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Is it ok to Bi-amp using different Brand/model of

amps or is it best to use the identical model for muliti-amping? I like to add another SS stereo amp, to get more snap, quickness, detail, and more power to the sound.

Currently I’m horizontally bi-amping my Hales Concept 5 speakers, which are a 3-way, with a pair of BAT VK-60s. One amp is driving the mid-tweeter (passive XO still being used here) section of the main speakers and the second VK-60 amp is directly powering the woofers. A Marchand active XO has the woofers set between 80-550Hz. A pair of self-powered sub-woofers handles below 80 hz.

The VK-60s can easily become monoblocs. As monoblocs, each amp will drive each speaker’s mid-tweeter section and a third amp, stereo, used to power the woofers.


On the BAT website, specifications for solid-state & tube amps such as; input sensitivity, frequency response, THD.... are all different. Will these differences in specs harm the sound if I were to join SS & valve amps together in the same system? Will timing and coherency be affected? Thank you for your inputs.
128x128norm
norm's avatar
norm OP
52 posts
 
Hi Al,

Very astute of you to notice the slopes are indeed not symmetrical on the Hales as noted on the Stereophile’s measurements. I did experiment with different slopes (i.e. 12 db slopes and did not like how it sounded) but ended up using LR 24 db slope on both the woofer and mid-tweeter section. However, I never tried to duplicate the off-setting slopes of the original design. I will give that a try.

Would you please elaborate further on your 3rd paragraph (“complicates things a bit further, because the crossover will introduce some loss at mid/hi frequencies but not at low frequencies”), didn’t get what you mean. Thanks.

Regards,

Norm
magfan
1,583 posts
 
when you changed crossover slope, you also changed the phase relationship between drivers.
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almarg
9,670 posts
 
Would you please elaborate further on your 3rd paragraph (“complicates things a bit further, because the crossover will introduce some loss at mid/hi frequencies but not at low frequencies”), didn’t get what you mean. Thanks.
Hi Norm,

I'm envisioning that resistors which may be present in the speaker's crossover, and/or to a much lesser degree the dc resistances of its inductors, may be significant contributors to the relative balance of lows and mid/hi's.

Since you have bypassed the low frequency section of the speaker's crossover, but not the mid/hi section, you may therefore be raising the sensitivity of the speaker to low frequencies relative to its sensitivity to mid/hi frequencies. If so, the level matching you would have to accomplish with the active crossover would have to reflect that difference, in addition to the difference in amplifier gains.

Regards,
-- Al
norm's avatar
norm OP
52 posts
 
Hi Al,

Ok, gotcha. Thanks.

Regards,

Norm
norm's avatar
norm OP
52 posts
 
Hi Magfan,

You raise a valid point. Perhaps, Marchand (the xo manufacturer) has some insight to this. I will post my findings once I have the answer. Thanks.

Regards,

Norm
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