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iCebReakEr409 7th August 2002 07:05 PM

PA Amp with TDA 7293...Questions...

I'm new here and I've got some questions:

Some time ago I bought this power mixer (2x150W @ 4Ohms; Bridged 1x300 @ 8Ohms):

Well, the whole amp (not the pre-amp) got destroyed and i tried to fix it (all 8 power transistors were destroyed and some other parts) but i had no luck - it's kinda hard working without the original schematic and a lack of original parts.

So I thought about creating my own amp (of course, i'll keep the preamp and mixer) as i dont wanna pay too much for reparing. since the heat sink had holes for 8 transistors i could easily install TDA7293s instead.

So this was my idea:
- Change the transformer (2x40 ~ V is too much) and replace it with my 2x30 V ~ . Is the voltage low enough ?
- I first only want to build one channel using 4x TDA7293 (4 parallel and bridged (2 and 2)) - How much power can I expect ? It will be more than original 150@4Ohms, right ?

I'm not big amp expert, so i thought this would be a kind of easy solution ? What do you think ?

Thanks :) .

PS: Some electronic parts store (germany) offers TDA7294V and TDA7293 (without "V") - does such a without-V-version exist at all or can i expect it to be the TDA7293V ?

djdan 7th August 2002 09:03 PM

TDA7293 it is a very good circuit, but in this case it is not the best option . You can make an amplifier with two STK4048 and you can use original transformer. It would be cheaper solution. Try to make a search on this forum and you will get many topics about STK4048. I know a pro-amplifier with STK4048 [ 2x200w/4ohm ] wich is runing for 5 years every night in a small nigh-club.

Herman 8th August 2002 12:09 AM

Right, the STK series is good and quite convenient to use. But you have to be careful about the heatsink. The hybrids dissipate a lot of power, so take care to have a big enough heatsink or use fans. You can easily burn your fingers at the heatsink (my experience!).
If necessary, you will find a lot of data sheets at

Good luck!


P.S. In Germany, most of the circuits can be obtained at Reichelt electronics, check at

lohk 8th August 2002 01:30 AM

I would suggest the "UB" way.

You get all the necessary information and the parts (in german, also pdf) from SCHURO
and from the constructors site

The TDA7293 is kind of tricky for newbies, so be careful with bridged - or better - paralleled versions.

At the Audiomap forum
under "Selbstbau-Elektronik" you will find guys who have already gained lots of experience.

hope that helps

iCebReakEr409 8th August 2002 07:10 PM

Thanks for the information.

Looks like Reichelt ( doesn't have the 4048 any more (Yesterday I found the V version, but not the XI) - Today the only thing >4044 I found was the STK 4050 V. Is it any good ?

And the TDA 7293 is available.

I guess I have to replace the transformer anyway cuz it is probably not power enough for a more powerful amp. And I have a 2x30V ringcore transformer here anyway.

Well, I just want a simple, powerful and stable amp :) Some more power than the 150 W would be cool.

Dj BASS AMP 8th August 2002 09:59 PM

2 Attachment(s)
the STK4048XI is powerful then TDA 7293
and more high q..... the sound on stk4048XI batter then TDA 7293........

if u want more power :
STK4050V - 200W
LM12 (in Bridged) - 300W - very very simple!!!! to build
PA03A - 1000W the site -
PA05A - 300W

lm 12 :

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