Helios 1r Stereo Type 69 Mic Pre / EQ

The Helios 1R Stereo Type 69 is a 1U dual-channel recreation of Dick Swettenham’s legendary Mic preamp and three-band EQ that defined the sound of 1960’s and 1970’s and made famous by bands like the Beatles, Rolling Stones, Bob Marley, Led Zeppelin ad more.
The Helios1R Stereo Type69 is hand-built in the UK and endorsed by Dick Swettenham himself. In recreating the Type 69, Helios improved greatly the manufacture process by using military grade components and feature modern appointments based on Helios users’ requests including a 30Hz LF frequency and 16kHz mid-band frequency to accommodate modern full-bandwidth recording requirements and a polarity reversal switch.
In addition, the preamp section features a custom Sowter 8666X input transformer based on the highly praised but now discontinued Lustraphone transformer found in the original Olympic Studios model favoured for its open sound. Just like the original Type 69, this modern recreation features a five position mic and line input gain ranging from 20dB all the way up to 70dB in 10dB steps. In addition the input section includes a -20dB pad switch and works at a fixed impedance of 1200 Ohms. Line level impedance works at 10k Ohms and is selected via a toggle switch. An ATT switch engages a small front panel trim pot for small range input level changes.
The three-band passive EQ design follows closely that of the original and uses the same combination of RC and LC tone circuits with the addition of a 30Hz LF frequency and 16kHz frequency in the mid-frequency band for a tighter HF control. The RC-based HF band uses a static 6dB-per-octave, 10kHz shelf with a +/- 10dB range ideal to add sparkle and presence to any incoming source. The bass band features a somewhat more complex architecture including a five frequency selectable including 30Hz, 80Hz, 120Hz, 240Hz and 400Hz peaking frequency with a 15dB boost and cut. The same frequency switch lets you select a 70Hz fixed frequency, 6dB-per-octave shelving filter with 3, 6, 9, 12 or 15dB roll-off. Turn the gain control fully counter-clockwise to switch the bass EQ section out of the signal path. When boosting the bass in peaking mode, it is also possible to keep the low frequency tight with an additional 12dB-per-octave roll-off with selectable 40Hz or 80Hz.
The midrange offers a wide range of frequencies including 700Hz, 1kHz, 1.4kHz, 2kHz, 2.8kHz, 3.5kHz, 4.5kHz, 6kHz and the newly added 16kHz with a Peak / Trough (cut) toggle switch and 15dB boost/cut. In addition, the midrange section uses a proportionate Q starting at a wide three octaves at 700Hz and 2 Octaves from 6kHz. As the boost/cut is increased the Q narrows, this makes for a very musical EQ. The sound of the hints at Pultec EQs with a creamy low-frequency as well as sweet and musical high frequency.
Finally, the Helios 1r Stereo Type 69 features an unbalanced output section similar to the original design but with a new Philips/BEC electrolytic coupling capacitor which emulates the sound of the circuit used at Olympic Studios.
Helios 1R Type 69 Mic Pre and EQ Overview:
• 2 Helios Type 69 Mic Pre/EQ in a 1U rack
• Legendary Olympic Studios design
• Custom Sowter 8666x input transformer based on original Lustraphone design
• Improved manufacture with military grade components
• Added 30Hz and 16kHz frequencies for modern full bandwidth recordings
• Five position 10dB stepped gain
• Added polarity switch
• Three-band passive EQ with fixed 10kHz HF Shelving
• Extensive range of midrange frequencies: 700Hz, 1kHz, 1.4kHz, 2kHz, 2.8kHz, 3.5kHz, 4.5kHz, 6kHz and the newly added 16kHz
• Unique LF EQ design with selectable Peaking and Shelving frequencies
• 15dB cut/boost on LF and MF bands, 10dB on HF
• Self-contained design including 32V PSU