buschfsu

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #140 on: February 15, 2011, 02:13:13 PM »
guys i wanted to put this meq500 into a channel strip with a mic pre so i didn't add the input transformer.  will this circuit have any issue with a normal 600ohm load from my mic preamp or do i need the input iron.  on the output side i have a carnhill 600:600.

thanks
PRR said...
OHM'S LAW. Not as an abstract thing: you should be able to glance at a small circuit and "instantly" know I and V, the way a soccer player glances at the ball and knows the angle and kick


EmRR

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #141 on: February 15, 2011, 02:26:47 PM »
Should be fine.
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #142 on: February 15, 2011, 02:27:08 PM »
guys i wanted to put this meq500 into a channel strip with a mic pre so i didn't add the input transformer.  will this circuit have any issue with a normal 600ohm load from my mic preamp or do i need the input iron.  on the output side i have a carnhill 600:600.

thanks



I was thinking of doing the same with a particular project.  As long as you terminate the OT on the preamp with a 6xx resistor it should do ok.  When I was recently building my MEQ I was running program material from a line amp output to the MEQ input and A/Bing the MEQ input w/ & w/o input transformer - w/o using a 620r resistor and it worked well. 

EmRR

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #143 on: February 15, 2011, 02:29:05 PM »
the MEQ500 has a 620 termination already. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

mata_haze

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #144 on: February 18, 2011, 04:46:27 PM »
Hello,
I am building this beast right now, but I am not sure to understand how to achieve che narrow/broad with the switch?!
can somebody quickly explain it / draw a diaghram?

thank you!
 :)

Mattia.

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #145 on: February 18, 2011, 05:15:48 PM »
Short/bypass the 270R resistor.

EmRR

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #146 on: February 18, 2011, 05:19:53 PM »
and look back at my plots in this thread, which made me decide it was a pointless exercise. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

mata_haze

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #147 on: February 18, 2011, 05:34:34 PM »
thank you guys!

Mattia.

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #148 on: February 18, 2011, 05:52:21 PM »
I omitted this switch as well in the MEQ I recently completed.  I really couldn't hear the difference on source material well enough to justify it.

I experimented with several different inductors for the mid dip section and getting the broader sounding curves would've meant committing to a different inductor (with a different Q value).  I wound up using the Cinemag which felt about right for 11 positions.

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #149 on: March 05, 2011, 06:22:46 PM »
Here's some pics of an MEQ style program EQ I recently built.  The high boost section was rearranged a bit with boost points at 1K, 2.5K, 10K, 14K, & 16K.  Mid dip section is as the original.  The low boost section goes from 30Hz, 60Hz, 200Hz, 300Hz, 500Hz, & 700Hz.  As you might guess this was somewhat of an attempt at combining the EQP1A frequency range with MEQ mid cut/boost abilities.

Make up amp is a two stage PP tube type that gives an additional 10db gain past unity or -28db if needed.





« Last Edit: June 10, 2012, 12:55:51 AM by lassoharp »


jensenmann

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #150 on: February 25, 2012, 04:28:00 AM »
Just a quick note on Doug´s handdrawn schematic: the second half of the 5532 hybrid amp is drawn with the inputs reversed. Negative input (Pin 6) should be tied to the output (Pin7) and positive input (Pin5) should be tied to ground.

Did anyone try the midcut with more than 270Ohm for a lower Q? I guess I´ll try that....
Jens
Quote from: PRR
The tubes of course don't care what frequency they distort

EmRR

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #151 on: February 25, 2012, 11:25:43 AM »
Drawing fixed and replaced, funny no one caught it till now. 

More than 270 won't change the shape, just limit the depth further. 
« Last Edit: February 25, 2012, 04:24:50 PM by emrr »
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

jensenmann

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #152 on: February 25, 2012, 02:40:22 PM »
More than 270 won't change the shape, just limit the depth further.
Ok, then I´ll stick with 270Ohm. Thanks for saving me some time ;-)



First one is up and running. The output transistors are running quite hot. Still touchable, but definitely hot. Did anybody run into trouble with that, yet?
Soundwise it eats up quite some lowend which is perfect for my task since it will reside on backing vocal group in my FoH rack. That way I can forget about engaging HPFs in 5 backingvocal channels. The other PCB in the background´s going to be a bassdrum version with custom LF inductor for different frequency choices, INA134 sand input instead of iron and Edcor XS1100 at the output for increased LF harmonics. Frontpanels were done by our member Frank of nrg-cnc.de

Thanks to everybody involved in this project!
Jens
Quote from: PRR
The tubes of course don't care what frequency they distort

EmRR

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #153 on: February 25, 2012, 02:56:02 PM »
Are you liking what 7K, 10K and 14K boost give you?   I didn't find it useful myself.  Or maybe you changed them to shelves? 

You shouldn't be losing lows with the INA134 input, unless it's having problems driving the 620.  That's why I went with the THAT1646 driver as part of the input scheme.  Or maybe I misunderstand your meaning. 

So far in 2 years the provided op amp hasn't burned up on either of mine, it does run very hot.   I intend to get 2520's in there when I can find the time. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

jensenmann

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #154 on: February 25, 2012, 03:12:22 PM »
According to the datasheet INA134 should be able to drive 60mA to Vrail-1,4V. That should be good enough to drive the filter. I saw your post and read the threads you were pointing to regarding the debal. circuit. Very interesting! You didn´t misunderstand me, I chose the INA because I want not to loose LF in my Kickdrum version of this EQ.

I´m not sure about the 7/10/14kHz boosts. They sounded very narrow and unnatural to me. But I finished it only one hour ago so I had not much possibilities to test it, only sending some CD tracks through it. I have a gig next weekend where it will be put into reallife use. I´ll give you a feedback what I think about it. The idea of changing the highest frequencies to shelving is very good, though. Maybe I should give it a try, shelving could be much more useful to what I want to achieve with it.
Jens
Quote from: PRR
The tubes of course don't care what frequency they distort

EmRR

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #155 on: February 25, 2012, 03:35:34 PM »
Shelf would be easy.  I thought about that and a lot of other changes after I'd already made panels; too late. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

jensenmann

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #156 on: March 03, 2012, 11:50:30 AM »
Just a quick note about the additional frequencies I´ve added to the HF boost (7k, 10k, 14k). My original intention was to use the MEQ on backingvocal subgroup to add some air and cut out some mids to leave space for the leadvocalist. Yesterday we had the first show since my MEQ is finished and I put it on a subgroup as well as an EQN on another subgroup for comparison. The 7k and 10k HF boost kind of did what I expected but sounded a bit narrow and unnatural, not so silky and pleasing as the EQN HF shelv did. Besides the general sound difference between both units I prefered to have shelv over bell for the "air". The MEQ midcut was very effective and exactly fitted my need and the general LF absence because of the input tranny worked as a feature rather than a bug in this application. So I guess I´ll give it another try with the 7k-14k frequencies modded into shelving. The other frequencies below worked pretty good in bell and are worth to be kept that way. Maybe I´ll have a look at different DOAs, maybe I can make the MEQ behave a little smoother.... or simply get another EQN  ::)
Jens
Quote from: PRR
The tubes of course don't care what frequency they distort

EmRR

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #157 on: March 03, 2012, 11:56:35 AM »
That's what I expected to hear about those highs, thanks. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

weiss

Re: MEQ mid-range EQ pultec style (was meq500)
« Reply #158 on: October 08, 2014, 06:14:34 AM »
is anyone supplying pcb's?


 

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