You should grab another one and go BTL, or try a hand at a dual supply design, but that would complicate things a bit more.
There's a big thread about this chip
http://www.diyaudio.com/forums/showthread.php?s=&threadid=82953&highlight=
http://www.diyaudio.com/forums/showthread.php?s=&threadid=82953&highlight=
TI's webpage offers tpa3122d2 in a
20pin DIP.
15W+15W, bridgeable... PDF seems
to suggest 40W into 8ohm 28V BTL
is quite reasonable.
Around 4 bucks last I looked, I dunno
which distributor or shipping to use...
I would suggest solder to a PCB with
a heatsink worthy ground plane.
The DIP boards I have worked with,
did not use a socket. I suspect that
decision to solder was intentional.
http://focus.ti.com/docs/prod/folders/print/tpa3122d2.html
I've never tried MPS, I could not compare.
And to be fair, I rarely ever crank the
power supply past 12V unless a test
procedure calls for it. Its just too loud.
20pin DIP.
15W+15W, bridgeable... PDF seems
to suggest 40W into 8ohm 28V BTL
is quite reasonable.
Around 4 bucks last I looked, I dunno
which distributor or shipping to use...
I would suggest solder to a PCB with
a heatsink worthy ground plane.
The DIP boards I have worked with,
did not use a socket. I suspect that
decision to solder was intentional.
http://focus.ti.com/docs/prod/folders/print/tpa3122d2.html
I've never tried MPS, I could not compare.
And to be fair, I rarely ever crank the
power supply past 12V unless a test
procedure calls for it. Its just too loud.
The MPS7720 Amp arrived, 6 days from Hong Kong to NJ....Not bad...
It sounds nice right out of the box, smooth and tight with none of that 'new chip' harshness. It has plenty of punch on 14V and I'll let it burn-in for a while.
The only issue I've found is a really odd Cap discharge sound when turned off...Kind of Ray Gun like.
No big deal, but it would be nice lessen it.
It sounds nice right out of the box, smooth and tight with none of that 'new chip' harshness. It has plenty of punch on 14V and I'll let it burn-in for a while.
The only issue I've found is a really odd Cap discharge sound when turned off...Kind of Ray Gun like.
No big deal, but it would be nice lessen it.
I notice that when you click the "buy" button on Monolithicpower's website, you get routed to Avnet USA as the vendor, and as a non US person (New Zealand) I'm very wary of playing the "Shipping will be calculated on despatch, just give us your credit card number" game of Russian roulette. Has anyone bought these (or indeed any other chips) from Avnet this way, shipping to a non US address, and how were the shipping charges. FFS Microchip Direct can work it out, why can't these guys.
Cheers
M
Cheers
M
Hi,
I just received 2 board from Sure Elec.
I have also noticed a cap discharge sound when turned off...Kind of Ray Gun like.
The Av gain is set too low so when you crank up the amp it creates some weird distorsion artifact. Based on the schematics I received from them (and the actual components on the PCB) the gain is set to 8.2 which is quite low compared to the T-Amp by sonic impact set at 21.6 or the one from Sure Elec. (TA-2024) set to 12.
f3 (input) is set at 16Hz and f3 (output) is set at 42Hz via the 470uF driving an 8 ohm load.
The sound is quite good and will be even better when I increase the gain to about 16-18 to avoid these nasty artifact spike.
It's too late now to give it a try but if anyone is interested I will report back. By the way the IC is surface mount type and not DIP8.
Regards,
Eric
I just received 2 board from Sure Elec.
I have also noticed a cap discharge sound when turned off...Kind of Ray Gun like.
The Av gain is set too low so when you crank up the amp it creates some weird distorsion artifact. Based on the schematics I received from them (and the actual components on the PCB) the gain is set to 8.2 which is quite low compared to the T-Amp by sonic impact set at 21.6 or the one from Sure Elec. (TA-2024) set to 12.
f3 (input) is set at 16Hz and f3 (output) is set at 42Hz via the 470uF driving an 8 ohm load.
The sound is quite good and will be even better when I increase the gain to about 16-18 to avoid these nasty artifact spike.
It's too late now to give it a try but if anyone is interested I will report back. By the way the IC is surface mount type and not DIP8.
Regards,
Eric
e_fortier said:
I have not had good results with these Sure Elec amps
This is what I got with a 24 volt supply and an 8 ohm load
An externally hosted image should be here but it was not working when we last tested it.
The thing LOOKS competently laid out and they are claimed to
be tested.
M
mobyd said:
The amps I made with the MP7720 used split supplies (+/-12V rails) and I never saw what your picture shows as the amp output. I tested them hard too, clipping into 8 ohm and 4 ohm loads and the chip got so hot I couldn't even touch it but the output was just a clipped sine wave. That could be the result of a problem with a component in the boost cap circuit.
Hi,
I have just finished to modify a Sure Electronics PCB that comes with 2 x MP7720 (7 USD + 5 shipping Intl) it is cheap fun for $12 USD
From a +18Vdc, 5A power supply I get 20W rms into 7.5 ohm just before any sign of clipping on the scope.
Modifying the unit is quite simple, a few component to remove, bypass the output cap and 2 x 2pF cap to add in the pre-filter feedback loop. I had the schematics for the PCB and thanks to BWRX I was able to synchronize both amp by looking at MP7731 IC, Thanks !
I'm missing the cap connected to the load, how do you calculate that one...
Regards,
Eric
I have just finished to modify a Sure Electronics PCB that comes with 2 x MP7720 (7 USD + 5 shipping Intl) it is cheap fun for $12 USD
From a +18Vdc, 5A power supply I get 20W rms into 7.5 ohm just before any sign of clipping on the scope.
Modifying the unit is quite simple, a few component to remove, bypass the output cap and 2 x 2pF cap to add in the pre-filter feedback loop. I had the schematics for the PCB and thanks to BWRX I was able to synchronize both amp by looking at MP7731 IC, Thanks !
I'm missing the cap connected to the load, how do you calculate that one...
Regards,
Eric
Required mods to get bridge amp from MP7720 of Sure Elec.
Hi,
While I do a nicer copy and scan the document, here are the required modifs.;
Remove the following components;
1. R2
2. R4
3. C5
4. R10
5. C14
6. C19
7. R7 and R13 (Zobel)
Bypass the following components;
8. C8 and C21 (output cap)
Add the following;
9. 0.68uF in parallel to the load (8 ohm min.)
10. 2pF film cap. from pin 7 (output) of U1 to pin2 of U2
11. 2pF film cap. from pin 7 (output) of U2 to pin2 of U1
12. small wire from pin 1 of U1 to pin 2 of U2
13. small wire from pin 2 of U1 to pin 1 of U2
That 's it, now Left input is the + audio signal and Right input is the
- audio signal (gnd)
Connect the loudspeaker between both speaker + terminals.
Enjoy
Regards,
Eric
Hi,
While I do a nicer copy and scan the document, here are the required modifs.;
Remove the following components;
1. R2
2. R4
3. C5
4. R10
5. C14
6. C19
7. R7 and R13 (Zobel)
Bypass the following components;
8. C8 and C21 (output cap)
Add the following;
9. 0.68uF in parallel to the load (8 ohm min.)
10. 2pF film cap. from pin 7 (output) of U1 to pin2 of U2
11. 2pF film cap. from pin 7 (output) of U2 to pin2 of U1
12. small wire from pin 1 of U1 to pin 2 of U2
13. small wire from pin 2 of U1 to pin 1 of U2
That 's it, now Left input is the + audio signal and Right input is the
- audio signal (gnd)
Connect the loudspeaker between both speaker + terminals.
Enjoy
Regards,
Eric
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.