Features
Vacuum tube microphone preamplifier available in two and four channel versions
Flawless performance with very low noise, high headroom, and high gain
Two stage minimalist design with unrivaled sophistication
SQ German NOS pentodes
Lundahl input and output transformers
No electrolytic capacitors in the signal path
Optional DI input
Overview
Knif V804 Pre is a high-end vacuum tube microphone preamplifier available in two and four channel versions.
The preamplifier pays homage to West-German engineering from the 1950’s while utilizing modern components and construction techniques. The front end is based around the Telefunken EF804S, a very special and sought-after NOS pentode, combined with a high step-up ratio Lundahl® input transformer. The most distinctive feature in the classic German 1950’s designs was the use of pentodes in the first stage of sensitive electronics.
Thanks to the special front end, the self noise of V804 Pre is very low, fully comparable to the best solid state rivals and the maximum gain is also very high. The latter of the two tube stages in the amplifier also features a SQ pentode, the E180F. This stage is also coupled to the outside world through a Lundahl® transformer. The core of this transformer is silicon iron which adds a hint of thickness and smoothness to the top register.
The gain of V804 Pre is adjusted in 4 dB increments via an Elma® rotary switch. The gain adjustment is equipped with an automated -20 dB pad for the lowest gain settings. There are no electrolytic capacitors in the signal path.
The V804 Pre is also available with optional DI inputs with capacitance of only 15pF. This vanishingly low value is roughly equivalent to one foot of the very best cables available and greatly helps in squeezing out the last bits of treble from Hi-Z sources, such as guitars.
There are no other tube microphone preamplifiers on the market with such degree of sophistication and minimalism. The performance of the V804 Pre is flawless.
Downloads
Pricing and options
V804 Pre, two channel version
2800 €
DI inputs
+200€
V804 Pre, four channel version
5100 €
DI inputs
+400 €
All prices excluding VAT, duties and shipping costs
Tech specs
MIC / LINE INPUT
Impedance
1 kΩ
Maximum Level
+26 dBu
DI INPUT (OPTIONAL)
Impedance
2 MΩ, 15 pF
Gain
0 … 52 dB
OUTPUT
Maximum Level
into 10 kΩ
into 600 Ω
+32 dBu
+25 dBu
Frequency Response,
gain 20 … 60 dB
±0.5 dB, Ref. 1 kHz, 50 Ω source
±0.5 dB, Ref. 1 kHz, 150 Ω source
10 Hz … 40 kHz
15 Hz … 22 kHz
THD + N,
20 dBu Out
10 kΩ load, 0 … 64 dB gain, 30 Hz … 20 kHz
600 Ω load, any gain, 30 Hz … 20 kHz
0.4%
<0.6%
Crosstalk,
Gain 0 … 60 dB
100 Hz
1 kHz
10 kHz
-90 dB
-95 dB
-68 dB
Crosstalk,
Gain 72 dB
100 Hz
1 kHz
10 kHz
-80 dB
-80 dB
-55 dB
0 … 72 dB
Gain
XLR female, Neutrik, 3‑pin, gold-plated
Connectors
6.35 mm jack, Neutrik, locking
Connectors
Impedance
<200 Ω
XLR male, Neutrik, 3‑pin, gold-plated
Connectors
PERFORMANCE
-1 dB, Ref. 1 kHz
High Frequency Cutoff, max gain
20 kHz
Any gain
Channel Balance
better than 0.1 dB
A-weighting
Noise (EIN) 60 dB gain, 50Ω source
-133 dBu
MAINS
Mains Frequency
50 / 60 Hz
Power Consumption
2 channel version
27 W
Connector
IEC, C13
TUBES
EF804S
2 pcs
E180F
2 pcs
GENERAL
Dimensions (w × l × h)
430 × 352 × 132 mm (3U)
Weight
10.3 kg
CONTENT
V804 Pre
1 pcs
Spare tubes (E180F, 2pcs)
1 set
115 / 230 VAC, selectable
Mains Voltage
WARRANTY
2 years (for terms and conditions, refer to Warranty section)