EWalter

Re: REDD EQ, Helios 69 and Dick Swettenham
« Reply #380 on: August 26, 2019, 04:01:26 PM »
Hey, glad you got it sorted Erik, nice one.
Easy mistake to make.  I haven't turned on a piece of gear I made yet that failed to amaze me when audio comes out the other end.
Down some wires. 
Cool 👍

It really does sound so much better when you make it yourself!  ;)


Sorr

Re: REDD EQ, Helios 69 and Dick Swettenham
« Reply #381 on: September 20, 2019, 11:02:05 PM »
Ian,
You wrote in post 285, "Hooking up the Helios EQ PCB is quite simple. Your input goes (via a 10K:10K transformer) to the pad labelled IN "
I thought it required a low I/P driving Z, such as 600 ohms?

ruffrecords

Re: REDD EQ, Helios 69 and Dick Swettenham
« Reply #382 on: September 21, 2019, 03:16:57 AM »
Ian,
You wrote in post 285, "Hooking up the Helios EQ PCB is quite simple. Your input goes (via a 10K:10K transformer) to the pad labelled IN "
I thought it required a low I/P driving Z, such as 600 ohms?

Transformers do what it says on the tin - they transform. The input impedance of the EQ is about 10K so I recommend a 10K:10K transformer to successfully reflect this input impedance to its primary. It looks like a regular line input to the outside world. The EQ is designed to work from a source impedance of no more than 2500 ohms. This is so it can be used directly after a 10K fader in a mixer. If you drive it from a low impedance source you can add a series resistor (there's a place on the PCB for this) to raise the soirce impedance to 2500 ohms. You don't have to do this though - if you drive from a low impedance source without the extra resistor, all that happens is the maximum boost and cut is increased by about a dB.

Bottom line is for a bakanced input you need a 10K:10K transformer but you can drive it from a low impedance source.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


 

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