Midboost original "Mont Blanc"
Flexible EQ + Boost Pedal development
A new Midboost effects pedal for the working guitarist
About three years ago I had the idea to create a versatile, but also user-freindly EQ pedal.
EQ is one of the most useful effects for guitar and vintage keyboards.
I started researching circuits for EQ and relied heavily on my experience working back in the early 1990s in the R&D for SSL (the studio mxing console manufacturer).
Quickly I decided I wanted my pedal to be:
- Tough for gigging - I mean I wanted to be able to plug it into teh wrong supply or a reverse supply and it not blow up! I've seen many pieces of gear damaged during huried gig setup this way
- All analogue. Yes I know this is the digital age, AI and all that stuff, and I can design digital circuits, but there's something really nice about old-skool analogue pedals and especially analogue EQ
- Pro quality. Having worked on pro-audio designs in the past I wanted this thing to be suitable for studio use - low noise, repeatable setups, use known levels etc.
- And being pro-quality I wanted to use really good quality components for pots, switches, caps, connectors - without making the thing so expensive no-one would buy it
I decided I should have a parametric EQ and, yes, I know historically guitarists don't have a good relationship with these, but they are SO useful for tone sculpting. I looked at a few types of circuit and listed to them, finally settling on one. I decided I wanted a clean boost/cut too so I could fix a signal level (too low OR too high).
I also wanted this thing to have as few knows as possible so pretty much ANYONE could understand how to use it (that I think has been the hurdle with parametri EQs in the past - fine for sound engineers but not so fine for plain old players).
So I made a prototype which was anything but low noise, but it did work:
First prototype Midboost Flexible EQ + Boost circuit
Bench testing the first prototype Midboost Flexible EQ + Boost circuit
The first prototype Flexible EQ and Boost sounded pretty good but there were a few things I didn't like
- It had a constant buzz of background noise
- When I stomped on it it made a loud pop (lots of commercial pedals from pretty well-knwon manufacturers do this too I should add)
- The range of frequencies wasn't quite right for guitar
Back on the drawing board I made circuit mods including designing a completely new audio switching circuit using a relay to put the pedal in and out of circuit. I liked using a relay because it meant the pedal could be True Bypass.
The next prototype was built. This time I designed my own printed circuit boards. I fitted all the components myself and hadn assembled the pedal myself.
Here's the new True Bypass Audio Switcher board (I figure I will use this in all future Midboost pedal designs now).
Midboost True Bypass audio switcher board
Midboost EQ pedal audio board
This second prototype pedal went through some extensive bench tests. I won't bore you with all the details but I checked stuff like the signal-to-noise ratio, the frequency response in different modes, the THD, the noise level from the new footswitching circuit etc etc. The sort of stuff we did when I was doing pro-audio.
Probably over the top for a guitar / keyboard pedal but hey I like stuff to be right.
Some specs I measured are:
- Freq response with EQ flat: 10Hz to 20kHz +/-1dB
- Clean cut/boost: +/-15dB fully adjustable
- EQ/notch centre frequency range:
- Range Lo: 45Hz to 1.8kHz
- Range Hi: 240Hz to 10k
- EQ max boost/cut: 18dB / -18dB (some pedals measured more than 18dB)
- Notch cut (nax): -38dB
- Noise (input shorted, gain max): better than -75dBu(A)
- Noise from engaging pedal on 1kHz 0dBu tone: -50dBu
I was fairly happy with these measurements. Pro-audio would be better than this but the limitation is only having a 9V low current supply to play with.
Then the pedal went out for real testing to a couple of friends in bands for road testing. I actually built three of these prototype pedals.
I'll extend this page soon to include their (positive) comments!
Here is the finished pedal, ready for production (that means me building some :) You can see some ideas about how it can be used back on the Shop page.
Midboost FEQ-1 Flexible EQ + Boost pedal
"Can I buy this amazing pedal" Answer is "You will be able to buy this soon!"
(basically I have to build some more pedals first)
If you want to be on a waiting list then drop me a message using the link at the bottom of the Home page