LM3886 vs TDA7294

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
ashok

I didn't meant to say anything bad about tube amps or any other topology ( they all have pros and cons - I'm actually planning to build a tube amp myself one day ); all I said is that LM3886 has better electrical characteristics ( and it's simpler to build an amp with )

best regards

Paul (raindog)
 
I think my TDA's should now be set up as the LM vs TDA question has come up again. All components being the same type ( psu , caps and resistor etc ).

I didn't get it done so far due to various other issues. I have the 7293 and 7294 . But I guess it's better to try the 7293 first.
Cheers.
 
The TDA 2050 (ST) sounds as good if not better than a $1000/- plus amplifier ! And it's only 20 watts per channel . That should be good enough to say that it is a good chip ! It doesn't go as loud as the more expensive amp but in the compareable range ( very loud ) it does sound better in many areas.The TDA 7293 or 7294 should equal that or be better ........ maybe ?
Implementation can make all the difference.

:)
 
7294 certainly does not sound bad, or Yamaha wouldn't use it...always been a fan of their stuff... sure they have crappy entry level stuff like everyone else...

One advantage the 7294 have over the LM range is effiency when driven at low levels, as you can power it with 2 seperate power supplies... incrementing the power as and wehn needed... probably makes it popular with car stereos etc. too.
 
TDA7294 now working and.................

My TDA7294 project got speeded up when I picked up two simple pcb's a few days ago. The circuit is straight off the application note . There is no Zobel on board and I have not fixed one either.
On board supply capacitors are 2,200uF /50 V with 0.1uF/63V film caps. Non inverting input version.

I also have a LM3886 running in inverted mode.
Both circuits use the same type components. Carbon film resistors and same type film and electrolytic caps.
The LM3886 is a shade better with only one film cap at the input. 'Plus' input goes straight to ground. In the TDA7294 the minus input goes to ground via a NFB resistor and electrolytic cap 220uF/50V / Samwha .

The 7294 appears to sound brighter ! Cleaner highs and clear cut bass notes. The bass appears to sound lighter but much better defined. Mids sound a bit harsh (?)

I removed the NFB capacitor to ground and the harshness disappeared . The remainder is still the same. This makes it a shade better than the LM3886 ! Offset with capacitor 1mV and 3 mV on Left and Right channels respectively. Without capacitor 59mV and 106mV !

Both run off the same power supply of +/- 35 volts with 2x 10,000uF on each rail.

Maybe I should run the LM3886 in NI mode and then compare.
Leaves scope for more experimentation.

I have some TDA7293 also . I will have to try them out also. I have two more unused boards for comparison.

Right now the non-inverting TDA7293 sounds more 'attractive' than the LM3886 in inverting mode.
Better HF extension but lighter in bass than the LM3886. However the LM3886 seems a bit smoother with complex sounds , especially in mid range.
The TDA pcb could have a better layout . I will have to build an improved board and then compare again. Meantime the LM3886 will have to be converted to non inverting mode.

Do I need to burn in the amp ? Maybe. Will run it a few days before comparing it again.
Cheers.
 
I tried the LM3886 in NI mode with same type parts as used in the TDA7294 . There are small differences but both sound good.

I did not find the TDA7294 sounding 'warm' as some have reported.
The LM3886 seems to be easier to find in my market ! The TDA7294 used to be cheaper . Why ? Less demand ? I would assume the die size might be somewhat similar (?).

Edit: I might add that I found the inverted mode LM3886 sounds as if the HF is rolled off a bit. The treble lacks a bit of bite that I find in NI mode. In a Ninv-T feedback mode it is worse.

Anyone else find this ?
 
"................To me TDA was a bit more powerful with same supply as LM............."

Absolutely ! This might draw a lot of flack. But the difference is not just mild ! The 3886 lags far behind here.
I might add that it is also VERY sensitive to implementation.
 
Shock ....horror.....!
Today I checked the distortion vs output curve of the TDA7294. It's nowhere as flat as the application manual. It isn't as low either. The LM3886 seems closer to the application note.

I suspect it could be due to the pcb of the TDA7294 . I picked it up from the local market and I didn't like the way some tracks were done. But it does sound good even with all that !

I tried a 6922 cathode follower ahead of the TDA7294 . It killed the 'transient bite' that was so attractive. However it was still musical.

I see lots more experimentation ahead !

:D
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.