HPM-100 - suddenly way too much bass?

[rocketrobo]

I've has a pair of HPM-100's for over a decade. Got them cheap, refinished the cabs, rebuild the XO according to the AK recommended spec and replaced one bad driver with a part number match. I've been very happy with the sound!

A few months ago, I installed a vintage tube amp. And for some reason, the HPMs are pumping out a CRAZY amount of bass, like rattle the dishes, vibrate the windows, Turn The Bass Down! amounts. I mean, I like a solid, tight bass as much as the next guy, but this!

I swapped in a pair of newer EPOS speakers to see if it was the amp, and they sound pretty damn good. No bass weirdness.

SO, I'm trying to figure out, has something happened to the XOs that I need to pull them and look them over, or is it some odd synergy with the tube amp causing this frequency boost?

Any AK expert input would be really appreciated!

 

[JoeESP9]

Have you tried the tube amp on any other speakers?

 

[rocketrobo]

yes - I am running it into the EPOS speakers now, and they sound fine.

 

[NH-MAN]

To help others answer, what were you powering them with before?

 

[teal'c]

It's called synergy, enjoy the bass.

 

[rocketrobo]

Closing this thread ...

I discovered that litle fingers had switched the mode to MONO (a small slider switch on this tube amp) . Not sure why that had such an impact, but it certainly did.
The amp I had it on was a Bogen RF-35... Now that the bass is under control, I've swapped in a Fisher 500-C rebuild, and am grooving to the tunes!

Can't find an emoji for <facepalm> but there it is.

 

[toxcrusadr]

Always great when you find out it was something simple.

No idea why Mono mode would do that, but look at the bright side. You've now discovered the Mono switch on that amp is also a Super Bass Boost for HPM-100s switch.