Electro-Harmonix Doctor Q Envelope Follower Demo

Welcome to Perky's Analog Gear Demos. Please subscribe for more demos of vintage & rare effects pedals!

This is the Doctor Q - an envelope filter by EHX from 1977. Think of it as a very basic Q-Tron. It's very simple and only has two controls: a range knob & a bass switch to remove your clean signal from the effect.

Certainly not the most versatile auto-wah in the world, but I think it's very cool.

Aren't envelope filters fun? Comment below!

Guitar is a Fender Strat through a Cornell Romany Plus (recorded with an sE Electronics RNR1 Ribbon) and a Hughes & Kettner Puretone (recorded with a 57)

[MFHLA]

A classic pedal, unmatched by current envelope filters! Note that active pickups tend to push this pedal too hard, resulting in a lot of high frequency noise at most points in the sweep range. Single coil passive pickups work "best" with this pedal. I also agree with the commenter who noted that single string riffs, or just a few strings at a time, provide a very satisfying experience compared to playing full chords.

[chriswatson]

I used the "external in" jack on an old Roland sh01 and used the frequency oscilators 2 sliders (frequency and feedback, I think) to get a really good envelope follower. It reacted to volume ie. How hard you played. And if you let it balance right on feeding back you got the best "Hawkwind" sound. In the studio it was like mixing in star wars blaster shots into your solo once you got sea legs with it

[markhammer]

Actually, the Bass/Normal switch reconfigures the filter to a different *type* of bandpass form, and does not add any dry signal in either position. It only sounds like that because the "Bass" setting moves the sweep towards a lower range. There is a trimmer inside on the circuit board. Although it is there to adjust for optimal response from the transistor in the circuit, to a limited extent it can be used to "tune" or customize the sweep range, not unlike the way one can "tune" a wah pedal by moving the foot-controlled pot over a gear tooth or two in this direction or that. I own an original big-box Dr. Q and have made myself multiple clones. A nice simple and fun circuit with lots of possibility for interesting mods.

[Datanditto]

In every review the player is slamming the strings with incredibly way too much velocity. If you can get your meat hooks to play softer it will close and work over a much wider frequency range.
ALSO better on single note grooves rather than slamming full 6 string bar chords—> use a wawa for chords.
You all miss the point of the envelope filter.🙄

[SNALCAIN]

You find some of the absolutely coolest old stuff. Nice!

[thepricillove]

Oh my I remember those guys back's in the 70's. One of those a phase shifter a good fuzz box and a wah pedal is all you needed. Oh that and a LOUD fender tube amp. You could cover most top 40's stuff. Now all you need in the 2020's is a had yard of distortion pedals. Forgive them Roger Troutman for they know not what they do.

[petezy]

definitely saving up for one! thanks for the cool demo :)

[bass]

Sounds like Donald Duck trying to whistle and sing a guitar part at the same time

[marekw]

Hey man! Cool demo. I just buy same pedal and I don't know if it takes 9v or more. What power supplier I need?

[joeyskar]

It sounds like someone swishing Scope and trying to whistle at the same time.. Mu-Tron did this effect right.

[TonyLovell]

I had this baby. When you are 14yo and don't know how to play the guitar well (or even how to overdrive an amp), this sort of schlock was indispensible.

[ivanm]

duuude… try playing single notes with it… chords not cool as an example