The Almighty MarK G-EQ

[Zorshelter]

Hi! I really like the Eq on my mark IV and was wondering if a similar EQ (same specs) was available on the market on any form (pedal rack...) tthanks

 

[Sebby123]

Maxon EQ is a great one! Make sure you put it in the loop.

 

[Elpelotero]

There's really nothing out there aside from a high quality parametric EQ.

 

[Zorshelter]

Thank you, what I really like with this Eq is that it's fairly simple and I can shape the tone as I want, I also have a 10band Mxr Eq but it gets harder for me that's why I'm looking for an Eq acting on the same frequencies....

 

[Zorshelter]

Just had a quick look at tha MAxon EQ and the frequencies seem well choosen the 800hz must be close to the 750hz of the MarkIV...

 

[Facelift]

Furman PQ-4.

thread/

 

[Zorshelter]

Thanks for the tip I'll have a look at this one

 

[mr_fender]

You can find the schematic for a Mark series amp online and try copying the EQ section. It's a transistor based circuit that uses caps and inductors in each band. Those inductors would likely be the tricky parts to find and match up. Also, it runs at something like -40V for more headroom to handle the much larger signals in the tube path, but it could be scaled down to the usual 9V or 18V of pedal EQ's. It's feasable, but it would probably be easier to just tailor an existing EQ pedal to the correct frequencies with a few resistor and capacitor swaps. All the Boogie GEQ's are centered at frequencies 80Hz, 240Hz, 750Hz, 2200Hz, and 6600Hz. I'm not sure of the exact "Q" (bandwidth) for each band, but it the bands are at approximately 3 octave intervals. I'm sure that the rest could be calculated from the schematic also. Could be a fun little project.

 

[Zorshelter]

Thank you very much, It's way beyond my knowledge I hardly know how to solder properly but it would be the best alternative

 

[stephen sawall]

What makes the Mesa EQ better than the others is the over sized capacitors.

Most of the other EQ's mentioned here sound like crap when A/B ed with the Mesa EQ.

 

[Philhouse]

Mr fender,

Can you tell me what the sliders are pushing/cutting dB-wise ? ie how much is full slider up boosting. I only have a GE-7, but I've always wondered what the Mark EQ boosts to ? GE-7 does +/- 15dB.

thanks very much,

Phil.

 

[mr_fender]

Based on spice simulation of the circuit, the numbers I get are approximately these:

80Hz Slider - Peak Center is 85Hz and range is +/- 16dB
240Hz Slider - Peak Center is 368Hz and range is +/- 16dB
750Hz Slider - Peak Center is 726Hz and range is +/- 15dB
2200Hz Slider - Peak Center is 1626Hz and range is +/- 11dB
6600Hz Slider - Peak Center is 5024Hz and range is +/- 11dB

Now these measurments were taken for each band individually. The actual response of the sliders overlap a bit and are very interactive since each band is not individually buffered. Modern IC based EQs allow for much more precise and individual boost/cut of frequencies. Older RLC filter designs like the Boogie EQ are a bit more finicky. Take these numbers as a general guide. Spice simulation is usually pretty close, but due to component tolerances and other variables, the end result is usually a tiny bit different.

 

[Philhouse]

Very thorough and interesting !

Thanks very much.

 

[Zorshelter]

Thanks Mr Fender, these numbers can be pretty useful

 

[stephen sawall]

Based on spice simulation of the circuit, the numbers I get are approximately these:

80Hz Slider - Peak Center is 85Hz and range is +/- 16dB
240Hz Slider - Peak Center is 368Hz and range is +/- 16dB
750Hz Slider - Peak Center is 726Hz and range is +/- 15dB
2200Hz Slider - Peak Center is 1626Hz and range is +/- 11dB
6600Hz Slider - Peak Center is 5024Hz and range is +/- 11dB

Now these measurments were taken for each band individually. The actual response of the sliders overlap a bit and are very interactive since each band is not individually buffered. Modern IC based EQs allow for much more precise and individual boost/cut of frequencies. Older RLC filter designs like the Boogie EQ are a bit more finicky. Take these numbers as a general guide. Spice simulation is usually pretty close, but due to component tolerances and other variables, the end result is usually a tiny bit different.

Thanks for the info.

http://www.5spice.com/?referrer=GoogleAd5&gclid=CObKrOz81ZoCFSMSagodYDEJ2w

What can you tell me about this ?
I am very interested.
Can you build your own Axe Fx here ?