Products

I spend a lot of time building and evaluating basic amplifier concepts with an eye toward producing the highest quality sound with elegantly simple circuits.

There is no such thing as a perfect amplifier, but there is a best amplifier for each type of speaker, music, and listener. Each First Watt piece is a unique design and is “best” in some particular way. They look alike because they all use the same basic chassis and power transformer. On the up side, it makes it easy for me to test ideas and compare different designs with the hardware being a fixed constant.

Looking for tomorrow’s faceplate with yesterday’s circuits?

You’re in the wrong place.

AMPLIFIER COMPARISON CHART (Click on the product name in the left column for more information)
Model Stereo/Mono Output8 Ohm Output4 Ohm Feed-back Output Ohms Input Ohms Input Bal/SE Distortion % Noise UV GAINdB Mosfet / Jfet / SIT SE PP Available New?
S
10w
5w
N
4
100K
SE
0.6
75
20
S
SE
S
25w
15w
Y
0.2
100K
SE
0.02
100
15
J
SE
S
18w
30w
N
0.26
200K
SE
0.2
50
11.5
S/M
DEF
S
20w
30w
Y
0.08
10K
SE
0.05
100
14
M
PP
S
25w
50w
Y
0.5
100K
SE
0.05
200
14
M
PP
M
10w
8w
N
4
100K
SE
0.6
100
18
S
S
S
10w
8w
N
4
100K
SE
0.6
100
18
S
S
S
25w
13w
Y
0.4
100K
Both
0.03
100
20
J
S
S
25w
40w
N
0.4
100K
SE
0.05
500
15
M
P
S
25w
40w
Y
0.1
100K
SE
0.01
100
15
M
P
S
25w
40w
N
0.2
47k
SE
0.05
50
0
M
P
S
15w
10w
Y
1
10K
SE
0.01
50
12.5
J
S
S
5w
10w
N
15
50k
SE
1
30
14
M
S
S
5w
10w
N
15
10K
SE
0.3
30
14
J
S
S
10w
7w
N
80
100K
Both
0.1
30
15
M
BS
S
10w
7w
N
60
10K
Both
0.05
30
15
J
BS
S
25w
13w
Y
0.4
240K
Both
0.05
100
20
M
S

Notes:

Distortion figures are at 1 watt into 8 ohms at 1 Khz. See the specific product information for more detail.
Noise figures are unweighted from 20 Hz to 20 Khz.
For Damping Factor, divide 8 by output ohms, for example, 8 ohms / 0.4 ohms = 20
Bal/SE means XLR and/or RCA input connectors.
F1, F1J, F2, F2J, F3, SIT-1 and SIT-2 are single gain stage amplifiers. The others have two stages.
Mosfet/Jfet refers to the output transistors. Two-stage amps with Mosfet outputs have Jfet input devices.
All amplifiers are available in 240 or 120 volts AC. Consumption ranges from 160 to 200 watts. All amplifiers operate at temperatures between 45 and 55 deg C.

Line Stage Products

As with the amplifiers, at one point I ordered up a bunch of metal to put line level electronics in. Here’s what has occurred so far, some of these still in progress.

B1

A stereo buffered passive volume control with two inputs. The buffer circuit is a simple Jfet follower operated with no feedback.

B2

A stereo buffered bi-amp splitter with relative level adjustment for high and low power amplifiers. If you are bi-amping it is very likely that you need this.

B3

A stereo gain stage with one pair of inputs, two level controls and a high gain / high voltage swing stage with no feedback. Suitable as a front end for power follower amplifiers and also for bridging and/or isolation.

B4

A stereo active crossover with adjustable frequencies, slopes, and level. Active circuitry is provided by Jfets operated with no feedback.

B5

A stereo active crossover with adjustable frequencies, slopes, and level. Like the B4 but filters and equalization for full-range drivers with woofers in open baffles.