Backplate crossover settings and bias control

[kilkil]

Since you mentioned different rooms, you can see my room setup in the following link.
This is a headphone meet i hosted at my place last November:
https://www.head-fi.org/threads/nashville-center-hill-lake-whiskey-fi-head-fi-meet-nov-7-2020-impressions.946596/

[yoshi]

The newer regulated bias supply seems to be much more sensitive to adjustment on my set up and the has about 30-40 % more output than the original bias supply output. I was able to turn up the old bias supply almost 100% on the new BF panels, but the new bias supply operates at 1/3 open on my panels to generate diaphragm discharge.

[yoshi]

Thanks for your reply Kikil. While I acknowledge we all different room acoustics, I was interested who else landed on the those settings.

K

[kilkil]

I haven’t really played with my bias as the person i bought it from said he just set it. Now that i’ve had them for 15 months, maybe i should actually adjust verify it is set correctly. I do think that they are not sensitive, Pass XA160.8 is pushing them and it is loud at max volume, but I expected louder. I never listen loud except when I’m cooking in the kitchen (open floor plan and the kitchen is opened to the main listening area).

I replaced the brilliance control with a 4ohm resistor.

I have the +3 setting on both the bass and mid, as i thought it sounded best. I tried other settings, but quickly settled on the +3. If it had a higher number i definitely would have tried it and see if i like it better.

[yoshi]

Hello all:

I have been tweaking my pristine 2 bass focused panels for a while now. The backplate was updated with Toroid 1, Reg. Bias supply, new caps and some other mods. By Roger.

I have found that the newer bias supply is very sensitive to the smallest of adjustment affecting the panel sensitivity, almost like a mini balance control. This coupled with minute changes in the toe-in have a significant impact on the width of soundstage and tonal balance. It has taken me literally taken me months to get it close to what I think it should be. Comments on the bias sensitive in your setup?

Second item, I have defaulted the cross over controls to a middle setup, with the exception of a single resistor in place of the bias control pot. Today, I tried the +3 setting on both the bass and mid., and almost fell out of chair with the overall projection and holographic presentation. Almost a disappearing act of the speakers in the room. It always sounded good, but the optimum setting of the bias control( balanced level output, exact toe-in and now with a little extra in the bass and mid., it’s like a new system.

My question is, are the “0” settings really the flat setting? Does the +3 db affect the entire bass panel(s); and does the +3 db lift the entire midrange panels? In other words, will a +3 in the bass and midrange settings provide continuous efficiency gain right up the tweeter crossover? Is this how it works?

BTW, my room is somewhat small, reasonable damped with high ceilings. I running modified VTL deluxe 225t mono blocks operating in triode mode.

Look forward to any feedback on the items above.

Ken

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