ElecTech

Correct - there is no loop issue for "normal" loop users, or those who do not use the loop at all. But the published 1M loop return impedance is only true for DC measurements. For any audio frequency (AC) the input impedance will drop as the freq is increased. At 800Hz the effective input impedance of the effects return is ~100K Ohms. Still high enough for most effects units, but 10 times lower than the published spec.. At 80 Hz the return impedance will be ~500K Ohms. At 2KHz the input impedance will be ~40K Ohms. At 5Khz it will be ~16K Ohms. A 10:1 impedance ratio is considered the minimum for modern connections, so @ 5Khz the output impedance driving the effects return must be 1.6K or less. But at 10KHz this figure is halved again: 8K:800 Ohms. A far cry from the published 1M Ohm spec. This is exactly what is happening on the Guitar input also, but the impedance figures are double because the capacitance is half as much. I don't know how the 360K Ohms @ 1KHz figure was measured, but personally I think it is optimistic. My calculations, derived from the values published in the Pod Go schematic, put it @ ~137K Ohms.

wagdog - You're welcome. ;)

LINE 6 PodGo Treble Loss @ Guitar Input The problem with the treble loss at the input jack is that Line 6 connected a 1000pF (.001uF) cap (C124) from tip to ground at the input jack. This combined with your pickup's impedance and the series resistance introduced to the signal when you turn down your guitar volume creates a filter that cuts off the treble at a frequency that drops as the impedance (resistance) is increased. So the more you turn the volume down the more treble is cut off. But it's not just the Input jack, the same thing happens on the effects returns, only on those inputs there are TWO .001uF caps to ground, or 2000pF from each return (L/R) to ground. If you want to run a standard volume pedal within the loop, which is something I have always liked doing, the treble drop is even more severe than at the guitar input jack. The part that bothers me is: No other pedal in the Pod or Helix line has this kind of heavy filtering on its inputs. I would love to hear from Line 6 as to why they felt it was necessary to employ brute-force filtering on this model and not on any others. Was it a band-aid to a poor design in order to keep interference from the processor clocks at acceptable levels? Was is an engineering error, where they meant to spec 10pF caps and instead spec'd 1000pF? As a technician and a guitarist who owns a PodGo, I would love to get a real answer to this, as well as to what might happen if I remove these caps from my unit, besides voiding my non-existent warranty. The offending treble cut caps are: Guitar Input: C124 (.001uF/1nF/1000pF) Effects Return 1: [Tip] C121 & C135 (.001uF) Effects Return 2: [Ring] C110 & C129 (.001uF)