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Group-think: What would a Harbeth amplifier look and feel like?

A.S.

Administrator
Staff member
Munich 2015 introduced us to the world of modern amplifiers, which combine advanced networking/streaming (and similar) facilities into one box. Tube amps, so prominent at the show in previous years were hard to find; the market has truly changed.

We claim no particular insight into what the modern consumer expects from his audio amp other than the basic facilities of adequatre power and sensible input sensitivities to match the sources properly. What is clear is that if even one up-and-coming feature is accidentally omitted from the design due to ignorance of market trends, the resulting product could struggle. Even amp designers are sometimes too close to their technical work to see and sense the changing consumer environment around them.

We as a group can use the next four days to assemble a specification for the VITAL features for such an amp, the DESIRABLE features, and the OPTIONAL (perhaps plug-in after-market) features. Three very clearly defined categories.

Take, for example, a phono stage, inside the amp case. How many would consider that a vital feature or only an optional one? If I'd invested in a fancy phono head amp, it would be a feature that I'd not need or want to pay for again.

I think we all know that the power reserve must be generous - no need to even dicuss that - that's assumed and available. What we're curious about is the digital side of the design in terms of hardware, software features, GUI and technical interface with streaming systems and of course, target retail price, which from what I have been told knowing something of the costs, would be around $6000 (US) for this all-in-one high end box.

Over to you. All considered and justified features will be discussed in a meeeting next week. Those present will be reading this thread over the next four days.
 

Jeff_C

Member
Built-in DAC is essential

Built-in DAC is essential

I would be looking for an amp that had a built in DAC capable of decoding all sample rates up to 24/192. Then there is no need to worry about matching input sensitivities. Ideally the DAC would have S/PDIF (coax and optical),HDMI, and USB inputs. Asynchronous USB would be desirable.

I would consider a phono stage definitely as an optional extra.
 

Jeff_C

Member
DACs in streamer units - build in

DACs in streamer units - build in

One of the things about streamers, particularly upmarket streamers is that they will all have sophisticated DACS within them. It would likely be the case that dedicated streamer users will want to take the analogue signal from their streamer unit to the amplifier's input, and then the issue of input sensitivity matching is introduced.

If the amp has in-built DAC then one or other of the DAC's will be redundant. I cannot think of a good solution but then again I am not an audio engineer.

I just know I would much prefer an amp with in-built DAC.
 

chirhonix

Member
My Harbeth amplifier

My Harbeth amplifier

Vital: adjustable gain on all inputs, Tape Loop, Pre out, remote
Optional plug in: Phono, DAC (min. 2x S/PDIF, 2x optical/TOS link, 1x USB)

Retail price hopefully nearer to 3000 Euros (there is an English apmlifier with optional phono and dac boards, 110 Watts into 8 Ohms, just lacking the tape loop, for around 2500 Euros)

{Moderator's comment: What is that amplifier please?}

To Moderator: Creek Evolution 100A. Alan Shaw used it in Bristol IIRC.
 

hifi_dave

Well-known member
Quality components

Quality components

The vast majority of my customers use turntables, so a phono stage would be very desirable. This could be an add-on, plug in board so that those without a TT aren't paying for something they don't need.

Similarly with a digital input and internal DAC. Many already own a DAC or quality CD player, so an add-on board would suit everybody. Another thing is that digital does tend to change, as manufacturers chase the numbers game. An optional plug in board could be upgraded as new procedures become available.

Adequate output, reliability and a remote are important. No one ever asks about tone controls or room correction. Put the money into quality components.
 

A.S.

Administrator
Staff member
Apple AirPlay?

Apple AirPlay?

Does anyone know anything about Apple 'AirPlay' and its relevance to high end audio? Is is a super-set of Bluetooth? Is it popular? Up and coming? Useful?.......
 

acroyear

Active member
Wish list

Wish list

Vital: sufficient power naturally, variable gain at input (usable from front), tone controls.

Desirable: clip indicator

Optional: Phono stage with subsonic filter (switchable). DAC inputs.
 

Milosz

Active member
Potential features and market

Potential features and market

Vital: sufficient power for all models from P3ESR to M40.1, good power saving standby mode, remote control, variable gain, realistic input sensitivities

Desirable: tone controls, clip indicator, main in / pre out inputs

Optional: phono stage, DAC inputs (S/PDIF, optical, asynchronous USB) - all on add-on boards ready for easy future upgrades

Useless: tape loop, headphone amp (at least for the manufacturer of loudspeakers)

To think about: whether the Harbeth amplifier should be an integrated and/or separate amp? The latter design choice gives more flexibility with regard to both power demands that much vary between different Harbeth models and the digital features that can be implemented in the preamplifier only to save the power amplifier from getting outdated.

***

As regards the digital side of the design, I would think that 90% of those amplifiers, at least during the first years of manufacture, will be bought by existing Harbeth customers who, as it seems to me, are rather conservative. Therefore, in my opinion you should focus on quality components, reliability of the product and providing future maintenance at reasonable cost.

I'd rather see a simple remote, instead of control via wi-fi, iPad and/or in-built LCD display, DAC inputs only on an optional plug in board for those who really need them and leave the features like Air-play, DLNA, Bluetooth or Wi-Fi to the manufacturers of streamers because it is not very likely that you would be able to implement those features so well as they do without the (expensive) help of talented programmers. Moreover, those digital standards change all the time while the Harbeth amplifier should be built to last.

At the moment, for example, Tidal hi-fi streaming option seems very interesting. But will it last? WiMP was popular too and supported by many equipment manufacturers, but as for today it doesn't exist anymore. It's hard to keep up with those rapid changes in digital market. But for now it seems that direct streaming of the digital content, without the need to download it to the user's hard drive, will prevail. It is definitely much more convenient for everyone, including customers, record companies and equipment manufacturers as the whole system ready for downloading and/or ripping of the content, storing it and sending to the hi-fi system is very complicated and puts off many people from the so-called PC-Audio.

Streaming is much more convenient than dowloading, but it's hard to say whether Spotify, Deezer, Tidal or any other service, and there's plenty already, will dominate the market in the end. Probably it would be sensible to stick by the big players like Google (Google Play Music) or Apple (Beats Music) but Tidal is currently the only service that provides streaming of the content in CD quality. All the others currently provide streaming/digital radio at 320kbps at best.

Summing it up, I'd rather see a conventional amplifier with manufacturing cost reduced and retail price closer to 3000 Euros. Retail prices of the competing amplifiers have to be taken into account as well. If the retail price of the Harbeth amplifier is sensible, I am sure that huge number of the existing owners of Harbeth loudspeakers will be looking to buy.
 

mattw

New member
Digital features

Digital features

My 2 cents...

Vital: Inputs - RCA, optical and co-ax digital, USB (async); input gain control; tone controls (bypassable & stored on a per input basis); standard IR remote control

Desirable: Ethernet connection for TCP/IP streaming (SMB/NFS client); Extensible software for new digital formats and streaming standards - able to be updated over the internet (e.g. AirPlay, ChromeCast, DLNA, Sonos, etc, etc...); mobile app remote control.

Optional: Phono module; WiFi module; bluetooth module

The reason I included the digital domain stuff is that they are relatively cheap as far as components go and make the amp much more attractive (at least for me!)
 

willem

Well-known member
My spec sheet and market overview

My spec sheet and market overview

I think at the budget end a receiver like the Yamaha R-N500 ticks just about all boxes: 2x80 watt rms, airplay, dlna network connectivity, coaxial and optical digital inputs, wired internet connectivity, remote by apps for android and apple. Tone controls and input sensitivity selectable through the app. It even has a phono in, and a pre out.

My suggestion would be to buy one and experiment at home until you appreciate the possibilities for yourself. I do not think Harbeth should ever dream to compete with such offerings: just is cheap and excellent gear for the smaller Harbeths, used in smallish rooms. Comparable specs can be found in micro systems like the Denon Ceol Piccolo.

What is Airplay: a licensed Apple protocol. It differs from Bluetooth in two ways. First, it is fully CD Red Book quality. Second, unlike Bluetooth it is not a device to device protocol, but something using the domestic wifi network. Apple laptops, ipads and iphones have it. There is third party software to give the same functionality to windows and android devices. You can use it to stream music wirelessly in redbook quality from your phone/tablet/computer to your audio system.

A Harbeth amplifier/system can only succeed at the expensive and powerful end of the market. So the power amplifier (separate or integrated) should have plenty of power to drive M40's in larger rooms, but also other and more difficult to drive speakers. The only other desideratum for me would be electrical efficiency. I am in the process of getting solar panels installed, and I do believe we owe it to the next generation and to the planet not to waste electricity. Maybe look at the Benchmark AHB2 for inspiration.

I do not believe in dedicated streamers. I think these closed systems will go the way of the dodo, just like dedicated word processors did once pc's came to the market. So for me a small headless pc is the ideal source, controlled through windows remote from a tablet. You may not want to get into this market, but it may be attactive to offer a matching fanless case for micro pc boards, with just a slot for one bluray drive. Any pc shop can build a basic pc into such a case that will do all that is needed, and rebuild it with a new motherboard a few years later.

This then leaves the pre amplifier, either separate or integrated with the power amplifier. For me, analogue inputs are a waste of resources, but the market may demand otherwise. So my suggestion would be to have two slots for plug in boards. You can then offer three types of boards: line level analogue, mm analogue, and mc analogue. These should all be adjustable/programmable for optimum matching. Make sure that these slots can all be used for later digital input boards as well, to cope with new technologies.

The essence would be digital inputs, however. Here I would like at least one usb input, two coax inputs, and two optical inputs. I don't particularly believe in support for HD audio formats, but the market will demand them. As for connectivity, I think you need dlna standard connectivity for home network connection to a NAS (networked hard drive for ripped music and films, approachable from any computer or player in the home network - like a Denon Ceol Piccolo in the bedroom) and Airplay. Wired ethernet is mandatory, wifi desirable in the market (perhaps on a separate board to enable later upgrades - this is a rapidly moving technology).

Traditional remotes are on the way out: you need apps for Apple and Android to control the pre amplifier. Digital tone/balance controls can be built in. However, I would prefer the full feature set of something like the DSpeaker Antimode Dual Core. That has dsp room equalization, but also tone and tilt control, plus manual eq filters for the entire spectrum. If tone controls are a good idea, implementing them in the digital domain gives far more precise possibilities.

Whereas power amplifier technology is not changing that much (even though manufacturing technology does change), standards and possibilities in the digital domain are moving fast. So the dac/preamplifier should be ugradable as much as possible, but there is a practical limit with as yet undiscovered new technologies. As a consumer I therefore expect to have to replace the dac/preamplifier well before the power amplifier. For expensive gear I therefore would prefer to have a separate power amplifier that I can keep well after the pre amplifier/dac has had to be replaced. Separates also allow for two power amps with say 250 watts and 500 watts per channel, depending on requirements, or two in bridged mode.

Finally, and this is a very personal thing, I like my gear small, and minimalistic looking. For styling, Dieter Rams would be my inspiration, rather than the dull and horrid retro styling of e.g. Leben. If I look at the section 'pictures of my Harbeths' I am struck by the prominence of modern decor.

If you want to sell in countries like the Netherlands or Germany, I think you need a modernistic design. I would never pay big money for something looking like a 1950's radio or worse.
 

royals1871

New member
Good Yamaha

Good Yamaha

I think at the budget end a receiver like the Yamaha R-N500 ticks just about all boxes: 2x80 watt rms, airplay, dlna network connectivity, coaxial and optical digital inputs, wired internet connectivity, remote by apps for android and apple. Tone controls and input sensitivity selectable through the app. It even has a phono in, and a pre out.

My suggestion would be to buy one and experiment at home until you appreciate the possibilities for yourself. I do not think Harbeth should ever dream to compete with such offerings: just is cheap and excellent gear for the smaller Harbeths, used in smallish rooms. Comparable specs can be found in micro systems like the Denon Ceol Piccolo....
In regards to Yamaha R-N500 being a good product I agree, same with the Pioneer N50/70's, good products. I used to use an expensive Linn streamer as a source, but that was sold off a long time ago.

Regarding amplification, I still cannot fathom the vast differences in price per Watt.
 

coredump

New member
Specs

Specs

optional add-on:
Phono stages MM / MC
DAC (current version, I don't what are the latest version)
Streaming
Balanced input


Delete:
Tape in / out
Pre out / power amp in
tube output or input buffer
headphone output
loudness compensation
mono/stereo
AV bypass

must have:
oN/OFF button on front faceplate
Class A / AB type of amplifier (like Simaudio, they have first 5W operating in Class A)
one set of L/R speaker output only
remote controller with mute, On/off
power output + robust power reserve (large high efficiency transformer)
low power consumpion standby mode
wide Freq response / Bandwith
Tone control
Digital volume display and input
MOS-FET output stage
nice faceplate, simple and clean look button
 

A.S.

Administrator
Staff member
What's the catch?

What's the catch?

That Yamaha R-N500 looks astonishing value, here.

I'm not up on all this streaming stuff* - what doesn't it do for GBP 300 incl. tax?

*I'm rather ambivolent about combining computer and audio technolgy. In my old fashioned way of thinking, if music is worth playing, it's worth owning. And that means a physical media that I can collect, is at arms length and is mine forever. Yes, I know: old fuddy duddy thinking and I'm well aware that my personal requirements are not those of today's market.
 

Jeff_C

Member
Is DLNA that useful in an amplifier?

Is DLNA that useful in an amplifier?

This is a response to those who have put forward the suggestion of network DLNA compatibility. I have never found it that useful as a bundled feature and I would consider that it would be particularly over the top in an amplifier. I am ready to be proved wrong but here is why I think it would be opening up a can of worms.

The amp would presumably be a DLNA client. My understanding about DLNA clients is that they "pull" data (media files) from DLNA compatible media servers. There would need to be a monitor/TV screen attached (or at least an app in a remote smartphone/tablet computer) to link up with DLNA servers and navigate through the various media libraries, not a good point for an amp (but excusable for a Home Theatre amp). The DLNA client in my blu-ray player is very basic and cannot play music files back gaplessly.

The Simple Audio Roomplayer (a streamer unit by ex-Linn employees) complete with amplifier never got gapless playback working before they went bust I believe. It would be a big ask to expect a Harbeth amp to jump this hurdle when the Simple Audio team whose efforts were surely focussed on the streamer side of things rather than the amp never got gapless playback as a working feature of their streamer/amp.

This discussion is about amplifiers not all-in-one streamer/amplifiers. I would certainly want a streamer/amplifier to do all that I expected from it (gapless playback included). I would not want an amp with some media playback capability built-in, if it only did half a job (i.e. no gapless playback)

I would be in favour of airplay and/or bluetooth capability where data as media files can be "pushed" to the amplifier from an independent playback device such as a 'phone, tablet computer, or desktop computer.

Please feel free to disagree if my perception of DLNA is wrong.
 

mattw

New member
The real value of features

The real value of features

Regarding the proposed $6000 market price...

I don't see how this delivers value for money over my Yamaha A-S501. That paired with a streaming box of some kind will do exactly what I want for 15% of a $6000 asking price. What would the other 85% bring me?

If we accept the 'all reasonable quality amplifiers sound the same' argument, which I tend to; then all we are comparing is features.
 

Bensim09

New member
Who wants more?

Who wants more?

I'm not sure people who have Harbeth loudspeaker want to buy an amp from Harbeth.

They are already so many good choices on the market of amp/streamer. A company like Devialet has great success with top convenience, good power, flexibility and apple like look and other companies follow that trend.

I believe that, in the future, loudspeaker will be more and more active ones. New music lover doesn't want boxes/cable everywhere any more.

I can imagine Harbeth loudspeaker with inside implementation of light, powerful and electrical efficiency class D amp type and an associated DSP chips. This will permit the Harbeth designer to improve loudspeaker linearity by removing passive crossover, allow tone control and room correction in the digital domain. Wireless operation would be a big plus as bluetooth for the younger "connected" generation.

Simple, convenience, great sound quality. Who wants more?
 

Milosz

Active member
Basic audio enginnering

Basic audio enginnering

I totally agree with Jeff_C about the DLNA connectivity, which would be simply over the top in a high end amplifier. I also like the old school way of thinking about amplifiers that Alan seems to prefer.

What should be really considered is the quality of components and quality of sound. I certainly do not want to incite here the old discussion whether all amplifiers sound the same or not but I recently read an owner's manual of the QUAD 909 (easy to find on the web) and there is a chapter about the current damping amplifier design. It is basically two amplifiers: one is a small class A amp, the other is big class AB amp. There is a diagram of a current dumping amplifier as well, which is unfortunately very unusual to be published in today's owner's manuals.

Let me quote the QUAD 909's manual:

"909 series amplifiers use a current dumping output circuit, a Quad invention (covered by patents in several countries) which eliminates many of the problems associated with transistor amplifiers. In a current dumping amplifier there is in effect both a low power, very high quality amplifier and a high power, heavy duty amplifier. The low power amplifier controls the loudspeakers at all times calling on the high power amplifier to provide most of the muscle. The low power amplifier is so arranged - it carries an error signal - that provided the larger power transistors (the current dumpers) get within the target area of the required output current, it will fill in the remainder accurately and completely. The reproduced quality is solely dependent on the small amplifier which, because of its low power, can be made very good indeed.

Problems of crossover distortion, quiescent current adjustment, thermal tracking and transistor matching all disappear. There are no internal adjustments or alignments and the choice of power transistor types is less restrictive. The performance of Quad 909 series amplifiers is as accurate as it is possible to achieve by careful design, selection of components and rigorous test procedures."

Does the current dumping amplifier - or a similar design - make sense? I'd think that QUAD knows their thing and wouldn't implement it if it didn't. Would it be of interest for Harbeth then? I'm positive that design issues like that should be seriously considered by Harbeth, not just bling-bling modern features that are in style today but you can forget them tomorrow.
 

Jeff_C

Member
The amp does not need to connect to a NAS

The amp does not need to connect to a NAS

...The essence would be digital inputs, however. Here I would like at least one usb input, two coax inputs, and two optical inputs. I don't particularly believe in support for HD formats, but the market will demand them. As for connectivity, I think you need dlna standard connectivity for home network connection to a NAS (networked hard drive for ripped music and films, approachable from any computer or player in the home network - like a Denon Ceol Piccolo in the bedroom) and Airplay. Wired ethernet is mandatory, wifi desirable in the market (perhaps on a separate board to enable later upgrades - this is a rapidly moving technology).
Willem, I am usually on a similar wavelength with your thoughts and comments but I do not agree that a Harbeth amp needs to communicate with a NAS via DLNA(uPnP), SMB, NFS or any other protocol. It would only need such communication ability if the Harbeth amp were to be the music player itself. Surely you are not suggesting that are you? That would add lots of complications surrounding issues such as file compatibility, gapless playback etc. which I believe are best left to a dedicated music player sited in front of the amp in the replay chain.

I agree that linking to a home network via ethernet and/or wifi may be a desirable feature in the amp, so it can act as an airplay receiver, I do not believe the amp should try and be the music player as well. So I see DLNA (and all other communication protocols) as unnecessary. The amp does not need to "see" DLNA compatible media servers on the network, that's best left to the music player.

As more features which are usually associated with computers are included in the amp, the less likely it is that someone with a CD player, and TT will show any interest in the amp.
 
My suggestions

My suggestions

The previous posts cover most of the possible functions for an integrated amplifier designed to be future-proof for the next 10 (??) years, however the ranking of their relative importance is the crucial question. Judging from the way I am seeing the younger generation acquire and listen to music my split between vital, desirable and optional features for the amp would be:


Vital

Sufficient power - I'd suggest 100-150 watts as a baseline to keep within the target price, but this should be offered with the ability to bridge the amp so that 300-400 watts would potentially be available by buying another slave unit (possibly having only the power amp section).

The architecture should be based on a microprocessor with re-programmable memory so that the functionality of the pre-amp can be upgraded using software, loaded via ethernet.

Ethernet access (RJ45) that supports the IEEE 802.11ac standard.

A DAC capable of handling PCM up to 24bit / 192 kHz and DSD with inputs: SPDIF with BNC, RCA, & AES/EBU electrical sockets, and Toslink optical.
The DAC should include hardware to convert ethernet packets of music to a form the DAC can convert to analogue (SPDIF or I2S).
This functionality should include support for UPnP so that the amp may be seen and music playback controlled by generic applications running on an iOS or Android device.

Two analogue inputs, one on RCA and the other balanced connectors.

A Multifunctional electronic display that can be customised.
Controls on the amp should allow choice of source including both the users music available on the local network, and from internet sources such as music streaming services (Spotify, Qobuz etc)
These controls should be duplicated on custom remote hardware.


Desirable

Customised applications for iOS and Android devices to control the amp, including volume control and source selection (not available in generic control apps).

USB input: while this is a very common way of connecting a computer to the hifi system to playback music from a library (particularly in the USA), it can produce variable results in terms of sound quality, largely because of the direct linkage between the hifi and the electrically noisy environment of the computer. With expert design of the USB interface in the hifi, the power supplies and the music storage system (hard discs, solid-state drives) it can give good results, but using ethernet (classed as a vital requirement above) gives far greater isolation and hence typically better sound quality.


Optional

Wireless connectivity: because of the potential for RF interference degrading the amps performance (e.g. adding noise to low-level signals in the pre-amp section) I would not rate this highly for inclusion but potential buyers could see this as a convenient extra. Note a wireless network would be required to control the amp as outlined above, but this requirement can be met by having the transmitter remote from the amp and connected by wired ethernet (e.g. an Airport Extreme can act as a wireless transmitter and network switch).

Support for Airplay. This is not universal like UPnP but it is in common use in the Apple computing environment. It has a licence cost. It has limitations e.g. the universal conversion of the sample rate of music between 44.1 and 48kHz. Airplay capability is now available on some non-Apple playback devices. Whereas in the past it was necessary to have iTunes running on a system computer this is no longer the case so that, for example, internet radio from the BBC iPlayer radio can use airplay as an output device as an alternative to using the control device on which the iPlayer is running.

Headphone amplifier: headphone listening is now the most common method for playback, judging from headphone sales. Having this option would attract buyers who would like private listening as an alternative to using loudspeakers.

Phono amplifier: to meet the requirements of a growing niche group.

Balance control, phase control, tone controls, and a mono switch: I have found none of these necessary since I switched to primarily using digital sources but in the past listening to LPs did on occasion require their use.
 
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hifi_dave

Well-known member
Keep it simple?

Keep it simple?

Harbeth would go broke trying to accommodate that vast list of facilities and features in an amplifier. If someone wants that lot, they might just as well buy an AV receiver for a fraction of the cost. Believe me, Harbeth customers and potential customers never even enquire about numerous facilities and features.

The Harbeth amplifier must provide great sound (sorry), performance, battleship build, adequate power, reliability and plug in boards for DAC and phono. Simple and practical is the way, as with the speakers.

Any more than that - go and buy a Quad or Yamaha.
 
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