Mic, Line, EQ... Preamps

[mathez]

hi mile,
i have made thiss amp
DSC04886.jpg,
sound good,the PSU 20Vac/5A..but when volume pot fully opened ,.the final TR(tip142+tip147) very hot,and less than 1minut,tip142+tip147 got damaged.why?

[smartx21]

Maybe someone finds this useful:
2 Speed Fan Controller
Regards,
Max.

[apexaudio]

Originally Posted by mathez

hi mile,
i have made thiss amp
Attachment 199366,
sound good,the PSU 20Vac/5A..but when volume pot fully opened ,.the final TR(tip142+tip147) very hot,and less than 1minut,tip142+tip147 got damaged.why?

TIP142/147 must have heatsink.
Regards

[apexaudio]

Measure TP1,TP2 voltage, must be about 10mV for 20mA BIAS

[rakesh_sharma23]

Originally Posted by apexaudio

This simple x-over work in range 20-100Hz, if you need this low pass instead 80-250Hz you can just use pot 2x50k instead 2x10k and sound will be same.
Regards

I have tried 50K pots but no improvement.. Even replaced the TL IC with two new ones, both purchsed from different vender... Still bass is not low as with the Lowpass circuit.

If any one else can try it.. may be all TL ICs can be faulty..

Waiting for reply from members...

Rakesh Sharma

[sudhir kumar]

Hi apex,
Please post a simple stereo 3way active crossover.

[rhodrich]

hi apex,

do you have pre-amp buffer that can drive several b500 amps of your? same us 1 input with 8 out.

thanks

[engel dela pena]

Originally Posted by rhodrich

hi apex,

do you have pre-amp buffer that can drive several b500 amps of your? same us 1 input with 8 out.

thanks

b500 have balanced input,you can use parallel balanced input,(or through)
apex just confirm if it is ok up to eight?or need new buffer for eight?

[apexaudio]

Originally Posted by engel dela pena

b500 have balanced input,you can use parallel balanced input,(or through)
apex just confirm if it is ok up to eight?or need new buffer for eight?

In PA is usual to use active x-overs with amps, and there is output buffers on each channels.

[engel dela pena]

can you please share this buffer ckt.