Welcome, Guest
Username: Password: Remember me

NOTE: This is a "Community" forum. Please be mindful that community members are here to help as part of a community effort. We therefore appreciate your effort in keeping this forum a happy place!

If you have a specific issue (e.g. hardware, failure) and want help from our support team, please use our tech support portal (Support menu - > Contact Us).
Thanks a lot of your help in making a better community.
  • Page:
  • 1
  • 2

TOPIC: miniDSP 2x4 balanced to Hypex UcD34MP

miniDSP 2x4 balanced to Hypex UcD34MP 3 years 9 months ago #32678

  • Fenalaar
  • Fenalaar's Avatar
  • Offline
  • Senior Boarder
  • Posts: 70
  • Thank you received: 18
  • Karma: 2
For using the UcD 3xMP modules with a MiniDSP, a buffer should be used.

The JLM audio regurgitator kit might be a suitable buffer for this use.

I've used a cheap single-ended to balanced buffer module bought off eBay for this. However, this buffer isn't totally transparent.

Johan-Kr
The administrator has disabled public write access.
The following user(s) said Thank You: devteam

miniDSP 2x4 balanced to Hypex UcD34MP 3 years 5 months ago #34354

  • Graham Allen
  • Graham Allen's Avatar
  • Offline
  • Fresh Boarder
  • Posts: 9
  • Thank you received: 3
  • Karma: 1
So, 18 months later I finally get to complete this project. I've taken Devteam's advice from earlier in the thread and have tried using a 2x4HD to drive the Hypex UCD34MP amplifier module because I had the HD here for another project and I'm hoping the 2V output will be enough to drive the Hypex amp with its 12.5 dB voltage gain.

I'm not ignoring the other advice on this thread, that I really need a buffer before the Hypex amps, but I was keen to see how the MiniDSP goes driving the amps directly because that would be a nice simple system with no need for another board in the enclosure.

The quick answer is that the 2x4HD drives the Hypex amps to perfectly acceptable volume considering the little 3 inch drivers I'm using. The cheapo 8inch subwoofer also seems to keep up when driven from one of the channels on its own. I have the option now to bridge the two spare channels to run the subwoofer, but I don't think this is going to be needed.

The longer answer is that, as above, it works, but only sort of.

Putting a CRO on the output of the 2x4HD with no load connected and feeding a sine wave in and gradually increasing the signal level I can see clipping starting at about 5.8 volts peak to peak, or 2.1 volts RMS. So far so good, the MiniDSP does what it says on the box.

However, when I connect the Hypex amp to the 2x4 output the clipping (measured again at the 2x4 output) starts at 4.6 volts peak to peak, 1.6 volts RMS. So clearly, the amp is loading the 2x4 output down so that it can't reach its rated 2V output. At this input voltage, the amp is producing 20 volts peak to peak, 7.1 volts RMS at it's output (driving a nominal 8 ohm driver). If my (mechanical engineer's) calculations are correct this is about 6.5 watts into the nominal 8 ohm driver. Way short of the rated 30 watts, but still loud enough for this application.

So, I can take the advice and build an op amp buffer stage and figure out how to power it, or leave the system as it is where 6.5 watts seems to provide a perfectly adequate volume.

Graham.
The administrator has disabled public write access.
The following user(s) said Thank You: devteam, wberggren, ducnd

miniDSP 2x4 balanced to Hypex UcD34MP 3 years 5 months ago #34373

  • mwscholma
  • mwscholma's Avatar
  • Offline
  • Junior Boarder
  • Posts: 23
  • Thank you received: 2
  • Karma: 1
The output resistance of the DSP is 560 Ohm, the input resistance of the UcD32 OEM about 1800 Ohm. That's why the output drops in the end. With an input buffer you win 2,35 dB output on your speaker.
The administrator has disabled public write access.
The following user(s) said Thank You: devteam, Graham Allen

miniDSP 2x4 balanced to Hypex UcD34MP 3 years 4 months ago #34698

  • ducnd
  • ducnd's Avatar
  • Offline
  • Fresh Boarder
  • Posts: 2
  • Karma: 0
I would make some tweak for 2x4HD

- upgrade 2 clock to better grade: 24.576 MHz and 22.5792 MHz

- by bypass onboard opamp and use a external buffer, can you show me a conection point

thank
Attachments:
Last Edit: 3 years 4 months ago by ducnd.
The administrator has disabled public write access.

miniDSP 2x4 balanced to Hypex UcD34MP 3 years 4 months ago #34813

  • wberggren
  • wberggren's Avatar
  • Offline
  • Fresh Boarder
  • Posts: 1
  • Karma: 0
FYI, I connected 2 units UcD34 (each has 4 channels) to a miniDSP 4x10 to 2 loudspeakers, each with 4 speaker units (Linkwitz LX521). The miniDSP4x10 has dipswitches inside which allow a significantly higher output level to the amplifiers. With the lower setting of the dip switches the Hypex amps cannot reach their full output level. With the higher setting the volume of the amps can be moved up all the way. I have a big listening room (6 x 13m) and the volume is way more than sufficient for that room. Sound quality is excellent, even the large dipole subs deliver well controlled bass up to maximum output level. Amazing performance for such small and cheap amps. I wonder why these little amps are to be phased out (acc to Hypex webshop) as these are real gems.
Hope this helps, Wout
The administrator has disabled public write access.

miniDSP 2x4 balanced to Hypex UcD34MP 3 years 3 months ago #35185

  • mwscholma
  • mwscholma's Avatar
  • Offline
  • Junior Boarder
  • Posts: 23
  • Thank you received: 2
  • Karma: 1
Indeed the UcD32/34/36 are very compact, powerful and good sounding amplifier units (now being sold-off). Only in some classical music in women voices you can hear an occasional faint third harmonic distortion playing along.
The administrator has disabled public write access.

miniDSP 2x4 balanced to Hypex UcD34MP 1 year 5 months ago #45228

  • Juoigâ
  • Juoigâ's Avatar
  • Online
  • Gold Boarder
  • Posts: 233
  • Thank you received: 42
  • Karma: 11
Graham Allen wrote:
... I'm going to give it a try with the balanced. I can always add a separate buffer stage if I need to. .
And, was it a success?
The administrator has disabled public write access.

miniDSP 2x4 balanced to Hypex UcD34MP 1 year 5 months ago #45237

  • Graham Allen
  • Graham Allen's Avatar
  • Offline
  • Fresh Boarder
  • Posts: 9
  • Thank you received: 3
  • Karma: 1
Read my post #34354 above. I did not try the balanced 2x4. I used a 2x4HD that I had on the shelf.

The system has been running for 2 years, and sounds great. It just got re-purposed with the same satellite speakers and an old car subwoofer I had laying around. One UCD34MP drives the sub to impressive acoustic output.

Graham.
The administrator has disabled public write access.
  • Page:
  • 1
  • 2
Moderators: devteam