Hypex DLCP (DSP) with 6 Channel UcD Amp Project.

[Qwin]

I've been working with the analogue crossover boards made by KMTech for some time now, trying to keep everything pure analogue for the sake of my vinyl set up. I've done many modifications for various speaker applications, but got a little fed up of the work and expense every time I change a parameter like the crossover point. I've also been keeping an eye on what's happening in the Digital Signal Processing (DSP) market and think its about time I started looking at a digital crossover solution. What tipped the scales, in favour of digital, was when I heard Ali's vinyl set up using a miniDSP active crossover at the first MiBO meeting.
I was initially impressed with the out of the box solution from miniDSP, their 4x10HD has a stereo pair of balanced analogue inputs, would handle all my digital input needs and has balanced outputs, which matches my requirements. It comes ready built and tested in a nice 1U height case and would plug straight into my 6 channel power amp. What started doubts in my mind, were a few folks stating the analogue side on the 4x10HD was not as good as its digital and had a higher noise floor. I put the idea on the back burner and continued to read up on the subject and scope what else was available.

I've always liked the gear that Hypex makes and have drawn up a couple of 6 channel amps using their UcD modules in the past, but never got round to building one. I found some good user reviews concerning the analogue side of the Hypex DLCP (DSP) system. It's basically a 6 channel digital Pre Amp/digital crossover, has more analogue inputs than the 4x10HD and all balanced connections. Siegfried Linkwitz tested a DLCP paired with UcD amps on his LXmini speakers. He was astounded how much more low end definition there was and by the overall level of refinement, compared to his 4x10HD and AT1806 amplifier.
The cost of the Hypex DLCP set up, which is only available as a DIY kit of parts needing a case, is the same as the ready built 4x10HD from miniDSP. I was now giving this serious thought and could see the possibility of building a DLCP and my 6 channel UcD180 amp design into a single 2U 19” case of around 300mm depth.

http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_01.JPG

This is what I have in mind, as you can see there are plenty of inputs on the Hypex board, the "set up" USB socket, unlike those on miniDSP, can also work as a USB audio input. It uses all ballanced connections internally as well, to simplify connection with the UcD Amp modules.


http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_01A.JPG

I've tried to keep AC/DC/Signal apart, ignore the wires crossing each other, most are on different Z planes, so not touching. Because all the modules were designed by one maker and are meant to work together, there is a lot of design synergy. The DSP board for instance, can be powered from the Aux output on either of the SMPS, used to run the UcD Amp modules. Also the standby function on the DSP board can also send the SMPS's and the 6 Amp modules to sleep for power saving and click free start/sleep modes. This arrangement will give 180w into each of my 4ohm Woofers and 120w into the 8ohm Midrange and Tweeters.
I need to put this into action, limited funds dictates I will build this in two stages. The first involves building just the DLCP set up and a pair of SMPS into the case and using my existing 6 channel Power Amp to run the speakers. The second phase will be to drop the 6 Amp modules into pre drilled locations and connect them to the rest of the DLCP system.

I received the Hypex parts for the first stage of the project.
x2 SMPS
DSP Board
Input Board
Control Board
Various leads and a remote control

http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_02.JPG


http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_02A.JPG

The input board has plenty of connections.
You have the option of reducing the number of analogue balanced stereo input pairs from 4 to 3 or 2 if desired.
Three analogue sources will be more than enough for me so I snapped the end pair off. The circuit board is weakened at the right point and designed to break if you press it over an edge. Using this number reduces the overall length and allows a bit of subtle relocation, that gives better cable paths for the two ribbon cables and the RJ45 lead in my layout.

I won't be doing much on this till after the NEBO 8 meeting.

[Ali Tait]

Nice one Ken, I'd be interested in this for myself if it wasn't for the fact that my OB's are now 4 way. :-(

[Qwin]

Nice one Ken, I'd be interested in this for myself if it wasn't for the fact that my OB's are now 4 way. :-(

You can daisy chain em, one control board and input board, with a DSP board as master and a second DSP board as slave, connected through the RJ45/Cat5 connections.
So up to 6 way are possible using two boards. Cost does enter in to the equation, the DSP boards are 250 euro each plus 21% VAT plus 3% if you use credit card or paypal, plus shipping. :rolleyes:

Saving up for a nice case now, modushop (hifi2000) in Italy do customised cases with the front panel machined to accept the Hypex screen and push buttons. They can anodize it and engrave/print to your spec as well, all at a price of course. :)

[Ali Tait]

Yeah, that would make it a bit pricey, especially since I'm pretty happy with the way the 4x10hd sounds.

Be interested to hear yours once it's done though.

[Qwin]

I'm doing it in two stages Ali, first just the DLCP through the Nakamichi amp. That will happen over the next few months, to get a taste for how it performs and also, it will allow me to do some experimenting with my speakers.
Later I will install six UcD180HG Amp modules with HxR regulators into the case, but that will probably not happen till next year as they are not cheap. ;)

[Ali Tait]

Aye there is that. I'm running some vintage compression midrange drivers now, with an SB Acoustics Sartori tweeter on the top end. Woofers run to 200hz, Visaton B200 runs 200-800hz, compression driver 800-50000, then tweeter 5k up.

Sounding pretty good I think.

[Qwin]

Yeh, I caught on another thread somewhere you had gone 4way.
Horns you say, must be sounding pretty good, as the mid driver you used at Mibo was no slouch.
SB Acoustics have some nice drivers.

It was a close thing between the SB 12" bass and the 12" Scanspeak for me, if I had been going for a ported design, it would have been the SB.
Still considering the SB mid ranges, though I am really tempted to try the 3.5" Yamaha Beryllium mid dome with the Scanspeak bass.

So many combinations to consider, but you know all about that. :D

Ahh - I see you are still using the Visaton for upper bass/lower mids.

[Ali Tait]

Yes, though I have a pair of Alpair A12p's tucked away that will probably make the final design.

If you still looking for a mid, I'd highly recommend these drivers I'm using - pretty rare, but pairs do come up for sale now and again. Crystal D 500 is the driver, 70's Japanese stuff. Great drivers, and bettered the Altecs I was trying.

[Ali Tait]

Around 105db too!

[Qwin]

I'll have to look those drivers up, not one I've come across before.

[Ali Tait]

Me either, got them from Geoff here.

[walpurgis]

Those Cryslers are mega rare. I kept an eye out and I've never seen another pair anywhere.

[Qwin]

I've been re thinking the amplification......

I was going to use 6 identical Hypex UcD180, that's 180w/4ohm 120w/8ohm.

My bass drivers are 4ohm and the mids/tweeters are 8ohm.

Using my current lash up and 7 channel Nakamichi amp, which has identical channels, I am having to attenuate the signal a fair amount for the mid/tweeter before the power amp, to match the levels I get out of the less sensitive bass drivers.

I know it's all about the total gain/sensitivity, but show me a high gain power amp that isn't big on watts. Apart from variations due to design/losses, for all intents and purposes, when looking at power amps, large gain = large watts. So I tend to talk in those terms, as the actual gain is usually buried in the spec somewhere.

My concern is that if I use six identical modules (read identical gain), I am going to have to make a similar large attenuation to the mid/tweeter channels, but in the digital domain, as the Hypex DLCP functions as a digital pre amp with individual level controls on the six output channels. I don't like the idea of using so much digital adjustment.

My proposed solution is to use the UcD400 modules for the two bass channels 400w/4ohm. Its not that I need so much power, its the benefit it gives, by having a more balanced gain structure across the channels, that will need the minimum digital attenuation to achieve the correct levels at the drivers.

An added bonus is I will probably have power to spare in the bass, which will allow me to consider a Linkwitz transform to EQ the bass and lower the f3 point, if I feel I need to. The driver has plenty of Xmax if I were to attempt this.

Just thinking about the pros and cons at the moment, it will still fit in the same case footprint, but not in the planned 2U case height. The UCD400 are taller and will need a 3U case, which would also allow me to use a thicker piece of aluminium, as a heat sink in the bottom of the case.

[Firebottle]

I like your thinking Ken, particularly the Linkwitz transform.

Watching with interest :)

[Qwin]

Couldn't find anything about the Crystal driver Ali.
I've looked at Alpair before, the AL12P is a full range speaker but looks like it would make a good OB midrange.
I would have to use it in a sealed chamber. It gets good feedback from folks that have used it on diyaudio etc.
My first test, once the digital crossover is running, is to try the Yamaha Beryllium dome mid with the Scanspeak bass and Fountek Ribbon.
The mid and Ribbon are closed back and don't need a separate chamber, so I can just mount em OB style on a baffle board for a quick test.

[Ali Tait]

Yeah there's not much out there.

[Qwin]

Well, I've been busy for a while on other projects, but got back to the DLCP this week and made some progress.

http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_02B.JPG

I checked the Main/Aux output on the SMPS's, plus the voltage on the Standby Module and all were as expected. I wired it up to explore the menu set up and set the volume to minimum, prior to connecting to the Amp and testing the Audio.
I downloaded the latest firmware/filter software, created a basic filter set on the laptop and uploaded it.

I'm only using the auxiliary output from one of the SMPS's at present, to power the DSP. They are really meant for powering the Hypex Amp modules, to be fitted in stage 2 of the build, but I needed to test the pin out for the DSP standby signal, that puts them and the Amp modules to sleep. There are many ways of wiring these boards, better to understand how the plumbing works before fitting it all into the case.

Now I need to disconnect the analogue and passive crossovers from my speakers and add a series capacitor to protect the ribbon tweeter. I should then be ready to insert the temporary Nakamichi amplifier. :)

[Qwin]

I managed to get everything plumbed in and 50+ hours on it, to make sure everything was run in, not sure that it needed more than a few hours, but didn't want any niggling doubts.

So how does the DLCP sound..........?
Err, decidedly underwhelming!

There is detail, but dynamics are down, slightly bloated and mushy bass, lost some slam compared to my analogue active, on the plus side it is a cleaner less sibilant top end, not that that was a major issue with the analogue circuit, but it has improved slightly with the DLCP. Mid range is bland, not as transparent and boring to listen to.
Overall? I couldn't live with it, especially with a vinyl source, most definitely a backward step in its present form.

Configuration
I set up a basic filter set with the same crossover points 300/3200Hz and slope 24dB/Octave as the analogue circuit.
I used the same multi channel power amp and audio sources, so it was a pretty even comparison.

I'm not righting it off just yet, folks on various Hypex threads for other products, say beefing up the cables between boards/smps etc helps, I especially don't like the 14way ribbon cable that transfers the analogue and digital signals from the input board to the DSP board. Also, I am powering the DSP from the Aux output from their amplifier SMPS. Hypex confirmed this was possible, but I'm thinking, maybe not the best way of running it. Some DLCP specific threads have said improving their (linear) PSU regulation etc firmed up their woolly bass and Hypex do produce a custom SMPS for the DSP board. I have a high quality tracking PSU which I made for my Pro-Ject phono stage, it's the right dual rail voltage (+/-18vdc). I've ordered some connectors to make up a lead, it wont take long to see if this makes any difference.
I can wire the input board to DSP with some dual core screened for each channel to negate the ribbon cable, there is not much else I could change. The six audio outputs from DSP to power amp are short balanced XLR leads, so nothing to improve there. The whole set up is fully differential balanced circuitry from cartridge to power amp.

If nothing helps improve things, I'm not opposed to reverting back to an analogue crossover and using the DSP as a development tool to establish the best crossover points, slopes and shelf/notch filters. The Hypex filter design software is also the measurement software and filters can be applied to measured results to overlay a predicted outcome in a graphical form, in a before and after comparison. You can also upload changes from your laptop to the DSP while music is playing and hear the instant change, its a useful tool in its own right.

I will keep you updated as to how it all pans out.

[Ali Tait]

That's a shame Ken, hopefully you can sort it.

[Qwin]

Well, that was a quick fix.
Not being used to some of the techniques, I had set the Q for the cascading Butterworth biquad's at the wrong level.
I ended up with straight Butterworth cross overs with +3dB humps and not flat LR crossover points.
This is what was causing the muddy upper bass/mids.

Its a lot better now, bass and mids better defined and more transparent, comes across as more dynamic.

If I'd had a suitable mic/interface and taken measurements it would have been obvious, but I just had a flash of inspiration when reading about creating LR filters and realised I had not done it correctly. It's a learning curve. :rolleyes:

[Ali Tait]

Good news.

[Qwin]

I've now had a good listen to the DLCP and put my analogue active crossover back in the system, I think that says it all!

The DLCP just doesn't cut it, not bad on digital sources, but my analogue crossover is better.
With my analogue (vinyl) source it is way behind.

Just too soft and rounded off for my taste, with a reduction in bass weight.

I didn't even get to try room correction etc. In a like for like set of basic crossover filters, without any EQ the basic tonality from both set ups was similar, but the digital just sounds flat and lifeless in comparison. Some folks might see it as an acceptable sound, especially if not using vinyl. I feel I have definitely stepped backward and I'm looking to move forward. I tried moving the crossover points and changing the slopes, but they were pretty much optimum where they were. The DLCP just has a signature sound that will not change with minor tweaking and is fundamental to the product.

Music used:
Vinyl
Grace Jones-Night Clubbing
Yello-The Race-45rpm
"Tracey Chapman"
Joni Michell-Hissing of Summer Lawns
London Grammar-If You Wait-45rpm
Jo Jackson-Night & Day
Dire Straights-Love Over Gold

CD
Malia-Convergence
Kenny Burrell-Midnight Blue
Web Sisters-Savages
Otis Taylor-Collection
Laura Mvula-Sing to the Moon
OMD-English Electric
Calexico-The Black Light
Gregory Porter-Take me to the Alley
Sea Sick Steve-Walkin Man

Streamed (Deezer)
Alison Moyet-Other
"America"
B B King-Lets do the Boogie
Kraftwerk-Minimum Maximum (Live)
Yello-One Second

I will mount the DLCP in a case, it will now be relegated to a development tool. When I get the measuring sorted, I will use it to finalise my analogue active set up. I need to reduce the rising response of the ribbon tweeter, a 5dB hump between 7kHz and 24kHz, the DLCP proved very effective at quickly trying this and it was a noticeable improvement. I used the plot from the driver spec sheet for the parameters, measuring real world combined driver response, should give even better results. I've been using the passive filter for the tweeter and it dealt with the hump, but I want to be fully active in the final version, even with the DLCP the ribbon tweeter sounded nicer active (flattened).

So I tried it and it didn't work as well as I had hoped, moving on to plan B. :)

I've now heard the DLCP and several mini-DSP offerings and not liked any of them. Gordon (Halfway tree) uses software based active filters through good quality stand alone ADC and DAC's. His results are a major step up over these one box solutions and I see this as the future for high end DSP.

[Qwin]

I've been very disappointed by the sound quality of the DLCP, light in the bass, soft and woolly mid range, not good at all. Double checked everything, nothing wrong with the way things were connected or with the filters I created, which are exactly the same as the analogue ones.
I re-read some of the threads on the diyaudio forum and folks were very pleased with the sound, so something wasn't right. I thought about the power supply, I was using the Aux output from one of Hypex's amplifier SMPS, which is an option suggested by Hypex. I thought about buying their dedicated SMPS for the DLCP which outputs the main dual rail voltage but also produces the single 8v standby voltage. I was very surprised when I read the spec sheet for this supply:

"This switch mode power supply is specially designed to be used in mixed signal applications such as DSP and audio applications requiring a single low voltage output for powering the digital parts of the circuit and both a positive and negative output rail for powering the analogue circuitry."

So the single 8v output may not be just for the standby function, I had used a cheap switching supply about 25x35mm for this, you can see it front left in the previous picture (post #17), as I presumed from the blurb, that it was not in the audio path. I decided to buy the dedicated supply.

http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_02C.JPG

Didn't take long to swap out the Amp SMPS for the dedicated supply.
What a difference, instantly more drive, solidity in the bass and crisper more transparent mid range, this is more like it. :carrot:
Still slightly better with digital rather than analogue sources, but not a lot in it, much much better.
Hypex are known for minimal instructions, you don't actually get any and have to use the sparse information from the on-line spec sheets, which are great at detailing pin outs etc, but say little about what options you have, if straying from using an all hypex solution, (PSU etc) if you do your pretty much on your own. But to be fair, I have found them good at answering emailed questions relating to my build.

So, I'm a much happier bunny, after a few hours of running, this is sounding very good indeed.
I need to give this careful consideration now, as to whether the performance is better than my analogue active set up, enough to persuade me to enter stage two of the project and purchase six amp modules. These would form a Digital Pre/DSP/Power Amp's in one case, as detailed earlier.

I think I need some extra ears now to give a second opinion on this. :)

[Qwin]

Still tinkering with this as well as other projects.

I'm at a bit of a crossroad situation...... I need to optimize the sound of the Hypex DLCP before making my final choice of using a Digital or Analogue active crossover.

I'm taking my time over this as there is a lot to take in and learn. If your drivers are reasonably well matched, its easy to get a fairly good sound out of some basic filters quickly thrown together. To get the best out of your driver combination, is another matter and I've gone about as far as I can without measuring what is happening.

To this end, I have just purchased a Focusrite 2i2 USB interface and I'm waiting on a Dayton EMM-6 mic from the States. The mic has been purchased from and calibrated by Cross-Spectrum Labs, to be accurate from 5Hz to 25kHz. All this technical malarkey is a big sideways step from enjoying my music, but it's my hobby and a necessary evil if I want to build something that will compete with commercial offerings well beyond my price point.

One of the best features of the Hypex system, is that their DSP software is also the analysis software and it all works together in a single interface.

The easiest way of explaining this principle is with a screen shot from their very minimal manual.

http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_02D.jpg

The Red trace is the measured and imported response, you can work on an individual channel (driver) or the summed response for all channels (drivers).
To add a filter, you click on the approximate position you want it (Green Dot), then in the main menu select the type of filter and adjust the frequency and +/- dB figures etc in the dialog boxes, to the exact ones required. This creates a filter and it's displayed as the Cyan trace. The Orange trace is the programs prediction of how this filter will effect the imported response. Users have reported a very similar measured response, to that which was predicted. You can add multiple filters/adjust/delete as required, it's quite a nice interface and fairly easy to pick up, through trial and error.

It may not have all the bells and whistles of something as powerful as REW, no waterfall display for instance, but you do get Magnitude, Impulse and Step screens to work with. It's aimed at the DIY market, not at Audio Engineers and its feature set and interface have been designed with that in mind.

It's a very useful tool, but Hypex make the point that they expect you to have a basic understanding of some of the audio science behind it all. I would add that, just as owning a CAD system will not automatically turn you into a mechanical engineer, using this type of software does not make you an audio engineer, with the knowledge of how to interpret and respond to the displayed results. That said, with a bit of reading, from their manual and around the forums, you can gain enough knowledge to produce very satisfying results.

I need to put some of this to use now.

[Qwin]

.
I have taken my Yamaha NS1000M Project about as far as I can with my semi active (analogue) solution and I am very pleased with the results.

I feel another speaker project coming on, maybe my ultimate 3-way. The DLCP will be the ideal tool to help me design the crossover, but it's about time I put it in a case, so I got an appropriate off the shelf item from HiFi2000.


http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_03.JPG

I had previously worked on a layout, but I decided not to build in any amplification this time and leave that external.



http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_03A.JPG

The fixed block of controls required some pretty accurate drilling to guarantee the push buttons didn't stick. I made an Acrylic window for the display to make it tidy and keep the dust off the screen.



http://www.jkwynn.co.uk/Project_Images/DLCP/DLCP_03B.JPG

The business end was just as tricky to make, as the top row of inputs is a fixed assembly on a PCB, so no room for error when making the apertures. Being a Hypex unit the 6 outputs are all balanced to match their Amp modules inputs, but they will work with single ended using adapter connectors or leads. I used my usual traffic light system for identification. Red for Tweeters, Amber for Mids and Green for Bass. So it's ready for action. :eyebrows:

[Firebottle]

Nice job Ken. Excellent work with the holes :thumbsup:

[Ianmac]

Ken
Ive not been on the forum for over a year due to a health issue. Im getting slowly back to normal and looking at using the new Hypex Fusion Plate amp to dip my toe into actives.
I looked at the DLCP solution before my illness with a view to modding my ATC SCM40's put pulled back re difficulty in getting information on setting up the filters, a free space to set up the LS ( outside in the garden was my best option), the possibility of devaluing my ATC's and the overall cost.
Im having to donate most of the gear from my 2nd system to my son and will be left with a pair of Kef reference 1point2s (3way dual concentric tweeter / mid and ported bass driver)
Fusion 3 way F123 100w tweet + 125 watt mid & bass or F253 100w tweet + 250 watt mid & bass are possible options. Like you I am finding the lack of info on the hypex software an issue and the correct method of using the varios filters a problem.
I did have a calibrated mike two years ago but unforunately sold it. I have a focusrite 2i2 and a separate mike pre.
I dont want to jump into spending on amps without a much better understanding of what Im doing.
Can i ask how you are getting on with your DCLp project particularly the results from using your analogue input as I'm not too keen on the A to D conversion required.
Many thanks
Ian

[Qwin]

Hi Ian
The Analogue to Digital conversion on all these one box DSP solutions is not good enough, regardless of who the manufacturer is, Hypex is better than miniDSP, but still not good enough. Analogue from a turntable will definitely take a large step back in quality. They concentrate on the Digital to Analogue side and you can get great results if you only use digital sources.

I completed the DLCP as shown above, nice tidy, self contained unit, now in a case, but uses XLR balanced outs to plug into external amplification. I use this purely for crossover development and it's not part of my audio set up.

For my 3-way speakers I now use an (Analogue) active filter (Rod Elliott's) which works at 500Hz, the bass amp/driver is fed the <500Hz and >500Hz is supplied to a separate amp feeding a simplified Passive for mid/tweeter, crossing at 6kHz. By using the Active as a pre filter, the Midrange does not need a band pass, which simplifies the circuit and removes the need for the big value series capacitor, that most 3-way passive circuits use on the mid driver. You end up with a simple 2-way passive circuit.

This set up works for me, and the TT sounds great through it.

You can follow it here, from "A Fresh Start" at Thumb Yam_38 onwards. http://www.jkwynn.co.uk/Yam_HTML/Yam_Thumbs.html

The basic advice on filter design, in the DCLP manual is all I found, so it was trial and error after that. As I now use DLCP just to determine the values for a passive or simple analogue active circuit, I tend to be using simple 12 or 24dB/Octive LR filters and experiment to find the best crossover points using these. The built in measuring and predictive software help with this a lot. I also use a Focusrite 2i2 with a calibrated mike from Cross Spectrum Labs.

[Ianmac]

Ken
Thanks for the feedback. I note your comment re the A to D issue I suspected.
Ill have to give this more thought.
Having built a quality phono pre Ive got my techie sounding good and use it a lot with this system (Benchmark Ncore's KEF)

In the meantime ill look for a S/H Benchmark DAC 1 hdr and use a Cyrus amp I have to drive my KEFs
many thanks
Ian

[Qwin]

An alternative approach is to use your DLCP for digital only, direct from your sources and buy a separate, quality ADC and attach your TT to that and feed the digital output into the DLCP.
Mytek etc make such products in two channel and multi channel form like the Stereo 192 here: https://mytekdigital.com/professional/products/stereo-192-adc/

A big favorite amongst studio users is the Burl Audio B2 Bomber, many producers swear by it for the analogue sound it produces. Several interviews reguarding this on youtube. But its over £2.5k see here: https://sxpro.co.uk/burl-b2-bomber-adc-dante?gclid=EAIaIQobChMIzqL8zLSq4AIVQZztCh2jsQIrEA QYASABEgJ_zPD_BwE

I made an offer for a second hand B2 on gear slutz, but was outbid.