Tonemender Stompbox as a Preamp

[blindsjc]

Hi friends,
I'm using a "Tonemender" from RunOffGroove as a preamp im my project, it acts
as a preamp for a "TDA2050" (Datasheet Project) power amp. The problem is, i got
distortion at very low volume, a really ugly clipping and worst, my "TDA2050" burned
after 5 minutes. The PSU is working perfectly and provides 22-0-22 (at 4ohms speaker).

What I need to work? The preamp input? The preamp gain? The preamp out?
Something on the amp like the input impedance? Thanks in advance.

Ronaldo

[blindsjc]

Nobody made it before me?
Please help...

[Ge_Whiz]

You did have the TDA2050 on a heatsink, I trust?

[blindsjc]

Hi Ge_Whiz,
I'm using a big heatsink. Making other tests I see that the signal
that comes from tonemender appears to be too much for the amp,
but I was waiting for more sound volume before clipping. Maybe I'm
waiting too much from TDA2050.

[d95err]

I don't think the preamp is responsible for burning the chip. There must be something wrong with the poweramp.

Give us more detail. How big is the tranformer? (I.e. how many amps can it produce at +-22V? What kind of rectifier and smoothing? A schematic would be preferable.

[blindsjc]

Hi again, thanks for the attention.
Well, the transformer is a 16-0-16 with 4 amperes.
After rectifier with a diode bridge a I get +-22v,
smoothing uses a 2200uF. Measure with multimeter
is ok.

I changed the dead TDA with a new one and everything
appears to be working, except for the early clipping.
May my Epiphone Special sending a signal too strong?

Oh, sorry about my bad english.

Thx.

[blindsjc]

Friends,
The problem is resolved,
I changed the power voltage to +-15 and all the clipping and burning
chips are gone. Everything is working perfectly. I'm sure that the
datasheet says +-22, but...

Thanks for all replies.

Ronaldo

[B Tremblay]

Great!  So the Tonemender is doing well as a preamp?

[blindsjc]

Oh man,
What I can say... It's amazing...
I'm in love with the final result, really great amplifier.
Tonemender makes it sound perfectly.

Thanks

[B Tremblay]

Very good news indeed.  How much can you turn up the Tonemender output/gain before clipping occurs now?

[blindsjc]

I start to have some clipping
using hi, mid and low at 3 hour (pointing left) and the volume at 12 hour.
The guitar is set to full volume and is a les paul special II ( 2 humbuckers).

May I add some resistor to the guitar input (in series) to decrease guitar signal
and have clipping just at 22 hour with the same equalization setup?
Whats the better way to do this.

Thanks