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previous: Shon I am in the market for a good pream... -- 4/18/2000 8:22 PM

Re: Marshall DSL 50/100 preamps

4/22/2000 10:40 PM
Ray Ivers	Re: Marshall DSL 50/100 preamps Shon, When a Marshall tube amp is available in 50 and 100 watt versions, the preamps are almost always identical. Even though the voltages at the power amp are usually higher on the 100 watt models than the 50's, different values of power supply series dropping resistors are chosen to keep the preamp at roughly the same voltage for both models (heater voltages are always 6.3 volts, AC or DC, in Marshalls). Are you planning to get a DSL 50 or 100 head and then use the preamp to drive your Plexi reissue? The DSL 50 and 100 preamps are identical (Marshall uses the same schematic for both preamps, common practice for them in the past 15 years), and of course the power amp is different from the 1987x. Why not just try out a DSL head alone, and see what you think? You may actually like the additional volume and bass you get from the 100 watt output section. It would be difficult to modify your 1987x into a DSL, although doing only one channel might not be too hard. On the other hand, looking at the schematic it wouldn't be too hard to convert a DSL 50 watt power amp to a 1987x - it's almost there already. With these new Marshall schematics you gotta be real careful, though; they often refer to ribbon cable connectors on different pages of the schematic - it's helpful to have a copy machine, colored markers, and Maalox handy. Ray Ivers

4/22/2000 10:40 PM

Ray Ivers

Re: Marshall DSL 50/100 preamps

Shon,

When a Marshall tube amp is available in 50 and 100 watt versions, the preamps are almost always identical. Even though the voltages at the power amp are usually higher on the 100 watt models than the 50's, different values of power supply series dropping resistors are chosen to keep the preamp at roughly the same voltage for both models (heater voltages are always 6.3 volts, AC or DC, in Marshalls). Are you planning to get a DSL 50 or 100 head and then use the preamp to drive your Plexi reissue? The DSL 50 and 100 preamps are identical (Marshall uses the same schematic for both preamps, common practice for them in the past 15 years), and of course the power amp is different from the 1987x. Why not just try out a DSL head alone, and see what you think? You may actually like the additional volume and bass you get from the 100 watt output section. It would be difficult to modify your 1987x into a DSL, although doing only one channel might not be too hard. On the other hand, looking at the schematic it wouldn't be too hard to convert a DSL 50 watt power amp to a 1987x - it's almost there already. With these new Marshall schematics you gotta be real careful, though; they often refer to ribbon cable connectors on different pages of the schematic - it's helpful to have a copy machine, colored markers, and Maalox handy.

Ray Ivers