The easiest way to go would be something like the miniDSP EARS w/ REW.
If you’re handy with electronics/DIY you could build something yourself for less, but you’d need to know enough to then calibrate and compensate the rig.
Beyond that things get expensive and complicated very quickly, with rigs/HATS/ear simulators from Brüel & Kjær or GRAS and on the analyzer side of things Audio Precision
This latter stuff is the path I decided to go for a recent (and current) project.
Agree that the sound without pre-amp is quite good (with Sr1a).
I did a quick experiment, no proper tube preamp at hand. I compared sound from my Metrum Adagio and Hugo 2 both directly into HSA-1a, as well as through my Cavalli Liquid Fire (… 1/4" TRS headphone out to RCA).
I consistently like the tube sound better under almost all circumstances. Not a night and day difference, more like switching between ss and Tube with the Cayin N8 …
I got a good deal on an Ayon Spheris III preamp and expecting delivery next week, my expectation is to take the HSA-1a to the next level. It definitely provides a good foundation where improvements in the chain will be noticeable.
The new preamp arrived yesterday …
Quick impression: I can’t stop listening (right now: Nicola Benedetti, “Italia”), got way to late last night without ever even feeling tired.
This is the best and most involving system I have ever heard. Even 1980s fare like Bon Jovi’s “Slippery When Wet” is massively transformed and rocks harder than ever before (hdtracks hi-res version) - Livin’on a Prayer sounding great at any volume (and tempting to turn it way up).
Whatever music I turn on, I am finding that I don’t even want to skip tracks because it is so engaging. Incredible happiness across genres … Early Depeche Mode “Love in itself” to Angela Gheorghiu’s “Habanera” (Carmen) to Deep Purple “Smoke on the Water” (Live in Japan) …
Net/net: Putting in a high quality preamp between DAC (Metrum Adagio) and HSA-1a for me has a magnificent impact. If Torq wrote that the HSA-1 takes the SR1a “to 11”, then this Ayon Spheris III takes it to 13+.
Perhaps for system tuning purposes one should think of the HSA-1a/SR1a as a power amp/speaker system, not a headphone?
If you’re looking to use a pre-amp to add color/flavor, sure.
Otherwise, you’re only bypassing the volume pot in the HSA-1a … which will add less noise/distortion/color than any pre-amp I’m aware of.
Horses for courses, but for me personally, if I was going to put a pre-amp in the chain, I’d also be using high-end speaker amps and the normal interface box. It’s more boxes and much more expense that way, but there’s a crossover point where it regains the lead over the active compensation circuits in either the HSA-1a or the Jotunheim R no matter how you feed them.
Thanks for the suggestion - I had initially not even bought the interface box, as I was under the impression that HSA-1a was going to be superior by design … due to all the conceptual and component quality (not really high-end) concerns. I will give this a thought, I have suitable power amps at hand.
The compensation done in the HSA-1a is active, vs. passive in the interface box. And it’s internal power-amp is tuned specifically for the SR1a, so nominally, the HSA-1a starts out ahead. Quite a bit ahead if the comparison is to a similar quality/level of speaker amp.
But if you’re using the kinds of speaker amps I would expect to see coming off an Ayon Spheris III, they’re going to be much more capable than the one in the HSA-1a. Which leaves its only advantage as the built-in active compensation.
The net effects is that, there’s nothing I know of this side of $10,000 in power amplification that the HSA-1a doesn’t see off quite effectively. Once you get into that realm (obviously adding the cost of a comparable pre-amp), it starts to swing back towards favoring the pre-amp/speaker-amp/interface again.
Thank you everyone for this information and the reviews over the past few weeks. I have ordered the HSA-1a and SR1a as a result, and also purchased a Dave to further ruin my budget. As much as I love the Hugo TT2 and Utopias, it is time to sell these and slightly balance the scales.
@Torq:
Re: Bypassing volume pot in HSA-1a - my HSA-1a (without active power regeneration - I am considering one of the big PS Audio Powerplants) is only silent with no music playing up to about 30 on the volume scale (which goes to 100).
To overcome this, I am driving the Adagio at “12 o’clock” (claimed -150db noise), into Spheris III at -5 to 0 db, to keep the HSA-1a between 30 and 50.
So that’s the opposite of running the HSA-1a at 100 and using the pre-amp for volume control that you had assumed …
There was no assumption … the volume pot in the HSA-1a (or any other unit using a resistive attenuator) can only add Johnson-Nyquist noise to the system.
Based on its claimed performance and specifications, your pre-amp is adding 100x more noise/distortion than that.
Anyway … setting the HSA-1a to 100 is what you have to do if you want the HSA-1a to act as a pure power/speaker amp (which is what you were suggesting it be treated as). And if you’re getting noise via your chain when you do this, then you’re proving my point … that the internal volume potentiometer adds less noise/distortion than the pre-amp.
Doing a quick test, with no source connected, the HSA-1a set at 100 (max volume) into the SR1a, is silent. No audible hiss or noise at all.
The noise you’re hearing, is the amplified noise from your pre-amp (or there’s something not right with your HSA-1a, which I doubt). And that’s 100% to be expected.
Which means that you may well have to use the HSA-1a as an actual headphone amplifier (i.e. pre and power) and not just as a power-amp, to get the quietest result. And that’s a big part of why I wouldn’t put a pre-amp in front of the HSA-1a and instead would do pre/power into the interface. But if you like the sound better with the pre-amp in the chain, that’s great.
HSA-1a has a distinct ‘hum’ at >30 volume, without any devices connected. So it’s not the quality of inputs …
I have pretty poor power … Other amps, e.g. ML-585, Marantz 9S2, NAD M2, … apparently have power architectures that eliminate those issues. The Spheris III pre-amp even comes with its own power regenerator.
HSA-1a being a smaller box and all may have a higher dependency on a clean power supply?
If you’re getting hum at that low a setting, with nothing connected (which would eliminate the possibility of a ground loop), it’s more likely that you have a DC offset on your AC line interacting with the HSA-1a’s transformer than it is anything to do with any other factor of power “quality”.
You might want to try one of these, as that’ll eliminate the DC offset concern.
Bingo - wow, that (DC offset) was it! I had a CMX-2 ready, sitting on a shelf … easiest solution ever.
Thank you!!
Like @chianti, I really like the sound tubes offer - and had determined my next amplifier would absolutely be tube-based. Until the SR-1a headphones came out…
It seems the HSA-1a (at four times the cost) outperforms the Jot-R, and the Jot-R outperforms sub $5,000 integrated amplifiers (or sub $5000 separates) coupled with the interface box.
With the SR-1a/HSA-1a combination, adding a tube-based preamp adds what we would expect, and what some of us love, but also detracts from the sound/noise level in other ways. Let’s say @chianti and I “must” have a tube-based preamp in the chain, at the least a tube-based preamp needs to be a real good (so, expensive) one to add (in our eyes) more than it detracts?
Then we get into the question of, suppose one has $20K worth of amp and pre-amp sitting around (probably “sitting” means powering their nice two-channel system under normal circumstances); some (maybe most) think that certain expensive and high-powered components paired with the interface box still comprises a “better” sounding system that the SR-1a simply paired with the HSA-1a. Some of the more expensive combinations with the interface box sound a little better than the HSA-1a and (of course) no interface box. But, at four or five times the cost.
Which brings us to:
If cost is no object, how can I get the best from my SR-1a headphones? It seems if one already has a superior quality amp and pre-amp, the limiting factor is easily the interface box. And maybe a couple of people are building their own boxes using more expensive components (resistors being the primary component?). And perhaps some are reducing the number of resistors by 15% to 25%, to some good effect? I’ve heard the figure of $3K or $4K to build one’s own (high-end) interface box. If one already has $25K invested in headphones, amp, and preamp (which means I’ll bet they have another $5K to $10K invested in cords, interconnects, vibration isolation, and power conditioning), then being able to (yet again) significantly improve one’s listening experience by building a better interface box for $3K (if it can be done) while saving $500 on the “regular” Raal interface box seems a no-brainer?
My super long-winded question/point: At the uber high end, the limiting factor quickly becomes the interface box? Just like it is the limiting factor when comparing almost any reasonably priced amp/preamp (plus interface) option with the SR-1a/HSA-1a setup?
One has to spend A LOT to beat the “factory” combo of headphones and amp, and if an enthusiast has done so, spending a less than 10% more on a custom interface box seems a reasonable thing to do.
Are there any 3rd party replacement cables for the SR1a that have improved upon the stock version?
I don’t know of anyone selling an SR1a “upgrade” cable as part of their “standard” offerings.
I’ve seen a couple built on a custom basis by existing cable vendors - but neither was built correctly, so I’m not going to reference them directly.
Specifically, neither came in at under 0.2 ohms (higher impedance will drive up the treble level if using the interface box), one was using TRS instead of TRRS connectors (which can work, but isn’t really the right way to do it) and both had a fairly significant deviation in resistance between left and right sides (which can yield both audible tonal shifts and balance issues between channels with the SR1a).
I was offering a couple of different SR1a cables (with resistance options of 0.05, 0.1 and 0.2 ohms) but I’ve stopped doing that.
Moon Audio seems to have a SR1a upgrade cable as a standard offer: https://www.moon-audio.com/black-dragon-premium-cable-for-raal.html
Not sure but to your point may use TRS connectors.
I will be interested to hear if it makes any improvement, as the sound is already superb!
The wire they are using, without accounting for the resistance of the solder-joints or the connectors, yields a 0.146 ohm cable at 5 feet long. So assuming perfect joints, that’ll come in around. 0.2 ohms when all is said and done and should meet spec for an SR1a cable.
The 10 feet cable will be at 0.292 ohms (again, just the wire), and that will result in an audible increase in treble level - longer cables even more so.
Doesn’t strike me as a designed-for-purpose cable. Just their normal build/configuration but with an SR1a pin-out on either end.
Looks like the HSA-1 is available to order on RAALrequisite site as a combo with the SR1a.
I don’t see it available to order separately but it should be soon I would imagine.
…And it looks like the price of the HSA-1a has been revised.