Members guitarist17 Posted October 9, 2006 Members Share Posted October 9, 2006 I have no idea how to bias a marshall tsl100. and im trying to help my buddy learn how to do it. hes got a voltmeter, and a set of new Svetlana El34 power tubes. can someone give us a website, or a step by step process of how to do it? thanks. chris Link to comment Share on other sites More sharing options...
Members A 11 Posted October 9, 2006 Members Share Posted October 9, 2006 You should take it to an expert. Link to comment Share on other sites More sharing options...
Members oryan Posted October 9, 2006 Members Share Posted October 9, 2006 You're welcome MARSHALL SERVICE BULLETIN SUBJECT: Bias Info/Procedure for JCM2000 series Marshall amplifiers THEORY OF OPERATION: We are setting the bias using the current method instead of cross over distortion method. The Bias PCB assembly is as follows: PR1: Bias mini-pot adjustment for pin1 which is one side of the push pull amp (two output tubes in a 100watt amp and one output tube in a 50watt amp). Pin1: Connected to the cathode of the output tube(s) which then goes through a 1 ohm resistor then to ground. Pin2: ground reference. Pin3: Same as pin1 but for the other side of the push/pull amp. PR2: Bias mini-pot adjustment for pin3, the other side of the push/pull amp. PROCEDURE: 1. Make sure amplifier is connected to a load with the proper impedance selected. 2. Power up amplifier on STANDBY and let the circuit stabilize for a couple of minutes. 3. Locate the male three pin molex connector (CON2) with the two mini-pots (PR1 and PR2) on both ends found on the bottom of the tube bay. 4. Connect DMM (set to read mV) with alligator leads, reference common lead to center pin (pin2) on molex connector CON2 and positive lead to pin1 on CON2. 5. Take amplifier off of STANDBY with no signal, adjust mini-pot (PR1) closest to pin that the positive lead from your DMM is connected to and set it to the mV voltage that is listed in the chart below. 6. Repeat steps 4 & 5 for pin3 and until both pin1 and pin3 mV are the same. BIAS CHART mV SETTINGS (pin1 and pin3) DSL50 45mV TSL60/1/2 80mV DSL100 90mV DSL401 1.375V TSL100/122 90mV DSL201 .675V Link to comment Share on other sites More sharing options...
Members oryan Posted October 9, 2006 Members Share Posted October 9, 2006 Originally posted by A 11 You should take it to an expert. No need for that. The TSL and DSL are super easy to bias. Link to comment Share on other sites More sharing options...
Members batlas Posted October 9, 2006 Members Share Posted October 9, 2006 http://www.eurotubes.com/euro-Marshall-DSLTSLV.htm Step by step video. Link to comment Share on other sites More sharing options...
Members ProjectX Posted October 9, 2006 Members Share Posted October 9, 2006 Originally posted by batlas http://www.eurotubes.com/euro-Marshall-DSLTSLV.htm Step by step video. Good vid. Link to comment Share on other sites More sharing options...
Members i_hate_user_names Posted October 9, 2006 Members Share Posted October 9, 2006 Anyone think that guy (bob i believe) has a slight resemblence to Ted Nugent? Also when just using a multimeter your just using it in mA to check both sides right? Link to comment Share on other sites More sharing options...
Members oryan Posted October 9, 2006 Members Share Posted October 9, 2006 Originally posted by i_hate_user_names Anyone think that guy (bob i believe) has a slight resemblence to Ted Nugent?Also when just using a multimeter your just using it in mA to check both sides right? When using a multimeter on the three pins below the tube sockets you're reading mV, not mA. Link to comment Share on other sites More sharing options...
Members i_hate_user_names Posted October 9, 2006 Members Share Posted October 9, 2006 Originally posted by oryan When using a multimeter on the three pins below the tube sockets you're reading mV, not mA. ok yeah sorry about that. SO there really isnt a need for a bias probe if your biasing a dsl/tsl then? Link to comment Share on other sites More sharing options...
Members oryan Posted October 9, 2006 Members Share Posted October 9, 2006 Originally posted by i_hate_user_names ok yeah sorry about that.SO there really isnt a need for a bias probe if your biasing a dsl/tsl then? Not really, but a bias probe will read it more accurately. When using a multimeter Marshalll suggests setting each side to 90mV. But like Bob at Eurotubes said, that's a little hot, especially when you compare it to mA on a bias probe. When I had my DSL, I experimented with the bias using a multimeter and found it to sound best at 84 mV. Link to comment Share on other sites More sharing options...
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