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ADM Mic Preamp Transformer IN/OUT 2 Channel Discrete Opamp 1668 /API footprint.
ADM 2668 2 channel Discrete ADM custom Opamp.
4 Channels of discrete mic preamps
Racked Pair ADM 1668 Discrete opamp Mic Preamps, plus a racked Stereo ADM 2668 discrete mic preamp card with
Transformers in and out. Internal PS 110V or 220 Volt Option.
Four channels of discrete mic preamps from early 1970's 770 series ADM consoles and 2 channels of ADM-2668 discrete opamp mic preamps from early 1980's 780 ADM consoles.
4 Channels of discrete opamp mic pres in a single rack space box.
Discrete Opamp Based Mic preamp Plug and Play ADM-1668 console booster cards. Racked and refurbished
ready to use.
Transformer balanced in and out.
Discrete Opamp Based Mic preamp Plug and Play stereo ADM-2668 console booster card . Racked and refurbished
ready to use.
Transformer balanced in and out.
Internal Power Supply 110
or 220 Volt 220 Volt option requires additional shipping time.
Gain control for setting the gain of the amplifier, Gain control adjust the gain of the amplifier from 25db to 56db of gain.
Output attenuator to keep from overloading your convertors, Drive the input hot and attenuate the output going to your A/D convertors.
48V Phantom, Pad and , Polarity switch
These modules are
excellent mic preamps.
They are extremely musical. The ADM 1668 booster cards are racked side by side in a 1 space chassis with power supply and
internal Toroidal transformer. The chassis is a one unit 19" rack mount
with the power supply installed and input voltage switchable for 110V or
220V.
ADM custom discrete Opamp ( replaceable with API 2520) , wima caps , replaced electrolytic caps , very high quality build .
A Bi-polar +/- 20V power supply is included in the enclosure with
an internal toroidal 25V transformer .
ADM 1668 have both Input and
Output Transformers by UTC and ADM.
These booster cards are like a API312 card and come from a early 1970's ADM Console ,
The ADM 2668 stereo booster card is racked side by side in the 1 space chassis next to the 1668 cards.
The ADM 2668 has an "improved " ADM discrete opamp and a different output transformer .
See my Ebay Store for more
VPA-ADM RACKED AND READY FOR STUDIO USE MIC PRES/ EQUALIZERS/ HI-PASS LOW PASS FILTERS/NOISE GATES AND
COMPRESSORS.
Coming soon empty racks to put your ADM modules in .
Up for auction ADM-2 channel 1668.
ADM 1668-4LN and ADM-2668 2 and 4 Four channel 1 and 2 space racks .
In my store Dual 2780/1540 ADM Channel Strips . ADM-1541/1540 EQs.
ADM 320/1320 Compressors. ADM 310/1310 Noise Gates .
ADM 1551 Low Pass High Pass filters.
The ADM 1540 EQs , 320/1320 Compressors, 310/1310 Noise Gates and 1541 Filters all use the same pin outs
and can be combined in any combination in our 1 space Racks .
All
ADM racked and ready to use ADM Systems are guaranteed for 30days.
All
return shipping is the customers responsibility.
I have been getting a lot of questions about the ADM booster cards and the 320/1320 Compressors
so here is a little more info on the above products.
The 2668 is part of the 780/2780 series console booster cards. from late 1970's through the Mid 80's
The 1668 is part of the 770 series consoles booster cards.from early 70's to late 70's.
The
discrete opamp in the 1668 is very much like a 2520 API ( I had a ADM
TV 32 that had all 2520's replacing ADM opamps) the input transformer
is the same on both cards . The output transformers are different.
To
add more confusion the ADM 668 cards are all discrete (5 transistors) a
UTC O-12 ( same as an 1176) and a custom output transformer.
These were in late 1960's to very early 1970's consoles the 700 series console..
All of these booster cards ( like API-312 cards) are about 55db of gain.
The 2780 input modules have an IC after the discrete opamp to get the extra 20db.
Unfortunately it requires a ton of labor to get them into a real usable state.
Lots of rewiring and mods , lots of time. and I can't get what they are worth so I am not building( modifying) them any more.
The 668 card all transistor (friends say they are Neve like ?)
The 1668 card UTC input transformer>discrete opamp>output transformer.
The 2668 card UTC input> later discrete opamp> different output transformer.
The
2780 has the same input Xfrm same discrete opamp ( as 2668) from here
it differs as it goes into a 4 transistor class a output driver to the
same output transformer as the 2668..
The 1922 Card has the same
output transformer driven by the same 4 transistor output circuit but it
has a 5534 IC instead of the discrete opamp.
with the same input transformer as the 2668.
This
card is a candidate to put a dip socket to discrete opamp adapter in
and make it the discrete section of the 2780 ( or at least make it the
way we mod the 2780 to be all discrete ( eliminates the additional +20db
IC gain.)
The Compressors and the Noise Gates were designed to be on
the buss . So they are rare buss compressors as most ADM consoles were
only 4 buss plus the stereo buss. Not all boards had them installed, very rare option on the ADM consoles.
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