0

Amp+ Specs

Charles809

January 15, 2015 00:57

None

Follow

Would love to see Amp+ specs specifically
+ plot THD+N vs Pout for 4 & 8 ohm over the whole path (incl DAC).
+ plot THD+N vs frequency - class D is suitable to distortion problems approaching 20kHz
+ frequency response

• Facebook
• Twitter
• LinkedIn

9 comments

• 0
  
  HiFiBerry team January 15, 2015 06:37

  Hi,
  
  we don't have these plots available. One issue of THD+N measurements of class-D amplifiers is the filtering of the output. Depending on the filter used for measurement, figures can differ a lot. As our measurement equipment is not really optimised for Class-D measurement, it does not make sense to publish these figures.
  
  Best regards
  Daniel
• 0
  
  Charles809 January 15, 2015 06:48

  Agree the filtering is an issue and tends to hit the top end most which is where the problems often are.
  Which chip set have you used as the base?
  I assume the 25W into 4ohm is half that into 8?
  
  Cheers
  Charles
• 0
  
  HiFiBerry team January 15, 2015 11:35

  Hi,
  
  it's based on the TAS5713. Based on the specs, it is about 25W into 8 and 22W into 4 Ohms. With 4 Ohm, output voltage is lower (lower supply voltage or set amplification lower).
  
  Best regards
  Daniel
• 0
  
  Charles809 January 15, 2015 22:52

  Great thanks, will try one then look to a whole house system.
  
  Cheers
  Charles
• 0
  
  c-roe February 18, 2016 12:14

  Hi Daniel,

   

  I am not sure, if I get this right.

  If I use a 18V power supply I get 25W with 8 Ohm speakers, for 4 Ohm I should use less power? Can I use 18V with 4 Ohm?

   

  Thanks and Regards

  Christoph

• 0
  
  HiFiBerry team February 18, 2016 12:15

  Hi Christoph,

  you can use 18V also for 4 Ohm speakers.

  Best regards,
  Daniel

• 0
  
  c-roe February 18, 2016 12:20

  But what is the difference according to your post 'January 15, 2015 12:35' then?

  My understanding is: less Ohm -> more output power for amplifier

  Is there any limitation on the circuit?

  Thanks

  Christoph

• 0
  
  HiFiBerry team February 18, 2016 12:23

  Yes, there is a limitation. Using 4 Ohm speakers will result in higher switching losses and therefore more heat. Therefore you won't get more power into 4 Ohm speakers.

  Best regards,
  Daniel

• 0
  
  c-roe February 18, 2016 12:41

  btw: I am already using two AMP+ - one with 4 Ohm, one with 8 Ohm for some time with the recomm. Meanwell power supply

  I want to understand it completely. Is there any disadvantage using 18V with 4Ohm compared to a lower voltage (apart from the heat)?

  I do not drive any of the AMP+ on (very) high volume for a long time (it's very loud) and could not notice a high temperature on the systems yet.

  Thanks

  Christoph