I'm looking for feedback about an observation I made last night.

I have my M100v4 connected to an external amp which in turn is connected to my Onk pre-outs. There's an 800v4 in the mix. This was the first time I added an external amp to this system. I was listening to 2.1 yesterday and I kept turning it up and up and up. The volume reached a point where the deep, 3D soundstage started to compress until it was just a 2D plane right up front where the M100 drivers are. The width and height were preserved. Also the well-detailed images with darkness between them sort of merged together, got larger and shifted positions. The effect was like wearing glasses and seeing everything in focus and then removing them and things got fuzzy.

I haven't taken any SPL measurements to see if the M100s may be compressing or the amp or pre-amp is reaching its limits. I very much doubt it's the M100s because I can't imagine the system is anywhere near 600W of power or the pre-amp because I am at +3 on the Onk and still have 9 more dB to go. It could be the amp.

Any similar experience from any of you would help. Thanks in advance.

Youre starting to reach the limit of your preamp output voltage.

What are your channel trims at?

Best guess without measuring your level vs clipping voltage at 1K.

Thanks, Trevor. That could very well be actually because the trims are at +4 and +4.5. I will measure later. BTW, the SPL was scary. I thought I'd blow something up but I am sure the M100s can take a lot more. Also the feeling it evokes is worse than an amp self-protecting. Like something out of Inception or Dr. Strange where the room is folding in on you!

I don't expect this to be a problem with the ADA-1500. I'll be able of put 2V in, which is less than half of maximum voltage on the pre-outs, and get more than 1000 peak Watts into each M100. I hope the cross-over survives.

I can't help but I am curious whether you are running your towers as large (with extra bass in the avr settings) or small?

I am running them as small, crossed over at 80 Hz. I can get more out of the external amp that way. It also sounds better.

Ah good the ADA1250 and 1500 have higher voltage. 2volt I think.
That was my concern when I purchased my 1250, not having enough power from my pre outs.


Over on HTF the moderator has an in depth article on setting gain connecting a Pro Amp. and all the tidbits that go with it. Quite lengthy but very informative.{Make sure the voltage is compatible crank AVR to clipping roll back to before clipping. Then set Amp. gain to just before it can start clipping} Very short hand. But the idea is that they can reach Max and clip together if point is reached.

P.s. the article on HTF is of no relevance to an ADA Amp. since the ADA doesn't have any gain knobs. Though quite informative and useful when getting into external power.

Thanks. The ADA-1250 sensitivity is 1.5V. The 1000 is 1.2V and 1500 is 2V.

To close this off, Serenity was correct. The preamp was saturating. Need more 'nad mass.