as 1000hz ) .
- The N110a has an LCR impedance correction circuit centered around 1800hz ( which is a dead give-away as to your existing tweeters Fs ).
- They are parts "L4" + "C5" seen in the schematic of the network. Altering the value of C5 will allow you to apply this LCR to your new tweeter ( if the Fs of the replacement tweet is not 1800hz ).

(3) Get a tweeter with a rated sensitivity of around 91 to 93db ( that will allow you to turn it down some with that variable LPad ) .
- 6 ohm tweeters will always be a bit more sensitive than their 8 ohm brethren.

(4 ) Buy whatever diaphragm type "floats your boat" .

Solen Tweeters would be my first place to shop ( due to selection ).

JBL L100A Tech Sheet

[Earl K]

Personally, I'm a compression driver and horn type of guy.

As a result, I wouldn't be spending much more than $100 Cdn per tweet ( and also I'd be looking for a tweet with a metal diaphragm that's garnered some good reviews ).

If one wants to go crazy ( tossing about speculative monies ) then buy into a newer name/tech such as Bliesma ( either their straight Be or their Al/Mg composite ).

BTW, with a 4K crossover point one doesn't really need a tweeter that has a diaphragm larger than 25mm ( even smaller could suffice ).

The variable LPad will take care of level issues ( as long as you follow the original criteria that I laid out ) so you won't need to add any extra resistance.

I would choose a tweeter with a smooth response ( unlike the ScanSpeak you mentioned ).

You might enjoy reading the following thread hosted over at diyaudio ; Energy Veritas 1.8 Tweeter Quit

[Earl K]

Well I messed up my calculations pertaining to the Fs of the tweeter's LCR filter ( mentioned above ) >> instead of 1800hz I should have stated that it's 1186hz.

Sorry, My bad <> EarlK