KurtW
500+ Head-Fier
- Joined
- Jun 26, 2001
- Posts
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- 13
Note: I am posting this at both HeadWize and Head-Fi so if you read it at one place you don't have to read it again…it is very long.
The day following the Bay Area get-together at my house I still had a table full of amps, so I spend another evening doing comparisons. When we had as many as 8 people in one room, doing amp comparisons using open headphones was at times challenging, so spending a bit more time in a quieter environment was a plus.
The Equipment used:
I used the Linn Ikemi CD player since it has two identical pairs of RCA outputs. All of the amps were tested with the Sennhieser HD600 with the blue Clou cable. Additionally all of the portable amps were also tested with the Grado SR80 and the Panasonic SL-CT470.
The new Max has two sets of inputs with a switch on the back of the unit to select the active one. This makes cable comparisons easy to do so the first thing I did was compare the two sets of DiMarzio cables that HeadRoom sent…nice looking cables by the way. They seemed to be similar except for the length and the fact that one had locking RCA connections on both ends and the other had them only on one end. The purpose of the later cable was to have somewhat smaller RCA connectors that could be inserted in the recessed receptacles on the HeadRoom Cosmic and Supreme amps. The two cables sounded identical to me, so they were used from the Ikemi to two amps under test at any given time. At the end of the testing I also compared a few other cables including two DIY cables made from Kimber PBJ and Beldon 89259, and the MIT T2. At times I heard slight differences between them but they all sounded very similar to me. Maybe it was the high quality of the equipment that was being used that minimized the cable interactions.
The CDs used:
I used four cds that have not only have great sonics but I also really like the music:
Schubert, Arpeggione Sonta for piano & cello, Decca 289 460 974-2
Sonny Rollins, Contemporary Leaders, XRCD2 VICJ-60244 (this is the Japanese version)
James Carter, Chasin' the Gypsy, Atlantic 83304-2
Joe Lovano, Flights of Fancy, Blue Note 72435 2761821
This last one was recorded live to 2 track analog tape and as a result of no mixing board it has very wide separation. If you have trouble hearing the effect of crossfeed, try this one out.
The Amps: I'll describe each one briefly and then give a summary at the end. Further details can be gotten from the manufacturer's web site. You can see a picture of the amps here: http://www.superhost.com/~jude/BA/BAHequipt51.JPG Unless mentioned otherwise the testing was done with the crossfeed and filter circuits off. I took some measurements on couple of the amps but this was done after all listening tests. The prices listed were accurate at one time to the best of my knowledge but of course this is subject to change, so look again before leaping. HeadRoom is unique in that they offer 30 day free trial (at least within the US), but I found all of the companies nice to do business with.
The HeadRoom new Max: description
The new model adds an additional pair of inputs as I mentioned above. I find that this is a very nice addition, adding to the flexibility of the unit since it also comes with a set of outputs and can be used as a preamp. The input selector switch is in the back of the unit, which isn't really handy but on the other hand it simplifies the front panel by one switch and many people will never use it. The new models also have a high-med-low gain switch that the old one didn't. Medium seemed to correspond to the old unit. When the volume control was at 12:00 (straight up) on Medium, you could get about the same volume from the headphones from 10:00 at the high setting and 2:00 at the low setting. They also added a second level of high frequency boost to the previous filter switch. The effect of this is fairly subtle; I measured about 2dB of extra boost at the highest frequencies. The new locking headphone jacks (it has two) aren't quite as attractive as the old ones but they have some additional functionality as XLR connectors so I guess that's the trade-off. They obviously didn't take any shortcuts in the quality of materials, which were all top notch. I didn't open the unit up, so I can't comment on the insides but I bet they didn't skimp there either. You can get more info from their website at www.headphone.com Price $1777.
The HeadRoom new Max: sound
During the get-together I compared the new and old Max and didn't really pick up the differences; at least one other person mentioned the same thing. The next day's testing was done comparing the new Max to the older Maxed-out Home, which was said to be almost identical sounding to the old Max. I found both units to be very similar, but the Max seemed at times to have a slight edge on overall transparency and detail. In general both units are very detailed with excellent extension. I later measured the frequency response and found it to be flat from 20 Hz out to 20kHz. This is a change from previous HeadRoom designs which had a slight rolloff of the highest frequencies. I measured this rolloff on the MOH to be 1.4dB at 16kHz and 2dB at 20kHz. My hearing rolls off before this but most of the guys at the get-together had good hearing at 16kHz when we did our hearing tests and this difference didn't jump out at them either, so it is subtle.
The Berning micro-ZOTL: description
This is a push-pull tube amp that doesn't use the traditional output transformer. It is the only unit in this report that does not have crossfeed capability, although I use an external crossfeed circuit with it with good results. More details can be found from the manufacturer's web site: http://www.davidberning.com/ . I have upgraded to NOS Sylvania tubes, although the factory tubes sounded pretty nice too. The locking headphone jack, volume control and power switch are on the top of the unit. The quality of the hardware is also top notch, down to the tight-fitting ceramic tube sockets inside. It has 1 watt per channel power and has speaker connections on the rear. It can also be powered from a 12volt DC source, but cannot take the 13.5+ volts from a charging car battery. It comes in three colors: blue, red and brown. I have the brown one. Price: $750.
The Berning micro-ZOTL: sound
This amp in many ways sounds very similar to the Max, which is somewhat surprising given the two completely different circuits. The biggest thing that stood out to me was the ZOTL had a more "liquid" sound compared to the "drier" sound of the Max. This is pretty much what I would have expected from tubes vs solid state. Both amps had excellent transients, a clean crisp top end and deep powerful bass. The ZOTL bass is very slightly fuller or richer sounding without being at all tubby, but again the difference is very small. I find the more liquid sound of the ZOTL to be more musical, although the drier sound of the Max may be more accurate.
The HeadRoom Maxed-Out Home: description and sound
This is the older unit, maybe about two years old. It is supposed to have the same circuitry as the old Max, but with different headphone jacks (it also has two) and a different volume control. It also has the set of outputs and the quality of jacks is excellent. In some ways I like the simpler, less massive looks of this unit over the Max, but that's a personal call. As for the sound, see my description in comparisons with the Max and Corda. Price: $999.
The Meier-Audio Corda: description
This is a unit I built from a kit but it is also available assembled. It's slightly bigger than the Cosmic but almost twice as tall. You can get more information from the website http://home.t-online.de/home/meier-audio/. This amp is different from most here as it and the Total Airhead are the only ones that come with the smaller mini-jacks for the headphones. It also stands out in that it has 3 different crossfeed settings as well as no crossfeed. The headphone jacks are recessed into the front panel so if you are using a *" to mini adapter it needs to be one with a small diameter case near the connector or it won't fit into the recessed panel all the way, resulting in a bad contact. I only had this trouble when using a cheap adapter; the Sennheiser and AKG adaptors worked fine, and many phones come with the small plugs anyway. It has a second headphone jack that has a 120 ohm resistor in series, which is said to be better suited for some of the Beyer phones. Overall the quality of the jacks isn't quite as high as the pricier HeadRoom and Berning units, but the quality of the components inside is excellent as is the casework. Price: $250 kit, $320 assembled.
The Meier-Audio Corda: sound
The Corda had a very similar sound to the Max with excellent bass and clear crisp highs but perhaps not quite as airy and transparent. It was actually very very close to the sound of the Cosmic powered by the Base Station One.
The HeadRoom Cosmic: description
I found the new Cosmic to be nicer looking than the old one. It has the same filter and gain adjustments that I described on the new Max. The full size headphone jack has been improved with stiffer contacts and it appears to be the same as used on the older Maxed-out Home. Like the older unit it has a remote power supply connection on the back for use with the Base Station One which I also tried. It is a nice compact unit that is about the size of a portable CD player. It can be powered by a 5v walwart power supply or 4 D cells. Price: $599
The HeadRoom Cosmic: sound
I was hard pressed to tell the difference between the old and new unit; I times I thought the new one might be slightly more transparent but they were very, very close. As I mentioned in the Max comments, there is a measured difference is the very top frequencies and if you have excellent hearing you may better appreciate the extra sparkle in the new unit. Compared to the Max, the Cosmic is a little less transparent and doesn't have quite the super sharp attack on plucked strings, for example. It also had a lighter sound to the bass and the highs may be slightly harsher. When I used the Cosmic with the Power Station One, however, the bass got substantially better and the overall sound was noticeably improved. This is a nice way to have portability on the road and great sound at home.
The HeadRoom Supreme: description and sound
The Supreme is the same handy size of the Cosmic but uses BB604 op amps instead of the BB627 that is also used in the Max and MOH. My unit is probably at least 7 or 8 years old and has provisions for 4 internal AA cells. So my unit may not sound exactly like a recent older Supreme, but they now have the newer version out anyway. Compared to the Cosmic, the Supreme sounds slower and a little duller. Price: $399
The HeadRoom Total Airhead: description and sound
My unit is less than a year old and I think reflects the latest of many versions of this model. This unit is built for portability as a top priority so you get a plastic instead of metal case, small thumbwheel volume controls instead of nice big pots, small plastic switches etc. It goes without saying (now that I think about it, it shouldn't be taken for granted) that all of the units above are dead quiet. Earlier TA designs had some noise problems but this one is also quiet. Compared to the Supreme, the TA sounds slower yet and has some graininess. It also has weaker bass. However, when comparing (with Grado SR80s) the headphone output of the Panasonic 470 to the 470's line output fed to the TA, the Panasonic by itself sounds relatively harsh and thin. A note about portability: I typically walk my dog every evening for about 20 minutes and take the TA and a Panasonic portable in a small sports pack that attaches to my waist. I barely notice that I have it. I use Grado SR60s which not only are comfortable (with comfy pads) but also keep my ears warm. When I got the Traveler bag with the Cosmic, 4-D cell pack and Panasonic 470 I tried it out on the walk. The sound was noticeably better, actually way better, but I couldn't wait to get home and get that 10 lb pack off of my shoulder. Maybe I'm a wimp so YMMV. TA Price: $159
Crossfeed Comments:
The HeadRoom amps and the Corda both have switchable crossfeed circuits, but the design of these are quite different. I find that both are effective in minimizing the feeling of a gap in the center of your head. The HeadRoom circuit ends up reducing the treble a little so all of their amps other than the Airheads have a filter switch that brings the treble back. They also have a small boost in the bass, although the new units seem to have slightly less boost. This is to compensate for the case when bass is mostly in only one channel and there will be some phase cancellation of the bass in this case. These affects are measurable if you feed in a monaural signal and measure one of the outputs, but they are less than 2dB in amplitude. The Corda crossfeed measures flat under the same conditions. I would have preferred to see a switchable bass boost circuit in both amps rather than the second level of treble boost of the HeadRoom or no boost in the Corda. I do find the multiple settings on the Corda to be useful, although I use one setting for 90% of what I listen to. Overall I prefer the Corda's crossfeed.
RATINGS:
The reason I'm giving ratings on the amps is to give the reader a better feel for the relative differences in the sound quality. A difference of a half a point or less is subtle or even questionable. A one point difference is clearly noticeable and two or more points is pretty major. They apply only to the sound quality and reflect my own personal opinions and preferences. I have chosen a basic 10 point scale (with the famous modification) with the max being defined as the Max. Here we go:
The Max, 10
ZOTL, 11
Maxed-out Home, 9.5
New Cosmic with Base Station One, 9
Corda, 9
New Cosmic, 7.75
Old Cosmic, 7.5
Supreme, 6
Total Airhead, 4.5
Panasonic 470, 2
The day following the Bay Area get-together at my house I still had a table full of amps, so I spend another evening doing comparisons. When we had as many as 8 people in one room, doing amp comparisons using open headphones was at times challenging, so spending a bit more time in a quieter environment was a plus.
The Equipment used:
I used the Linn Ikemi CD player since it has two identical pairs of RCA outputs. All of the amps were tested with the Sennhieser HD600 with the blue Clou cable. Additionally all of the portable amps were also tested with the Grado SR80 and the Panasonic SL-CT470.
The new Max has two sets of inputs with a switch on the back of the unit to select the active one. This makes cable comparisons easy to do so the first thing I did was compare the two sets of DiMarzio cables that HeadRoom sent…nice looking cables by the way. They seemed to be similar except for the length and the fact that one had locking RCA connections on both ends and the other had them only on one end. The purpose of the later cable was to have somewhat smaller RCA connectors that could be inserted in the recessed receptacles on the HeadRoom Cosmic and Supreme amps. The two cables sounded identical to me, so they were used from the Ikemi to two amps under test at any given time. At the end of the testing I also compared a few other cables including two DIY cables made from Kimber PBJ and Beldon 89259, and the MIT T2. At times I heard slight differences between them but they all sounded very similar to me. Maybe it was the high quality of the equipment that was being used that minimized the cable interactions.
The CDs used:
I used four cds that have not only have great sonics but I also really like the music:
Schubert, Arpeggione Sonta for piano & cello, Decca 289 460 974-2
Sonny Rollins, Contemporary Leaders, XRCD2 VICJ-60244 (this is the Japanese version)
James Carter, Chasin' the Gypsy, Atlantic 83304-2
Joe Lovano, Flights of Fancy, Blue Note 72435 2761821
This last one was recorded live to 2 track analog tape and as a result of no mixing board it has very wide separation. If you have trouble hearing the effect of crossfeed, try this one out.
The Amps: I'll describe each one briefly and then give a summary at the end. Further details can be gotten from the manufacturer's web site. You can see a picture of the amps here: http://www.superhost.com/~jude/BA/BAHequipt51.JPG Unless mentioned otherwise the testing was done with the crossfeed and filter circuits off. I took some measurements on couple of the amps but this was done after all listening tests. The prices listed were accurate at one time to the best of my knowledge but of course this is subject to change, so look again before leaping. HeadRoom is unique in that they offer 30 day free trial (at least within the US), but I found all of the companies nice to do business with.
The HeadRoom new Max: description
The new model adds an additional pair of inputs as I mentioned above. I find that this is a very nice addition, adding to the flexibility of the unit since it also comes with a set of outputs and can be used as a preamp. The input selector switch is in the back of the unit, which isn't really handy but on the other hand it simplifies the front panel by one switch and many people will never use it. The new models also have a high-med-low gain switch that the old one didn't. Medium seemed to correspond to the old unit. When the volume control was at 12:00 (straight up) on Medium, you could get about the same volume from the headphones from 10:00 at the high setting and 2:00 at the low setting. They also added a second level of high frequency boost to the previous filter switch. The effect of this is fairly subtle; I measured about 2dB of extra boost at the highest frequencies. The new locking headphone jacks (it has two) aren't quite as attractive as the old ones but they have some additional functionality as XLR connectors so I guess that's the trade-off. They obviously didn't take any shortcuts in the quality of materials, which were all top notch. I didn't open the unit up, so I can't comment on the insides but I bet they didn't skimp there either. You can get more info from their website at www.headphone.com Price $1777.
The HeadRoom new Max: sound
During the get-together I compared the new and old Max and didn't really pick up the differences; at least one other person mentioned the same thing. The next day's testing was done comparing the new Max to the older Maxed-out Home, which was said to be almost identical sounding to the old Max. I found both units to be very similar, but the Max seemed at times to have a slight edge on overall transparency and detail. In general both units are very detailed with excellent extension. I later measured the frequency response and found it to be flat from 20 Hz out to 20kHz. This is a change from previous HeadRoom designs which had a slight rolloff of the highest frequencies. I measured this rolloff on the MOH to be 1.4dB at 16kHz and 2dB at 20kHz. My hearing rolls off before this but most of the guys at the get-together had good hearing at 16kHz when we did our hearing tests and this difference didn't jump out at them either, so it is subtle.
The Berning micro-ZOTL: description
This is a push-pull tube amp that doesn't use the traditional output transformer. It is the only unit in this report that does not have crossfeed capability, although I use an external crossfeed circuit with it with good results. More details can be found from the manufacturer's web site: http://www.davidberning.com/ . I have upgraded to NOS Sylvania tubes, although the factory tubes sounded pretty nice too. The locking headphone jack, volume control and power switch are on the top of the unit. The quality of the hardware is also top notch, down to the tight-fitting ceramic tube sockets inside. It has 1 watt per channel power and has speaker connections on the rear. It can also be powered from a 12volt DC source, but cannot take the 13.5+ volts from a charging car battery. It comes in three colors: blue, red and brown. I have the brown one. Price: $750.
The Berning micro-ZOTL: sound
This amp in many ways sounds very similar to the Max, which is somewhat surprising given the two completely different circuits. The biggest thing that stood out to me was the ZOTL had a more "liquid" sound compared to the "drier" sound of the Max. This is pretty much what I would have expected from tubes vs solid state. Both amps had excellent transients, a clean crisp top end and deep powerful bass. The ZOTL bass is very slightly fuller or richer sounding without being at all tubby, but again the difference is very small. I find the more liquid sound of the ZOTL to be more musical, although the drier sound of the Max may be more accurate.
The HeadRoom Maxed-Out Home: description and sound
This is the older unit, maybe about two years old. It is supposed to have the same circuitry as the old Max, but with different headphone jacks (it also has two) and a different volume control. It also has the set of outputs and the quality of jacks is excellent. In some ways I like the simpler, less massive looks of this unit over the Max, but that's a personal call. As for the sound, see my description in comparisons with the Max and Corda. Price: $999.
The Meier-Audio Corda: description
This is a unit I built from a kit but it is also available assembled. It's slightly bigger than the Cosmic but almost twice as tall. You can get more information from the website http://home.t-online.de/home/meier-audio/. This amp is different from most here as it and the Total Airhead are the only ones that come with the smaller mini-jacks for the headphones. It also stands out in that it has 3 different crossfeed settings as well as no crossfeed. The headphone jacks are recessed into the front panel so if you are using a *" to mini adapter it needs to be one with a small diameter case near the connector or it won't fit into the recessed panel all the way, resulting in a bad contact. I only had this trouble when using a cheap adapter; the Sennheiser and AKG adaptors worked fine, and many phones come with the small plugs anyway. It has a second headphone jack that has a 120 ohm resistor in series, which is said to be better suited for some of the Beyer phones. Overall the quality of the jacks isn't quite as high as the pricier HeadRoom and Berning units, but the quality of the components inside is excellent as is the casework. Price: $250 kit, $320 assembled.
The Meier-Audio Corda: sound
The Corda had a very similar sound to the Max with excellent bass and clear crisp highs but perhaps not quite as airy and transparent. It was actually very very close to the sound of the Cosmic powered by the Base Station One.
The HeadRoom Cosmic: description
I found the new Cosmic to be nicer looking than the old one. It has the same filter and gain adjustments that I described on the new Max. The full size headphone jack has been improved with stiffer contacts and it appears to be the same as used on the older Maxed-out Home. Like the older unit it has a remote power supply connection on the back for use with the Base Station One which I also tried. It is a nice compact unit that is about the size of a portable CD player. It can be powered by a 5v walwart power supply or 4 D cells. Price: $599
The HeadRoom Cosmic: sound
I was hard pressed to tell the difference between the old and new unit; I times I thought the new one might be slightly more transparent but they were very, very close. As I mentioned in the Max comments, there is a measured difference is the very top frequencies and if you have excellent hearing you may better appreciate the extra sparkle in the new unit. Compared to the Max, the Cosmic is a little less transparent and doesn't have quite the super sharp attack on plucked strings, for example. It also had a lighter sound to the bass and the highs may be slightly harsher. When I used the Cosmic with the Power Station One, however, the bass got substantially better and the overall sound was noticeably improved. This is a nice way to have portability on the road and great sound at home.
The HeadRoom Supreme: description and sound
The Supreme is the same handy size of the Cosmic but uses BB604 op amps instead of the BB627 that is also used in the Max and MOH. My unit is probably at least 7 or 8 years old and has provisions for 4 internal AA cells. So my unit may not sound exactly like a recent older Supreme, but they now have the newer version out anyway. Compared to the Cosmic, the Supreme sounds slower and a little duller. Price: $399
The HeadRoom Total Airhead: description and sound
My unit is less than a year old and I think reflects the latest of many versions of this model. This unit is built for portability as a top priority so you get a plastic instead of metal case, small thumbwheel volume controls instead of nice big pots, small plastic switches etc. It goes without saying (now that I think about it, it shouldn't be taken for granted) that all of the units above are dead quiet. Earlier TA designs had some noise problems but this one is also quiet. Compared to the Supreme, the TA sounds slower yet and has some graininess. It also has weaker bass. However, when comparing (with Grado SR80s) the headphone output of the Panasonic 470 to the 470's line output fed to the TA, the Panasonic by itself sounds relatively harsh and thin. A note about portability: I typically walk my dog every evening for about 20 minutes and take the TA and a Panasonic portable in a small sports pack that attaches to my waist. I barely notice that I have it. I use Grado SR60s which not only are comfortable (with comfy pads) but also keep my ears warm. When I got the Traveler bag with the Cosmic, 4-D cell pack and Panasonic 470 I tried it out on the walk. The sound was noticeably better, actually way better, but I couldn't wait to get home and get that 10 lb pack off of my shoulder. Maybe I'm a wimp so YMMV. TA Price: $159
Crossfeed Comments:
The HeadRoom amps and the Corda both have switchable crossfeed circuits, but the design of these are quite different. I find that both are effective in minimizing the feeling of a gap in the center of your head. The HeadRoom circuit ends up reducing the treble a little so all of their amps other than the Airheads have a filter switch that brings the treble back. They also have a small boost in the bass, although the new units seem to have slightly less boost. This is to compensate for the case when bass is mostly in only one channel and there will be some phase cancellation of the bass in this case. These affects are measurable if you feed in a monaural signal and measure one of the outputs, but they are less than 2dB in amplitude. The Corda crossfeed measures flat under the same conditions. I would have preferred to see a switchable bass boost circuit in both amps rather than the second level of treble boost of the HeadRoom or no boost in the Corda. I do find the multiple settings on the Corda to be useful, although I use one setting for 90% of what I listen to. Overall I prefer the Corda's crossfeed.
RATINGS:
The reason I'm giving ratings on the amps is to give the reader a better feel for the relative differences in the sound quality. A difference of a half a point or less is subtle or even questionable. A one point difference is clearly noticeable and two or more points is pretty major. They apply only to the sound quality and reflect my own personal opinions and preferences. I have chosen a basic 10 point scale (with the famous modification) with the max being defined as the Max. Here we go:
The Max, 10
ZOTL, 11
Maxed-out Home, 9.5
New Cosmic with Base Station One, 9
Corda, 9
New Cosmic, 7.75
Old Cosmic, 7.5
Supreme, 6
Total Airhead, 4.5
Panasonic 470, 2
