bradman
New Head-Fier
- Joined
- Mar 11, 2007
- Posts
- 26
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Hi everyone. I've been contemplating an integrated DAC/Amp solution for some time now and I am considering the Headroom Desktop line of Amps. The features that attract me are:
. The small footprint.
. Built-in DAC so everything's in one small box. I live in a small one-bedroom apartment, so I'm a bit limited in space unless I really want to clutter the place up. they're also pretty light which is a definite advantage for international shipping compared to other similar amps I have looked at.
. Crossfeed. Well, it's not really necessary, but I sure like it. An amp with it will probably get my preference over one that doesn't have it. A hardware crossfeed means less for the source to do and works for sources that can't do it.
. Optical in (as well as USB). I don't have an immediate use for coaxial in, but who knows what the future holds.
Anyway, I have considered quite a few different amps, but the HR desktop line seem to meet my requirements and really pack a lot into a small space, even if they're not the cheapest, and they appear to be fairly well regarded around here. Incidentally, the new Micro line of amplifiers that Hr are releasing soon also look very interesting, not to mention the 2007 Desktop Portable.
So, I am looking for advice and opinions for deciding what to get and what options to pack into it. As I'm in chile, trying before buying isn't really an option. I haven't found much head-fi activity in South America, but perhaps I just haven't hit on the magical search term yet. I'm certain their are serious audiophiles here, but higher-fi headphone listening doesn't seem to be well known in this country as far as I can tell. So this is going to be a purchase sight unseen (or should that be sound unheard?).
Before starting, I should mention that I plan to pair the amp with an hp upgrade to some Senn. HD650's. I may get some AKG K701's down the track to compare, but the 650's sound like they will do me (initially at least, this is head-fi after all!). I'll summarise the various choices and options accompanied by my current thoughts and questions. My objective is to obtain some other points of view to help me decide just where to draw the line on the curve of diminishing returns. Of course, before placing an order, I intend to grill the sales staff at HeadRoom, but I wanted to canvas experienced folk here on head-fi first.
1. Single-ended Desktop Amp (DT) vs. Desktop Balanced (DB). The DB Amp is the only balanced system within the sort of price range I'm considering which has all the other features I want. It's awfully tempting to go for this. However, I have come across opinions indicating that the single-ended DT is possibly better bang for the buck, in particular, the maxed out DT (with max modules) vs. the maxed out DB (with home modules). I've read quite a lot of discussion on head-fi about balanced operation but I'm still not particularly clear on something. At what point does balanced operation offer substantial improvement in performance? For example, is it more beneficial to have class A amplification before considering balanced operation? Which has more to offer, class A or balanced operation? I observe that it is possible to purchase the DB with the desktop module which uses class AB operation if I am not mistaken. From all I have read, it is clear that class A is apparently the way to go, but is balanced operation something that truly falls into the top end of the diminishing returns curve, or does it have something to offer in the price range of the HR Desktop line? I have to admit to being very curious about balanced operation, but it is an extra hassle in terms of cabling and surely there must be compromises at the entry level. Furthermore, does balanced operation offer a really obvious enhancement to spatial presentation, etc., or is it a fairly subtle improvement? Headroom have a couple of very attractive packages involving the maxed out DT and DB, but as the price is the same, price alone is not much of a deciding factor.
The one feature the DB lacks, which could be nice to have for the future, is line out so the amp could be used as a pre-amp. The DT has this.
also, I note that the DB can power single-ended headphones. While this isn't of course how you'd want to primarily use it, it makes the amp flexible and is probably a handy feature to have. However, I've read that the 1/4 inch jacks do not provide the same quality of sound as the balanced XLR outs because they feed from the "line driver". to satisfy my curiosity, can anyone tell me what a "line driver" is and why its output would be inferior to a fully single-ended amplifier output? While I'm at it, how does a properly implemented line-out actually work on a headphone amplifier? My guess would be that the line-out somehow feeds off the amplifier output in a way that is independent of what is happening at the headphone out, with a fixed voltage divider being used to provide the appropriate voltage level at the line-out jacks. Incidentally, is the volume adjusted on an amplifier by using a voltage divider in series with the output or the input? Or am I just completely off the mark and it's done some other way? Ok,I'm getting off track.
2. Home modules vs. Max modules. I might as well go at least for the home modules. There are cheaper amps out there that are also fully class A so paying this much without getting some class A action would seem to be a shame. Plus, the home module upgrade is not that expensive. The real question however would be deciding between max modules, which of course only apply to the DT, and home modules. The price difference between them is pretty substantial. The max DAC, which upsamples and reclocks (in addition to the oversampling carried out by the CS4398) as I understand it, is a tempting upgrade over the home DAC. However, as the principal differences between the home and max amp modules seems to be in quality of materials, workmanship and a change in op-amps, and Headroom themselves claim the difference in resultant sound quality to be fairly subtle, I'm not sure if the max module is worth $300 over the home module. I'm not even sure that a max DAC can be mixed with a home amp module. However, as the fully loaded DT costs more or less the same as a fully loaded DB, a more pertanent question may be what are the benefits of max modules in single-ended configuration as compared to home modules in balanced operation?
3. ALPS pot vs. stepped attenuator (SA). I understand the benefits and drawbacks of having a stepped attenuator over a continuous variable resistance pot, but I'd like some other's thoughts on the stepped attenuator implementation on the desktop line of amps. I've read that the SA on the DB is rather finnicky to adjust exactly as you like because of the difference in resistances between successive volume levels. I don't know if this is because of the design of the attenuator or simply because the 6 dB difference between single-ended and balanced operation effectively doubles the perceived step size. In any case, it makes sense to me that when laying down a pile of denero for an expensive audio component, having a SA with its superior reliability (not to mention affect on sound quality) in terms of possible mechanical failure (when compared to a variable resistor) is a good thing and should increase the mean time between failures, that is, help to protect my investment. Anyway, I haven't read any negative comments about the SA on the DT (just the DB), so I would like to ask if the SA on the DT is difficult to adjust and if the SA on the DB really is as finnicky as I've read? Perhaps it is worth having an SA on the DT, but not worththe the trouble on the DB? Whether or not to have an SA will be the last thing to consider after I've decided on the amp and modules.
4. Could it be worth hanging off to check out the new Micro line? It seems that the new standard Micros (DAC and amp) will be going for around $400 a piece and the Ultra Micros for around $700 a piece from what I've read. Pros seem to be size, stackable and hopefully having the same sq as their desktop equivalents while the cons would be having a pair of Astrodynes to deal with instead of a single power supply. Together, the two units aren't that much smaller than a Desktop amp and I'd have to wonder about ventilation and cooling if stacking the ultras.
Any ideas and corrections to wildly inaccurate statements I have made would be welcomed, in addition to any further thoughts and considerations anyone wants to throw into the pond to properly stir up the silt and really confuse me.
Finally, I'd like to thank all you fine folks on head-fi in advance for any help. I must also offer my a posteriori thanks to you all. I haven't posted much on head-fi, but I've been lurking for over half a year now and have learnt an enormous amount from reading discussions here.
Cheers.
. The small footprint.
. Built-in DAC so everything's in one small box. I live in a small one-bedroom apartment, so I'm a bit limited in space unless I really want to clutter the place up. they're also pretty light which is a definite advantage for international shipping compared to other similar amps I have looked at.
. Crossfeed. Well, it's not really necessary, but I sure like it. An amp with it will probably get my preference over one that doesn't have it. A hardware crossfeed means less for the source to do and works for sources that can't do it.
. Optical in (as well as USB). I don't have an immediate use for coaxial in, but who knows what the future holds.
Anyway, I have considered quite a few different amps, but the HR desktop line seem to meet my requirements and really pack a lot into a small space, even if they're not the cheapest, and they appear to be fairly well regarded around here. Incidentally, the new Micro line of amplifiers that Hr are releasing soon also look very interesting, not to mention the 2007 Desktop Portable.
So, I am looking for advice and opinions for deciding what to get and what options to pack into it. As I'm in chile, trying before buying isn't really an option. I haven't found much head-fi activity in South America, but perhaps I just haven't hit on the magical search term yet. I'm certain their are serious audiophiles here, but higher-fi headphone listening doesn't seem to be well known in this country as far as I can tell. So this is going to be a purchase sight unseen (or should that be sound unheard?).
Before starting, I should mention that I plan to pair the amp with an hp upgrade to some Senn. HD650's. I may get some AKG K701's down the track to compare, but the 650's sound like they will do me (initially at least, this is head-fi after all!). I'll summarise the various choices and options accompanied by my current thoughts and questions. My objective is to obtain some other points of view to help me decide just where to draw the line on the curve of diminishing returns. Of course, before placing an order, I intend to grill the sales staff at HeadRoom, but I wanted to canvas experienced folk here on head-fi first.
1. Single-ended Desktop Amp (DT) vs. Desktop Balanced (DB). The DB Amp is the only balanced system within the sort of price range I'm considering which has all the other features I want. It's awfully tempting to go for this. However, I have come across opinions indicating that the single-ended DT is possibly better bang for the buck, in particular, the maxed out DT (with max modules) vs. the maxed out DB (with home modules). I've read quite a lot of discussion on head-fi about balanced operation but I'm still not particularly clear on something. At what point does balanced operation offer substantial improvement in performance? For example, is it more beneficial to have class A amplification before considering balanced operation? Which has more to offer, class A or balanced operation? I observe that it is possible to purchase the DB with the desktop module which uses class AB operation if I am not mistaken. From all I have read, it is clear that class A is apparently the way to go, but is balanced operation something that truly falls into the top end of the diminishing returns curve, or does it have something to offer in the price range of the HR Desktop line? I have to admit to being very curious about balanced operation, but it is an extra hassle in terms of cabling and surely there must be compromises at the entry level. Furthermore, does balanced operation offer a really obvious enhancement to spatial presentation, etc., or is it a fairly subtle improvement? Headroom have a couple of very attractive packages involving the maxed out DT and DB, but as the price is the same, price alone is not much of a deciding factor.
The one feature the DB lacks, which could be nice to have for the future, is line out so the amp could be used as a pre-amp. The DT has this.
also, I note that the DB can power single-ended headphones. While this isn't of course how you'd want to primarily use it, it makes the amp flexible and is probably a handy feature to have. However, I've read that the 1/4 inch jacks do not provide the same quality of sound as the balanced XLR outs because they feed from the "line driver". to satisfy my curiosity, can anyone tell me what a "line driver" is and why its output would be inferior to a fully single-ended amplifier output? While I'm at it, how does a properly implemented line-out actually work on a headphone amplifier? My guess would be that the line-out somehow feeds off the amplifier output in a way that is independent of what is happening at the headphone out, with a fixed voltage divider being used to provide the appropriate voltage level at the line-out jacks. Incidentally, is the volume adjusted on an amplifier by using a voltage divider in series with the output or the input? Or am I just completely off the mark and it's done some other way? Ok,I'm getting off track.
2. Home modules vs. Max modules. I might as well go at least for the home modules. There are cheaper amps out there that are also fully class A so paying this much without getting some class A action would seem to be a shame. Plus, the home module upgrade is not that expensive. The real question however would be deciding between max modules, which of course only apply to the DT, and home modules. The price difference between them is pretty substantial. The max DAC, which upsamples and reclocks (in addition to the oversampling carried out by the CS4398) as I understand it, is a tempting upgrade over the home DAC. However, as the principal differences between the home and max amp modules seems to be in quality of materials, workmanship and a change in op-amps, and Headroom themselves claim the difference in resultant sound quality to be fairly subtle, I'm not sure if the max module is worth $300 over the home module. I'm not even sure that a max DAC can be mixed with a home amp module. However, as the fully loaded DT costs more or less the same as a fully loaded DB, a more pertanent question may be what are the benefits of max modules in single-ended configuration as compared to home modules in balanced operation?
3. ALPS pot vs. stepped attenuator (SA). I understand the benefits and drawbacks of having a stepped attenuator over a continuous variable resistance pot, but I'd like some other's thoughts on the stepped attenuator implementation on the desktop line of amps. I've read that the SA on the DB is rather finnicky to adjust exactly as you like because of the difference in resistances between successive volume levels. I don't know if this is because of the design of the attenuator or simply because the 6 dB difference between single-ended and balanced operation effectively doubles the perceived step size. In any case, it makes sense to me that when laying down a pile of denero for an expensive audio component, having a SA with its superior reliability (not to mention affect on sound quality) in terms of possible mechanical failure (when compared to a variable resistor) is a good thing and should increase the mean time between failures, that is, help to protect my investment. Anyway, I haven't read any negative comments about the SA on the DT (just the DB), so I would like to ask if the SA on the DT is difficult to adjust and if the SA on the DB really is as finnicky as I've read? Perhaps it is worth having an SA on the DT, but not worththe the trouble on the DB? Whether or not to have an SA will be the last thing to consider after I've decided on the amp and modules.
4. Could it be worth hanging off to check out the new Micro line? It seems that the new standard Micros (DAC and amp) will be going for around $400 a piece and the Ultra Micros for around $700 a piece from what I've read. Pros seem to be size, stackable and hopefully having the same sq as their desktop equivalents while the cons would be having a pair of Astrodynes to deal with instead of a single power supply. Together, the two units aren't that much smaller than a Desktop amp and I'd have to wonder about ventilation and cooling if stacking the ultras.
Any ideas and corrections to wildly inaccurate statements I have made would be welcomed, in addition to any further thoughts and considerations anyone wants to throw into the pond to properly stir up the silt and really confuse me.
Finally, I'd like to thank all you fine folks on head-fi in advance for any help. I must also offer my a posteriori thanks to you all. I haven't posted much on head-fi, but I've been lurking for over half a year now and have learnt an enormous amount from reading discussions here.
Cheers.
