Sound Master PA head

[Ivarrr]

I found a Sound Master PA by Barnum head at a thrift store today, $10. Has anyone heard of this company? I can't seem to find any information about the company. The PA doesn't have an model number anywhere visible (I haven't taken it apart, yet.) It had a plaque that said it was custom made for Powell Junior High in Mesa, AZ.

I was astonished to find out it actually worked when I got home, it's pretty beat up and I can hear some things rattling on the inside. I plugged my bass into it and plugged the head into my 115BX and it started feeding back horribly. I turned all of the knobs to 0 and started adjusting from there. When I turn the midrange or bass up is when it starts to feedback, treble just induces hiss and noise. The sound is pretty distorted and it drops in volume sometimes. Most of the knobs can use a bit of cleaning or replacing.

How would I start fixing this up to make it actually usable?

Outside of all of these negatives, it does sound pretty good. It's fairly loud, too. Enough words, onto pictures.

Oh and ignore the room, it's in the middle of being redone.

[s_mcsleazy]

damn. that looks bloody cool. ill give you $20 and a piggyback

[billfitzmaurice]

It looks to be home made. An expert tech might be able to diagnose the problems, but not without it on his bench.

[Ivarrr]

I don't think its a home made piece, through the venting I can see a sticker that says

SOUND MASTER
Custom design & MFG.
SOUND SYST-MS

Rest of it is scratched off and can't make out what it says

I think the distortion isn't an issue anymore, the amp is just too powerful for my cab. This PA was probably in a school auditorium or something. I have it on 1 and anymore it starts to distort and its LOUD. It sounds pretty amazing! I'll see if I can get some soundclips tomorrow. Besides the occasional volume drop and scratchy pots it's working perfectly.

I think I'm going to refinish it in matte black. That blue is so ugly D:

[Ivarrr]

I unscrewed the face plate to get a glimpse of the internals and the transformer is only held in place on one side and is bouncing around. Theres also a bit of electrical tape on some of the wires and this really needs to be checked out by a professional.

Does anyone know of a good amp tech in Phoenix who's also reasonably priced?

[bottomend!]

Dont touch the blue - it's looks very space age 60's.

[Ivarrr]

Originally Posted by bottomend!

Dont touch the blue - it's looks very space age 60's.

It looks pretty awful in person, it reminds me of being in middle school again, where everything was covered in the same cheap plastic veneers. And the bottom of the amp is red (?)

I think it'll look even more spacey and classy being black

The midrange EQ control seems to also act as a gain too, when I turn it up it ends up pushing the VU into the red and gets a groovy overdriven sound. I played my g****r through it and with the built in reverb it sounded pretty great.

As far as I can tell, the tone knobs don't do anything.

[anderbass]

SOUNDMASTER P.A. AMPLIFIERS

INSTRUCTIONS FOR USE

U.K. 220 - 240v


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Before you use this equipment please read these instructions.
Congratulations on purchasing a high quality SOUNDMASTER PA Amplifier

The Soundmaster SPA range of amplifiers are available with 4, 6 or 8 input channel mixers and an integrated mono power amplifier.


SPA 4150 4 inputs 150 watt amplifier
SPA 6200 6 inputs 150 watt amplifier
SPA 8300 8 inputs 300 watt amplifier
The mains lead supplied with this equipment should be wired as follows:
The BROWN wire should be connected to the LIVE terminal
The BLUE wire should be connected to the NEUTRAL terminal
The GREEN / YELLOW wire should be connected to the EARTH terminal



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Input Channel Facilities
Input Connectors

Channel 1 has two phono connectors for stereo tape or CD player which are mixed to one mono input and a ¼" jack socket for line inputs. The other input channels have an XLR type connector for balanced low impedance microphones and a 1/4" jack socket for line inputs.

Volume Control

The Volume control sets the input signal level for each channel. It is used in conjunction with the Master control to obtain the optimum signal level through the amplifier. It should be adjusted so that the input is not distorted and the noise floor is not amplified.

Tone controls

The Treble and Bass controls (often called EQ.) are provided to adjust the sound or to correct for deficiencies in microphone performance. The centre position of these controls allows the signal to pass without altering its sound.

Effects

Two effects sends are provided on each channel. The REV switch sends the signal to the internal digital reverb and the FX is for an external echo or other effect


Output facilities
Master

The master volume control sets output level of the power amplifier.

Presence

The presence control alters the sound of the mid band of frequencies, it is used to give bite to the sound.

Reverb

The reverb control sets the level of the internal digital reverb which is mixed to the master output. The reverb footswitch socket is provided so that the reverb can be switched on and off by a remote control.

FX send and FX return

These two jack sockets are for connecting an external effect to the amplifier.

Rear Panel

There are two ¼" jack sockets for speaker connections. The minimum load should not be less than 4 ohms (ie two 8 ohm speakers in parallel). The slave jack socket is provided to enable the amplifier to be connected to another slave or power amplifier which has an compatible input level of 0dB (0.775v). The monitor socket provides a line level output signal which is suitable for monitoring the output using a pair of high impedance headphones or to drive the line input of a tape recorder.

Power Supply

A double pole rocker switch is located on the rear panel. When the unit is on the Power On LED on the front panel will be illuminated. The amplifier requires a 220v to 240v, 50 or 60 Hz mains supply. The fuse is rated at 5.0A quick blow. In the event of the fuse blowing it should be replaced with one of the same type.


THIS UNIT MUST BE CONNECTED TO EARTH AT ALL TIMES - FAILURE TO DO SO COULD BE FATAL

Overload protection

The power amplifier is a MOS - FET design which is inherently reliable. The presence of an overload will cause the power transistors to heat up, the negative temperature coefficient of the transistors will automatically reduce the output power. In the event of severe overload the internal fuses will blow, these should only be replaced by a fuse of the same type by a competent electronic engineer.



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SOUNDMASTER® P.A. MIXERS

INSTRUCTIONS FOR USE
U.K. 220 - 240v

Before you use this equipment please read these instructions.

The SOUNDMASTER name and logo are the registered trade marks of M-Jay Electronics Limited


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Congratulations on purchasing a high quality SOUNDMASTER Mixing desk
The Soundmaster range of P.A. Mixers are available in three sizes:

PAM 8-2 Eight input channels and one output / monitor module
PAM 12-2 Twelve input channels and one output / monitor module
PAM 16-2 Sixteen input channels and one output / monitor module


The mains lead supplied with this equipment should be wired as follows:
The BROWN wire should be connected to the LIVE terminal
The BLUE wire should be connected to the NEUTRAL terminal
The GREEN / YELLOW wire must be connected to the EARTH terminal


THIS UNIT MUST BE CONNECTED TO EARTH AT ALL TIMES -- FAILURE TO DO SO COULD BE FATAL.


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Input Channel Facilities
Input Connectors
Each channel has two input connectors. The XLR type connector is for a low impedance balanced microphone, the ¼" jack socket is for high level or line inputs such as the output of a guitar, keyboard or tape recorder.

Gain Control

The gain control adjusts the input sensitivity of the channel to match the output of the microphone. Adjust this control so that loudest peaks of signal make the peak LED light briefly.

Peak LED

The Peak LED indicates when the input is approaching distortion. In normal use the LED should not be illuminated, occasional peaks indicate that the signal is 10 dB above its normal operating level, but it is not distorted. If the LED is continuously illuminated the input is overloaded and the Gain control should be reduced.

EQ. (Equalisation)

The Treble, Bass and Middle controls (usually known as EQ) are provided to adjust the sound or to correct for deficiencies in the microphone performance. The centre position of these controls allows the signal to pass through this section without adding or subtracting to the sound. Rotating these controls will add or subtract from the signal at the respective band of frequencies. Care needs to be exercised when using these controls because excessive amounts of boost may exceed the mixer headroom (+20dB) therefore the gain control may need to be reduced accordingly.

AUX 1 & AUX 2

The Auxiliary send controls set the amount of signal which is sent to the foldback or the effects. These send signals are mixed and then sent to the Aux outputs. Aux 1 is pre fade and is usually used for foldback, Aux 2 is post fade and is usually used for the effects send.

Pan

The Pan control sets the stereo image (it pans between the left and right speaker).

PFL

The signal can be monitored on headphones before it is fed to the outputs by the fader (Pre Fade Listen) Press the PFL switch and the LED will be illuminated to indicate that the channel PFL has been selected. This operation does not affect the signal output. This facility can also be used to monitor or set the correct output level from the channel. The PFL is a full mix buss so several channels can be monitored at the same time without interaction.

Fader

The signal level which is fed to the main mixing buss is set by the fader. During a performance the faders will be adjusted to alter the sound, increasing or reducing differing parts of the show. The Fader is calibrated in 5dB divisions and the line indicates the 20dB headroom. If the output of the mixer is above 0dB when the fader is set to the start of the 20dB line then distortion will be present at the output.


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Output Facilities
Master Output
The two Faders control the signal level which is fed to the power amplifiers, the output level is indicated by the two bargraph meters. The yellow LED is 0dB, the most common input for power amplifiers and tape recorders. The stereo outputs are available on two 1/4" jack sockets.

Aux Sends and Return

The output from the Aux mixing busses is available via the two 1/4" jack sockets. The level is 0dB and is the same as the stereo outputs. The aux return is fed into the 1/4" jack socket. This input has similar facilities to those provided by the input channels, gain, EQ, Pan and the channel fader being used in the same way.

Monitoring

The stereo output from the mixer can be monitored on the headphone amplifier, the monitor level is set with the volume control. The PFL is fed to the headphone amplifier when the PFL switch is operated and this is indicated by the PFL LED being illuminated. When the monitoring is fed from the PFL buss the right hand bargraph displays the level on the PFL while the left hand bargraph displays the output signal. This facility is used to set or monitor the level of the signal on each channel.

Power supply

The built in power supply has a 20mm 1A quick blow fuse. In the event of the fuse blowing it should be replaced by one of the same type. The unit requires a mains supply of 220v to 240v, 50 or 60Hz.



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THIS UNIT MUST BE CONNECTED TO EARTH AT ALL TIMES - FAILURE TO DO SO COULD BE FATAL.

[billfitzmaurice]

Originally Posted by anderbass

SOUNDMASTER P.A. AMPLIFIERS


Channel 1 has two phono connectors for stereo tape or CD player ... internal digital reverb

Soundmaster isn't the same as Sound Master. By the looks of it this rig pre-dates both CD players and digital reverb by a few decades.

[KramerBassFan]

Probably one of the many brands made out of peoples garages and music stores out west, such as AIMS and Alamo.

$10 wasn't bad. Much more, and it could have stayed there.