[Build] Helios 69 Tube EQ

[Holger]

I've recently finished a two channel Helios based on Ian Thompson-Bells designs.
The noise floor is at -94 dBu (flat), measured with a Neutrik Minilyzer.
I've used an external PSU, to me the key to a low noise floor.

Frequency response:

Noise floor:

 

[ruffrecords]

I like the idea of the 'bass cut' characters in a fainter colour.

Cheers

ian

 

[Rocinante]

What's a Holger external Helios EQ psu look like if you don't mind?

 

[Holger]

Like this:

 

[ruffrecords]

I LOVE that dc power connector! Even its style says vacuum tubes to me. Do you have the part number for it and its mating half?

Cheers

Ian

 

[Holger]

Ian, its the HAN E Series from German manufacturer Harting:

https://b2b.harting.com/ebusiness/app/displayApp/%28cpgsize=5&layout=7.0-12_132_125_140_130&zShowProducts=1&carea=0001100384&zNoOfProds=137&cpgnum=1&cquery=han+e&zSearchCategory=zAll%29/.do?rf=y

 

[ruffrecords]

Ian, its the HAN E Series from German manufacturer Harting:

https://b2b.harting.com/ebusiness/app/displayApp/%28cpgsize=5&layout=7.0-12_132_125_140_130&zShowProducts=1&carea=0001100384&zNoOfProds=137&cpgnum=1&cquery=han+e&zSearchCategory=zAll%29/.do?rf=y

The one you are using looks to be this one:

https://b2b.harting.com/files/download/PRD/PDF_TS/09330062701_100129971DRW005A.pdf

It says it is 6 way but you seem to have 6 connections plus the chassis. Is that right?

Cheers

ian

 

[Holger]

Yes, that's right.

 

[Rocinante]

That psu is awesome. Utilitarian with style. Thank you.

 

[Holger]

The guy who's testing my stuff for VDE compatibility measured the EQ today.
The noise floor is, measured with an AP One, at - 95 dBu.
The frequency response is almost the same as the RMAA measurement done earlier by me.
An excellent, awesome sounding EQ that is also a wonderful line amp.

The "Mode" switch switches a 10k pot and an additional tube to the circuit before the passive EQ. This was intended to add some "THD" mojo and works surprisingly well.

I named the equalizer "Kirke", latinized Circe which is one of the daughters of Helios.

 

[Rocinante]

The guy who's testing my stuff for VDE compatibility measured the EQ today.
The noise floor is, measured with an AP One, at - 95 dBu.
The frequency response is almost the same as the RMAA measurement done earlier by me.
An excellent, awesome sounding EQ that is also a wonderful line amp.

The "Mode" switch switches a 10k pot and an additional tube to the circuit before the passive EQ. This was intended to add some "THD" mojo and works surprisingly well.

I named the equalizer "Kirke", latinized Circe which is one of the daughters of Helios.

Bravo.  Seriously.  It's beautiful and bad ass.

 

[jensenmann]

Since I heard Holger´s tube console I´m really lusting for Helios EQs. The day will come that I won´t be able to resist any more.

 

[ruffrecords]

Since I heard Holger´s tube console I´m really lusting for Helios EQs. The day will come that I won´t be able to resist any more.

It won't be long before I get the prototype PCBs for my new version of the Helios 69 EQ with built in tube gain make. Tube mojo is built in.

Cheers

Ian

 

[ruffrecords]

@Holger, would you like to send me a couple of pics of this for Pierre to add to the gallery?

Cheers

Ian

 

[Holger]

Ian, sent a Drop Box link.

More pics:

 

[alexc]

Awesome 

Hope you do some screenshots of sweeps  ....  maybe with Room EQ Wizard  Be interesting to see some THD plots too!

Great work on the external psu with proper PROPER dc connector - noise floor measurements of -94dBu is  just stellar  ;D ;D

 

[skidmorebay]

I just found this.
Have you done any traces of the eq curves? I would be interested to see. I am finishing up a sort-of-point-to-point version of the Helios 69, with make up gain via 2520 op amp. It would be nice to see what the curves are supposed to look like.
JS

 

[ruffrecords]

I just found this.
Have you done any traces of the eq curves? I would be interested to see. I am finishing up a sort-of-point-to-point version of the Helios 69, with make up gain via 2520 op amp. It would be nice to see what the curves are supposed to look like.
JS

Back in 2012 when I designed this EQ I measured the curves. If you go to the DIY folder of my web site:

http://www.customtubeconsoles.com/diy

And look in the Helios69 folder you will find a pdf file called helios69tests.pdf

Cheers

Ian

 

[Whoops]

Hi,
yesterday I scanned the full tech docs I have for the Helios Musicland console so I could help in the "stay at home type 69 project" thread here:
https://groupdiy.com/index.php?topic=74779.msg948062#msg948062


I'm posting the individual docs in the Tech Docs section.
Hope it can be helpful for you and future projects

Best Regards