a.palfreyman
pfm Member
Yes, current output so no voltage swing on the opamp input, but uses I/V via OP27 opamp so pin 6 of each opamp should have voltage swing on them.Hmmm - then maybe not the DAC itself. Muffled doesn't sound right, but to be sure you could provide a link to a WAV file and we could check? If you have a meter, start checking voltages around analogue output stage. If you have a scope you can also use that to trace signals out of DAC into first opamps (can't remember if you'll get a signal on audio out of DAC, it's current output so a very low signal. I assume you have a service manual?
OP: Worth checking voltages on TDA chip. As a rough and ready measure you can see if there is any ac on these using your voltmeter: use DC setting to measure the DC volts, then on AC setting to check for gross ripple if you don't have a 'scope. Pins 27 & 28 are +5V, pin 26 is-5V and pin 15 is -15V
Hope this helps.
AP