Hula Cow Studios - Cincinnati, OH

Welcome to Hula-Cow Studios! Click on a link above to learn more.

We are a digital recording and voiceover studio in Cincinnati, Ohio, specializing in video game, radio, cartoon, and character voice.
We also know a great SFX/music engineer. We now do audiobooks and audio book production!

Stripped U87 Ai

Bill of Materials (BoM)

Add-ons

PCB kit board for building

Basic version: Stripped U87ai based on ORS circuit:
PCB BOARD: $29 + Tax/Ship

ORS87 103-sized Version/Board

THEY'RE HERE!!

SFF Lei-87ai plus add-on expansion daughterboards

Base board plus OPTIONAL* daughterboards to add attenuation pad switch, hi-pass filter and brightness / EQ select switch. This MINIATURIZED version fits in a tlm-103 style body, but packs the punch of a U87 style build.

NOTE: THIS IS AN ADVANCED BUILD ON A SMALL BOARD. We do not recommend this for beginners/new hobbyists.

PCB BOARDS: $29 + Tax/Ship

*Mic can be built without using any of the optional switch features.

~~NOTE: THERE IS CURRENTLY A WAIT TIME~~ We now have the version with daughterboards. Basic version is retired, and daughterboard version can ship immediately.

THIS PAGE IS CURRENTLY UNDER CONSTRUCTION. Thank you for your patience.

- Mouser

Click here for the Mouser BoM Link:

-Mouser BoM for Stripped 87ai (Luau/Kahuna)-

-Mouser BoM for Stripped 87Nano (Lei)-

Note: BoM above does not include daughterboard components.

BoM List for Stripped 87Ai:

PCB:

Hula-Cow Studios Stripped 87Ai printed circuit board (left)
Hula-Cow Studios Att Pad daughterboard (right, optional)

MATERIALS/BoM:

Resistors:

1G || 1M || 330k || 300k || 56k || 47k || 10k || 2k2 (x2) || 7k3

Trimmer Resistor:

25K

Capacitors:

33nF (NP)** || 120-180(220*)pF (NP) ||
(*NOTE the 220pf seems to work well. Higher values temper the highs.)
** In the Lei/Nano build, can best be replaced with a 68nf
470 nF (NP) || 10uf 63v (x2) || 4u7 35v || 20uF 6v || 10nF ||
1uF 160v

Transformer:

Cinemag CM2480 or sim. (10.5:1)
OR:
Neutrik NTE10/3 (NOTE! This is the one on the Mouser BoM. This transformer gets wired in reverse, swapping primary and secondary, for correct turn ratio.)

FET:

2n3819 or sim.

Zener:

1N4749a

===================

H-PAD DAUGHTERBOARD:

Resistors:

500r (x4) || 967r (or close. -5dB) || 470r (-10dB) || 220r (-15dB)

Switch:

1p4t (for 4-position -0,-5,-10, -15) OR:
1p3t (for 3-position -0,-5/-10/-15) OR:
1p2t (for 2-pos on/off)

===================

Brightness/EQ Switch Daughterboard:

Capacitors:

120-220nf (lower = brighter)
220-400+nf

Switch:

1p2t on-on

===================

Hi-Pass Switch Daughterboard:

Capacitors:

470nf

Resistors:

150k-180k

Switch:

1p1t (spst) on-off

Assembly Video:

- Attenuating 2-4 position H-pads/other add-ons

Luau-87: Stripped U87ai plus add-on expansion daughterboard for base board plus. A backboard to add up to 3-way attenuation pad switch, and brightness switch.

Next Gen coming with Hi-Pass filter option, too! (You can add it manually to the current gen, as well. Contact us for info/assistance.)

PCB BOARDS: $39 + Tax/Ship

H-pad/highEQ(brightness) expansion daughterboard only:

Should work with any U87 clone board, nut just Hula-Cow Studios'.

Next Gen coming with Hi-Pass filter option, too! (You can add it manually to the current gen, too. Contact us for info/assistance.)

PCB BOARDS: $15 + Tax/Ship

Available to add back some of the functionality removed from the ORS version of the 87ai circuit. This installs a fairly transparent single- or multi-positional H-pad between the mic circuit and the interface. You can use it with an on-off, and on-off-on, an on-on-on or an on-on-on-(on/off) switch.

It's based on the circuit from the Hydra - a splitting attenuator with pass-through we and our customers have enjoyed using over the years. It's a reliable, tested circuit that we're happy to include into this build.

There's also a fun little feature in the form of a brightness switch function to swap between two capacitors near the backplate, to add a treble pad/boost.

AVAILABLE NOW!

Fits in a tlm-103 style body:

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