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

Official AMP/DAC/DAP Model Discussion
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Really a very impressive review! I wasn’t even aware of this site. I thought headfi, hifi guides, and ASR were the main go-to forums…but even a casual look through some threads shows great advice, activity, and stimulating convos. Either way I just signed up! I’m not sure if my question is better off here or the advice thread:

My setup is as follows. Raal SR1a + Utopia - Pass Labs HPA-1 + Jot R - Aqua La Voce S3 DAC.

I’ve been completely blown away by the sr1a (I got it last week). It truly is an experience all its own. I want to get the most I can out of it but wanted to know if it could effectively replace my pass labs (an amp I absolutely love). I would prefer to only have a single amp but I don’t know how the hsa-1b matches up to a high end ss amp.

Does the $4500 price represent what sort of ‘tier’ the amp is in? Or does part of that reflect its speaker function too…

Thanks!..and sorry for the long winded post

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Here is the right spot.

I suppose that depends on how “high-end” is defined. And I don’t really find the notion of “tiers” based on price to be terribly useful nor at all accurate.

For example, I feel the HPA-1 is somewhat overpriced for what it is. I think some of that is down to the front-panel/volume knob and the name. Not that it isn’t an excellent amplifier; it is, but I’ve heard units I thought bettered it technically and/or were more enjoyable for much less.

This, of course, is subject to personal preferences and biases.

The HPA-1 may be a better unit, technically, for a primary diet of regular headphones simply on the basis of its lower output impedance and higher power output. It’s a more neutral sounding piece. Where the HSA-1b has some color to it and more explosive dynamics.

I really like the Utopia from the HSA-1b. More so than I did from the HPA-1, though not as much as from various tube amps. That’s part synergy and part personal preference. If we were talking about, say, the Meze Empyrean, or an HE1000SE, I might lean towards the HPA-1.

It’s not clear to me if you’re running the HPA-1 as a pre-amp into the Jotunheim R, or are feeding both amplifiers directly from the dual outputs on your DAC. If it was me, I’d do the latter; I think the HPA-1 as a pre is not going to do what I’d want in combination with the Jotunheim R, especially compared to the HSA-1b.

But if you really want the BEST out of the SR1a, you’re back to using the interface box and MUCH more expensive speaker amplification.

–

As to the $4,500 price tag … you have to look at the overall functionality of a unit, and how much of that you’ll use, as well as qualitative factors and intangibles (e.g. how much single-box convenience is worth vs. cost or performance, aesthetics, form-factor) when considering price vs. value.

I can’t make those calls for someone else.

It was more than worth it to me to get close enough to my favorite solid-state amplifier (I’ve heard most of them at this point) that I wasn’t going to miss it with my collection of regular cans and was markedly preferable with the SR1a. Thus I shed a box and got a more compelling overall result into the bargain.

If you didn’t have the HPA-1 and Jotunheim R already, I’d say go for the HSA-1b. As is, you’re better off doing the home-trial with the HSA-1b and seeing what you think for yourself.

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Sir. Have you compared your Blu Mk2<Chord DAVE<Chord Etude<SR1A chain to the same chain but replacing the Etude with the HSA-1b?

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Yes.

That was the first thing I compared.

I prefer the HSA-1b directly into the SR1a over the Étude via the interface.

I’m replacing the Étude with a Chord Ultima 5 and keeping the HSA-1b.

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the thing that I am not sure I understand is why given the relatively low power ratings that the hsa-1b drives my susvara as well as it does…in theory it shouldnt but it does a better job than many far more powerful amps I have heard

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Thanks for the thorough response! Yeah I don’t use the hpa-1 as a pre-amp to the jot r. What do you mean by ‘home-trial?’ It’s a pricey amp and even though the dealer I bought the sr1a from has a 30 day return policy (with paid return shipping) I’d never want to inconvenience him by buying an amp that I may very well return…but like all other hifi stuff I’m not sure if it will be the right fit without trying it (the hsa-1b would replace my pass as well. Selling my pass before I know what the hsa-1b is like probably wouldn’t be wise).

There is no used market for the hsa-1b yet right? After seeing the price the sr1a/jot r was selling used I decided to just buy it new and get that 5 year non transferrable warranty.

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Hi Torq. First of all thanks for the detailed review, it is much appreciated.

Is there any sound quality differences running SR1a by HSA-1a and HSA-1b despite the improvements by adding a stepped attenuator ? Thank you.

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RAAL-requisite offer a no-risk 14-day demo period. You pay return shipping if you don’t keep the unit. If your dealer offers a better deal there, better still.

Doing that for something you KNOW you’re not going to keep is one thing; it’s a shitty practice, often abused, especially by various “YouTubers” to get free/loaner gear for their “channel” (and that’s not what you’re doing).

Doing it as a demo/audition is part of why your dealer is getting a 30-45% margin on the product. If they’re not providing a proper demo/audition/comparison, then you should be getting a significant discount on the unit. Otherwise they’re adding no value (for a product you can buy direct) and you should cut them out of the chain*.

I don’t know, as I haven’t tried to sell one.

After the HSA-1b was announced, I listed my HSA-1a for sale and that was sold in 24 hours. And there is a definite backlog of HSA-1b orders.

*Some products are only available through dealers, which changes the percentages/model a bit, but personally I am not giving anyone 40% margin simply for accepting an order and shipping a box - haven’t in 30+ years and wouldn’t start now. Most dealers are very good about this, at least if you’re a regular customer, otherwise sometimes some will need a prod in the right direction.

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From my review (it might be harder to parse than it should be), I found the HSA-1b improved over the HSA-1a, driving the SR1a, in terms of better channel separation and lateral imaging, a more lucid/liquid and holographic midrange, greater refinement in the highest registers and the resolution took a step up.

Those elements were similarly improved with conventional headphones, and you also got better channel balance and a blacker background with normal cans too (i.e. that is in addition to the above).

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Thanks for the input Torq.

So other than the volume pot the electric circuit and components has also been changed?

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There are various changes, in layout, parts, and so on. If you want specifics you’d need to talk to RAAL-requisite. I didn’t do a topology comparison nor a part-by-part tear-down.

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Hi Torq.

1a has all the 1b updates possible for that unit. Other upgrades, like 24-step attenuators, are limited to component size due to chassis layout.

This is the official response from Raal.

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That’s a bit vague … not that it bothers me either way - if it did, I’d ask Danny directly.

However, simply changing the layout of a unit can significantly impact various aspects of performance; be that noise, differential channel performance, EM/RF sensitivity/rejection etc.

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Got it. Thanks for the detailed explanations Torq.

All the best.

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I posted this question on the RAAL thread at Head-Fi but thought I’d post it here as well.

As I get within 2 weeks of ordering an HSA-1b for myself and in reviewing some of the information in the spec sheet and not being too tech-y inclined myself, I have question.

“There is no protection of output from short-circuit. As with high current peaks, output protection is often the cause of instability. All components were chosen to avoid oscillation and compensations are minimal, preserving speed and authenticity of presentation.”

  1. I suspect this would refer to an incorrectly-wired headphone or it’s connecting cable to the HSA-1b? (And it’s always a good practice to turn down the volume first.)

  2. It is not referring to plugging or un-plugging headphones with the HSA-1b unit on?

(I can’t imagine anyone connecting or disconnecting at the speaker or speaker outputs of the HSA-1b with it turned on. Intentionally, anyway.)

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I did get a response from someone on Head-Fi using the HSA-1b, no problems plugging or un-plugging phones with the amp on.

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With any amplifier, I always turn the volume all the way down/mute it before connecting/disconnecting any TRS-style plug as these jacks will short the socket internally as they are inserted.

Most amplifiers won’t have an issue with it, but even those with short-circuit protection aren’t necessarily infallible in this regard. And some amplifiers are known to go “poof” pretty reliably if they’re playing, at volume, and you connect/disconnect cans from their TRS socket (e.g SPL Phonitor X/XE).

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I’ve never plugged or un-plugged any HP connectors with the amp on.Just the 4 pin or SE pin.

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I don’t know what “SE pin” means.

Just to be clear, the TRS (or TRRS/TRRS) connections I’m talking about are the standard headphone connections, be they 2.5mm, 3.5mm, 4.4mm or 6.35mm (as found on the front of the HSA-1b).

4-pin XLR and dual 3-pin XLR headphone sockets are non-shorting, so there’s no issue there with any amp.

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SE for 1/4" type connector. So this type could be problematical?