Quote:
Originally Posted by Rich400
Quote:
Originally Posted by Edward Huggins
As well as "Trim", the OP is using other words/phrases that I do not understand.
What does "Conditioning" and "RIAA Bias Adjustment" mean please?
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Hi Edward
Conditioning is applied to a signal this refers to changing the characteristics of it.
The RIAA signal from the cartridge has a bias towards mid/higher frequencies. That is when RIAA standard was applied at the recording stage, the bass component was minimised to permit shorter track length. The amplifier in my SRG600 is expecting in its original EXT input this type of signal, so when a full range signal is applied the output sound would be incorrect. To enable the amp to work correctly the signal has to be ‘conditioned’ through high snd low pass filters (Bass and Treble for you) this adjusting the RIAA bias.
It’s nice to give something back to you Edward again, if there’s anything you don’t understand just ask.
Regards
Richard |
The amplifier in your radiogram is not "expecting" an "RIAA conditioned" signal.
The RIAA "conditioning" (or "deconditioning", I suppose) is performed by the way the ceramic cartridge works in combination with the 1 megaohm resistors. After that the now "conditioned" signal is fed to the grid of the first ECC83 valve which amplifies it so as to overcome the losses in the treble and bass tone controls, then to the second triode of the ECC83 for further amplification and negative feedback from the output transformer, then to the phase splitter and finally to the push-pull output stage. You need to input your external line stage after the two 1M resistors but it might overload the first triode of the ECC83 so you probably need to attenuate it somehow.