Bass amp for a tri-amped system?

I have a speaker-required active crossover which feeds the mid/highs to 2, fet input/tube output 200 watt mono amps and the low frequencies to a Belles 350 stereo amp. I'm interested in tightening up the bass a bit and wondering if there is an older amp out there that might replace the Belles. I know the Krells have always had good grip on the bass, but wondering if there is anything else out there. Should I be thinking of any issues? Compatibility?
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Usually you will get a more coherent sound by using tha same amps top to bottom.
If you require an amp that will grab your bass bins by the stones, look no further than Plinius.
Tmsorosk. I'll do some research on them. thanks
I instinctively agree with your comment. However, I've tried that configuration with my hybrid amps configured as stereo. what I found is I didn't have quite the dynamic resolution and power of low frequencies I get from my current set-up. My mono amps and speakers are manufactured by the company and compliment each other very nicely with the exception of the bass which the manufacturer suggested this set-up. The speakers have 2, 15" woofers in each speaker and require that additional power. The integration of the tri-amped set-up has been pretty seamless using the active crossover.
If interested, please see my posted virtual system for reference.
IME, you can definitely optimize certain aspects with various amps that address a particular range better.

But in the long run, after you've gotten used to the sonic effects of that combo, the more cohesive and musically compelling sound from matching amps outweighs the "audio excellence" of disparate amps with disparate dynamics, tone, phase response, etc.

So the job of discovering the best amp that will work at all frequencies is much more difficult.

About the only time I've had luck mixing & matching was with subs working from 40 Hz or lower.

I am a stickler for coherent sound. So, I would say the same amplifiers should be used throughout the entire system. I am not sure what you mean by "dynamic resolution", but if you are not happy with the sound while using the same amplifiers maybe you should look elsewhere for the problem. It could be something as simple as cables.
there's a pair of Electron Kinetics Eagle 400 Mono block amps advertized on A'gon. I don't know the seller but the Eagle amps deliver excellent tight bass. Given your system, you may want to send those amps to Russ Sherwood at EKSC to have them checked. You'd probably want to send any old amps in to the Mfg too.
Thanks for your comment. I've had several high-end audiophiles (including a reviewer for DAGOGO) and musicians listen to my set-up.
And I think, again as a result of the outboard active crossover, a lack of coherence has not been an issue. In fact, I've received unanimous compliments.
I'm also fortunate to hear some 6 figure systems and where my humble rig consistently suffers is ultimate articulate, resolving bass. (And maybe my speakers are just not capable).
What I mean by "dynamic resolution", compared to those high buck rigs, mine is a bit sloppy at the lowest of frequencies. Upper bass, lower mids have actually very good resonance and articulation.
As to cabling, I've reworked my entire system with Stealth Indra, Metacarbon, Nanofiber and Air King. The Air Kings are solid silver and I have them connected to the Belles. No comprise there - they are really stunningly transparent.
So short of reconfiguring speakers and amps, which someday, I know I will have to do, my short-term fix/mod might be the bass amp - at least that's what I'm considering. I have no reference for comparison.
And you may be right that I'm chasing a tweak that cannot be enhanced. However, ultimately your advice is sound. thank you.
Just one more note. I've been addressing this issue for about 15 years in this room. I've placed Bass Busters in all four corners along with very careful speaker placement. (Vandersteen, Tannoy, Martin Logan and now Signature- 5 yrs). Amplification has been ARC, B&W, BAT, and now Signature. It could be just the nature of the room which I know will not change.
And with all the upgrades I've made in the last couple of years - the entire front end sources, all cables- interconnects and power. The system has taken several fantastic steps to where maybe the ultimate next step is probably speakers. But that will be for another decade.
I'm totally unfamiliar with Eagles. I took the liberty to see them on your virtual system. They look interesting. I'm using 200 watt monos which these mammoth speakers need to sing. I'm actually completely content with my Signature amps - they are really quite wonderfull. The best of both solid state and tubes. Thanks for the suggestion.
Please forgive me, but I don't understand the "disparate" problem if the active crossover prevents frequency overlap. and once again, it is the lowest of frequencies I'm trying to address probably below 40 Hz. Getting "used to it" doesn't explain the evaluations performed by qualified audiophile visitors. Once again, I think I understand the reality of mixing amps, it's well documented. however, I believe in this case, it minimally applies.
I've heard setups both ways. I think with a passive crossover, using the same amps makes sense and in my experience sounds better. With an active crossover it will sort of blend the two or three amps sound's together so there may be less sonic differences in the end and should sound like one voice. I would make sure to use all the same cabling either way I think. Your system looks and I'll bet sounds awesome. My speakers, Legacy Helix, are quadruple amped using a Xilica digital crossover and are supplied with about 3,600 watts per channel. Talk about headroom!
You might want to check out my system as well.
Thanks Sgr, I appreciate your perspective, especially after seeing your system!
Cabling to the amps are all Stealth Metacarbons with Stealth Indra upstream so I think I'm following your advice.
I asked this same question recently and didn't get a useful response -- maybe because I didn't provide enough info. What is the low frequency driver's nominal impedance and how about efficiency? I have a pair of subs with a 2.5 ohm nominal impedence that are over 90 dB per watt efficient. I don't need a lot of watts; I need current drive into low ohms. I'm looking at a Magtech or possibly a Coda. Plinius attracted my attention but not sure how it'd fare at sub- 4 ohms. My system is tri-amped, I use different amps and I have no problem with coherency but I have heard this argument. It certainly shouldn't be much of an issue with an active XO @ a low crossover point and a steep slope.
Nice to hear from you and thanks for the realistic feedback.. The Signatures have 2, open baffle 15" woofers in each speaker. They are 90dB efficient, but I don't know what their nominal impedance is. So you can see I'm looking for some "iron fisted" control at just those low frequencies. I took the liberty of checking out your system - very nice. I love my Tri-Planar arm too.
For good tight dry punchy low bass you need solid state amps with big low impedance power supplies, preferally DC coupled from input to output, with good current output so forget mosfets and go for bi-polar output devices.
You also need an amp that has good high damping factor (low output impedance) without the need of large amounts of feedback to get it, as too much feedback can make amps unstable.
Krells are good for this and over in Australia big ME (Modular Electronics) poweramps are even better.
Cheers George

If you are interested, you have an opportunity for an experiment here, regardless of the amp you settle on:

Since you are separately amplifying deep bass, you might want to try a Velodyne SMS-1 (+/- $400 from or SVS/Audyssey DRC box (+/- $800 from SVS) for room correction. This will provide parametric EQ to correct for the room response. IME, this will likely provide vastly more improvement than optimizing the right amplifier (unless you choose a REALLY wrong amplifier).

I believe that both units are sold on a "money back" basis, so there's no meaningful risk to trying the approach. However, I have found that there are huge benefits to be had up above 50/60/70 hz, so you might want to cross an octave higher than 40hz when checking this out.

Good luck

Thanks I'll look into it. Is it anything like the Copeland room correction that was floating around a few years ago? I tried that it and it was very detrimental to the overall sound - plus I needed to add another set of interconnects into the signal path which I think added to the negative results. It provided several equalization curves upon analyzing the room response also. And then one could also, via laptop customize the curve. It tended to ultimately distort the signal. What you are suggesting might be different. Thanks for your input!
I believe that these devices use a similar idea to the Copeland (which I've never heard), but the distinction (I assume) here is that either of these units will sit between your active x-over and the bass amp only. The rest of the system's bandwidth above the bass driver's x-over point is completely unaffected. Conceptually, there's still a trade off between "purity/transparency" in the range below your bottom x-over point due to the extra device in the signal path, but - in my experience - I've found that the benefits from smoother FR and precision level matching at the x-over point completely overwhelms any such costs.

However, this my own judgement and I am 100% sure that some others here would/have come to the opposite conclusion....the old YMMV.

I mention it because I'm a believer and because your set-up with active tri-amplification lends itself to the approach without involving the mid-band (or above).

very interesting. I like the idea of limiting any correction to those low frequencies. I think that might be a viable option. Thanks
I'd certainly encourage you to give it a try. IMHO, it's a night and day kind of improvement that returns a crazy bang for the buck. Not everyone will agree, but the good news is that you can always ship it back for a refund if you decide that it doesn't float your boat.

I've never heard the SVS unit, but it's gotten some very good WOM.

Good luck

I checked the internet of the SVS/Audyssey and it appears it is discontinued. The attractive feature of this unit was that it appeared to be able to adjust two sub-woofers (two speakers?). I think I would need to purchase two of the Velodyne for each speaker... But with the money back policy- it seems it may be worth a try.
McIntosh Makes very tight deep bass....Almost all of thier more powerful amps are double bal push pull design. Also, Bryston is great for bass And so is Classe Audio. Krells run Hot,They burn up too,overtime.
I would be nice to be able to try some of those amps if I could find a "bargain". You know, I'm only paying for those bottom octaves. I'll keep my eyes out on Audiogon.
For bass only and amps only, it just comes down to brute force. It's cheaper and easier to get that from switching amps. Look at Wyred4Sound and Spectron or pro amps, if XLR is available.
I agree with bdgregory regarding the Eagle/EKSC amps. They match well with full range speakers requiring great power reserves (B&W 801 for example) but are particularly good as bass amps. Either the 2 series stereo or 400 mono blocs are powerful, solid, clean, and dynamic. The bonus is their used prices make them great buys. John Iverson* knew how to design great amps and Russ Sherwood is, I believe, still available to service them.

*For those not familiar with the fascinating story about Iverson, see this link to the TAS article -
Update! Well, I've discovered a part of the solution. I replaced the supplied active crossover unit, which was fixed ( that is no adjustment options). In it's place is the Bryston 10B Sub crossover (all analoge). It allows me to adjust the crossover frequencies of the low and high and slopes. As a result I've been able to tweak the bass to accomodate both my room modes and the inherent properties of my speakers. I've been able to eliminate some of the low bass sloppiness. I think if I wanted to take this any further would require replacing the speakers rather than the bass amp. I think.