preamp and tone control circuit with pcb

[john g]

hi all
can anyone pls help with a preamp tone control circuit with pcb layout? iv built the tda 1514a as per data sheet with the tda 1524a tone control as per data sheet and as soon as i turn up treble or bass sounds crap i have tried two versions of the tda 1514 amp and the same preamp still no good i think the preamp is my problem. any help pls.
txs
john

 

[Mark.Clappers]

Do you have a scoop to look at the output of the tone controll / amp? maybe you are clipping either when you turn up the gain.

 

[pinkmouse]

Thread moved to appropriate area.

 

[Mark.Clappers]

Another way to check if it is clipping due to gain; If you turn down the bass / treble controlls does it distort?

 

[john g]

hi mark
yrs ago i orderd a cmoy headphone amp and i disconected the tda1524 and put the cmoy as preamp crystal clear sound the tda1514a amp seems perfect i need a descent preamp tone control or maybe i should change comp in the tda1524 but im looking for a baxendall circuiy pcb so i have been advised from goories here
txs john

 

[KatieandDad]

I'm not familiar with these chips but I've just looked at the datasheet for the TDA1524A.

It appears to have a volume gain of approximately 20dB and bass and treble gains of 20dB.

At full volume and full bass it will be producing 40dB of gain at the centre frequency of the bass roll-off point.

Depending on the power supply you are using - I suspect 15V, the TDA1524A will start to clip with an input of greater than approximately 0.5mV.

Please correct my maths if they are wrong but your problem is almost certainly due to clipping.

 

[john g]

hi katie
i c u also a dog lover love my dogs,anyway i am gonna redo the preamp tda1524 using diff caps i used cer multi layer im gonna try prop and change some values as the schematic i used said as per data sheet (not true) but after i read ur post an checked the data sheet just tell me what caps i should use please
txs
john

 

[KatieandDad]

The caps aren't the issue here. Yes you can improve on what you have.

The problem is that at full tilt the TDA1524A just cannot produce the signal that you are asking of it - ie it maxes out and clips.

For an experiment just try wiring a pot at the input to reduce the input voltage.