![]() ![]() ![]() Frequencies above 1/(2*PI*RC) are NOT volume attenuated normally but rather per the "taper" resulting from "added" resistor (R) being in parallel with the "upper" portion of the volume potentiometer. The schematic and layout diagram hint at transformer redesign. Some notes Ive gathered, so no credit to me other than cut and paste: Capacitors (680pf-.0015uf) + RESISTOR (100k-300k) The cap allows some of the high frequencies to pass around the volume pot direct to the output and the resistor limits the amount of them that get past. R the resistor value in ohms, C the capacitor value in farads and (pi) 3.14159. SERIES RC treble-bleed circuit: here, the "added" resistor (R) and capacitor (C) are connected in-series across the volume pot, so the volume potentiomenter "acts" normal for bass- and mid-range frequencies however, at some high frequency, the "added" cap "shorts" the "added" resistor across the "upper portion" of the volume pot causing it's volume setting to "appear" higher (ie, more volume).but, this variation "changes" with the volume pot setting.ie, LOT's of effect at LOW volume settings and LITTLE effect at HIGH volume settings. Perhaps the engineers at Fender decided at some point to design a double-duty transformer, one that could supply the needed voltage for a Champ with a 5Y3, but with sufficient current to supply a Princeton and the increased voltage output from its GZ34 rectifier. Its been a closet queen for the last few years, I had originally bought it to play an electric mandolin through and then forgot about it. Has a beautiful clean and warm tone and sounds much bigger then its size. Its a tweed w/ a 6' speaker and made in the 50s. Frequencies above 1/(2*PI*RC) are passed through with NO volume attenuation. 1 Looking for some info/opinions on an old much neglected amp of mine. Technically, it's called a "high-frequency SHELVING circuit" because it causes the highs (and ONLY the highs) to be passed through at a higher volume than ANY of the bass- or mid-range. Hey guys, I am testing the speaker knowledge here. However, for the higher frequencies, the "added" capacitor (C) "shorts" across the added resistor, making the volume pot "act" as if it's at full volume. Linear "taper" is 10% rotation = 10% of resistance, 50% rotation = 50% resistance, etc. PARALLEL RC treble-bleed circuit: the "added" resistor (R) is ALWAYS in the circuit, so it affects the "taper" of the potentiometer, ie: how much resistance per unit of rotation. The headphone signal which is centered at 1.65V leaves the audio codec, it goes into the capacitor that removes the DC Offset, there is then a resistor afterwards which serves to charge the capacitor on power up to remove the pop when headphones will be plugged in and out. ![]()
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