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On 4/13/2015 7:44 AM, Iņigo Cubillo wrote:
> Just a question, related to tailored EQ curves, etc.
> Years ago I bought an Esoteric Sounds Re-Equalizer, a device that added
> within the chain, eliminates the RIAA from the phono stage, and adds
> whatever curve you want, among 6 turnover and 6 rolloff settings
> (independently). It worked fairly well. But one sad day the transformer
> burnt out, when connected at 220 volts with the selector accidentally set
> at 125 volts. Bye-bye to the Re-Equalizer. I cannot find replacement for
> that transformer. It is 220 volts (125 too) to twin opposite 12 v AC
> signals to feed the Equalizer cockroaches.
Assuming that nothing else in the Re-Equalizer got fried while this was
going on, you could probably get a replacement transformer from Allied
Electronics. They do sell for export, though shipping on a big chunk of
iron might be expensive, and you'd need to make sure beforehand that the
new transformer would fit into the case.
> So I then had to return to the old system I used when I did not have any
> Eq, which is to use the tone controls to lower the bass response and raise
> the treble. My question is: How do the tone controls work? Do they shuffle
> up and down the 6dB/octave ramps? Do they raise the overall level
> horizontally? Do they increase the ramp slopes? Mine is a common home use
> Pioneer A209-R (MOSFET). Not Hi-End...
The thing is, both types of tone control have been used in consumer gear
-- sliding inflection point and fixed inflection shelving.
>
> I worked out a tricky scale supposing the tone controls simply shuffle the
> 6dB/octave ramps up and down the freq scale, starting from the RIAA points,
> and moving to the left or right,
>
> I recalculated the turnover and rolloff points resulting from this
> hypothesis, for several positions of the controls, assuming also a
> logarithmic linear response. Based on the information from the manual
> specifications, which says that the tone controls increase the response +/-
> 8 dB at 100 Hz (bass) and at 10 kHz (treble). So I worked out a new scale
> for the control knobs.
> The bass control lowers the zero point from 500 Hz (RIAA, central position)
> down to 198 Hz when twisted down completely to the left, or up to 1260 Hz
> when twsted to the right. I worked out intermediate positions (supposed
> linear variations of freq with knob angle) and drawn a scale with four
> intermediate points at left and four points at right, being 198 - 250 - 315
> - 397 - 500 - 630 - 794 - 1000 - 1260 Hz. For the treble it is more simple,
> as the dB added or removed are the usual familiar numbers, so from left to
> rigth, adding the RIAA -13.7 dB we have eigth positions which are -22, -20,
> -18, -16, -14, -12, -10, -8, -6 [log in to unmask] So I made a paper scale which I
> slide over the control knobs and I use these for approximate re-equalizaton
> of 78s using only the control knobs. I have to say that it more or less
> works. The only thing is that I cannot get rid of the -6 dB@10kHz, as the
> treble cannot be raised further... Am I right or wrong?
What are you recording onto? Or are you using this setup strictly for
live listening?
Peace,
Paul
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