MT-2 Boss Metal Zone Schematic

Technical specification:
    Input Impedance: 1MΩ
    Output Impedance: 1kΩ
    Recommended Load Impedance: 10kΩ or greater
    Equivalent Input Noise Level: -110 dBu or less (IHF-A, Typ.)
    Power Supply: 9V Battery or PSA-Series AC Adaptor
    Current Draw: 20mA (DC 9V)

Overdrive Effect

Ibanez Tube Screamer TS-9

Boss Super Overdrive SD-1

Marshall Pedals: Blues Breaker, Drive Master & Shred Master

Marshall Blues Breaker

Marshall Drive Master

Marshall Shred Master

Fender Blackface Preamp

Parts List : 

P1,P2                          220K  Linear Potentiometers (or 250K)
P3                               10K  Linear Potentiometer
P4                               1M  Log. Potentiometer
R1                               1M  1/4W Resistor
R2,R3                         68K  1/4W Resistors
R4,R5,R6,R7,R8        100K  1/4W Resistors
C1,C7                         47µF  25V Electrolytic Capacitors
C2                               220pF  63V Ceramic or Polystyrene Capacitor (or 250pF)
C3                               100nF  63V Polyester Capacitor
C4                               47nF  63V Polyester Capacitor
C5                               100µF  35-50V Electrolytic Capacitor
C6                               120pF  63V Ceramic or Polystyrene Capacitor
C8                               47nF  63V Polyester Capacitor
Q1,Q2,Q3,Q4             2N3819  General-purpose N-Channel FETs
J1,J2                            6.3mm  Mono Jack sockets
SW1                            SPST Toggle or Slide Switch

Hampton Moving Coil Preamplifier

 Components List  :

R1-5= 100ohm 1% 1/4W R2-6= 150ohm 1% 1/4W R3-7= 33ohm 1% 1/4W R4-8= 12ohm 1% 1/4W

R9...12= 47Kohm 2W R13-14=1Mohm 1% 1/4W C1-2= 1uF 250V MKT V1-2= ECC88 - 6DJ8

S1-2= DIL Switch J1...4= RCA Jack

Application 

Some of the services today preamps using vacuum tubes still in their ability to deliver high-quality audio and unique colors when used with amplifiers. The vacuum tube preamplifier used in the musical instrument amplifier with tone control circuits In this connection it is of the coil wire applications, the ability to obtain high-quality signals and Equalization

Conventional MC-MM Pre Amplifier

The circuit is (more or less) conventional, with a common emitter stage constant current source modulation. When the series is a mirror that is reproduced for both positive and negative supply voltage. Net output voltage again a low DC offset, but may be slightly higher than previous models, because of the lack of power to 0V DC bias to obtain a correct output.

Benefit from a 2.2k resistor from the collector of the output device (parallel, 1.1k) and a 15 ohm resistor (MC or moving coil position) optionally controlled in series with a 150 ohm (MM Moving Magnet or position).

This results in a theoretical advantage 74 (37dB) in the MC position or 7.6 (17.6 dB) for the MM setting. In practice, one can expect very little profit to be less than these figures, especially for MC setting.

I can not comment on the relative noise performance of both pre-amp, but because they are both on a design by renowned audio designer, I would hope that the noise either be a problem with the circuit.