elskardio
Well-known member
According to That’s design note, the gain trajectory vary depending on the reverse pot tolerance.abbey road d enfer said:
That 1512 gain adjustment driving me nuts!
- Thread starter elskardio
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Read again:elskardio said:According to That’s design note, the gain trajectory vary depending on the reverse pot tolerance.
"Eigure 3 shows how the decibel gain of the circuit of Figure 2 varies with pot rotation using a 1510 and various 10 kΩ pots for RGV. The pots are all reverse audio (log) taper, usinga two-segment piece-wise linear approximation to the log function; the tapers vary from2.5% to 20%. "
Not tolerance, taper The graph shows clearly that C2.5 gives the smoothest law.
elskardio
Well-known member
abbey road d enfer said:
Oops... my bad. Thanks
ETrop
New member
Yipp, correct always following the THAT design notes. In this case a 100ohm instead of a 5k poti, does the trick.
Next weeks i will test een a few THAT based designs RIAA pre-amp and Mic pre-amp. I will post the results.
Next weeks i will test een a few THAT based designs RIAA pre-amp and Mic pre-amp. I will post the results.
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Newmarket
Well-known member
From someone who worked at P&G last century albeit across the corridor from the pot / fader production. In production Accuracy for Audio taper (near Log but not quite) is only considered critical down to -40dB. Beyond that the emphasis of on offness. Similar applies to others eg OMEG.
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Note that the THAT1510/12 are not the best choice for a moving magnet phono cartridge.
These chips have an OSI (Optimum Source Impedance) of about 1kohm.
A typical MM cartridge has an impedance of about 8kohm at 3kHz. The conribution of noise current becomes excessive in the area of audition's maximum sensitivity.
