Unfortunately no version of the analogue Electric Mistresses does have a LED to indicate if the effect is activated or in bypass.
See the Ultimate-No-Mod how to easily add a LED to a Mistress.
Some people like to add input and output buffers to effect devices. Although the Electric Mistress already has an input buffer the Ultimate-No-Mod adds an input and output buffer.
The vintage Mistresses V1, V2, V3, V4, V5 and V6 have a lower volume level when actived. This so called volume drop can easily be compensated by the Ultimate-No-Mod.
The Deluxe Electric Mistress versions have a built in volume drop compensation which can be adjusted by the gain trim. If your Deluxe device had a volume drop, it just needs to be properly aligned, not modded.
If you want a flanging effect mixed with the unflanged signal you can apply the Ultimate-No-Mod.
O.k. here it is - the Ultimate-No-Mod. It adds a LED, output buffer, compensates the volume drop and can mix a dry signal.
I have seen so many pedals tinkered to death by inexperienced people. As long as the SAD1024 is not reproduced the vintage Electric Mistress is too precious to suffer such fate. I will not encourage anyone to mod his Mistress. But fortunately there is a possibility to 'mod' the Mistress without soldering iron or even opening the case. You just need a line switcher like the Boss LS-2:
If you want no dry signal mixed you need to set the LS-2 to "B <-> BYPASS". Set the red knob to compensate volume drop.
If you want to mix the flanged signal with the dry unflaged signal set the LS-2 to "A+B MIX BYPASS". Set the amount of dry signal with the green knob and adjust the volume by the red knob.
All Deluxe Electric Mistresses have a voltage regulation with a 78L interated circuit. No need to mod anyting here.
All standard Mistresses V1 to V6 have an op-amp/transistor voltage regulation. Compared to the 78L it is missing some protection functions like limiting and thermal protection. Due to this I reccomend all vintage Mistress owners not to replace the voltage regulation, but to add an overvoltage and reverse polarity protection similar to the Deluxe reissue.
I strongly recommend that you apply this mod only if you have sufficient knowledge in electronics. You can easily damage the BBD which is no more available as spare part which means your Mistress is irreparable damaged. Take ESD precautions.
I reccomend to get the power supply or other mods done by Howard Davis or RonSound. This will guarantee that your Mistress will keep or even increase it's value despite being modded.
Step by step instruction for the power supply mod:
- Remove the wire from solder point 'A'
- Solder a 180 Ohm 2 Watt resistor to the cathode of a 0.5 W 30 V Zener diode
- Solder the wire from point 'B' to to the solder point mentioned in step 2
- Solder a black wire to the cathode of the Zener diode
- Solder the free lead of the resistor to the DC socket ('A')
- Solder the black wire to ground 'C'