VAC PA160 Mk I User Manual
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SPECIFICATIONS
The VAC System has been developed with the critical ear as the major arbiter of quality, with both
conventional and unique measurements providing insight and guidance as necessary. The lack of emphasis
on measurements is due to the fact that engineering's arsenal of equipment and techniques do not operate
on the pattern recognition principals that control human perception of sound. In the immortal words of
Daniel von Recklinghausen, if it measures good and sounds bad it is bad. If it measures bad and sounds
good you've measured the wrong things.
The following describes typical measured performance of a PA160 operated at 120 VAC, 60 Hz.
Power Output:
Continuous average power at 1 kHz depends upon the tube type fitted and the operating
mode selected. The following table summarizes a few popular combinations. The entries
show power, and load impedance connected to the 4-8 ohm tap. In each case THD is less
than 2% with feedback setting of "A" for triode, "D" for ultra-linear, "E" for pentode.
Mode
KT88
KT77
EL34
6L6GC
Pentode
160/4
125/4
150/4
100/4
Ultra-Linear
152/4
120/4
118/4
70/8
Triode
79/4
60/4
58/4
30/5.5
Frequency Response:
down 0.5 dB at 5 Hz and 48 kHz, ref 0 dB = 1 watt @ 1 kHz.
down 3.0 dB at 3 Hz and 82 kHz, ref 0 dB = 1 watt @ 1 kHz.
Power Bandwidth:
down 0.5 dB at 12 Hz and 42 kHz, ref 0 dB = 150 watts @ 1 kHz.
down 3.0 dB at 8.5 Hz and 75 kHz, ref 0 dB = 150 watts @ 1 kHz.
Ultra-linear mode, KT88 tubes.
Distortion:
Typically .23% THD at 1 kHz 10 watts, < 1% 20-20,000 Hz.
Noise:
< 1 mv at the output, S/N ratio > 88 dB
Negative Feedback:
Variable. Table shows amount for triode/ultra-linear/pentode modes.
Set
KT88
KT77
KT66
6550
EL34
6L6GC
"A"
0.0/0.0/0.0
0.0/0.0/0.0
0.0/0.0/0.0
0.0/0.0/0.0
0.0/0.0/0.0
0.0/0.0/0.0
"B"
1.0/1.3/1.9
1.2/1.6/2.5
0.7/1.1/1.4
0.9/1.2/1.8
1.1/1.5/2.0
0.7/1.1/1.4
"C"
2.0/2.6/3.8
2.5/3.4/4.7
1.5/2.2/2.9
1.8/2.5/3.6
1.3/3.0/3.9
1.5/2.2/2.9
"D"
3.0/3.8/5.4
3.5/4.6/6.5
2.3/3.1/4.0
2.5/3.5/5.0
3.2/4.2/5.4
2.3/3.1/4.0
"E"
4.0/5.2/7.1
4.7/6.4/8.5
3.2/4.2/5.5
3.6/4.9/6.8
4.5/5.7/7.1
3.2/4.2/5.5
"F"
5.0/6.5/8.6
6.0/7.6/10
4.4/5.4/6.7
4.5/6.0/8.2
5.6/7.0/8.6
4.1/5.3/6.6
Absolute Polarity:
Does not invert signal polarity.
Fuse:
Slo-Blow type, 4A for 100 & 120 Volt configuration, 2A for 220 & 240 V.
Power consumption:
288 watts at idle, 528 watts driven to full power.
Dimensions:
11.75" x 8.5" x 20.5"
Weight:
Approximately 53 pounds each (unboxed)
Standard tube compliment: 4 x KT88 (new Golden Dragon version), 2 x 6SN7.