orangeart

New multi channel ncore amplifier

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Not strictly DIY but hopefully of interest and something that will help with the burgeoning amount of DIYers either building active speakers from scratch, taking their existing passive speakers active, who have an interest in home cinema, or maybe just want a cheap stereo N-core amplifier. Mods if you think this should go somewhere else please feel free to move it buy DIY seemed like the best place.

I'd like to try and gather opinion on the direction and options of a new multi channel amp I am developing based around the latest Hypex Ncore modules. The basic idea revolves around built in flexibility for configuration. I want to build an amp that is primarily for use with active speaker projects but that would be equally at home in any multi-channel situation such as home cinema.

The basics of the amp are already set and development has begun but I have a few questions I’d like to ask of those I’ve come to trust here.
The amp will be able to be configured when it is ordered with modules of the customer’s choice. 

Choices would be for between 2 and 8 channels. The modules themselves come in mono and stereo although the stereo modules only share a power supply, and even that is split into two circuits for the most part.

Configurations available would be 

Mono modules

6 x 500W
8x 250W
8 x 125W
These could be configured in whatever configuration the user required for their active speaker project, for example.

2 X 500W, 2 x 250W, 2 X 125W

There is also what Hypex call the add on tweeter module which is powered by one of the amp modules, that is a 100 W module. Each of those would take the place of one of the modules above reducing the cost and the power requirement, for example, for a pair of 3 way speakers.

4 x 250 W
2x 100 W tweeter modules

Or 4 ways

2 x 500 W
4 x 250 W
2 x 100 W Tweeter modules

The same configurations could also be duplicated using the stereo channels as well so 

6 x 500W would use 3 x 500W stereo modules
8x 250W would use 4 x 500W stereo modules
8 x 125W would use 4 x 500W stereo modules

The tweeter modules could still be used as well, again each tweeter module can be powered from one stereo module so for a pair of 3 ways you could use

2 x 250 W stereo module plus
2 x 100 W tweeter modules

The configuration could be changed at any point in the future by simply purchasing additional modules through the website and returning the whole amplifier for the boards to be swapped, the internal wiring swapped out and the addition of new connectors to the back panel as needed. This ability to reconfigure is the unique selling point of this product, that the tentative active 2 way builder could become an active 4 way builder using the same box as time and funds allowed.

The input to the modules would be via Neutrik Combo plugs which offer balanced connection via either XLR or TRS (Tip Ring Sleeve) ¼” Jack connector or for unbalanced connection via TR (Tip Ring) ¼” Jacks. As the Hypex modules are fully differential amps, a balanced connection scheme needs to be provided, but obviously some Hi-Fi users will be using a single ended source. That said, I’d expect most of the users to be using one of the new wave of DSP crossovers or a multi channel studio interface for PC based systems, both of which mainly offer balanced outputs. I did think long and hard about offering a standard phono connector alongside either and XLR or the combo, but that would have involved adding some sort of switch between the two connectors to tie pins 1 and 3 together for phono use, this would probably have required relays and extra circuitry. Using the combo connector keeps things much simpler as the use of a TR ¼” jack ties 1 and 3 together on connection, this keeps costs and circuit complexity in the signal path down. I’ll offer Phono to TR jack cables on the website (not silly money ones made out of unobtanium though).
The amp package will have on board microprocessor control which will offer several advantages, some of which I’ll definitely include, and some of which I’d like to garner opinion on. 

Definite includes

Standby – all the modules can be placed into low power mode, a push switch will we provided on the front panel (maybe two colour, one for standby/error, one for on, what do people think?)

Start-up sequencing – While the full load of the incoming mains will not be exceeded by the modules during operation, like most amps there is a large in rush current as the reservoirs are charged, adding multiple modules may blow the incoming fuse. The microprocessor will start the modules up in a given sequence to ensure that doesn’t happen.

Heat shut down - If any of the modules experience over heating that amp module will be shut down and error stated by lighting the alternate colour on the front panel switch.

DC detection and shut down – If DC is detected on the output of any of the modules, that module would be shut down and error stated by lighting the alternate colour on the front panel switch.

Not sure if I should include

Clip - I could provide LEDs on the back panel for clip detection per channel or I could make the front button flash the alternative colour when any one of the channels clip, or I could do both. Thoughts?

Mute – The amps can be placed into mute mode, I could add a button to the front panel to switch the amp into mute mode, what do folk think about that? I don’t really like to many buttons but it might be handy, although is it much handier than standby?

Remote control – Adding to the mute I could add an IR detector so that the amp could be switched to and from mute and into standby, this may negate the need for a mute switch if people thought mute was needed? I wouldn’t supply a remote, Either I could supply the codes or I could make it work with a standard remote like the apple one. I might have to add a remote defeat switch to the back panel to switch this off should it interfere with the operation of other remotes. Making the remote receiver programmable in some way would probably be beyond at least the initial release. Adding any sort of IR would add to the complexity and hence cost.

Signal detection – A little nod to Tony (Bemused) here, it might be a nice idea to get the amp to switch into stand-by after say 1 minute of inaction and to switch back out of standby when a signal is detected. Adding this would add to the complexity and hence cost, although this solution wouldn’t be as complex as Tony’s, it would be done via the microprocessor which would already be on board. This seems like a better idea than a 12V trigger but that could be added as well if folk wanted as I know that some with custom cinema installs use this feature.

I’d like to keep this as accessible as possible price wise and while the facilities above obviously add cost it’s mainly development costs, the BOM get more expensive as well but relatively speaking the facilities are inexpensive. Case costs are the highest of the costs. Machining a posh looking case will add a lot to the overall cost to the customer although it may broaden the possible customer base. Adding vibration isolation and all the other stuff we don’t do in the DIY room but that they like in the other rooms will obviously add costs as well. Adding an extra button on the front or an IR window may not add a huge amount though.

My thoughts about a case are really no more elaborate than the type of case DIYers have been using from Modushop over the years with some customisation and some nicer feet. Thoughts?

Price wise, I need to pin a few more things down, some of which I’ve covered here but I’m aiming for about £700 inc VAT for a 2 channel (stereo module) 125W amp, £900 for a 500W version and rising to about £1850 for a 6 channel 500W amplifier. I might be able to get them cheaper once I’ve pinned down the needs and wants. The prices above would include VAT.

This product would need to go through some development to come to market and would most likely be crowd funded for the initial development, agency testing and first run which would be at a discount to the prices above. It would be good to hear some thoughts before I move to this stage though.

Looking forward to your thoughts.

Stefan
Edited by orangeart

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I like the idea, especially if you can get her majesty to cover the initial development. :P

Can I suggest changing the post to a poll and adding the options that you could do.  It takes a lot less effort to pick something from a list than it does to reply to a long list of questions. You may get more opinions that way.

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Hey Ross, yes good idea, didn't know I could do polls with multiple questions. I'll look at that tomorrow, thanks.

Perhaps I should ask the queen, maybe she might want one..

Stefan

Edited by orangeart

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Hi Stefan I think it's a good idea.  For home cinema I would think a lot of users would prefer a 5-channel option.   I for example could then use my integrated Anthem amp as a processor, and use the vastly superior Hypex modules for power amp duties.  Granted this is not optimal from a power supply perspective as you'd need three PSU modules.

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5 channels would be just fine or any odd number for that matter. 5 mono modules could be used, or 2 stereo and 1 mono. Basically any configuration up to a maximum of 8 channels (6 max for 500W)

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3 hours ago, orangeart said:

Hey Ross, yes good idea, didn't know I could do polls with multiple questions. I'll look at that tomorrow, thanks.

Perhaps I should ask the queen, maybe she might want one..

Stefan

:)  She's the queen, you should be thinking she might want a few dozen with all those rooms in her pad.

I'm not sure you can do multiple questions but even a longer list of options would give you a great insight if you group them.

A few other comments below....

Optional XLR to RCA adapters are common, cheap and easy to use if needed, so, I'd recommend balanced connections over RCA if both aren't practical.

For a DIY and active speaker conversion market, gain adjustment on the individual channels would be a useful feature to maximise digital headroom, if it's possible with these modules.  (Certainly for anyone wishing to control the volume digitally, like with a minidsp).

A clipping indicator is also a big bonus, especially for anyone with power hungry bass drivers and lots of EQ.

I don't see the point of remote controls or mute options on a power amp. An on and off button is all you need when mute, pause or stop can be done at the source. Sound quality is usually the number 1 priority for amplifiers, if you add a load of useless features then people are going to naturally assume your USP is functionality rather than sound quality.  The functionality usually becomes more important on a source component and not a power amplifier where people mainly associate less with more.

The auto-standby option is a good one but it could get very annoying if it went in to standby after just 1 minute and there wasn't any signal detection to turn it back on.

Edited by rv295

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Looking forward to an interesting thread. I think for this product to do well it would come down to 2 things sound quality and price.

In regards to some of the things mentioned and with cost in mind I'd go with the simplest design you can. So for me balanced XLR only if no RCA option, no remote, no mute, no signal detection, standby is fine as long as it's not automatic. End of the day it could be always on as it wouldn't draw that much power. Clipping indicator would be useful but mostly at early stages of any project. Once project is completed I'd want it as plain as possible with no lights flashing. 

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19 hours ago, rv295 said:

:)  She's the queen, you should be thinking she might want a few dozen with all those rooms in her pad.

I'm not sure you can do multiple questions but even a longer list of options would give you a great insight if you group them.

A few other comments below....

Optional XLR to RCA adapters are common, cheap and easy to use if needed, so, I'd recommend balanced connections over RCA if both aren't practical.

For a DIY and active speaker conversion market, gain adjustment on the individual channels would be a useful feature to maximise digital headroom, if it's possible with these modules.  (Certainly for anyone wishing to control the volume digitally, like with a minidsp).

A clipping indicator is also a big bonus, especially for anyone with power hungry bass drivers and lots of EQ.

I don't see the point of remote controls or mute options on a power amp. An on and off button is all you need when mute, pause or stop can be done at the source. Sound quality is usually the number 1 priority for amplifiers, if you add a load of useless features then people are going to naturally assume your USP is functionality rather than sound quality.  The functionality usually becomes more important on a source component and not a power amplifier where people mainly associate less with more.

The auto-standby option is a good one but it could get very annoying if it went in to standby after just 1 minute and there wasn't any signal detection to turn it back on.

Yeah, definitely won't be doing the phono thing, the industry standard is now the combo plugs. Neutrik now recommend them for all applications where an XLR plug would have been used. They are great because of course you can just use a jack if you need single ended. As you say, for those who already have a favourite phono cable, XLR to phono adapters are available, I'll make sure I have these on the site when it comes to market.

Gain adjustment isn't really possible, at least not by the user. It's physically set in the buffers.

I'm inclined to agree with having no mute as standby works to allow the same really. Sound quality wise, it's a bit of a given really, the Ncore sound precedes itself having appeared in some silly expensive amps over the last few years some well into the £10k category. The Hypex boards come loaded with outputs for various error states as standard so not using them is a bit of a shame and none or the circuitry I'd need to leverage them would interfere with the audio path what so ever.

I really like the auto standby feature, not sure what sort of time we would have it shut down after but a couple of minutes would seem like a good plan. The amp would switch out of standby again as soon as a signal was detected or the standby button was pressed again. No to to start back up in sequence as the power supplied would already be charged so should only take 100ms or so.

Stefan

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12 hours ago, insider9 said:

Looking forward to an interesting thread. I think for this product to do well it would come down to 2 things sound quality and price.

In regards to some of the things mentioned and with cost in mind I'd go with the simplest design you can. So for me balanced XLR only if no RCA option, no remote, no mute, no signal detection, standby is fine as long as it's not automatic. End of the day it could be always on as it wouldn't draw that much power. Clipping indicator would be useful but mostly at early stages of any project. Once project is completed I'd want it as plain as possible with no lights flashing. 

Sound quality is paramount I agree, again as I said in the above post, the Ncore modules really are best in class, certainly from a spec sheet point of view they are pretty peerless, of course sound quality isn't all about the spec sheet but subjectively quite a few people really rate them. Price wise, I'm pretty sure that there aren't any Ncore amps out there that would be any cheaper than the price points I am aiming for. 

I'm quite like trying to save energy where possible and so do the certification authorities which means having standby. These options only really add a few quid as mostly it's just development and programming time, physically just a bit of PCB routing and a handful of cheap components so hopefully any functionality that is added won't have a large knock on for the RRP.

Hopefully once speaker designers have finished thier speakers they won't be clipping and the light won't be on at all other wise something was designed wrong further up the chain! I think it's worth having the light for those times when the lids turn the wick up though. That said if demand goes that way i might see about adding some sort of defeat mechanism for the warnings, shouldn't be to hard.

Stefan

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Super Wammer

This sounds really interesting Stefan, I am hoping to go from 2 way active to 3way, so I would be keen to keep the box count down.  

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Thanks, yes that's one of the great things about small and efficient class D amps, they don't take up much space!

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I work a bit with power electronics and the thought of connecting any of my speakers to a 500 watt amp scares me. 125 should be more than adequate for ordinary mortals with neighbors... 

I don't think i would need one but 6 x 125 would make a nice 3 way active amp.

mr bruno has tickled my curiosity with his ncore...

Edited by dave

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Yeah for most 500W is over kill, but on the other hand you are unlikely to ever drive the amp into clip.

  • Upvote 1

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Hi, I like the idea of a configurable amp to suit the various power requirements of 3/4 way active speakers.  I have been looking into the Nord One products which use the Hypex Class D boards, although these are OEM modules not available to the public, is this what you are also considering?  The layout of the 4 boards connected up inside a standard chassis to make an 8 Ch amp looks pretty straight forward in principal and I would love to see a thread describing a DIY build process but I suspect you need some understanding of the power requirements/supply etc so you dont build a toaster and blow yourself up.  For me I would want a 4 way system 2 X 500W, 2 x 250W, 2 X 100W tweeter modules housed in a basic 19" rack mountable chassis with on off switch, standby indicator, protection circuits, XLR and nothing more.  Regarding price I would like to understand the cost of the Hypex modules and other components and the complexity of the build, hours spent etc before deciding if its is better to buy versus build.

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Yes same modules, more configurability than the Nord amps and a properly sorted integration not a rat's nest of internal wiring. 

I think there will definitely be a rack mount front panel available or at least a set of wings to add on.

In principle they are pretty straight forward to build if you could get hold of the modules yourself as an end user and if you had some basic PCB skill. However you can't get hold of the modules as they are OEM only, there aren't any DIY modules on the horizon either.

The connectors will be the new standard combo connectors so XLR connection is fine.

Just doing some case designs at the moment but it will be kept very simple visually. All the protection circuits will be present and a couple of useful but defeatable features.

At the moment im sourcing the parts, designing the PCB, and trying to sort out the rev .01 programming for the microcontroller

Stefan

Edited by orangeart

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