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Title: Connecting the 1 ohm bias resistor on power tubes V4 and V5 Post by: francois on December 18, 2012, 10:40:54 PM Hi there !
The originial Marshall diagramm do not show this resistor connected between pin 8 and ground on V4 and V5. Reading the METROAMP instructions for JTM45 the layout is a bit different as pin 1 is connected to ground and not to 8 (picture attached). Can you advice on the difference ? Is it important ? Thank you for your help. Title: Re: Connecting the 1 ohm bias resistor on power tubes V4 and V5 Post by: T Wilcox on December 19, 2012, 01:28:52 AM There is a jumper between pin 1 and 8 of the power tubes so electrically there is no difference between pin 1 or pin 8
Todd Title: Re: Connecting the 1 ohm bias resistor on power tubes V4 and V5 Post by: francois on December 19, 2012, 11:22:48 AM Thank you Todd,
So, i think instructions for Metro (and the schematic in my previous post) are false as the resistor is not used due to the internal jump.between 1 and 8 ;) I deduce also that the external strap between 1 and 8 on the CERIATONE layout is a spare. Right? So i will correct my homework to better comply with the layout |