Point 2 Point (no PCB) for TDA7293, TDA7294, TDA7295, TDA7296.

[simply14prem]

I have to report that the discharge imbalance has started again..I might be having some defective parts.Daniel do you have any other good dual secondary psu schematic?

[danielwritesbac]

Sorry, I don't have any power supply designs made for using bad caps, so just simply replace any defective parts.

But I do have some questions:
Did you add adjustable snubbers to the secondaries like we discussed previously?
Do you have alloy transformer hookup cables from transformer to bridge rectifier?
Do you have the bridge rectifiers on the power supply board, per the schematic?
How much voltage discrepancy in the DC power?

[simply14prem]

It's happening with load.The left speaker has a bit lengthy wire ,,so it has some unequal load resistance from right speakers.

[danielwritesbac]

Transformer or bridge rectifiers.

[martin martinez]

hey mr daniel!
i´m building a 7293 in bridge config.,
as by the 7294 bridge mode, but using your
rc values; my question is: the resistor from
IC1 out to IC2 neg in, should be 60k too?
the transformer is a 25-0-25 125VA
and 4700uFx4 any comments?
thanks for your postings and your time
and attention.

martinnez martin
uruapan michoacan

forgot to say its going to replace burnt amp
and ps board from an amplified speaker.

[danielwritesbac]

Hi Martin,

Originally Posted by martin martinez

hey mr daniel! i´m building a 7293 in bridge config., as by the 7294 bridge mode, but using your rc values; my question is: the resistor from IC1 out to IC2 neg in, should be 60k too?

Yes, a "bridge resistor" is same value as your feedback resistors. The simple bridge method works okay for making a guitar amplifier.


However, you could have a look at the OP275 datasheet, find +15v and -15v regulators, and then try a high quality bridge adapter:

Originally Posted by martin martinez

the transformer is a 25-0-25 125VA. . .

I'm currently building a power supply that could help this. I was almost done, but the soldering iron quit working.

[martin martinez]

i have a little doubt: my xfrmer is from another amplified spkr,
25-0-25 i have dual bridge rectifiers and 4x4700uf. it was used
with single rectifier and 15000 x2 caps to feed 2 lm3886 bridge
for lo freq and another 3886 for hi freq.
Since i want to use fullrange amp for 8 ohms spkr wpassive xover,
what doyou recomend with that ps?
Its 25-0-25 125va dual rect and 4x4700...
My doubt is about what would fit better either single or bridge
3886 or 7293; any sugestions?
thank you very much
for your reply
martin martinnez
uruapan michoacan

[martin martinez]

Originally Posted by danielwritesbac

Hi Martin,

OP275 datasheet, high quality bridge adapter:


.

can use ne5532 more easily available here, or another choice?
so that way of bridgin with the feedback res its not so good?
Then i have to use opamp brdge adapter?

this speaker has integrated mic line pre,eq and usb-card mp3player
then i can use gain 29x?
i´ll change my res and caps for feedback

[martin martinez]

excuse me if to much posting;
what is your time zone, so i´ll
try to not bug much at wrong times
or right times either!

[danielwritesbac]

See also Rod Elliot's site, and alternative schematic with TL072. Bridging Adapter For Power Amps