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Cristi 14th January 2010 05:52 AM

Class T Audio Amplifiers
Discussions about class T audio amplifiers from Connexelectronic

col 5th February 2010 01:24 AM

Hi Cristi,

Congratulations on setting up the new threads, much better.

I have a question regarding "parallel" operation with the TA3020 amps. Is it possible to parallel 2 channels so that they are able to handle more current?


col 5th February 2010 03:55 AM

Iv'e been looking at this TA3020 "bridged" datasheet:

I'm most interested in the 600W 2ohm rating ;-)


zog666 20th February 2010 08:20 AM

TDA8920 module: happy customer several months onward
Just thought I'd mention I'm a happy user of one of the ConnexElectronics TDA8920 modules (which I got from Col).. very nice sound with my EconoWave speakers. And even though I'm using quite high efficiency compression drivers the amp is very quiet (after I got my grounding set up properly).

Also I measured the power usage with one of the Jaycar power meters.. 6-7W at normal listening volume, essentially 0 when silent.. I can leave it on 24/7 and not worry about power use. my preamp uses more power than my power amp.

zog666 8th March 2010 10:18 AM

Connex TA3020 amps.. what is the key differences between 3a, 3b, 3c

Col visited a few days ago and we compared his ConnexElectronics TA3020 amp (V1) with DIY PSU including 4 x 10,000 uF filter caps.. VERY impressive, it has noticeably firmer bass and more detail than my "reference" amp, a class AB ART SLA-1 studio power amp - driving my "econowave" style speakers.

Listening to "South Of The Line" by NZ dub band Pitch Black I could hear more fine detail I hadn't heard before, and better bass, as my current amps must have been struggling to put out the power to reproduce the fine detail and deliver the low end bass lines in this track at the same time.

Anyway, looking on the Connex site I can see 3A, 3B and 3C models.. what are the key differences between these models? I can see the 3C has the filter caps on board, while I am guessing with 3A and 3B I would get an extra linear PSU (PS10K63, PS10K80, or even PS18K71) to deliver the power - which would be best? I don't listen at very high volumes - but I often listen to very bass driven music, and it was very apparent the extra control and detail with the cnx ta3020 v1 in some of my favourite bass heavy tracks.

Measuring the power draw (with jaycar power meter) I can see the v1 uses about 13W idle or at low volumes, and only up to 22-28W at deafening volume levels in my house. This is a lot better than the ART SLA-1, but not quite as efficient as the my cnx TDA8920 (essentially 0 watts idle) - are the versions 3A, 3B or 3C any different with their idle power consumption?
(Note in standby mode the v1 does use zero power, unlike some bits of gear I have!)

I've had some good results with my Connex TDA8920 amp (though it has a strange sonic artifact with piano sounds I just noticed) and my ART SLA-1 but the improvement in trying out the TA3020 was quite noticible - and there are quite a few options to run with implementing one on the Connex web site.

zog666 8th March 2010 10:57 AM

more TA3020 questions: input connectors
I can see the v1 and v2 use a screw in terminal header for the inout connections while the 3a and 3c use a plug in connector - I found this plug in connector a bit hard to work with when I was boxing up my TDA8920, is there any advantage to this connector? I can't see what kind of connector the 3b uses but am i right in assuming its not a screw in terminal header?

zog666 12th April 2010 04:27 AM

TA3020 v3c with softstart and 500VA toroid
Here's my very simple implementation of the v3c in a spare steel box I found in recycling, but already had some of the mains wiring and EMI filter and is the perfect size.

Ugly but I think I managed to get a good layout internally.

Sounds very good.. low power use (about 11W idle).

Can hear faint white noise if I put my ear next to the waveguide (high efficiency compression driver), but not audible away from the horn.

When I had the amp module bolted to the chassis with metal nuts and bolts it caused some ground loop noise. Replacing the metal nuts and bolts with polycarbonate ones and the sound went away. Soft start is still bolted down with metal nuts.

Cristi 12th April 2010 04:42 AM

Congratulations !!! it looks very "industrial" :) and robust. the amplifier mounting holes are isolated from GND except the middle one between the inductors, and that can be used as the GND star point.

dvenardos 14th April 2010 07:29 PM

Question on the TA2022
From the datasheet when used in bridge mode:

The maximum output power will be about 110W at 4 ohm or 180W at 8 ohm.
Is that correct? I would expect it to be 180W at 4 ohm and 110W at 8 ohm.

Cristi 15th April 2010 01:15 AM

The maximum output power is limited by the maximum output current capability. on 4R load impedance cannot get more than 110W due to the current limit. on 8R can get the sum of the power of each channel working in single ended mode on 4R load impedance.

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