RAAL-requisite HSA-1b - Switch Drive Amplifier Review

I agree completely and hold the differences I hear suspect given the change. Perhaps the cable is a slightly different impedance? I do not know, but even when doing my best to account for the volume difference, I think they are frustratingly, slightly, more detailed than stock. I am a cable skeptic, and was expecting to re-coup 70-80 cents on the dollar for the cable for having tried it, but, alas it sounds just a little more to my liking.


Very true, just like boosting colors in TV’s at a store. In comparing the sound of amps with the same HP it is very easy for me to match to within 0.1db before focus’d listening with my $70.00 SPL. Comparing HP’s probably not possible unless one has one of the pricey dummy heads with internal mics and probably some other pricey measuring tools as well to match levels. Characterizing sound traits is all I can do with HP’s and that’s with my ears, my head, and my likes and dislikes. Not really an exact science to my way of thinking about it.


I am new to comparing cables. So far I don’t hear any difference between stock and silver. For instance, in the first minute of the 3rd movement of Mozart’s Gran Partita (Jacob’s new recording)–a movement Torq uses for testing staging–I don’t hear any difference in staging, detail, or sibilance. Similarly, I don’t hear any difference in sibilance in the sibilant-rich finale to Shostakovich’s 5th symphony.

I am hoping some fans of upgraded cables (including the RAAL silver) could nominate a specific track or part of track where they hear a difference to help me test it out.

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Not everybody does hear differences, might be a blessing for your wallet. One could also take a position of not wanting to work that hard at it but would instead just like to focus on the music / performance. The more hours you accumulate with any piece of equipment the more refined your evaluation should become, if that’s what you want to accomplish. Still if you don’t at least taste the soup you won’t know how salty it is, or isn’t, for your taste. Over time we determine whats meaningful to us in terms of sound reproduction. For example, I’ve never heard a meaningful difference between well made AC cables, or various digital cables. IC’s can have an effect on the sound, but I find the biggest contributor to sound where the wires that connect them are concerned is the amp to transducer cable. Of course the differences I don’t hear in any component in my chain can always be chalked up to a weaknesses somewhere else in my reproducing chain.

Unlike a blindfold test of vanilla versus chocolate ice cream to determine which is which, most of this component comparison subjective stuff is a long slow process that may reveal differences in the short or long run, or possibly not at all. Experience over time in this type of focused listening (as I like to call it) may also help.

One can look at the $500 cable and the $1,000 cable and think the $1,000 cable should be leaps and bounds ahead with an easily heard difference, right? It rarely works that way. I think we’re usually dealing with subtleties that are hard to put into words. How would you convey to someone in words the difference between an amp with 0.01 % THD and 0.05% THD. Sometimes the only way to covey my thoughts is to make more of them than they may actually be in the scope of a bigger picture, in an attempt to make myself clear to others.

Over time and with adequate break-in time of the cable and with your own reference material (the stuff you’ve been listening to for years and know what kind of sound stage they set, how they image, etc.), you may determine that there is or is not any difference or that the difference is so small as to be a non-factor for you.

Also, I’ve always contended that the harder I listen, the less I hear. I find small chamber ensembles / Jazz groups make comparisons easier. Fewer instruments to focus on individually and simultaneously.

Often times different sound characteristics jump out for me when I’m not trying to listen for them. And in my opinion comparing cables of different types / manufacturers is a akin to self-flagellation. Transducers are a lot more fun and easier to compare than electronics and the wires that connect them.

By the way, the Shosti 5 is a favorite of mine, which recording is being referred to?


Thank you, FLTWS, for the thoughtful and thorough reply. I

My own attempt to hear a difference has been to focus on one or two minute segments, or to find parts of a recording that are sibilant (like the entrance of the oboe in the Gran Partita K 361 Adagio on the Jacobs) and to compare. I take your points, however, it might take lots of critical listening experience and background to hear the difference and that anyhow its best for my wallet if I don’t hear a difference.

Shosti’s 5th is intense. Last night, I tried (and very much like) the Rostropovich recording. Any favorites?

I use 2 different methods; the quick A/B (sounds like what your doing) and the slow full process (listening thru an entire, say, movement or composition and over time I build a sense of the overall sound in comparison to the other component its pitted against. I’ll use both over time to develop my thoughts on any differences I can zero in on.

Its very easy to do this when comparing 2 headphones and evaluating their various sound characteristics, harder with electronic box components, and very, very difficult with the various wires used to connect them all.

Remember this is a hobby, not a job, things come easier when you don’t grind over them. You’d have an easy time comparing two headphones in all their sonic parameters. First just listen and enjoy the music, the other stuff will come to your attention in time, or not.

I like Barshai on the Brilliant Classics label; I have his complete set but the 5th is available separately.


and Maazel’son Telarc 5th’s.

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I am currently comparing the JotR and the HSA-1b with the SR1a’s. I was expecting to hands down prefer the HSA-1b, but at least on first impression, there are times I miss the energy of the JotR, e.g. a lot of baroque or the “Dies Irae” of Verdi’s Requiem.

Anyhow, I’d like to try to EQ the HSA1-b to have a similar sound signature to the JotR so I can see how flexible it is and focus on other variables like sound stage. Trouble is that I am new to EQ (and audiophilia more generally). Can anyone suggest some rough EQ settings to make the HSA-1b sound more like the JotR? I am using MusicBee to EQ.

Your help is much appreciated.

EQ is only going to make a small difference, since the tonal differences between the Jotunheim R and HSA-1b are not particularly pronounced.

I don’t use MusicBee so don’t know how it’s EQ is applied, but assuming a proper parametric EQ facility, you’d want to start by droppng gain or pre-gain by -2.1 dB, then apply a High Shelf filter at 10 kHz, with a gain of +2 dB and a Q of 0.5.

That’ll yield a very gentle increase in energy from the lower treble all the way up to 20 kHz.

You can play with things from there, just remember to reduce overall gain (or pre-gain) by at least the amount of the highest increase you apply elsewhere (I’d add an extra 0.1 dB to be safE), or you’ll get digital clipping - which sounds awful.

That should barely affect apparent tonality, while still yielding the impression of faster transients/more energy.


the Jotr is actually a pretty good amp solution for the sr1a…the hsa-1b is better for sure…more refined would be the way I would describe it but like everything else in this hobby it is not 6 times better as the price would suggest…that is just the way it is…you pay multiples more money for improvement that are measured in small multiple


I agree with @Torq that the differences are not pronounced. I owned both amplifiers for the SR1a at the same time, and am content now to only have the JotR. I also like the MB DAC inside it and use that almost exclusively now. But if I still needed the additional functionality of the HSA1b I’d be just as happy with it, but a little lighter in the wallet.

I am responding just to encourage you to play with EQ as I have recently done with the SR1a. I thought I was happy with the SR1a “as is”, and for certain genre I am still. But I find myself surprised at how well the Raal takes EQ and how it can adapt while still retaining its absolutely convincing timbre, especially for acoustic instruments.


Happy Cake Day @MokhaMark! :tada:


Thanks, I just noticed that. I cannot believe it has been a year, and how much $$ I spent on this hobby in that time span.


Thanks, everyone, and especially Torq, for helping a neophyte out. I really appreciate it and wish I had something productive to contribute to this forum, which has been so helpful in convincing me to purchase the SR1a’s, which I absolutely love.

I have three further questions:

  1. What is meant by midrange “lucidity/liquidity” (in Torq’s review) and what track might be a good example of it?
  2. What do people suggest for EQ? I listen to music I own via MusicBee, but it doesn’t seem to have a gain/pregain control. I listen to the bulk of my music over Primephonic however, which doesn’t offer EQ. I see lots of people use Loki, and maybe that’s the solution I need. In the meantime, is there a better software solution I should try
  3. Is it normal for the HSA-1b to sometimes make a small static noise between volume levels (I see the consensus on headfi is that this is fine…)?

Thanks again!

Quoting myself here to clarify something …

EQ is only going to make a small difference in terms of making the Jotunheim R sound like the HSA-1b. That’s because EQ primarily affects frequency response (tonality), and there are not huge tonal differences between these units.

There are other effects that come in to play with shifts in frequency response, including apparent changes in things like perceived “speed”, “stage”, “openess”, “presence”, dynamics and even detail. Though this remains the case regardless whether the changes in frequency response when comparing one item to another are brought about through EQ or just because the natural response of those items is different.

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Pretty much the dictionary definitions … extremely clear, well delineated, transparent, free flowing, unconstricted etc. Female vocals, in complex mixes, are an easy way to see how lucid the delivery is, but an easier place to start is a simpler track like “Twist in My Sobriety” (Tanita Tikaram) - as while it is not an overall particularly complex arrangement there is a fair bit going on in the same frequency domain.

I think gain/pre-gain is called “pre-amp” in MusicBee.

If your player can use plug-ins then my favorite EQ tools are the DMG “EQ” line (“EQuick” if you want something easy and reliable, “EQuality” if you need more control and “EQuilibrium” if you want to have absolute control over everything, including the ability to EQ channels independently).


Pretty much all manually-switched mechanical stepped attenuators do it to some degree or other. It’s more commonly audible with discrete parallel designs, like that in the HSA-1b, than the much simpler serial designs.


Thanks, Torq, for the help! Much appreciated. Off to play with EQ and then focus on liquidity.

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I am hoping someone can help me understand what kind of speakers would make a productive match with the HSA-1b. My main purpose for the amps is the SR1a’s, but I also sometimes have the chance to use speakers. I’ve got an old pair of Paradigm Reference Studio 20s–would those be safe to hookup to the amplifier? And if I were to buy new speakers, what kind of parameters/restriction would the HSA-1b’s impose for a good match? I know the complexity of the speaker/amp nexus ramps up fast, and that finding the perfect match is a huge undertaking, but I’m just looking for a general outline of considerations (like impedance?) to look at/for.

Thanks as always for the help.

The biggest factor is going to be the sensitivity of the speaker. Then their impedance. And then the listening distance.

Small speakers, like the Studio 20’s tend to be less efficient.

You’ve got 10W at 8Ω (or 20W @ 4Ω, 40W @ 2Ω ) to play with from the HSA-1b.

Running flat out, and at max-volume, the HSA-1b would drive the Studio 20’s to a PEAK volume of 98 dB/SPL at 6 feet away. That’d be an average level of 80-85 dB/SPL (depending on what sort of music you listen to). At 10 feet away, that’d drop to 93 dB/SPL PEAK.

Flat-out is really not how you want to run an amplifier. For one thing it’ll be at the peak of its distortion profile. For another you have no headroom. It will work, and its safe, but it’s going to be a long way from getting the best out of the amplifier and the speakers both.

You really want to be looking for something around 93-95 dB/SPL (at 1W @ 1M). That’d get you to 100-103 dB/SPL PEAK, but would give you some headroom at an 80-85 dB/SPL listening level.

And then once you’ve got the sensitivity at a better level, a lower impedance speaker will help you get the most power on top of that, further expanding the headroom and putting the amplifier closer to its sweet spot.


Thanks again, Torq. I read several websites trying to figure the answer out, but your explanation was so much clearer and more understandable. I think I finally grasp the basics. Much appreciated.


well done review for those interested