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Topics - nickbob00

#1
Preamps and Effects / Randall RG80/RG100 Preamp DIY
October 09, 2009, 04:37:26 PM
Hi guys

I am looking at the feasibility of cloneing the gain channel of the Randall RG 80 Or RG 100 series amps (to plug into a simple chipamp, <20W, maybe a TDA2003 for a practaise amp), however i find the way the schematic i found was drawn very confusing. I was hoping someone could help me interpret the circuit diagram. I am not a 'noob' and have built several electronic circuits before, so i dont need electronics 101. In case attatchments don't work, here is a link: http://www.schematicheaven.com/newamps/randall_rg100es-rg80es.pdf


I have a few questions:

1)Am I correct in thinking that the 'RED CHANNEL' is the distortion channel.

2)the circuit diagram says as a note 'All capacitors are rated in MFD at 100 volts'. I assume that means all values are in millifarads (as in 1000 uF?), but it seems strange to have a 10 mF (10,000uf) capacitor on the cathode of Q6?

3)D3 and D4 are captioned '4VZ'. Does this mean they are actually 4 volt zener diodes, even though they have the symbol of a normal Diode? A zener in the PSU is marked '12VZ'.

Thanks in advance!