Cosmic LAB-3000 Stereomaster Amplifier Schematic

[sdk]

Log pots are no longer available. You can instead use a 6pin linear pot and convert it to a log pot with 2 simple resistors in between its pins.

A simple photo or diagram with values of trusted resistors would be most welcome

TIA

 

[analogadikt]

Cosmic volume pots have an extra terminal for loudness, and the amp's mojo is lost if that is not working.

Log pots can be sourced from vendors abroad, look for "audio taper" in the pot specs.

Regards,

 

[reubensm]

suggestion - if replacing 2N3055s, opt for BEL versions (yes, they are still available). They cost about Rs.90 a piece but a far superior in comparison with their Chinese counterparts available for less than half the price. Regards.

 

[availlyrics]

A friend of mine sent these Cosmic amp schematics (poor image quality), incase if someone needs these to repair.

 

[JALAL]

A friend of mine sent these Cosmic amp schematics (poor image quality), incase if someone needs these to repair.

Thank you

 

[Anil kumar]

A friend of mine sent these Cosmic amp schematics (poor image quality), incase if someone needs these to repair.

Thanks for the schematics

 

[ronthedon]

A simple photo or diagram with values of trusted resistors would be most welcome

TIA

Resistor is connected between the centre tap and one other tap (depending on where you want the taper) and its value should be around 10% to 20% of carbon track value for each channel though the value also depends on other factors. Please refer to "Changing the Law of a Pot" under https://sound-au.com/pots.htm.