Helios Type 69 EQ curves

Does anyone have a set of curves for the Helios Type 69 EQ? Google seems not to be my friend.

Cheers

Ian

I've got a multisim file for this one. i could try to export it as generic spice file (if that exists) for import in a different (free) spice program. Then you can plot your own curves.

I've almost finished a type 69 stereo clone, finally since i've been working on it for about a year now. Just waiting for some cash for a frontpanel from shaeffer.

greetings,

Thomas

hobiesound said:

I've got a multisim file for this one. i could try to export it as generic spice file (if that exists) for import in a different (free) spice program. Then you can plot your own curves.

Click to expand...

Thanks for the offer Thomas. I was hoping for curves measured from an actual unit. I am building one myself right now and I am getting a very high Q mid trough (the peak is OK with a Q of about 3). I basically need to know if this is correct or not.

Cheers

Ian

i think that's correct:

here's a graph i found on the big helios picture thread PSW (not sure if this graph is for a type 69 eq, since the frequencies seem off)



 

i just checked my simulation and the through curves have a tighter Q than the peaking Curves.

spice programs are notorious for being inaccurate when simulating active components but i've noticed they're pretty good at simulating passive networks, like passive equalisers. Just my 2ct's...

they seem to roughly correspond with the graph i just posted, albeit at other frequencies.

i'll try to post some graphs when i'm off from work.

greetings,

Thomas

Thanks for that guys. My measured curves are very similar to those. That's a relief.

Cheers

Ian

and just to be complete: here's some plots from the uad helios plug-in: http://fader8.com/audioblog/uad%20helios%2069.html

greetings,

Thomas

Thanks for that Thomas, that confirms my findings almost exactly. Here's a set of graphs from the tests I made:

http://www.ianbell.ukfsn.org/data/HeliosTests.pdf

The reason some of the mid dips are rather small is that the Lindos tester I am using has one third octave fixed frequencies and if the dip is sharp and at a frequency not produced by the Lindos then you never see the full amplitude of the dip. Also the LF boost curve labelled 200 should of course be labelled 240Hz.

Cheers

Ian