Who Makes the Best Sounding Digital Amplifiers?

[Matthew J Poes]

Did you look into NAD C268? Can be bridged for 300W (although website doesn't state still 2ohm stable in bridged mode). Seems reasonably priced as amps go. Assuming its the same amp section as the C368 that Matthew Poes reviewed earlier this year as NAD states the C368 can be bridged and used with the C268 bridged for a 2 channel set up.

Yes it’s the same amp. It’s an NAD licensed version of the UCD module from Hypex. I’m a fan.

 

[BadJRT]

Yes it’s the same amp. It’s an NAD licensed version of the UCD module from Hypex. I’m a fan.

Matthew, have you or anyone else here ever looked at these amps https://www.d-sonic.com/ and how they compare to the ones mentioned in this thread? I've been checking them out and even talked to one of the designers on the phone, but I don't know enough to be able to ask the best questions. In your opinion are these good quality bang for the buck amps? I thought of either 7 channel or 3 channel depending on me getting a pre/processor or receiver to power the surrounds. https://www.d-sonic.com/amplifiers/

Thanks, Brian

 

[Matthew J Poes]

Matthew, have you or anyone else here ever looked at these amps https://www.d-sonic.com/ and how they compare to the ones mentioned in this thread? I've been checking them out and even talked to one of the designers on the phone, but I don't know enough to be able to ask the best questions. In your opinion are these good quality bang for the buck amps? I thought of either 7 channel or 3 channel depending on me getting a pre/processor or receiver to power the surrounds. https://www.d-sonic.com/amplifiers/

Thanks, Brian

As far as I know the D-Sonic amplifiers are based on ICEpower modules with custom input stages and protection circuits. If so, then nothing wrong with them. Probably very good. I happen to think Hypex NCore is better.

 

[BadJRT]

As far as I know the D-Sonic amplifiers are based on ICEpower modules with custom input stages and protection circuits. If so, then nothing wrong with them. Probably very good. I happen to think Hypex NCore is better.

If you wouldn't mind giving me a few good questions to ask, I'll call them back sometime this week and see what I can find out.

 

[Matthew J Poes]

If you wouldn't mind giving me a few good questions to ask, I'll call them back sometime this week and see what I can find out.

I’m sure they are very good amps that would make you happy. You could ask if they still use ICEpower and if so what is the nature of their improvements. You could also ask how they handle the power supply on multichannel units. For example, do they run 2 or 3 amps per ASP module or is every channel independent. This would impact sustained simultaneous power.

 

[BadJRT]

I’m sure they are very good amps that would make you happy. You could ask if they still use ICEpower and if so what is the nature of their improvements. You could also ask how they handle the power supply on multichannel units. For example, do they run 2 or 3 amps per ASP module or is every channel independent. This would impact sustained simultaneous power.

They use Pascal and all channels on multi channel amps have independent amps with 10-12 db of headroom. I hope I copied that correctly.

 

[Matthew J Poes]

They use Pascal and all channels on multi channel amps have independent amps with 10-12 db of headroom. I hope I copied that correctly.

Ah so they switched. Well yeah Pascal makes great modules too. I’ve read some negative press about them technically but only when compared to the best available, and it seems these complaints are debatable issues.

Emotive has an upcoming receiver that will use Pascal amps and I think it’s pretty exciting. I would be happy with a Pascal based amp.

 

[BadJRT]

Ah so they switched. Well yeah Pascal makes great modules too. I’ve read some negative press about them technically but only when compared to the best available, and it seems these complaints are debatable issues.

Emotive has an upcoming receiver that will use Pascal amps and I think it’s pretty exciting. I would be happy with a Pascal based amp.

I just saw that Emotiva has a monoblock D class coming out but I didn't notice a receiver. I've been wanting to see Outlaw and Emotiva get in the D class multichannel power amp game.

 

[Matthew J Poes]

I just saw that Emotiva has a monoblock D class coming out but I didn't notice a receiver. I've been wanting to see Outlaw and Emotiva get in the D class multichannel power amp game.

The RMC is going to have a receiver sister product. It was in our and Todd’s coverage. It’s been shown a bunch of times but hasn’t launched yet.

Basically it’s a 200 watt per channel receiver that likely will produce close to 200 watts per channel ACD. No receiver I’m aware of can compete with that.

In my opinion all receivers should be Class d at this point. Because of power supply limitations and because of wall current limitations, we can’t afford inefficiency anymore. Going to Class d ensures as much of that available power is converted to speaker driving watts and not heat.

Also, I’m tired of having to deal with heavy equipment. Class D with switching supplies are so nice to deal with.

 

[AudiocRaver]

The RMC is going to have a receiver sister product. It was in our and Todd’s coverage. It’s been shown a bunch of times but hasn’t launched yet.

Basically it’s a 200 watt per channel receiver that likely will produce close to 200 watts per channel ACD. No receiver I’m aware of can compete with that.

In my opinion all receivers should be Class d at this point. Because of power supply limitations and because of wall current limitations, we can’t afford inefficiency anymore. Going to Class d ensures as much of that available power is converted to speaker driving watts and not heat.

Also, I’m tired of having to deal with heavy equipment. Class D with switching supplies are so nice to deal with.

Matt, we are channeling the same thought-source. Love it!

Lighter, more efficient, great sound... I think we are not far from what you describe. It will make for some fascinating listening tests.

 

[Tony V.]

The Onkyo 920 I bought has class D amps and have been very happy with its sound

 

[Matthew J Poes]

Matt, we are channeling the same thought-source. Love it!

Lighter, more efficient, great sound... I think we are not far from what you describe. It will make for some fascinating listening tests.

I honestly don’t understand why it isn’t more common. The technology exists for it today, it shouldn’t be cost prohibitive, and it would resolve a current problem of inadequate power.

 

[Tony V.]

I think there is a fear from some manufacturers of using digital amps as there are lots of misconceptions about them. Given Pioneer has been using them for many years it is hard to say why the hesitation is still there

 

[Matthew J Poes]

I think there is a fear from some manufacturers of using digital amps as there are lots of misconceptions about them. Given Pioneer has been using them for many years it is hard to say why the hesitation is still there

It’s Great that Pioneer started using them and from your experience, that is trickling over to Onkyo. Great!

 

[Tim Hector]

I suspect that you'll see more and more Class D Amplifiers. They just make since. Low power consumption, easy and inexpensive switching power supplies and the sound has improved to the point that hard core audiophile amps are being produced. I have owned Abletec modules and have listened to Pascal and NCore modules. Standard audio gear should continue to see trickle down from the audiophile world and benefit greatly from the improvements as they come along.

 

[BadJRT]

Ah so they switched. Well yeah Pascal makes great modules too. I’ve read some negative press about them technically but only when compared to the best available, and it seems these complaints are debatable issues.

Emotive has an upcoming receiver that will use Pascal amps and I think it’s pretty exciting. I would be happy with a Pascal based amp.

Matthew,
I was just reading about balanced vs. fully differential balanced and I'm not understanding it very well, but will keep researching. I wanted to ask if one can tell an amp is of a fully differential balanced design, by looking at the spec sheets? I'm still checking out these D-sonic amps and since it doesn't specifically say in the headlines, I thought maybe there's an indication in the specs.

https://www.d-sonic.com/content/D-Sonic Data Sheet.pdf

https://www.d-sonic.com/amplifiers/upgrades/

Thanks, Brian

 

[Matthew J Poes]

Matthew,
I was just reading about balanced vs. fully differential balanced and I'm not understanding it very well, but will keep researching. I wanted to ask if one can tell an amp is of a fully differential balanced design, by looking at the spec sheets? I'm still checking out these D-sonic amps and since it doesn't specifically say in the headlines, I thought maybe there's an indication in the specs.

https://www.d-sonic.com/content/D-Sonic Data Sheet.pdf

https://www.d-sonic.com/amplifiers/upgrades/

Thanks, Brian

Think of it like this. A differential amplifier as I was talking is one that has two amplifiers paired up such that each one acts on the + and - phase of the signal respectively. One advantage of this is that the amplifier is more powerful for a given rail voltage. In addition it provides cancelation of common mode noise through to the output and is thus cleaner. The negative if this approach is that it doubles the noise making components and so the non-common mode noise is doubled. If that noise is extremely low, then going from day -127dB to -124dB is of little concequence.

https://www.ati-amp.com/differential_drive_amplifier.php
ATI is one of the few companies building true differential amplifiers. However some Class D full bridge amplifiers are as well. My Behringer NU6000DSP sub amp is fully differential for example (though it has none of the good attributes of one other than high power output).

The D-Sonic amplifiers appears to be balanced in but single ended out amplifiers. They are not a fully differential amplifier all the way through I don’t believe. It’s honestly not a bad thing. I don’t like amplifiers that use balanced convert chips, preferring a true differential input stage. However I am ok with really good single ended amplifiers.

I’m also being a bit fast and loose with terms so excuse me for that. In this case the “single ended” output is only referring to the actual output being a single +\- output referenced to ground vs a differential output with no reference to ground. The amplifiers, in both cases, are push pull designs.

 

[BadJRT]

Think of it like this. A differential amplifier as I was talking is one that has two amplifiers paired up such that each one acts on the + and - phase of the signal respectively. One advantage of this is that the amplifier is more powerful for a given rail voltage. In addition it provides cancelation of common mode noise through to the output and is thus cleaner. The negative if this approach is that it doubles the noise making components and so the non-common mode noise is doubled. If that noise is extremely low, then going from day -127dB to -124dB is of little concequence.

https://www.ati-amp.com/differential_drive_amplifier.php
ATI is one of the few companies building true differential amplifiers. However some Class D full bridge amplifiers are as well. My Behringer NU6000DSP sub amp is fully differential for example (though it has none of the good attributes of one other than high power output).

The D-Sonic amplifiers appears to be balanced in but single ended out amplifiers. They are not a fully differential amplifier all the way through I don’t believe. It’s honestly not a bad thing. I don’t like amplifiers that use balanced convert chips, preferring a true differential input stage. However I am ok with really good single ended amplifiers.

I’m also being a bit fast and loose with terms so excuse me for that. In this case the “single ended” output is only referring to the actual output being a single +\- output referenced to ground vs a differential output with no reference to ground. The amplifiers, in both cases, are push pull designs.

Thank you for taking the time to reply. I read the info in the link you posted. That gives me a better understanding, but I'm not so sure I have any better perspective regarding me personally realizing the real world difference between differential balanced or just balanced input/single ended, as you stated. Sometimes I get reading about audio equipment, and before I realize it, I'm going off track on some high end audiophile equipment or theories that are far beyond the comparative links in the rest of my system I'll be building. I guess that's part of my learning process, as I'm trying to figure out a system, based solely on theory and reviews. I'll audition speakers once I'm ready with my room, but the rest of the equipment I'll most likely just order, without listening too. (Amp, preamp, subs, surrounds) I'm trying to not end up wasting money with overkill links in my system, as I'm not really looking to upgrade for many years once I do this. I'd like to get it right, out of the gate.

Thanks again! I really appreciate you guys answering my sometimes out of left field questions.

 

[Matthew J Poes]

Thank you for taking the time to reply. I read the info in the link you posted. That gives me a better understanding, but I'm not so sure I have any better perspective regarding me personally realizing the real world difference between differential balanced or just balanced input/single ended, as you stated. Sometimes I get reading about audio equipment, and before I realize it, I'm going off track on some high end audiophile equipment or theories that are far beyond the comparative links in the rest of my system I'll be building. I guess that's part of my learning process, as I'm trying to figure out a system, based solely on theory and reviews. I'll audition speakers once I'm ready with my room, but the rest of the equipment I'll most likely just order, without listening too. (Amp, preamp, subs, surrounds) I'm trying to not end up wasting money with overkill links in my system, as I'm not really looking to upgrade for many years once I do this. I'd like to get it right, out of the gate.

Thanks again! I really appreciate you guys answering my sometimes out of left field questions.

Don’t sweat it, that’s why we are here.

As for the differences and issues, it just works differently. ATI will obviously tell you it’s a superior approach. Benchmark Audio will tell you it’s worse. I’m actually partial to the approach myself.

Having said that, it’s exceedingly rare to find differential output amps. I wouldn’t make a big thing out of it. Far more important is the power output of the amp. Differential amps might be a little cleaner, but that does you no good if you run out of power.

I also think people tend to overbudget amps and sources and underbudget speakers. A really great speaker with a decent but cheap amp will sound better than a mediocre speaker with a really good amp. As with everything, there are limits. You can get pretty good amps and speakers for not all that much money (at least relative to some of the audiophile stuff we are talking about).

 

[ddude003]

Keep in mind that the overall sound quality of your system is only as good as your least performing component... Finding a balance in quality/performance/synergy at your price point would be the goal...

Keep you eye on GaN-FETs with their high speed switching characteristics and low impedance power... This is ushering in a new age of Class D amplifiers...

 

[Soundsmith19]

I think there is a fear from some manufacturers of using digital amps as there are lots of misconceptions about them. Given Pioneer has been using them for many years it is hard to say why the hesitation is still there

I agree, I own a Pioneer Elite SC-07, it is my first ever Class D amplifier. It is extremely clean, powerful and revealing, however, I do miss the smooth top end of my previous Pioneer Elite VSX-52TX with its class AB direct energy MOSFET amplifier, but that doesn't make the Icepower amplifiers in my SC-07 any less accurate,they are actually more revealing than any other amplifier that i've experienced so far in a home theater amplifier. I'm new to class D amps other than in my subwoofers. I think that many people are used to the warmth of class AB and are afraid to give that up. Many companies know this and I think they are afraid to lose their customer base because of it. Pioneer's name I think defines their approach to the industry. They are often the forerunners in taking new approaches in the Audio Video Industry, both professional and consumer.

 

[NBPK402]

I used To have ML Sequel IIs, and I found they sounded excellent with Classe DR10 amps driven mono (400w in mono 8ohm load, and I believe it doubled in power to 4ohms too...been years though). I pulled out the Classe amps when upgrading, and tried a Crown pro amp, and a QSC amp...the QSC amp sound better than the Classe or the Crown pro amp. That is when I realized that a Pro amp can sound as good if not better than high end amps do. Now I am running B&O IcePower amp modules with very efficient speakers, and the amps are doing a great job for pennies compared to a high end or even a Pro amp when you consider I need less that 10wpc. Sadly I no longer have MLs , but I think you will need a high power digital amp as my experience was they loved power...sucked it up like nothing was there. A friend of mine has some Electrostats still (he had them when we ran the pro amps on the MLs), and his experience was that you could keep turning up the volume until the speakers would not get louder as they sucked up all the power they could use. I do not know if your MLs are like that or not as this was in the early 90s.

 

[NBPK402]

I run Icepower amps, and I have no complaints. Right now I am running Knobsound 50wpc amps with my rp160m speakers, and they sound great too. Of course the Knobsound amps would not be enough power for the Mps. The best sounding amps I ever had with my old ML Sequel his was a pair of Classe DR10S driven in mono...talk about coming alive! They were not any louder, but they sure sounded better.

 

[dlaloum]

An old thread that is worthwhile updating with an additional data point...

My own experiences involved comparing some of the higher powered Onkyo AVR's (876, Integra DTR 70.4), Quad 606 Current dumping/Feedforward, and Crown XLS2500 amps.

My Speakers:

Old history - I used to have Quad ESL63 & Quad ESL989 - towards the end of my "quad era" - these were setup as an all ESL surround setup.

The Panels tended to overwhelm the room, which led to WAF issues - I was unwilling to compromise on the transparence and low distortion aspects of the ESL sound... I had not heard speakers to match (within my budget).... a serendipitous walk past a set of Gallo ref 3.2's in a department store (!!) - led to these replacing my Quads.

Current speakers are therefore:

Gallo Ref 3.2 Left and Right, Gallo Ref AV Center, with PSB Alpha Intro Surround

Key points about these speakers...
They are nominally 8 ohm and can sound good with relatively low power amps... (88db spl/wm)
But the woofer drops to circa 3 ohm, and the tweeter presents a capacitive load dropping down to 1.6ohm
What this means, is that the amps driving the fronts must be stable into sub 2 ohm loads - any amps that start to misbehave into that 1.6ohm tweeter, end up sounding like rubbish!
Their designer, Anthony Gallo, used to demo them at audio shows with a 500w@8ohm Spectron Musician III amp. (company defunct since the designer/owner passed, and well outside my budget)

A brief look at the amps:

The Onkyo and Integra are identical chassis / amps - with earlier/later DSP/surround features - from a bare sound perspective the two are identical

Per Spec: 140W@8ohm - Measured/tested at 165+W/ch @ 8ohm - they are specified for 4 ohm and up... not specced for 2 ohm!

Quad 606-2 - Now getting long in the tooth, these were/are audiophile Amps, using the original Quad Current Dumping design, rated for 140W@8ohm... and specified as "unconditionally stable into ANY load"
Very nice amps, obviously did a fantastic job with the Quad speakers - but known to be somewhat current constrained into low impedance loads (ie: 2 ohm and down) - however they don't tend to "misbehave"

Crown XLS2500 - the most power of the first generation of Crown Drivecore amps, I purchased these used as an experiment... At circa $500 for two of these, I thought it worth while trying.
Rated 440W@8ohm & 1200W@2ohm - they have an onboard DSP which allows for adjustable crossovers, and the left and right channel can be set up to Biamp - can also be set up as Bridged
Their power rating was within a similar order of magnitude to the Spectron Musician that AG used to use to demo the Gallo speakers.

Starting point was a comparisons between the AVR and the Quad 606 on the Quad ESL's... the AVR's are very good indeed, and differences between the 606 and the AVR were minor, and perhaps purely psychological - did some back and forth over a period of months, and ended up just using the AVR amps... avoiding the added cabling and complexity, as it did not provide any "real" benefit.

After the switch to Gallo speakers - comparisons were done again... this time there was a slight but noticeable difference between the AVR amps and the 606's - I put this down to the 606's handling the low impedance better than the AVR's - the difference was however slight... the AVR's had good amps! - but the difference was audible and consistent - tried it a number of times over at least 18months.
Also experimented with BiAmping the speakers - with both the AVR's and a pair of 606's - did not find it to make much difference.

After reading a number of forums discussing the Crown XLS amps, purchased those, and started a lengthy comparison process over about 6 months... the Crowns were tried alone, and in BiAmp mode...

The Crowns sounded better than the Quad 606 - it was by no means a huge step up, just another noticeable and consistent improvement - again all I can put this down to is low impedance load handling / current. (and the Quad sound marginally better than the AVR)

I don't run things loud - usual listening volumes are circa 70db - which means peak power use (assuming +20db max for peaks) is circa 120W - and continuous power use is typically under 1W

I expected the Quad amps to end up as the superior amps, but that was not the case ultimately.

I think that difficult speakers, require the amp to cater to the peaks cleanly - and this takes priority over anything else - if those peaks clip (which includes running out of current at 1.6 ohm impedance load in my case) - then it tends to result in distortion artifacts right through the frequency range...

Circa 120W @ 8ohm - is circa 480W @ 2 ohm - and for my speakers in my setup, I think this is the critical factor.

If you have speakers that require a reasonable amount of power output at 2 ohm - don't compromise! It does make a difference. Quite a lot of power amps (class D and otherwise!) , cannot put this sort of power out into 2 ohms.

I don't believe the Crown's would have sounded any different to the AVR's or the Quad's had they been powering the Quad ESL's I had previously... they might even have been inferior (which is what I was expecting).

Looking around at today's amplifiers, getting an amp capable of 500W+ at 2 ohms is difficult, most amps are not even rated or measured at that impedance, and of those that are, few can achieve this.

If you have "difficult" speakers - the Crown XLS range may be a solution, at a very decent price (and usually readily available used from the Pro marketplaces - at even better prices)

 

[AudiocRaver]

An old thread that is worthwhile updating with an additional data point...

My own experiences involved comparing some of the higher powered Onkyo AVR's (876, Integra DTR 70.4), Quad 606 Current dumping/Feedforward, and Crown XLS2500 amps.

My Speakers:

Old history - I used to have Quad ESL63 & Quad ESL989 - towards the end of my "quad era" - these were setup as an all ESL surround setup.

The Panels tended to overwhelm the room, which led to WAF issues - I was unwilling to compromise on the transparence and low distortion aspects of the ESL sound... I had not heard speakers to match (within my budget).... a serendipitous walk past a set of Gallo ref 3.2's in a department store (!!) - led to these replacing my Quads.

Current speakers are therefore:

Gallo Ref 3.2 Left and Right, Gallo Ref AV Center, with PSB Alpha Intro Surround

Key points about these speakers...
They are nominally 8 ohm and can sound good with relatively low power amps... (88db spl/wm)
But the woofer drops to circa 3 ohm, and the tweeter presents a capacitive load dropping down to 1.6ohm
What this means, is that the amps driving the fronts must be stable into sub 2 ohm loads - any amps that start to misbehave into that 1.6ohm tweeter, end up sounding like rubbish!
Their designer, Anthony Gallo, used to demo them at audio shows with a 500w@8ohm Spectron Musician III amp. (company defunct since the designer/owner passed, and well outside my budget)

A brief look at the amps:

The Onkyo and Integra are identical chassis / amps - with earlier/later DSP/surround features - from a bare sound perspective the two are identical

Per Spec: 140W@8ohm - Measured/tested at 165+W/ch @ 8ohm - they are specified for 4 ohm and up... not specced for 2 ohm!

Quad 606-2 - Now getting long in the tooth, these were/are audiophile Amps, using the original Quad Current Dumping design, rated for 140W@8ohm... and specified as "unconditionally stable into ANY load"
Very nice amps, obviously did a fantastic job with the Quad speakers - but known to be somewhat current constrained into low impedance loads (ie: 2 ohm and down) - however they don't tend to "misbehave"

Crown XLS2500 - the most power of the first generation of Crown Drivecore amps, I purchased these used as an experiment... At circa $500 for two of these, I thought it worth while trying.
Rated 440W@8ohm & 1200W@2ohm - they have an onboard DSP which allows for adjustable crossovers, and the left and right channel can be set up to Biamp - can also be set up as Bridged
Their power rating was within a similar order of magnitude to the Spectron Musician that AG used to use to demo the Gallo speakers.

Starting point was a comparisons between the AVR and the Quad 606 on the Quad ESL's... the AVR's are very good indeed, and differences between the 606 and the AVR were minor, and perhaps purely psychological - did some back and forth over a period of months, and ended up just using the AVR amps... avoiding the added cabling and complexity, as it did not provide any "real" benefit.

After the switch to Gallo speakers - comparisons were done again... this time there was a slight but noticeable difference between the AVR amps and the 606's - I put this down to the 606's handling the low impedance better than the AVR's - the difference was however slight... the AVR's had good amps! - but the difference was audible and consistent - tried it a number of times over at least 18months.
Also experimented with BiAmping the speakers - with both the AVR's and a pair of 606's - did not find it to make much difference.

After reading a number of forums discussing the Crown XLS amps, purchased those, and started a lengthy comparison process over about 6 months... the Crowns were tried alone, and in BiAmp mode...

The Crowns sounded better than the Quad 606 - it was by no means a huge step up, just another noticeable and consistent improvement - again all I can put this down to is low impedance load handling / current. (and the Quad sound marginally better than the AVR)

I don't run things loud - usual listening volumes are circa 70db - which means peak power use (assuming +20db max for peaks) is circa 120W - and continuous power use is typically under 1W

I expected the Quad amps to end up as the superior amps, but that was not the case ultimately.

I think that difficult speakers, require the amp to cater to the peaks cleanly - and this takes priority over anything else - if those peaks clip (which includes running out of current at 1.6 ohm impedance load in my case) - then it tends to result in distortion artifacts right through the frequency range...

Circa 120W @ 8ohm - is circa 480W @ 2 ohm - and for my speakers in my setup, I think this is the critical factor.

If you have speakers that require a reasonable amount of power output at 2 ohm - don't compromise! It does make a difference. Quite a lot of power amps (class D and otherwise!) , cannot put this sort of power out into 2 ohms.

I don't believe the Crown's would have sounded any different to the AVR's or the Quad's had they been powering the Quad ESL's I had previously... they might even have been inferior (which is what I was expecting).

Looking around at today's amplifiers, getting an amp capable of 500W+ at 2 ohms is difficult, most amps are not even rated or measured at that impedance, and of those that are, few can achieve this.

If you have "difficult" speakers - the Crown XLS range may be a solution, at a very decent price (and usually readily available used from the Pro marketplaces - at even better prices)

Zowie! Talk about great minds thinking alike!

I have a pair of Crown XLS 1502 power amps that I have been using with my mains - MartinLogan Classic ESL 9's - off and on for almost 5 years. I say off and on because I was starting to write a review of the 1502's suggesting they be considered a true hifi amp for use with speakers that present a "difficult" load to drive, and kept thinking of different things to try. I think my favorite amp and configuration for the Classic 9's is the XLS 1502 in vertical bi-amp mode (both channels of an amp running the two sections of the same speaker, if I remember the the definition of vertical bi-amping correctly). The imaging seemed slightly sharper and more distinct.

You have inspired me to get that project back on the front burner! Thanks for bumping the thread!