He-69 build/support thread. PCB's/kits-available!

[Cyril Jones]

Interesting conversations regarding oils/inductors. I have wound quite a few for clients to correct values as found on Olympic, Strawberry and many other issues that have passed through my workshop. All response curves are recorded. My Lustraphone transformer cop/development mimics the original faithfully. Having 2 originals was essential to that end particularly to encourage the matching of the lamination characteristics by the manufacturer. so far approx 70 sold.

Unfortunately tomorrow I travel to the west of England to be with family as one member is very seriously ill and has entered a Hospice.

So be patient for further technical information. I will not be able to enter into discussions .

Cyril Jones

 

[Beatpeat]

Where can I purchase????

Have a Look at this Shop…

https://shop.frontpanels.de/HE69-Helios-Console-Mic-Preamp

 

[Beatpeat]

In attach are two pics of the orientation of the inductors;

I did some trace changes to the big inductor for the lows, see details in post below.

Now I discovered that @Rogy already found this workaround! Great! Good to be shure this is the right way to do it

 

[TwentyTrees]

Unfortunately tomorrow I travel to the west of England to be with family as one member is very seriously ill and has entered a Hospice.

Sorry to hear that your family member is ill Cyril. Sending all best wishes to you and the family.

On the inductor chat, to confirm that the 10H tap will get you where you want to be for the low frequency boost. I don't know how this version of the 0011 eq does things, but if I recall correctly then many originals just used a single 10H inductor for all the frequencies on the low boost band, simply switching the caps in the LC section. That has the effect of changing the Q with each step, so that the higher frequency values have a narrower bandwidth. Using a multi-tap inductor like this Carnhill gives you the opportunity to use lower inductance taps for higher frequencies (just like in the mid band), potentially keeping the Q more consistent across the low boost band.

Caveat 1: I've not done the maths on whether the taps on this specific inductor are spaced in such a way to make this work well with the Helios low boost frequency points. You'd need to use different capacitor values too.

Caveat 2: It would make the low boost band behave in a less "authentic" way, so I mention it more as an option for anyone who wants a different behaviour from their low boost band. In my own Helios clones, I used the 10H tap all the way as I rather like the sound!

 

[Bobby Baird]

As far as I know, Frank sales the inductors for this project that needs no modifications. Regarding the 9048 inductor see post #158 where I flipped the inductor and jumped to appropriate pads. Like I said before verify the desired frequencies with calculator before buying caps to better match the specific inductors used.

 

[Beatpeat]

As far as I know, Frank sales the inductors for this project that needs no modifications. Regarding the 9048 inductor see post #158 where I flipped the inductor and jumped to appropriate pads. Like I said before verify the desired frequencies with calculator before buying caps to better match the specific inductors used.

Hi @Bobby Baird Frank seems to went out of stock with the inductors, but Aaron from Don Audio could wind me some. @TwentyTrees I will check frequencys after the build up and add or change Caps when needed…

@Cyril Jones even if we do not know each other personally also from me sympathy for you and your family.

 

[Beatpeat]

Just another HE69… just finished one of the two builds… everything seems to work but I will need more time to check if frequencies are fine…

 

[Beatpeat]

I made a few improvements that i wantend to share. I replaced R17 with a trimpot 200 Ohm so it is easier to calibrate the voltage of the Relais. And I build in Sockets for the Relays so you just can swap them if they do not Work. Not a big deal but made it easier, since for me the Formula to calculate R17 did not work.

 

[HerbertR]

Hi guys. I want to reactivate this thread.
I have to ask if any of you have measured the filter curves on the original Helios 69? It's interesting that the filter curves of all ranges cause a drop in the highs of a few dB from 10-15k according to the UAD plugin presentations on their homepage. It doesn't matter which filter is used, whether lowband or parametric midband.


There is a reference to this in the technical documents on GDIY that is not clear but does not show one.


Edit: deleted some wrong measuerments because of some hints of Bobby Braid

 

[Bobby Baird]

Hi guys. I want to reactivate this thread.
I have to ask if any of you have measured the filter curves on the original Helios 69? It's interesting that the filter curves of all ranges cause a drop in the highs of a few dB from 10-15k according to the UAD plugin presentations on their homepage. It doesn't matter which filter is used, whether lowband or parametric midband.

In addition, Igor's EQ follows exactly the known properties described. I somehow don't understand the behavior of the plugin. The Midband as Example.
It's as if the plugin had been measured with an incorrectly operated impedance and then coded. My Makeup gain works very linear. Absolutely clean. No trace of this asymmetry in the curves, the higher the mid frequency the narrower the band, very narrow bands / notch with negative midband boost ... like in a picture book... Whats wrong with the Plugin, or is this really correct according to the original Helios?

Not the case here. I think the problem is you are using it in series with an external effect in Cubase causing a loading issue?

 

[Bobby Baird]

Herbert did you compare @JMan Brilliance filter with the Igor type 69? Which do you prefer?

 

[Bobby Baird]

Here's a project I have been working on for a while. H32C filters with Grayhill switches for recall. When I get some boards Ill send you a few @HerbertR

 

[ruffrecords]

The gra

Hi guys. I want to reactivate this thread.
I have to ask if any of you have measured the filter curves on the original Helios 69? It's interesting that the filter curves of all ranges cause a drop in the highs of a few dB from 10-15k according to the UAD plugin presentations on their homepage. It doesn't matter which filter is used, whether lowband or parametric midband.
View attachment 127650

There is a reference to this in the technical documents on GDIY that is not clear but does not show one.


Edit: deleted some wrong measuerments because of some hints of Bobby Braid

On the top graph the middle labelled frequency is 1KHz so the one on the right is 10KHz The very next line to the right is 20KHz where the response is maybe 0.5dB down. The others further right are at 30, 40 and 50KHz falling off sensibly as you would expect.

On the lower graph, the rightmost labelled frequency is 10KHz so the next line to the right is 20KHz where again the response looks to be about 0.5dB down
Looks good to me.

Cheers

Ian