Zanth
SHAman who knew of Head-Fi ten years prior to its existence
- Joined
- Oct 11, 2001
- Posts
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As with all reviews, these comments are based on my two ears and are my opinion only. YMMV.
Kevin Gilmore is infamous on Head-fi as well as Headwize not only for his expertise in the DIY forums but I would say moreso because the man is a complete psycho when it comes to amp designs. I use the word psycho in the kindest most admirable way I possibly can. Never satisfied with commercially available gear, this wizard takes it upon himself to design what he feels is THE BEST in power amps. His genius does shine through with the implementation of his work which often includes the simplest signal path, discrete instead of opamp-based circuits and all out craziness in the power supply department. I only have to mention Blue Hawaii and many here will shudder at the thought of all the power this amp has. Kevin is currently working on a magnificent beast, which could very well be the very last word in dynamic amplifiers. Until that time, Kevin has provided us with the Kevin Gilmore discrete amplifier.
Borrowing from the Headwize.org page and from Headamp.com the design is an all discrete design in the signal path with opamps only in the power supply circuit. “Stage 1 is a dual is a dual FET fully-differential fully-balanced front-end. The idling current is 2mA total per dual FET (1mA per FET) and 4mA for the complete front-end stage which consists of both dual FETs. The dual FETs generate the bias which runs the second stage, and keeps it and the resulting output section in class A at all times. The FETs are ultra low noise dual units specifically designed for audio uses. The total voltage gain of the first stage is 50.”
Stage 2 is the driver stage and is a standard class A voltage amp. The voltage gain is 0.5 and the idling current is 4.3 mA. The push-pull class A output stage is a series of paralleled emitter follower, current buffers. The voltage gain is 0.9 and the current gain is 75. The idling current is 15mA per transistor (or 60mA for the 8 transistors off the +16VDC rail and 60mA for the 8 transistors off the -16VDC rail).”
The power supply is a hefty one. “Its a dual tracking design. Because the open loop gain of the amp is low, its common mode rejection due to the power supply is not great. However if both the + and - voltage rails move up and down the same amount, there is no bias drift. Because of the pre-regulators, the total line/load variations are under 0.0001%. The opamp outputs are active in both directions; they can push or pull to keep the power supply at exactly the right point. The power supply design was an attempt to come up with the absolutely best power [supply for the amp].”
Headamp has packaged the Gilmore V2 unit in a single chassis, which is 1 case short of how the V1 was originally set up. Measuring in at 8” (W) x 8” (D) x 1.75” (H), it is fairly compact. The case is black, well built with fins on the side acting as heat sinks which is a good thing because even with them, the amp runs quite warm. (I realize I may be repeating what others have already stated regarding the amp, but just in case some may come across my review first I’d like to continue with the description.) The front plate sports a sharp silk screening with the Headamp name and logo next to an adequate knob attached to the Alps Blue pot. My favourite aesthetic feature is the blue LED. I have a thing for blue lights and this amp would fit in well with the look of my gear. Rounding up the front are a pair of neutrik headphone jacks. These are really nice and held snugly but not overly tight. I will soon be replacing my jack on the Melos SHA-X with a neutrik. If I had to be critical of the looks of the amp, I would pick on the knob. I wasn’t really taken with it. Justin is already looking at other options for the knob. Don’t get me wrong, it worked fine, but I would prefer something a bit more solid. While on topic of the volume control, after using a DACT stepped attenuator, I would absolutely want one. I know this is available on the SE version of the amp and that is the one I would likely go for. Gilmore V2 SE with a DACT knob.
The power switch is located at the rear of the unit, which was not a bother for me but some may prefer that on the side of front of the amp. The rear of the amp sports a series of RCA inputs and a pair of outputs when used as a preamp. The source selection switch is conveniently located next to the first set of audio inputs. The amp also has an IEC connector making power cord swapping possible.
I first tried the Gilmore amp when it was fresh out of the box. I plugged it in and hooked it up to the Shanling CD T-100 via Cardas Neutral Reference .5m IC’s. I popped in the KSC 35’s first so make sure nothing would happen, providing a load but nothing too costly to replace. When all seemed okay, I unplugged the Koss phones and plugged in the Grado SR200’s.
Upon first listen, I was really wowed by what I heard. I had been previously using the CHA47 to power the SR-200’s and frankly, the little amp just doesn’t have the juice necessary to make them sing. The sound is closed in, hollow, thin, and there really isn’t much bass to speak of. What I heard them powered by the Gilmore the sound immediately opened up and the bass was substantially deeper and fuller. Details I had only previously heard with the RS-1/RA-1 combo or the Etymotic/CHA47 combo were evident. I took the phones off, left the system run for 36 hours and then took my gear and the Gilmore to the Ottawa meet.
BEYERDYNAMIC DT 770’S:
I had the opportunity to listen to the Beyerdynamic DT770’s and the Sennheiser HD600’s with every cable out there. I am not overly familiar with either of the phones, that meet being only the second time I had heard the 770’s and it was only my third time hearing the Senns. I felt the 770’s had a valley shaped sound curve. Bumped bass and bumped highs with some suck-out in the mids. The Gilmore drove them easily and the bass became tight and very very present. Too present actually. I have stated before that these phones are not my cup of tea; however, if one is a bass monster, then this combo could definitely satisfy. Deep and tight but still too boomy for my taste. The highs were too strident for me as well. I know many criticize the RS-1’s as being bright so I would think I could handle a bit of bump in the highs but to me this was just too much. Maybe with some cable swapping and a different source (this was using the Roksan Kandy) the highs would not be so “present.”
SENNHEISER HD 600’S:
The HD600’s were much more pleasant with the Roksan/Gilmore. Since I had been told so many times that I had not heard the HD600’s in an ideal environment (only through RA-1, Shanling, Corda HA-1 and META42) I was very keen on hearing what a powerful SS amp could do for them. The Gilmore is very linear and transparent and with the quality juice it is capable of pumping out I found the typical “veil” was reduced. I can really understand now why many state the HD 600’s need lots of juice. They do. If only to get rid of the veil. I really liked the bass. It was tight and visceral while the highs were extended and controlled. The highs were not as fabulous as the Ety 4’s, Grado, RS-1’s or HP-1’s but I blame the signature sound of the HD600’s more than the amp. I often try to find combinations that would please me for life if I had not kept searching. Without being an obsessive/compulsive as I am, I feel the HD600/Gilmore is a great match and one that would provide me with endless hours of musical enjoyment. The Equinox has consistently been my cable of choice and it proved itself again here. The Gilmore has a tendency to sound dry but the Equinox was able to make something happen that made it more enjoyable. I guess the Equinox is not as neutral as the Cardas but in this case it is a good thing. I do enjoy a more neutral sound but too neutral sometimes takes away from the sound of “music.” Take that as you will.
Etymotic 4 Series:
My second favourite headphones with the Gilmore are my Ety’s. I have always felt the Etymotic 4 series didn’t really need a high-powered amp to get them going. They seemed to scale well enough and remain consistent. The Gilmore really pushed them to their limits. I felt with the extra juice, the Ety’s had a fuller and deeper bass, which is a good thing to have with Ety’s. The soundstage (er…headstage) was expanded enough to make a difference but don’t expect the world as these still have the signature “in your head” experience. Imaging was particularly impressive as was the increased blackness. I would say the dead black between notes was what really struck me with this combo. I loved it. I’ve never heard a set-up that competes in the blackness department as this one. The Gilmore provided more of all the Ety goodness I have raved about in the past. Lovely combination, and just unreal in the bedroom before sleep time.
GRADO SR-200’S:
My favourite headphones with the Gilmore are the Grado SR-200’s. They began the journey and they ended the journey. I loved this combination so much that I actually sold the SR-200’s to Beagle when I had to return the Gilmore. Why? Because I couldn’t listen to them knowing what they were capable of. Joe Grado made great headphones. His idea of diaphragms was to get them as close to neutral as possible, reproducing as accurately as possible what appeared on the media. The SR200’s are more neutral than any of the current offerings by his nephew John and with the Gilmore they really come alive. The bass is much plumper than the HP-1000’s (my reference) but are easier to drive and thus sing with the Gilmore. The Gilmore provides enough current to get them going. The bass is deep, full-bodied and visceral. The highs are not strident at all but they are extended. I would never call these phones “airy” but if one is looking for some air the Gilmore was the only amp other than the Melos SHA-X that could provide them with whatever is necessary to get at least bit of oxygen between notes
I have written that this is a reference quality combination. I stand by that statement. This is truly an excellent combination and one that will not kill the bank, just maim it a bit. The only amp that has outperformed the Gilmore with these phones has been the Melos SHA-X. It’s hard to really compare as my amp is about 3x the cost and has been substantially modified. Some have requested I do compare the two and I will below. I feel that my opinions with the HP-1/Melos vs the HP1/Gilmore are characteristic of the differences between the Melos and Gilmore regarding all phones I tried.
GRADO HP-1’S:
The HP-1’s with the Gilmore was very neutral, too neutral in fact. I said above that too much of one thing is not necessarily good. I think the Gilmore held its own with them, providing the power to get them going in all directions, but I felt the sound was dry, and boring at times. I much prefer the sound of the HP-1’s with the Melos SHA-X modded by carlo. There is a musicality that I have rarely found elsewhere (I happen to hear it in the RS-1/RA-1 combo) while maintaining the neutral character I so love. If one just wants a fast neutral sound then perhaps this is the last stop: Gilmore/HP-1000, but if one wants some zing with their music, some lushness then I would not stop here but look into a Melos and have it modded by carlo. With the blackgates installed the bass was much fuller and deeper with the Melos. I would say the Gilmore was even a bit lean in the bass, definitely so compared to the Melos. I have NEVER heard bass sound so good than I have with Melos. Perhaps if the Gilmore could incorporate some blackgates this would resolve some of the above issues. I know that Justin has mentioned that he really enjoys the SR-200’s with the Gilmore above the HP-2/Gilmore combo, so I am not alone. And this from the manufacturer!
The Present Line of Grados:
Now for some bad news. As much as the Gilmore is a match for the old series of Grados it is the opposite for the present line. Don’t get me wrong, the bass was tight and full and extended providing control of the bumped upper bass the present Grados are known for. The midrange was okay, nice but nothing to really get excited about and the highs…this is where the problem was for me. The highs were so strident, the sound so bright, that I could not listen for an extended period of time. The RS-1’s are said to be the darkest of John’s line-up. If this is the case then for my tastes, the Gilmore is not a match for them. I much prefer the RA-1 to the Gilmore, if only because it is not as forward. The RA-1 is a very transparent amp with little colouration, very similar to the characteristics of the Gilmore, so I don’t really understand why the sound is so very bright. Could it be the extra current provided? I don’t know what modifications could be done to the amp to decrease the forward nature when combined with these Grados but if I were looking into the Gilmore, I would definitely want this taken care of. I tried the RS-1’s, the 325’s, the 80’s and the 60’s. All of these phones exhibited the same characteristics. Good bass control, perhaps the leaner nature of the Gilmore’s bass (its not drastic just not blackgate-groovey-Melos bass) helps these Grados sound more true to the recording but damn those highs really hurt! It doesn’t help that the gain is set really high because it can be used as a preamp. Fortunately I was able to decrease the volume on my cd player to accommodate the high gain. If I were looking into this amp for my RS-1’s I would want blackgates, a low gain and maybe something to roll off the highs.
CONCLUSIONS:
After owning the Sugden and ringing in at $1000 US, it didn’t have much on the Gilmore except more control in the highs with present Grados. I feel the Sugden was too lean and lacking that foot-tapping love I get from the Melos. I sold it and bought the Melos and couldn’t be happier. The Gilmore, if I remember correctly, has similar bass characteristics as the Sugden and could have better bass given a parts upgrade. That of course is true also of the Sugden and I am aware that carlo has modded a Sugden and has transformed it. I would love to have a listen to this amp and hear the results.
I do enjoy neutrality, I do enjoy musicality and sometimes they seem polar to each other. Many have remarked that I enjoy colouration and that is why I love the RS-1/RA-1. Maybe that is true. Heck, it IS true. But I also love the HP-1/Melos combo and this is as close to neutral as one can come while maintaining a sense of PRaT and musical richness that I love. If I can find a speaker/amp combo that can match the HP-1/Melos then I will have a quick trip in the speaker world. Thank goodness!
The Gilmore, when paired with harder to drive headphones, really brings out their inherent goodness, provides wonderful control and does let the intended sound from the media get through. With easily driven cans, the sound is overly bright to the point that I can’t listen for a long period of time. This surely inhibits a fair evaluation of the amp and the phones together, but to me it is a big enough reason to leave that to other people.
Can this amp compete with amps at $500? I don’t really have much experience with SS amps in this category. It does best the HA-1 and the RA-1 for most phones (present Grados excluded) but I don’t have any experience with higher priced SS amps such as the Headroom Max (will be hearing that soon), Corda HA-2 and Pre-head, Emmeline, or Grace. It did, from memory, at least as well as the Sugden if not better in most categories.
Thanks to Headamp for providing me with the amp for an audition and for the Ottawa area meet.
Kevin Gilmore is infamous on Head-fi as well as Headwize not only for his expertise in the DIY forums but I would say moreso because the man is a complete psycho when it comes to amp designs. I use the word psycho in the kindest most admirable way I possibly can. Never satisfied with commercially available gear, this wizard takes it upon himself to design what he feels is THE BEST in power amps. His genius does shine through with the implementation of his work which often includes the simplest signal path, discrete instead of opamp-based circuits and all out craziness in the power supply department. I only have to mention Blue Hawaii and many here will shudder at the thought of all the power this amp has. Kevin is currently working on a magnificent beast, which could very well be the very last word in dynamic amplifiers. Until that time, Kevin has provided us with the Kevin Gilmore discrete amplifier.
Borrowing from the Headwize.org page and from Headamp.com the design is an all discrete design in the signal path with opamps only in the power supply circuit. “Stage 1 is a dual is a dual FET fully-differential fully-balanced front-end. The idling current is 2mA total per dual FET (1mA per FET) and 4mA for the complete front-end stage which consists of both dual FETs. The dual FETs generate the bias which runs the second stage, and keeps it and the resulting output section in class A at all times. The FETs are ultra low noise dual units specifically designed for audio uses. The total voltage gain of the first stage is 50.”
Stage 2 is the driver stage and is a standard class A voltage amp. The voltage gain is 0.5 and the idling current is 4.3 mA. The push-pull class A output stage is a series of paralleled emitter follower, current buffers. The voltage gain is 0.9 and the current gain is 75. The idling current is 15mA per transistor (or 60mA for the 8 transistors off the +16VDC rail and 60mA for the 8 transistors off the -16VDC rail).”
The power supply is a hefty one. “Its a dual tracking design. Because the open loop gain of the amp is low, its common mode rejection due to the power supply is not great. However if both the + and - voltage rails move up and down the same amount, there is no bias drift. Because of the pre-regulators, the total line/load variations are under 0.0001%. The opamp outputs are active in both directions; they can push or pull to keep the power supply at exactly the right point. The power supply design was an attempt to come up with the absolutely best power [supply for the amp].”
Headamp has packaged the Gilmore V2 unit in a single chassis, which is 1 case short of how the V1 was originally set up. Measuring in at 8” (W) x 8” (D) x 1.75” (H), it is fairly compact. The case is black, well built with fins on the side acting as heat sinks which is a good thing because even with them, the amp runs quite warm. (I realize I may be repeating what others have already stated regarding the amp, but just in case some may come across my review first I’d like to continue with the description.) The front plate sports a sharp silk screening with the Headamp name and logo next to an adequate knob attached to the Alps Blue pot. My favourite aesthetic feature is the blue LED. I have a thing for blue lights and this amp would fit in well with the look of my gear. Rounding up the front are a pair of neutrik headphone jacks. These are really nice and held snugly but not overly tight. I will soon be replacing my jack on the Melos SHA-X with a neutrik. If I had to be critical of the looks of the amp, I would pick on the knob. I wasn’t really taken with it. Justin is already looking at other options for the knob. Don’t get me wrong, it worked fine, but I would prefer something a bit more solid. While on topic of the volume control, after using a DACT stepped attenuator, I would absolutely want one. I know this is available on the SE version of the amp and that is the one I would likely go for. Gilmore V2 SE with a DACT knob.
The power switch is located at the rear of the unit, which was not a bother for me but some may prefer that on the side of front of the amp. The rear of the amp sports a series of RCA inputs and a pair of outputs when used as a preamp. The source selection switch is conveniently located next to the first set of audio inputs. The amp also has an IEC connector making power cord swapping possible.
I first tried the Gilmore amp when it was fresh out of the box. I plugged it in and hooked it up to the Shanling CD T-100 via Cardas Neutral Reference .5m IC’s. I popped in the KSC 35’s first so make sure nothing would happen, providing a load but nothing too costly to replace. When all seemed okay, I unplugged the Koss phones and plugged in the Grado SR200’s.
Upon first listen, I was really wowed by what I heard. I had been previously using the CHA47 to power the SR-200’s and frankly, the little amp just doesn’t have the juice necessary to make them sing. The sound is closed in, hollow, thin, and there really isn’t much bass to speak of. What I heard them powered by the Gilmore the sound immediately opened up and the bass was substantially deeper and fuller. Details I had only previously heard with the RS-1/RA-1 combo or the Etymotic/CHA47 combo were evident. I took the phones off, left the system run for 36 hours and then took my gear and the Gilmore to the Ottawa meet.
BEYERDYNAMIC DT 770’S:
I had the opportunity to listen to the Beyerdynamic DT770’s and the Sennheiser HD600’s with every cable out there. I am not overly familiar with either of the phones, that meet being only the second time I had heard the 770’s and it was only my third time hearing the Senns. I felt the 770’s had a valley shaped sound curve. Bumped bass and bumped highs with some suck-out in the mids. The Gilmore drove them easily and the bass became tight and very very present. Too present actually. I have stated before that these phones are not my cup of tea; however, if one is a bass monster, then this combo could definitely satisfy. Deep and tight but still too boomy for my taste. The highs were too strident for me as well. I know many criticize the RS-1’s as being bright so I would think I could handle a bit of bump in the highs but to me this was just too much. Maybe with some cable swapping and a different source (this was using the Roksan Kandy) the highs would not be so “present.”
SENNHEISER HD 600’S:
The HD600’s were much more pleasant with the Roksan/Gilmore. Since I had been told so many times that I had not heard the HD600’s in an ideal environment (only through RA-1, Shanling, Corda HA-1 and META42) I was very keen on hearing what a powerful SS amp could do for them. The Gilmore is very linear and transparent and with the quality juice it is capable of pumping out I found the typical “veil” was reduced. I can really understand now why many state the HD 600’s need lots of juice. They do. If only to get rid of the veil. I really liked the bass. It was tight and visceral while the highs were extended and controlled. The highs were not as fabulous as the Ety 4’s, Grado, RS-1’s or HP-1’s but I blame the signature sound of the HD600’s more than the amp. I often try to find combinations that would please me for life if I had not kept searching. Without being an obsessive/compulsive as I am, I feel the HD600/Gilmore is a great match and one that would provide me with endless hours of musical enjoyment. The Equinox has consistently been my cable of choice and it proved itself again here. The Gilmore has a tendency to sound dry but the Equinox was able to make something happen that made it more enjoyable. I guess the Equinox is not as neutral as the Cardas but in this case it is a good thing. I do enjoy a more neutral sound but too neutral sometimes takes away from the sound of “music.” Take that as you will.
Etymotic 4 Series:
My second favourite headphones with the Gilmore are my Ety’s. I have always felt the Etymotic 4 series didn’t really need a high-powered amp to get them going. They seemed to scale well enough and remain consistent. The Gilmore really pushed them to their limits. I felt with the extra juice, the Ety’s had a fuller and deeper bass, which is a good thing to have with Ety’s. The soundstage (er…headstage) was expanded enough to make a difference but don’t expect the world as these still have the signature “in your head” experience. Imaging was particularly impressive as was the increased blackness. I would say the dead black between notes was what really struck me with this combo. I loved it. I’ve never heard a set-up that competes in the blackness department as this one. The Gilmore provided more of all the Ety goodness I have raved about in the past. Lovely combination, and just unreal in the bedroom before sleep time.
GRADO SR-200’S:
My favourite headphones with the Gilmore are the Grado SR-200’s. They began the journey and they ended the journey. I loved this combination so much that I actually sold the SR-200’s to Beagle when I had to return the Gilmore. Why? Because I couldn’t listen to them knowing what they were capable of. Joe Grado made great headphones. His idea of diaphragms was to get them as close to neutral as possible, reproducing as accurately as possible what appeared on the media. The SR200’s are more neutral than any of the current offerings by his nephew John and with the Gilmore they really come alive. The bass is much plumper than the HP-1000’s (my reference) but are easier to drive and thus sing with the Gilmore. The Gilmore provides enough current to get them going. The bass is deep, full-bodied and visceral. The highs are not strident at all but they are extended. I would never call these phones “airy” but if one is looking for some air the Gilmore was the only amp other than the Melos SHA-X that could provide them with whatever is necessary to get at least bit of oxygen between notes
GRADO HP-1’S:
The HP-1’s with the Gilmore was very neutral, too neutral in fact. I said above that too much of one thing is not necessarily good. I think the Gilmore held its own with them, providing the power to get them going in all directions, but I felt the sound was dry, and boring at times. I much prefer the sound of the HP-1’s with the Melos SHA-X modded by carlo. There is a musicality that I have rarely found elsewhere (I happen to hear it in the RS-1/RA-1 combo) while maintaining the neutral character I so love. If one just wants a fast neutral sound then perhaps this is the last stop: Gilmore/HP-1000, but if one wants some zing with their music, some lushness then I would not stop here but look into a Melos and have it modded by carlo. With the blackgates installed the bass was much fuller and deeper with the Melos. I would say the Gilmore was even a bit lean in the bass, definitely so compared to the Melos. I have NEVER heard bass sound so good than I have with Melos. Perhaps if the Gilmore could incorporate some blackgates this would resolve some of the above issues. I know that Justin has mentioned that he really enjoys the SR-200’s with the Gilmore above the HP-2/Gilmore combo, so I am not alone. And this from the manufacturer!
The Present Line of Grados:
Now for some bad news. As much as the Gilmore is a match for the old series of Grados it is the opposite for the present line. Don’t get me wrong, the bass was tight and full and extended providing control of the bumped upper bass the present Grados are known for. The midrange was okay, nice but nothing to really get excited about and the highs…this is where the problem was for me. The highs were so strident, the sound so bright, that I could not listen for an extended period of time. The RS-1’s are said to be the darkest of John’s line-up. If this is the case then for my tastes, the Gilmore is not a match for them. I much prefer the RA-1 to the Gilmore, if only because it is not as forward. The RA-1 is a very transparent amp with little colouration, very similar to the characteristics of the Gilmore, so I don’t really understand why the sound is so very bright. Could it be the extra current provided? I don’t know what modifications could be done to the amp to decrease the forward nature when combined with these Grados but if I were looking into the Gilmore, I would definitely want this taken care of. I tried the RS-1’s, the 325’s, the 80’s and the 60’s. All of these phones exhibited the same characteristics. Good bass control, perhaps the leaner nature of the Gilmore’s bass (its not drastic just not blackgate-groovey-Melos bass) helps these Grados sound more true to the recording but damn those highs really hurt! It doesn’t help that the gain is set really high because it can be used as a preamp. Fortunately I was able to decrease the volume on my cd player to accommodate the high gain. If I were looking into this amp for my RS-1’s I would want blackgates, a low gain and maybe something to roll off the highs.
CONCLUSIONS:
After owning the Sugden and ringing in at $1000 US, it didn’t have much on the Gilmore except more control in the highs with present Grados. I feel the Sugden was too lean and lacking that foot-tapping love I get from the Melos. I sold it and bought the Melos and couldn’t be happier. The Gilmore, if I remember correctly, has similar bass characteristics as the Sugden and could have better bass given a parts upgrade. That of course is true also of the Sugden and I am aware that carlo has modded a Sugden and has transformed it. I would love to have a listen to this amp and hear the results.
I do enjoy neutrality, I do enjoy musicality and sometimes they seem polar to each other. Many have remarked that I enjoy colouration and that is why I love the RS-1/RA-1. Maybe that is true. Heck, it IS true. But I also love the HP-1/Melos combo and this is as close to neutral as one can come while maintaining a sense of PRaT and musical richness that I love. If I can find a speaker/amp combo that can match the HP-1/Melos then I will have a quick trip in the speaker world. Thank goodness!
The Gilmore, when paired with harder to drive headphones, really brings out their inherent goodness, provides wonderful control and does let the intended sound from the media get through. With easily driven cans, the sound is overly bright to the point that I can’t listen for a long period of time. This surely inhibits a fair evaluation of the amp and the phones together, but to me it is a big enough reason to leave that to other people.
Can this amp compete with amps at $500? I don’t really have much experience with SS amps in this category. It does best the HA-1 and the RA-1 for most phones (present Grados excluded) but I don’t have any experience with higher priced SS amps such as the Headroom Max (will be hearing that soon), Corda HA-2 and Pre-head, Emmeline, or Grace. It did, from memory, at least as well as the Sugden if not better in most categories.
Thanks to Headamp for providing me with the amp for an audition and for the Ottawa area meet.
