Review of Connexelectronic TA-3020 v3b audio amplifier

[Ciu]

Originally Posted by Richie B

Hello RC, I honestly can't remember, I'll see if i can see any markings on it... but I'd rather not take it out to inspect it. Why do you ask?

Rich.

It can be 20k , or 47k....

I still hesitate between TA3020, TDA7293 BTL, and LME49810 with BJT
I didn't have bought yet, but I intend to use with a passive filter (~200hz LP ) with a woofer, so I need something with medium (~47k ) input impedance.

[Richie B]

Well, whadda'ya know?! A cheap cable has gone a long way to sorting out the problems with this amp! I bought a cheap *** Cambridge Audio interconnect, here:

Cambridge Audio 1m Interconnect on eBay (end time 09-Apr-11 09:16:56 BST)

It seems to have almost sorted-out the "muddiness" in the lower mid ranges! And the interconnect I was using cost at least 6 x what I paid for this one!

There are of course, side effects - the upper mid range now is a bit emphasised, but I'd rather that than how it was!

Any suggestions for new speaker cable (biwire) greatfully recieved - I'm getting there slowly!

[v-bro]

If cables make a difference your source output is the problem. Really, sound differences should not occur unless the output impedance is so high the LRC parasitic components of the cable and connectors become a filter in the relevant part of the audio band. Usually these filtering effects occur in the megaherz + band, not in the audio band.

An example is a passive guitar, where hundreds of meters of copper wire of the pick up form a very high output impedance. Here a few nanofarad capacitance for instance can form a lowpass filter and the high frequencies can start to sound dull and lifeless.

With active equipment ANY decently made cable should sound EXACTLY the same....

[ChuckT]

Originally Posted by Cristi

Playing with the input caps will damage the amp again, for sure. then complain that was not your fault.

Are u sure? And I thought this is a diy forum.
Changing the input cap is the most basic and easiest tweak to improve the sound.
Sorry, I prefer to encourage rather than discourage the diy community.

[Sounds Great]

Originally Posted by ChuckT

Are u sure? And I thought this is a diy forum.
Changing the input cap is the most basic and easiest tweak to improve the sound.
Sorry, I prefer to encourage rather than discourage the diy community.

ChuckT:

For Class D/T sometimes additional care needs to be taken.

Class D/T amps produce a lot of EMI as an inherent part of their operation, primarily associated with the output stage switching.

Depending upon the size, inductance, position, orientation, and lead length of your replacement input AC coupling capacitor, you may inadvertently pick up output stage switching noise and introduce this back into the input of your amp - where it can be amplified further and lead to unwanted oscillations. This can lead to anything ranging from subtle sound quality degradation, through to substantial oscillations that may make the amp run hot or even damage amp components.

Hence, with Class D/T amps you need to take into account the above, in addition to the normal audio considerations associated with input capacitor sonic qualities.

Experimenting can be a lot of fun, and sometimes costly. Either way, knowing a little more about the possible implications of a change, before you make it, can be helpful - particularly when the implications may be costly and inconvenient for you (and the supplier of the amp).