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Marshall Jcm 2000 Dsl 50 Schematic For Smith
Try this: Use a short piece of cable to loop the FX send and return jacks - this enables the FX loop but returns exactly what was sent from the loop.. Select the red channel and turn the volume all the way to zero Play your guitar - notice the trebly sound coming through even at zero volume? As you turn up the volume you bring in your normal amp sound but the tinny sound remains. 1
Dual Op-Amp and Crosstalk The DSL 50/100 amplifiers use a number of dual op-amp integrated circuits to reduce total chip count and cost of the PCBs. HERE
Note that a single non-inverting op-amp buffer circuit is used IC2a is used to buffer the audio signal coming from the selected pre-amp channel after some attentuation to keep the audio signal within the limits of the op-amp at high volumes.. The proximity of the susceptible circuits to the large tone control voltages allows the buffer to pickup the higher frequency audio signals and transmit them into the FX loop. https://hub.docker.com/r/taworlnessett/macintosh-hd-storage-for-mac-pro-desktop-2012
I found that I didnt want to use the FX loop because of this If you turn the amp up, you can hardly notice the effect and it sounds much better - but I just couldnt get on with the low volume sound at all.. Man I have 2 JCM2000 dsl Both are modified to fix the problems. CON10 has IC voltage supplies and the FX send signals Hence, the modified circuit sits in between CON10 on the main tone control/channel selector PCB and the corresponding connector on the rear PCB.. Care was taken to minimise the track lengths within the noise susceptible areas and to use low noise metal film components.. On its own there is little wrong with the circuit, however the audio path between R40, R39 and IC2a ve input is a high impedance circuit and is susceptible to noise pickup, this is the source of the problem. 0041d406d9 4
The other half of the RC4558 op-amp (IC2b) is used in the tone circuits around the presence control and deep switching elements.. Whilst some of the problems I believe are caused by losses in the pedals/fx units themselves I did find the amp sounded horrible with the loop on at low volumes - the sort of levels you might use at home to practice.. Before we even get started here we need to address the MOST asked question about all Marshall DSL and TSL 50, 60 and 100 watt amps. 5