Adding a JBL O77, O75 Tweeter to two way altec system

[Animal 1954]

Hello, Anyone out there tried adding a 075, 077 Jbl tweeter to a pair of two way altecs? I have a 850 pioneer electronic xover i was thinking of trying. Thanks for any input , Roger

[ngccglp]

Hi Roger,

Do it, it adds depth to the overall sound presentation and the timbre of the instruments sounds more real because (I think) of the harmonics.

I just connect my JBL 2405 in parallel to the mid driver and experiment with the capacitor values. So far I have had great results with 0.2 uF. I've tried cap values ranging from 2.2 to 0.1 uF. You may initially prefer higher values because of the added sparkle, but after prolonged listening, I found the values between 0.2 to 0.4 uF to integrate well with my 288.

Try it and let us know what you think.

[just me now]

i have 075s above the 802Gs in my basement setup...

crossed at 7500Hz, some people suggest crossing over a bit higher tho'

[Animal 1954]

Hello, Thanks for the replies to the question . I was thinking of using something like a model 19 xover that has the Mid level and high freq out put on one xover and put a cap in between for the JBL 077. any ideas if this would work? Thanks Roger

[Wardsweb]

I added a 077 by adding the HF circuit of the JBL 3106 crossover to the Altec N501 crossover.

[Greg R.]

I added a 077 by adding the HF circuit of the JBL 3106 crossover to the Altec N501 crossover.
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How does one do that?? that sounds nice..greg

[Wardsweb]

Buy the parts from Parts Express, assemble using this schematic and just add to the input terminals of the N501. It can be a totally separate board, box or whatever, hooked to your +/- input terminals.

[bfish]

Just thought I'd add a comment here from Greg Timbers (JBL design engineer) that he made on the LH forum regarding JBL ring radiators and XO. Although he refers to the 2405, I suspect the 075 and other JBL rings would apply;

"The ring radiator hates passive networks. A major improvement in the upper range would be to drive the 2405 from its own little amp. You only need 3 or 4 v rms. The 2405 does 110 dB for 2.83v. It is padded way down in the system. There is little real power at those frequencies anyway. You only need to know the voltage output of the amp, power is irrelevant. The 2405 is about 12 ohms and won't draw much current. I would use some little chip amp with a 2ond or 3rd order low level highpass in front of it. Take off the passive network to the ring and just feed it straight. Make sure the amp doesn't make a DC thump on turn on or turn off. That will fatigue the diaphragm. The amp will also have to have really low noise characteristics as any hiss will be really loud directly into the ring."

[just me now]

I use a crown D-75 to power my ring radiators...

I like the combo alot...

[Animal 1954]

Hello, Thanks for all the input. This is directed to BFish and his theory of connecting the radiators to an amp without a passive> Am i correct in understanding to connect them without any cap to a low powered amp? Thanks for the reply