Hi There,
Having worked for Linear Power for two years back in the ‘90s, I can say that when they were installed and set up correctly, driven by a clean, high-voltage-out source, and running great speakers, they sounded very nice. Then again, so do most amps in the same situation. They fell apart with a lack of dampening factor, used a pretty mediocre amplifier topology and along with inefficient bi-polar switching devices, they lacked clarity and punch. They did use very good output devices, nice NE5532 op-amps, and very strong switching toroid cores. I left just after the development of the 8002iq (I hand carried the first prototype 8002iq in a box with a paper handle to the ’91 CES show in Vegas) (by the way, iq stood for one inverted channel and an output relay to “quiet” their horrendous turn on/off pop) and the 2.2HV and a few other models were still in the prototype stage. This was also not too long before their ultimate demise and subsequent sale to a couple of chuckle-heads who write emails like Neanderthals, but that’s a different thread.
Having heard and judged the best-of-the-best in car audio, my absolute hands-down favorite (besides the 700 watt beauty I hand built) car amps are the McIntosh line.
A good high-output, low noise head-unit is very critical to a clean system as is a good installation and very stable, low impedance supply voltage at the amp. Good speakers can make or break a system so easily, and it’s a place where so many decide to save money. Remember, every 3dB of speaker efficiency is twice the sound and a good speaker placed well and driven by a clean amp, can sound incredible. An okay speaker driven by the best amp and set up will only sound okay at best. I’d look for amps with a good dampening factor, good specs, and one that doubles its power with the halving of speaker impedance (indicates a good amp design and good power supply). Next, audition them (car audio shops) with a CD of music you are familiar with and listen for subtleties you’re aware of and any unusual coloring of the sound. With all of that, you should end up with something you’ll like and enjoy for years.
Regards
Having worked for Linear Power for two years back in the ‘90s, I can say that when they were installed and set up correctly, driven by a clean, high-voltage-out source, and running great speakers, they sounded very nice. Then again, so do most amps in the same situation. They fell apart with a lack of dampening factor, used a pretty mediocre amplifier topology and along with inefficient bi-polar switching devices, they lacked clarity and punch. They did use very good output devices, nice NE5532 op-amps, and very strong switching toroid cores. I left just after the development of the 8002iq (I hand carried the first prototype 8002iq in a box with a paper handle to the ’91 CES show in Vegas) (by the way, iq stood for one inverted channel and an output relay to “quiet” their horrendous turn on/off pop) and the 2.2HV and a few other models were still in the prototype stage. This was also not too long before their ultimate demise and subsequent sale to a couple of chuckle-heads who write emails like Neanderthals, but that’s a different thread.
Having heard and judged the best-of-the-best in car audio, my absolute hands-down favorite (besides the 700 watt beauty I hand built) car amps are the McIntosh line.
A good high-output, low noise head-unit is very critical to a clean system as is a good installation and very stable, low impedance supply voltage at the amp. Good speakers can make or break a system so easily, and it’s a place where so many decide to save money. Remember, every 3dB of speaker efficiency is twice the sound and a good speaker placed well and driven by a clean amp, can sound incredible. An okay speaker driven by the best amp and set up will only sound okay at best. I’d look for amps with a good dampening factor, good specs, and one that doubles its power with the halving of speaker impedance (indicates a good amp design and good power supply). Next, audition them (car audio shops) with a CD of music you are familiar with and listen for subtleties you’re aware of and any unusual coloring of the sound. With all of that, you should end up with something you’ll like and enjoy for years.
Regards
lumanauw said:
I am not in audio anymore. I did production for over 99% of the original Butler and Phaze Audio Tube Drivers. The rest were done by BK, himself.
Last year, he gave me a demo of his Class A mono-blocks, utilizing 300B tubes
Hi Again,
I’ve worked on a dozen or so Soundstream amps for friends and have never seen anything from them remotely close to McIntosh. I’ve heard some outstanding Soundstream installs and respect their designs. They keep things simple and strong, but kind of lack that certain ‘something’ to make them awesome.
I still have no idea what McIntosh does to make their amps so clean, durable, or bullet-proof, but I know what I hear and they are nice. I’ve looked for a long time for schematics for their car stuff, but haven’t found any. I’m pretty sure they don’t do anything magic, but are most likely just masters of many audio disciplines including topology, component selection, layout, and construction making the amps more a piece of artwork and less like electronics. I have several of their home amplifier schematics and most everything is straightforward and elegant, without corner-cutting or anything marginal.
I wouldn’t want to put together a DIY kit or plans for an amp. I’ve designed them, built them, and repaired literally hundreds of amps, but don’t want to end up stuck defending one particular design or another. Many amplifier manufacturers choose a particular topology and base all of their products around it with limited exceptions. If I designed a bipolar design, someone would hate it and want MOSFETs. I like using op-amps, but many consider them too noisy and “not audiophile enough.” I prefer to build what I like and constantly experiment with different designs. I’m also a quantitative guy and just can’t back (or afford) $10,000 RCA cables, micro-diode soldering, hearing a bug fart at 100 yards, and amps with DC-to-light frequency responses. I remember a great double-blind test we did once back at Linear Power. One amp was a Linear 5002 (250WPC, 24 TO-3 power devices, and quite nice) and the other was a budget Kenwood 60 watt amp. At low and medium volumes, there was no discernable difference and our sales guy actually picked the Kenwood as the better sounding amp. Of course, with the volume up, the Linear kicked *** and the Kenwood distorted.
Instead, I prefer to offer advice and share any technical knowledge with interested individuals. From what I’ve seen so far, it looks like the amplifier portion of car audio amps is pretty well covered in this forum, but the DC-to-DC areas could use some help. I’d be happy to help where I can.
Cheers
I’ve worked on a dozen or so Soundstream amps for friends and have never seen anything from them remotely close to McIntosh. I’ve heard some outstanding Soundstream installs and respect their designs. They keep things simple and strong, but kind of lack that certain ‘something’ to make them awesome.
I still have no idea what McIntosh does to make their amps so clean, durable, or bullet-proof, but I know what I hear and they are nice. I’ve looked for a long time for schematics for their car stuff, but haven’t found any. I’m pretty sure they don’t do anything magic, but are most likely just masters of many audio disciplines including topology, component selection, layout, and construction making the amps more a piece of artwork and less like electronics. I have several of their home amplifier schematics and most everything is straightforward and elegant, without corner-cutting or anything marginal.
I wouldn’t want to put together a DIY kit or plans for an amp. I’ve designed them, built them, and repaired literally hundreds of amps, but don’t want to end up stuck defending one particular design or another. Many amplifier manufacturers choose a particular topology and base all of their products around it with limited exceptions. If I designed a bipolar design, someone would hate it and want MOSFETs. I like using op-amps, but many consider them too noisy and “not audiophile enough.” I prefer to build what I like and constantly experiment with different designs. I’m also a quantitative guy and just can’t back (or afford) $10,000 RCA cables, micro-diode soldering, hearing a bug fart at 100 yards, and amps with DC-to-light frequency responses. I remember a great double-blind test we did once back at Linear Power. One amp was a Linear 5002 (250WPC, 24 TO-3 power devices, and quite nice) and the other was a budget Kenwood 60 watt amp. At low and medium volumes, there was no discernable difference and our sales guy actually picked the Kenwood as the better sounding amp. Of course, with the volume up, the Linear kicked *** and the Kenwood distorted.
Instead, I prefer to offer advice and share any technical knowledge with interested individuals. From what I’ve seen so far, it looks like the amplifier portion of car audio amps is pretty well covered in this forum, but the DC-to-DC areas could use some help. I’d be happy to help where I can.
Cheers
Switching power supplies are simple in concept and fairly straightforward, but can get very complex and exotic very quickly.
Here are the basic components of a DC-to-DC switching supply:
Input filter – a capacitor that filters the battery DC input.
Controller – typically a single IC that handles switching frequency, output signals, voltage monitoring, reference voltages, and often a variety of other functions.
Switching devices – Usually low voltage (around 60 volts), high-current (often 50 amps or more per device), moderate power (125 watts or so), and fast switching (in the MHz range, although not used that fast).
Switching transformer – often the most difficult part of the whole power supply to locate and implement. Most likely a toroid or double-‘E’ core ferrite part, typical material spec’d for 20KHz to 100KHz operation, and the necessary magnet wire (enameled copper) wire for the primary and secondary.
Secondary rectification – usually fast or ultra-fast recovery diodes in the 200 volt and 15 amp or greater range.
Secondary filter – capacitors that filter the rectified secondary voltage to provide the +/- DC voltages for the amplifier circuitry.
Extras – feedback and optocouplers for closed-loop voltage regulation, temperature sensors for protection, input and secondary filter inductors, snubbers, extra secondary windings, gate-drive circuits, reverse-protection diodes, and lots more depending on the level of complexity or exoticness desired.
General theory of transformer voltage conversion:
A conventional AC home-type 50/60 Hz transformer couples a primary input voltage to a secondary voltage through a magnetic field. The magnetic field is made more efficient and confined by way of an iron core usually made of many thin plates. While the primary and secondary voltages and currents can be changed considerably, the power coupled is constant (minus loss, of course). Transformers are usually represented as a ratio of primary to secondary voltages or turns with the total power coupled represented in a VA (volt-amp) rating. For example, a 1:1 ratio, 110VA transformer may have a 110 volt primary at 1 amp and a 110volt secondary at 0.9 (less than 1 amp due to losses). The same transformer could also (in theory) be used at 11 volts in at 10 amps (still 110VA) with 11 volts out at 9 amps (loss). Though these two examples have different voltages and currents, the VA is constant. A real-world audio power transformer used for home amps might be a 2:1 ratio with a VA rating of 500VA. In this case, it would have a 110VAC primary at about 5 amps and a 55VAC secondary (likely center-tapped – either two secondaries each = ½ 55VAC or one secondary with a wire “tapped” from the center of the windings) yielding +/- 27.5 at about 9 amps or +/- 4.5 amps. The AC secondary would then be rectified, filtered, and used to provide about +/- 39VDC. In all of these examples, I present full current for calculation purposes, but in reality, the currents are only high when the transformer (or what it’s driving) has a load on it. There’s more to it, but this is most of the critical stuff. If you’re planning to experiment with this, do some research and BE CAREFUL with live AC.
Theory of DC-to-DC voltage conversion:
A DC-to-DC converter used in a car amplifier operates on a superficial level much the same way as a home AC transformer. The biggest difference is that the 12 volts DC from a car battery is “switched,” “chopped,” or “modulated” (you pick your favorite term) to form a high-frequency (20+KHz) AC signal that is applied to the primary of the special transformer I described earlier. From there, the same winding ratios and VA ratings apply. So, DC is switched to a high-frequency AC, the AC applied to the transformer primary, the power is coupled and the voltage converted in a magnetic field in the transformer, the secondary produces a high-frequency AC voltage, the AC is rectified to DC, and then filtered to pure (more pure, at least) DC. For a car amp, the transformer ratios are different with a lower primary voltage, but the VA ratings are similar. Let try a 1:5 ratio, 500VA transformer example. 12 volts at 42 amps (assumes a load, of course) is switched to the primary winding. About 60 VAC appears at the secondary and would be rectified and filtered to about +/- 30 VDC (when rectifying and filtering pulsed DC, RMS calculations don’t apply quite the same) at about +/-4.2 amps.
One comment needs to be made about the primary of the DC-to-DC power supply transformer used in virtually all car audio amplifiers is that they run a push-pull topology. What this equates to is a primary with a center-tap or what equates to two primaries. The way most of these are configured is to have the positive of one primary phase connected to the negative phase of the other connected together. This “common” tap is connected directly to +12VDC. From there, the other end of the two phases is connected to the drain of the power FETs, and the sources of the FETs to ground. The way this works is that the FETs on one side are switched on building a magnetic field in one transformer primary phase and building a secondary voltage at the same time. Then, phase one turns off, phase two turns on building an equal, but opposite magnetic field in the secondary, and so on. So, one bank of FETs and one primary half “pushes,” and the other bank and phase “pulls.”
From here, there are regulation differences. Unregulated (the simplest topology and what I use – they tend to sound louder with good punch) simply count on battery voltage and transformer ratio to determine the secondary voltage. Amps with a higher output power at 14.4 volts than at 12 are usually unregulated. Regulated supplies sample the secondary voltage and modulate the primary’s pulse-width (pulse width modulation – PWM) to keep the secondary voltages constant. These car amps tend to have the same output power ratings with battery voltages from 10 to 16 volts. Linear Power ran unregulated supplies. They also used high-current bipolar switching devices with some weird designs. They worked, but were not very efficient and were very old-school.
Look at most any “decent” and better car amps and it’s very easy to discern the power supply section from the amplifier. The power supply will have the transformer somewhat central to the supply section flanked by the primary filter capacitors (they are usually high capacity at 16 volts) and also by the secondary capacitors (usually lower capacity and higher voltage). Also nearby will be the driver IC/electronics, filters (R/C snubbers), and other support parts. The rectifiers will generally reside in proximity to the transformer’s secondary and filter caps. The MOSFET switching banks can be anything from one-or-two to dozens of FETs per primary phase. The FETs and rectifiers will generally be secured to the heatsink to ensure they are kept within thermal limitations and to give the amp a symmetrical look.
The Linear Power 5002iq power amp I worked on used a FerroxCube TX51/32/19 toroid core in a 3C81 material. This core is good for about than 1.5KW of power. Remember though, 1,500 watts is not amplifier power. This is total power. Once amplifier inefficiencies, switching losses, wire losses, and a multitude of others are removed, it is good for maybe 1KW of amplifier output power. I used a similar core in my 700 watt amp. Anyway, the Linear transformer had four paralleled 18AWG windings per primary. It then had 16 secondary windings (X 2 for the +/- voltage), also of 18AWG wire to produce approximately +/- 55 volts for the 2-ohm power supply rails. Lastly, it had additional sets of four secondary windings to provide +/- 68 (55 + 13 = 68) volts for the 4-ohm rails. Linear used a set of “taps” to allow the user to select the appropriate supply voltage depending on the load being driven. The tap-selectable rail voltages kept the amp fairly efficient, but wasn’t real convenient as the amp had to be pulled and the taps changed if the speaker loads were changed. The transformer worked very well despite the bipolar switching devices.
This is a lot to digest and understand, but read through it a couple times, and I’ll try to post some schematics and pictures soon. From all of this, car switching supplies should no longer be a mystery and something the savvy weekend-warrior could prototype and put into use.
Enjoy!
Here are the basic components of a DC-to-DC switching supply:
Input filter – a capacitor that filters the battery DC input.
Controller – typically a single IC that handles switching frequency, output signals, voltage monitoring, reference voltages, and often a variety of other functions.
Switching devices – Usually low voltage (around 60 volts), high-current (often 50 amps or more per device), moderate power (125 watts or so), and fast switching (in the MHz range, although not used that fast).
Switching transformer – often the most difficult part of the whole power supply to locate and implement. Most likely a toroid or double-‘E’ core ferrite part, typical material spec’d for 20KHz to 100KHz operation, and the necessary magnet wire (enameled copper) wire for the primary and secondary.
Secondary rectification – usually fast or ultra-fast recovery diodes in the 200 volt and 15 amp or greater range.
Secondary filter – capacitors that filter the rectified secondary voltage to provide the +/- DC voltages for the amplifier circuitry.
Extras – feedback and optocouplers for closed-loop voltage regulation, temperature sensors for protection, input and secondary filter inductors, snubbers, extra secondary windings, gate-drive circuits, reverse-protection diodes, and lots more depending on the level of complexity or exoticness desired.
General theory of transformer voltage conversion:
A conventional AC home-type 50/60 Hz transformer couples a primary input voltage to a secondary voltage through a magnetic field. The magnetic field is made more efficient and confined by way of an iron core usually made of many thin plates. While the primary and secondary voltages and currents can be changed considerably, the power coupled is constant (minus loss, of course). Transformers are usually represented as a ratio of primary to secondary voltages or turns with the total power coupled represented in a VA (volt-amp) rating. For example, a 1:1 ratio, 110VA transformer may have a 110 volt primary at 1 amp and a 110volt secondary at 0.9 (less than 1 amp due to losses). The same transformer could also (in theory) be used at 11 volts in at 10 amps (still 110VA) with 11 volts out at 9 amps (loss). Though these two examples have different voltages and currents, the VA is constant. A real-world audio power transformer used for home amps might be a 2:1 ratio with a VA rating of 500VA. In this case, it would have a 110VAC primary at about 5 amps and a 55VAC secondary (likely center-tapped – either two secondaries each = ½ 55VAC or one secondary with a wire “tapped” from the center of the windings) yielding +/- 27.5 at about 9 amps or +/- 4.5 amps. The AC secondary would then be rectified, filtered, and used to provide about +/- 39VDC. In all of these examples, I present full current for calculation purposes, but in reality, the currents are only high when the transformer (or what it’s driving) has a load on it. There’s more to it, but this is most of the critical stuff. If you’re planning to experiment with this, do some research and BE CAREFUL with live AC.
Theory of DC-to-DC voltage conversion:
A DC-to-DC converter used in a car amplifier operates on a superficial level much the same way as a home AC transformer. The biggest difference is that the 12 volts DC from a car battery is “switched,” “chopped,” or “modulated” (you pick your favorite term) to form a high-frequency (20+KHz) AC signal that is applied to the primary of the special transformer I described earlier. From there, the same winding ratios and VA ratings apply. So, DC is switched to a high-frequency AC, the AC applied to the transformer primary, the power is coupled and the voltage converted in a magnetic field in the transformer, the secondary produces a high-frequency AC voltage, the AC is rectified to DC, and then filtered to pure (more pure, at least) DC. For a car amp, the transformer ratios are different with a lower primary voltage, but the VA ratings are similar. Let try a 1:5 ratio, 500VA transformer example. 12 volts at 42 amps (assumes a load, of course) is switched to the primary winding. About 60 VAC appears at the secondary and would be rectified and filtered to about +/- 30 VDC (when rectifying and filtering pulsed DC, RMS calculations don’t apply quite the same) at about +/-4.2 amps.
One comment needs to be made about the primary of the DC-to-DC power supply transformer used in virtually all car audio amplifiers is that they run a push-pull topology. What this equates to is a primary with a center-tap or what equates to two primaries. The way most of these are configured is to have the positive of one primary phase connected to the negative phase of the other connected together. This “common” tap is connected directly to +12VDC. From there, the other end of the two phases is connected to the drain of the power FETs, and the sources of the FETs to ground. The way this works is that the FETs on one side are switched on building a magnetic field in one transformer primary phase and building a secondary voltage at the same time. Then, phase one turns off, phase two turns on building an equal, but opposite magnetic field in the secondary, and so on. So, one bank of FETs and one primary half “pushes,” and the other bank and phase “pulls.”
From here, there are regulation differences. Unregulated (the simplest topology and what I use – they tend to sound louder with good punch) simply count on battery voltage and transformer ratio to determine the secondary voltage. Amps with a higher output power at 14.4 volts than at 12 are usually unregulated. Regulated supplies sample the secondary voltage and modulate the primary’s pulse-width (pulse width modulation – PWM) to keep the secondary voltages constant. These car amps tend to have the same output power ratings with battery voltages from 10 to 16 volts. Linear Power ran unregulated supplies. They also used high-current bipolar switching devices with some weird designs. They worked, but were not very efficient and were very old-school.
Look at most any “decent” and better car amps and it’s very easy to discern the power supply section from the amplifier. The power supply will have the transformer somewhat central to the supply section flanked by the primary filter capacitors (they are usually high capacity at 16 volts) and also by the secondary capacitors (usually lower capacity and higher voltage). Also nearby will be the driver IC/electronics, filters (R/C snubbers), and other support parts. The rectifiers will generally reside in proximity to the transformer’s secondary and filter caps. The MOSFET switching banks can be anything from one-or-two to dozens of FETs per primary phase. The FETs and rectifiers will generally be secured to the heatsink to ensure they are kept within thermal limitations and to give the amp a symmetrical look.
The Linear Power 5002iq power amp I worked on used a FerroxCube TX51/32/19 toroid core in a 3C81 material. This core is good for about than 1.5KW of power. Remember though, 1,500 watts is not amplifier power. This is total power. Once amplifier inefficiencies, switching losses, wire losses, and a multitude of others are removed, it is good for maybe 1KW of amplifier output power. I used a similar core in my 700 watt amp. Anyway, the Linear transformer had four paralleled 18AWG windings per primary. It then had 16 secondary windings (X 2 for the +/- voltage), also of 18AWG wire to produce approximately +/- 55 volts for the 2-ohm power supply rails. Lastly, it had additional sets of four secondary windings to provide +/- 68 (55 + 13 = 68) volts for the 4-ohm rails. Linear used a set of “taps” to allow the user to select the appropriate supply voltage depending on the load being driven. The tap-selectable rail voltages kept the amp fairly efficient, but wasn’t real convenient as the amp had to be pulled and the taps changed if the speaker loads were changed. The transformer worked very well despite the bipolar switching devices.
This is a lot to digest and understand, but read through it a couple times, and I’ll try to post some schematics and pictures soon. From all of this, car switching supplies should no longer be a mystery and something the savvy weekend-warrior could prototype and put into use.
Enjoy!
Zapco did this "modular" design back in the '80s, but is always seemed a little silly because no one would buy a supply without the amp or buy the amp without the supply. So why not combine them and reduce production costs with only one PCB and reduced construction requirements.
As far as building a variable car power supply to test amp designs, it certainly could be done. However, variable switching supplies are more complex and could present stability problems to the novice builder. I'd use home power supplies (transformers with diodes/caps) for the power supply section and once a power amp design and size is selected, build a dedicated car switching supply dedicated to your application.
It's your time and money (make sure to fuse everything well unless money is not a concern ; ) and there's nothing like the feeling of powering up a DC/DC converter and having it work well. There's also no smell like powering one up that doesn't work well.
Later.
As far as building a variable car power supply to test amp designs, it certainly could be done. However, variable switching supplies are more complex and could present stability problems to the novice builder. I'd use home power supplies (transformers with diodes/caps) for the power supply section and once a power amp design and size is selected, build a dedicated car switching supply dedicated to your application.
It's your time and money (make sure to fuse everything well unless money is not a concern ; ) and there's nothing like the feeling of powering up a DC/DC converter and having it work well. There's also no smell like powering one up that doesn't work well.
Later.
not sure how "high" end this is considered but I'm running a Memphis audio "Belle" amp. It's a 6 channel amp rated at 1400 watts (I think) that is actually 2 amps w/ independant power supplies and everything under the same shell. Extremely powerful, extremely clean. I've got it running my entire system and at 30% sub power it'll wear a pair of 12's out quickly if turned up to loud. The high's and mid's are cystal clean w/ no noise, static, or any other problems. Highly suggested.
i have the arc audio 1500 (class t) and the 2100 in my car. www.sounddomain.com/id/gompka I think they are among the best sounding amps in their price range. Brax and zapco do sound better but it all depends if you justify the improvement to sound by a large price jump.
In all honesty, though I feel I have a pretty well-tuned ear, I just can't hear much difference among the higher end amps. An Aura MR675 replaced my JL 300/4 and if there's a difference, it's less than 1%, even when sitting still. While driving, give it up... the difference is psychological. I'm a fan of topology and asthetics. As long as there is no noise, anything at the JL level and up will satisfy me.
Great thread here, I have not read all of them but I like all the input as well. I have heard and listened to alot of the amps in this forum, so with my response I may sound a bit old school but I have been usng the same two amps for 16 years now and I still think that they rate up their with the best of the best, I am using two ADS amps, one is a PQ20.2 and the other is a PH.15 both of these amps are quite and vvery conservative, when coupled with the right speakers they are amazing, I am running them with an audio control crossover and Nakamichi SP-80's and a NAK 10 and ADS speakers, and the combination is still as true as I have heard.
Well since it is back up top, I will add my input. Here some of my favorite amps:
Arc Audio SE's
Soundstream D200, D100, Class A's and MC's
Mac's
Linear Power 2.2's
DLS A3, RA20, A2
Zapco C2K's, and studio's
Brax 2 channel (can't remember which one it was)
Alto Mobile ADP's (Great midrange amps)
JBL Crown amp's
Genesis Dual Mono's
Sony M50, 2100G, M1, 260G, and M3 (This want to hear the super rare 2000R)
Pioneer ODR Class A's
Audsion (smooth and laid back)
PPI Arts
Blade's
All are top notch
Still want to play with the Sonfoni's, some of the other Genesis and Brax/Helix, some the Adcom's
Arc Audio SE's
Soundstream D200, D100, Class A's and MC's
Mac's
Linear Power 2.2's
DLS A3, RA20, A2
Zapco C2K's, and studio's
Brax 2 channel (can't remember which one it was)
Alto Mobile ADP's (Great midrange amps)
JBL Crown amp's
Genesis Dual Mono's
Sony M50, 2100G, M1, 260G, and M3 (This want to hear the super rare 2000R)
Pioneer ODR Class A's
Audsion (smooth and laid back)
PPI Arts
Blade's
All are top notch
Still want to play with the Sonfoni's, some of the other Genesis and Brax/Helix, some the Adcom's