Melcor

joel hamilton · Post by **joel hamilton** » Fri Nov 04, 2005 1:12 pm

Anyone have any good info about Melcor products?

I just got a pair of Melcor EQ's rom between '69 and '71... not sure exactly....

They have the original melcor discrete opamps in them it looks like...

Dave?

soundguy · Post by **soundguy** » Fri Nov 04, 2005 1:28 pm

melcor was the predessor to api. the 2520 was basically built on the 1731 that is in your EQ.

can you post or email me a picture?

there were two main eq's that had melcor brandings, one was a two band that shared quite a lot of similarities with the 550, think the 550 was remotely based on this EQ. They came in black modules with the frequency selector on a ring mounted below the boost knob for the gain. Same way electrodyne did it back in the day.

The other EQ's were also two band but were a licensed design that also popped up in spectra sonics consoles and electrodyne consoles, I wouldnt be suprised if others too. It used a wound inductor for each band and then the 1731 for makeup. I have a pair of these and they are fairly typical of what you'd expect out of an inductor EQ from the period.

I know those two types exist, I wouldnt be suprised if there are others.

If you can post a photo I can probably tell you more about it.

dave

joel hamilton · Post by **joel hamilton** » Fri Nov 04, 2005 1:34 pm

Dave, Here ya go! Thanks for the info, man. There isnt much out there oddly...They dont seem to be like the passive SSonics 500's I have.

soundguy · Post by **soundguy** » Fri Nov 04, 2005 1:52 pm

nope, those are the active shelfs like a 550. for all intent and purposes not a tremendous functional difference between those and 550's. You might investigate changing the blue caps for new BC's, if any of the orange cas are bad (which they shouldnt be) sprage still makes them, they are film and oil I think, mouser had them recently. you can get the BC's from digikey. Those should run at +/-15 volts, you could stick an api 325 on the output if you need it balanced. The 1731 should drive a pretty hefty load though, I dont think you NEED to put a balancing driver on there unless you wanted to, people use 550's in lunchboxes without all the time no biggie.

dave

joel hamilton · Post by **joel hamilton** » Fri Nov 04, 2005 1:55 pm

Exactly what i wanted to know. Thank you, man.

soundguy · Post by **soundguy** » Fri Nov 04, 2005 2:00 pm

no prob.

how do they sound?

do you have any 550's to directly compare them to?

dave

joel hamilton · Post by **joel hamilton** » Fri Nov 04, 2005 2:04 pm

soundguy wrote:no prob.

how do they sound?

do you have any 550's to directly compare them to?

dave

I dont have any 550's. I really like them, every time i work on an API or in a room with a 'box of them.

I havent used these melcor's before. I will post about them after I get them rolling.

What years was melcor around? These modules are supposedly 69- 71, does that sound right to you?

soundguy · Post by **soundguy** » Fri Nov 04, 2005 2:17 pm

joel hamilton wrote:
soundguy wrote:no prob.

how do they sound?

do you have any 550's to directly compare them to?

dave
I dont have any 550's. I really like them, every time i work on an API or in a room with a 'box of them.

I havent used these melcor's before. I will post about them after I get them rolling.

What years was melcor around? These modules are supposedly 69- 71, does that sound right to you?

yeah spot on.

Ive never got a clear answer on when melcor stopped and api started, but there were positively melcor consoles popular in nyc in 1968. I have a limiter from that era, I really need to hook that thing up. I do think that the passive eq's predate the ones you've got there, but thats just a guess.

dave

joel hamilton · Post by **joel hamilton** » Fri Nov 04, 2005 3:53 pm

Dave, if you were gonna throw these in a rack, what would you power them with?

They wanna see +-15, I know all that, but I want something that can live IN a rack, rather than a frikkin acopian on the floor behind the rack just for two modules like this...

I need to ask Ed at purple about this as well....

soundguy · Post by **soundguy** » Fri Nov 04, 2005 4:11 pm

www.jlmaudio.com

I like his power supplies alot. Plus you can use a wall wart transofmrer with them so you dont have to go crazy with shielding inside the box. Easy enough to build, they can be kinda finnicky sometimes, bt so far as what you can go out and buy, they are pretty awesome.

I have seen the little power supply PCB's that andrew did and those are really cool too, either will get you to where you need to be.

dave

joel hamilton · Post by **joel hamilton** » Fri Nov 04, 2005 4:16 pm

You rock full blast. Thanks a bunch man... Lets me know who i need to call so i can get back to mixing. i have a mix printing right now....

jamesfei · Post by **jamesfei** » Fri Nov 04, 2005 8:05 pm

The eq is probably the same as the AE-20, bridged-T RC cut and boost in the feedback loop of the op-amp. Schematic (without values):

Best,

James

Mix413 · Post by **Mix413** » Sun Nov 06, 2005 7:03 pm

My impression is that the GME20's are peak EQs. The Melcor SME-20 is a shelving EQ. They do in fact date from about 1969-71 or so. Melcor folded after that. Those opamps are pretty old now and tend to crap out over time. You can swap them out with api's or John Hardy 990c's.

The GME-20's sound really great on electric guitars and bass. Try extreme boosts on an upper band and a boost on one of the bottom bands with both the high and low pass filters engaged.

Try to find a 15V bipolar power supply on eBay. We use a Lambda LXD-A-152-R dual regulated PS for ours. I think it was about $25 on eBay.

wiring:
Pin F: PS Chassis
Pin A: PS common / 0 volt
Pin M: +15V
Pin E: -15V

Pin R: Input +
Pin P: Input -
Pin C: Output +
Pin A: Output -

joel hamilton · Post by **joel hamilton** » Sun Nov 06, 2005 7:07 pm

Thanks all!

pulse_divider · Post by **pulse_divider** » Tue Sep 19, 2006 10:22 am

Found this thread while searching for Melcor pinouts (thanks John!).

I just got a pair of EQ-20-1 and they don't look anything like the others internally. There are no opamps (discrete) and they are transformer balanced in and out. Just wanted to add this to the archive for posterity, as it seems there is limited info about these on the net.

For those of you who have racked these up, did you find a source for the connectors or are you wiring directly to the pins?

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