adding a input and output trany to GME 20 eqs? API

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JRE Productions

Well-known member
Joined
Dec 10, 2004
Messages
255
Location
Chicago, IL USA
I just got a pair of early API/Melcor EQs. They are 2 band with adjustable feqs, hi and low pass, and by pass switches. 2 melcor opamps and No tranies. Can I add an input and output trany to them? What would I look for as far as ratio etc?

Thanks

Joe
 
Input usually 1:5, 1:7, around there.
Output is 2:1 .
I can send you a couple of output kits if you want to roll your own.

You can add transformers to anything. I have one on my bicycle.

cj
 
I think 1:7 would be too much for a line level eq. I think you can just use 1:1's. I used a Jensen 1:1 on my outputs.
 
Could you not use the 2503 as 1:1 / 300Ohm:300Ohm on the output? That way, you'd get the "authentic sound of API". or any 600:600 on in or out?

FWIW, - Why do you need to transformer-link it to the outside world? I have many pieces of gear that are not balanced, and work totally happily with each other and with balanced stuff. Noise never seems to be an issue, and I prefer my Helioses, for instance, "as is", un-coloured with any transformers on the output, and on the line ins. You could save a lot of money by NOT adding trannies in my book. Of coarse, you might be wanting "That" sound . . .

Good Luck!


ANdyP
 
Thanks for the reply. Well, esentially these EQs are API's with only two bands. I think the API 550s have a transformer output. So while I was about to rack these up, the option of adding a transformer was available. While the color of these with the Melcor opamps are somewhat transparent, adding iron would add something. Not sure if it would be good or bad. So I was going to try it out. I just did not know what trannies I should use. I have a few around the shop.

JOE
 
The 2503 output has four identical windings that are nicknamed 75 ohms.
So you can go 1:3, 1:2 2:2, 1:1, 2:1, 3:1. Level diff only.

No, the output does not color the sound, it is a closer to transparent than air.

The input is a different story.
 
The 2503 Does color the sound, it adds distortion all by its self, about a full decimal place.
Transformers on the output of equipment can be very very clean also, one major advantage is they isolate the signals and eliminate ground loops.
But if you are not having problems then leave it be...
 
[quote author="Mike Keith"]The 2503 Does color the sound, it adds distortion all by its self, about a full decimal place.[/quote]

I think you need to search for CJ's 4804/2503 physical exam. Amazing stuff from what was a $14 transformer.
 

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