Greg Hanks Design BA-AD660

The BA-AD660 is an All Tube Mic Preamp Compressor/Limiter/AD converter/Master Clock.

There are multiple compressor/limiter emulations to choose from, each with an automatic or manual/trim setting. This makes the BA as versatile as a rack full of different compression units. Compression is all tube in the BA and handled by its V3 stage. The circuits are optimized and enhanced for the maximum levels and lowering distortion down to insignificance. This unit is easily the most linear tube amplifier we've tried. You can use any microphone [low or high output] with the BA660.

The BA-AD-660 adds un-clippable, analog-to-digital electronics and allows the user to fully realize its robust analog integrity with any compatible digital interface or workstation. Along with specially designed custom Soft-Limiting circuity to counter the onset of digital distortion, the BA-AD660 offers engineers a very wide saftey net and comfort zone for maximum headroom and peak levels, without distortion.

The newly designed 24-bit AD converter with AES/EBU output matches the available headroom within the internal analog circuitry. Along with sophisticated M-clock setup [less than 800 femtoseconds of jitter which is .8 picoseconds] ensures absolute timing accuracy of the BA's ultra wide frequency response. The BA should be used as the master clock with AES/EBU output.

Audio Example: Martin Grand J-28LSE Acoustic with a single Schoeps microphone.

*New BA-AD660 units feature "Linerized Mode" and now the Feedback/Feedforward Selector has been placed on the Front Panel.

The Compressor/Limiter emulations included-
-Fairchild 670
-Teletronix LA2A
-SSL Quad Bus Limiter
-Neve 2254 Bus Limiter
-RCA BA-6A
-Greg Hanks Manual Mode

Specifications

Gain
Mic In
>+90 db max.
<-24 db min.
Line In
> +40 db max.
< -20 db min.

· Input Impedance (20 Hz - 20 Khz)
Mic = 1k3 Ω
Line > 20K Ω
Insert Return > 100 K Ω
Side Chain Insert > 220K Ω

· Frequency Response
Mic In - 7 Hz - 28 Khz +0, -3
Line In -6 Hz ->36 Khz+0/-1

· S/N Ratio
> 125 db (Avg ~ -127)
· Output Impedance(20-20Khz)
Line Out: Transformer isolated. Less than 100Ω balanced
Insert Send < 100 Ω
· Phantom Voltage nom.
+48VDC (Internally adjustable to +300 VDC @ 5 ma.)
· Harmonic Distortion
< .6% at all levels up to +33 dbm (Avg ~ .3%)
· IM Distortion
< .1% at all levels up to +34 dbm

· Attack Time
3ms to 45 ms
· Release Time
50 ms - 1.4 sec
· Ratio range
1.2:1 - > 9:1
· Range of limiting
18db
· Maximum Input Level
Mic In
@ +14 > + 45 dbm
@ -15 > +25 dbm
Line In > +40 dbm
· Maximum output level
> +34 dbv

· Pin conventions
XLR connectors are wired as follows
Pin 1 = Shield
Pin 2 = Signal Plus +
Pin 3 = Signal Minus -
All 1/4" connections are TRS and are wired as follows
Tip = Signal Plus +
Ring = Signal Minus -
Sleeve = Shield/Chassis