STANDALONE REVERB - TREMOLO Latest project is nothing really new or original, basically a combination of long-established circuits that have worked, and been modded, for years. The primary goal is to come up with the least cost-effective and least effort-efficient pedal board in the history of music. As a secondary goal, these are the effects I would most like to have for the effects loop of my Trinity TC-15 amplifier (roughly similar to a Vox AC-15). Parts: 1. Fender harmonic vibrato (tremolo). This is the 5-triode version which has been suggested as easier to de-bug and tweak. Also, the design as a whole came out with an even number of triodes. 2. Fender spring reverb (mostly taken from AB763 deluxe reverb, with some fairly well-known mods. Except the reverb tone control, which I've only seen one other place. I sure do like reverb tone control though. Ideally I'd like it to be super-bright to start with, and be able to dial down the brightness as needed. I have a MOD 3-spring and an Accutronics 2-spring tank both on hand (both long tank) Both of the above are lifted from circuits that go post preamp, pre phase inverter - and I'm going to use them in an effects loop (it's buffered if that matters) 3. Marshall cold clipper tone stack into EF86 preamp - this will take an instrument input, not a signal from the effects loop send. I know it won't sound like a Marshall, but I do think (hope) I'll get a nice asymmetric distortion from this. I love my TC-15 for everything except super high gain tones; this is an effort to fill that gap. High res version is in an attachment. Questions: 1. I've got some components with values "TBC" - to be calculated. The values of voltage-dropping resistors are tricky because I don't know what value to put in for amps. I did add up all the heater currents for all the tubes - and there are no power tubes - so I think the rest of the draw will be trivial? Also, when the heater current is quoted for a 12AX7, is that for the whole tube, or just one of its component triodes? 2. I know all these circuits have worked in other applications, but not confident in how I have put them together. Would appreciate any input about how I've connected the dots. 3. I'm aware of the ground loop issue. My idea for this was to use 1:1 isolator transformers in both places where a signal goes to or from another amp (shouldn't make a difference on the instrument input). I've never known of anyone to do this for guitar amplifiers, but it's an established practice in the audiophile world. I found some 1:1 transformers from eBay that are 136 ohms and 290mH, 800:800 winds. Would also appreciate any input on this. PS, I'm also planning to use insulated jacks wherever ground isolation is required. So appreciate the experience and expertise here, and appreciate anywhere you see I am about to put my foot in a bucket! PS - I haven't labelled the tubes v1-a, v3-b, etc.