- Joined
- Mar 2, 2002
- Messages
- 4,213
Here's a classic Akai cr80dss quad player-recorder with a strange behaviour: probablyit has been pushed too loud on the amplifier stages.
First, the line out level is waaaay over the top: my soundcard can be set at -10dB or +4db as a reference level, with a possible amplification ranging from 0 to +18dB.
In order to record from the akai to the soundcard *without clipping* i had to:
1) set the soundcard to +4dB reference
2) set the amplification to 0
3) place a 22Kohm resistor on all four plug from the Akai to the soundcard; with a 12Kohm it was still clipping.
At least to me it's clear it has been pushed too much - but that's not the real problem.
The real problem is that with this overamplification, the circuit board is working now outside linearity. To be precise, if i play a very hot-recorded q8 (rca), the positive sinewave is kinda limited (shaved peaks), while the negative has peaks and valleys as expected. If the tape is recorded at more normal levels, the waveforms are ok on both positive and negative side.
Problem is, *where* is possible to regulate the amplification without screwing out everything? There are several group of trimmers on the board, but i have no idea what are the right ones to turn down.
First, the line out level is waaaay over the top: my soundcard can be set at -10dB or +4db as a reference level, with a possible amplification ranging from 0 to +18dB.
In order to record from the akai to the soundcard *without clipping* i had to:
1) set the soundcard to +4dB reference
2) set the amplification to 0
3) place a 22Kohm resistor on all four plug from the Akai to the soundcard; with a 12Kohm it was still clipping.
At least to me it's clear it has been pushed too much - but that's not the real problem.
The real problem is that with this overamplification, the circuit board is working now outside linearity. To be precise, if i play a very hot-recorded q8 (rca), the positive sinewave is kinda limited (shaved peaks), while the negative has peaks and valleys as expected. If the tape is recorded at more normal levels, the waveforms are ok on both positive and negative side.
Problem is, *where* is possible to regulate the amplification without screwing out everything? There are several group of trimmers on the board, but i have no idea what are the right ones to turn down.