MEQ mid-range EQ pultec style (was meq500)

[benlindell]

So I think I still want to do the bypass, I already have plenty of switches, just wondering whats the best way to hook it up. Should I just switch the cw pad to amp in? How did other people do this?

Thanks

 

[Denyle Guitars]

I put a dpdt b/t the bass ccw lug and the amp in, but I think it needs a resistor or two in there to pad down the level. You'll have a tough time fitting a 3p switch as the dpdt barely fits. I'll probably rewire mine so it's true bypass.

 

[benlindell]

I'm guessing it needs about a 12k resistor to make up for the bass and treble pots?

 

[Denyle Guitars]

12k seems about right.

I finally got back to work on mine. It has some issues: low output with EQ engaged and the opamp goes into overdrive in bypass. I've tried a 2520, 990 and the IC hybrid thingy and they all overheat.

 

[RedNoise]

Hi,
May I ask if you recommend MBB switches?eg: Lorlin CK1059?

 

[neujan]

hi,

just finishing some stuff, my meq opamp overheats, both 33r resistors are burnt, don´t know exactly why?
i put it in my api lunchbox, so this shouldn´t be the problem;
have any of you used the ioaudio opamps or are what are you using?

thanx and cheers  jan

 

[benlindell]

Finally got my pair of these powered up and tested and I'm getting a really faint signal when they are both engaged and bypassed. both times it has a really highpassed sound to it. Any ideas on where I'm going wrong on these?

Thanks

 

[benlindell]

I should also mention that I used a 10k for the bass just incase that has something to do with it. I have a 1k that I could throw in there but I wanted the full range of boost.

 

[RedNoise]

Hi BenLindell , what kind of switches did you use?MBB Lorlins?

 

[benlindell]

yes I used lorlins

 

[RedNoise]

Hi Ben , I meant : shorting lorlins?
PS : sorry I cannot help you with your faulty meq500.

 

[benlindell]

I can't remember, but I believe it's supposed to be shorting.

 

[RedNoise]

thanks.

 

[emrr]

Finally getting back to these.  Haven't really sourced or stuffed much yet.  Broke down and ordered the other pots from banzaieffects.com; I never found any appropriate US source.

You want shorting (MBB), otherwise the momentary open circuit of a non-shorting causes a gain fluctuation.  Shorting simply parallels filter sections momentarily. 

Sounds like Denyle is bypassing between the 620 and the 5100 ohm shunts at in and out of filter section.  Should be able to add a single series resistance between those points to match gain at flat filter setting.  Though, you might want to make a T attenuator to keep Z more inline with Z within filter, since we have 1K and 2.2K to ground in the filter. 

The burning up and overheating is curious.  It looks to be fool proof in regards to opamp input loading and bypass condition.  That was the first thing I thought of, bypass connections that left that opamp input unloaded.  But that doesn't look possible.  Makes me think overheating is an oscillation caused by lack of a ground connection somewhere. 

10K boost on bass should only reduce gain somewhat, when set for no boost, greater and sharper boost possibilities.  It might not work well, but I don't imagine it would cause serious problems. 

Has anyone with a working unit, having bypass, felt the desire/need to change the opamp gain setting?  Curiosity question.

I paralleled some small film caps with the pair of 2200's and the 47.  Did it underneath the boards, between the board and the metal frame.  Maybe a bit tweaky, but I like to do this. 

 

[emrr]

In assembling mine, I notice that it would be pretty easy to cut through the solder mask and short two traces with two screws around the output transformer.  Especially if you tried to use washers underneath the board.  Might be a culprit for some of the overheating and burning up?

I also notice how low the DC resistance of the output transformer is; lower than I expected to see.  I remember comments about the winding ratio in the sales thread, but it's gone now. 

 

[canidoit]

This calls for a bump and a drink.

I would like to know more about people's experience about this EQ sonically.

What sources have you found this EQ excells in? Does it have a crunchy or smooth sound to it?

What are it's weaknesses and strengths?

 

[Denyle Guitars]

I think I have mine licked now. The OT secondaries were reversed. Everything looks good now on the scope. I'll have a listen tonight and if all goes well, I'll report back.

 

[RedNoise]

Finally getting back to these ... Broke down and ordered the other pots from banzaieffects.com; I never found any appropriate US source.

Hi emrr , could you share the pots # your ordered @ banzai please?

 

[emrr]

Hi emrr , could you share the pots # your ordered @ banzai please?

SKU18830 Piher 4mm Pot Mono 2,5k lin 
SKU18832 Piher 4mm Pot Mono 10k lin
SKU20271 Axis Converter 6,3mm>4mm

I remember these being 16mm bodies, as opposed to 24 mm.  The larger diameter body looks too big for the space.  Shafts are definitely long enough. 

 

[RedNoise]

Thanks!!