For any of you that want to know and others searching the boards in the future..... Some people complain about how the reverb control and master volume (Presence) react to each other after the mod is done. There is a way to fix this. It requires to jumpers (wires), 2 trace cuts on the board and a .1uf 63v capacitor. The mod moves the reverb signal from going through the master (presence) pot and sends it through the Power Amp in, OP amp (IC) input to blend correctly? with the amp signal. It also changes the feed signal to be reverberated, by coming from the Pre Amp out, OP amp (IC) output. This mod is for the older YCV40's 2000 to 2005? The reverb now sounds very lush and Fen**ry and is no longer tied to the master volume. WARNING ! I am not an expert, just a hobbist sharing my experiences. If someone can explain better than me, please chime in. I am not responsible for what may happen to your amp ! I have made these changes to my amp and have logged several hours playing time on it with no ill effects, not syaing these changes are risky...I just don't know what you may do to your amp....they have worked fine for me. Attached are the scehmatics and layouts. Also adding a .22uf cap to the .33uf cap already there @ C27 made the OD channel a home run for me....very British sounding !
In the layout drawing, the portion circled is the regular master volume mod changes, made by most. The rest is the reverb control mod. The red circles with red lines in them indicate where to cut the traces on the circuit board. On the schematic these are indicated with a red " X". Instead of a 10k resistor in the master mod, you can use a pot instead, to retain the Presence control....if desired.
In the layout drawing, the portion circled is the regular master volume mod changes, made by most. The rest is the reverb control mod. The red circles with red lines in them indicate where to cut the traces on the circuit board. On the schematic these are indicated with a red " X". Instead of a 10k resistor in the master mod, you can use a pot instead, to retain the Presence control....if desired.
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