{"product_id":"helios-1r-stereo-type-69-mic-pre-3-band-eq-used","title":"Helios 1R Stereo Type 69 Mic Pre\/3 Band EQ (Used)","description":"The \u003cb\u003eHelios 1r Stereo Type 69 Mic Pre\/Eq\u003c\/b\u003e is built in an aluminum \ncase and has a glossy black front panel with white silk-screened \nlabeling. The unit is well constructed and neatly wired using all \ndiscrete components (no chips). It runs on a 32-volt rail supplied from \nan internal OEM switching power supply. The mic preamp uses a Sowter \nType 8666X input transformer based on the highly desirable Lustraphone \n(Olympic Sound Studios) transformer model. Input impedance is 1,200 \nohms. A separate switchable secondary winding provides for -20 dB of mic\n attenuation. \n\u003cp\u003eFront panel controls for each channel start on the left side with the\n mic\/line gain switching and a small output-level clip LED. A toggle \nswitch selects between mic, -20dB mic attenuation and the 10k-ohm line \ninput. A seven-position Elma rotary switch doubles as both line input \nand mic input gain control. There are -5dB and 0dB line gain positions. \nThe five mic gain positions start at 20 dB and go to 70 dB in 10dB \nsteps. Other toggle switches include phase (polarity) flip, EQ cut, mic \nphantom powering on\/off and the ATT switch, where you can engage a small\n front panel trim pot for a small range of input level adjustment.\u003c\/p\u003e\n\u003cp\u003eThe 3-band passive equalizer section uses a combination of RC and LC \ntone circuits, starting with an RC-based, 10kHz, 6dB-per-octave shelving\n filter with +\/- 10dB range. The LC-based midrange equalizer has a \nsurprising number of frequency choices on a single knob. They are: 0.7, \n1, 1.4, 2, 2.8, 3.5, 4.5, 6 and 16 kHz. There is a Peak and Trough \ntoggle switch. (Trough is Brit-speak for cut.) Up to 15 dB of boost\/cut \nis available on the unmarked +\/- control. The starting Q for the \nmidrange is a wide three octaves at 700 Hz; then, by 6 kHz, it narrows \nto two octaves. Q is proportionate: The more boost\/cut, the higher the \nQ.\u003c\/p\u003e\n\u003cp\u003eThe LC-based bass section allows up to 15dB boost\/cut, and when the \ncontrol is fully counterclockwise, the bass EQ section is switched out \nof the signal path. This is good for keeping things ultra-clean. Another\n rotary Elma switch selects 30, 80, 120, 240 and 400 Hz for the bass \npeaking section. The same switch rotates to a 6dB-per-octave shelving \nfilter mode that's fixed at 70 Hz with 3, 6, 9, 12 or 15 dB of roll-off.\n If you like to boost bass and roll-off at the same time, then use the \npeaking section and select another 12dB-per-octave roll-off filter at 40\n or 80 Hz.\u003c\/p\u003e\n\u003cp\u003eThe output section is unbalanced and uses an emitter follower circuit\n and a Philips\/BEC electrolytic coupling capacitor, much like what's in \nthe original Helios design. Dick Swettenham of Helios found that the \nengineers at Olympic Studios preferred the sound of this circuit \ncompared to the best output transformers.\u003c\/p\u003e","brand":"Helios","offers":[{"title":"Default Title","offer_id":44449451081831,"sku":"12409","price":2895.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/8848\/5479\/files\/used_helios_1r_stereo_type_69_mic_pre-3_band_eq_9e0f8f3c-a70b-48e0-ac80-ef7f96ba1fc2.jpg?v=1787089005","url":"https:\/\/vintageking.mom\/products\/helios-1r-stereo-type-69-mic-pre-3-band-eq-used","provider":"Vintage King","version":"1.0","type":"link"}