MEQ mid-range EQ pultec style (was meq500)

[Rob Flinn]

Denyle, Did you manage to do any more experimentation with the Q switches ??

 

[Rob Flinn]

Max,

Could you please post the dimensions for the front panel so I know the postions of the holes.  I've tried printing out your zipped files but they only seem to print really small or really big.

 

[ioaudio]

wow, i didnt even realize someone finished his - looks great!

rob, the zib is the fpe file - it should open correctly with the fpe software, no?

 

[Rob Flinn]

wow, i didnt even realize someone finished his - looks great!

rob, the zib is the fpe file - it should open correctly with the fpe software, no?

I guess, but I don't have FPE software.  Is it free ?

 

[ioaudio]

yes!
http://www.frontpanelexpress.com/en/download/front-panel-designer.html

 

[Rob Flinn]

Max

I'm having a problem with one of the eq kits I bought from you, that seems to be related to the output transformer.    One of them works fine & the other is heavily clipped.  If I connect the clipped output modules to the transformer in the good module it behaves properly ???  The dc resistances of both transformers seems to be the same !  Any adeas ??

 

[ioaudio]

hmm, not sure. can yoiu measure if there´s continuity between the windings?

 

[Rob Flinn]

I just checked the output transformer & it seems to have a primary to secondary short.  This is with it out of circuit. 

Although I'm not entirley sure how this would make the circuit clip.  The clipping is becuase the headroom has gone, because it clips at about 1-2v pk to pk.    Is the short loading the op amp too much ???  I've swapped out the op amps with API, Melcor, 990's & they all do the same.

Like I said with the transformer disconnected or with the other channels transformer hooked up the op amp behaves itself.

 

[ioaudio]

primary to secondary short is not so good. pls send me a email for a replacement.

-max

 

[3nity]

rotarys are they 1x12? or 2x6?

 

[Rob Flinn]

It says 1 x12 in the BOM on thefirst post of this thread !! ;-)

 

[Denyle Guitars]

Denyle, Did you manage to do any more experimentation with the Q switches ??

Sorry I missed this before. Mine developed an intermitent problem so I pulled it and set it aside. I haven't done anything to it since. I haven't bothered completing the rest until I sort out the first.

 

[benlindell]

Just wondering if these kits are available at all?

thanks,

-ben
http://www.benlindell.com

 

[ioaudio]

sry, not at the moment.

-max

 

[clintrubber]

Can you post the diagram for the make up amplifier ?

Hi,

I bought a few of these hybrid-opamp PCBs, at least I thought they originate from this project.
Is there a schematic out there ?
I thought to have understood there's none, but who knows.

Just by looking at the PCB things are pretty obvious though,
but also some potential issues show up. So I was wondering how many have actually
built this hybrid.

As I see it it might be good to 'define' the unused half of the 5532. As it is now
all pins are not connected, might be better to short 'out' to '-' & connect
'+' to the (so far unused) GND-pin (remember to connect it at the mother-PCB).

I'm not sure why the PCB wasn't made for the 5534 but that's another topic.

People indeed using LEDs for biasing ? What measured current-draw do you obtain ?


Bye,

  Peter

 

[3nity]

this is an hybrid like op-amp.....jlm hybrid...

 

[clintrubber]

Yep hybrid, PCBs I have are meant for 5532 + BD139 + BD140.

But thanks for mentioning http://www.jlmaudio.com/JLM%20Hybrid%20Opamp%20circuit.pdf
, i realized I could use also the second IC-opamp for a servo.

I'm not sure those mentioned PCBs were originally for this project, but FWIW.

Bye,

  Peter

 

[emrr]

I think you'd only have these if you'd bought the MEQ500 boards and popped the opamp board loose from the output transformer hole.  I'm unaware of them being offered otherwise. 

 

[clintrubber]

That's right, I bought 2 from Tungstengruvsten in the BM, advertized as 'Other opamp MEQ500' so he probably has used another opamp himself.

Stock, the board has the undefined second IC-opamp, but IIRC there's enough room to
make a few variations without messing it up too much. Might as well use another PCB, but I refuse   

 

[benlindell]

Do you guys think this would work for the low boost?

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CT2203-ND

Also the BOM says 1x 1000uf and 1x2200 uf, but the PCB says 2x2200, I'm guessing that everyone used 2200s?

Lastly, does anyone have the part number for the little pins that everyone uses for opamps.

thanks

-ben
http://www.benlindell.com