birt
3 april 2004, 12:21
mijn jmp 100w klinkt me te schel, de hoge tonen zijn niet warm genoeg terwijl ik de treble toch bijna volledig toe zet. ik zoek dus een mod die ik zelf kan uitvoeren (dwz goede uitleg) ik heb wel al wat gezocht maar ik ben leek en snap er niet genoeg van
dit vond ik:
Marshall JCM800 2203/2204 Mod(s)-
1. Locate the 68K input resistor (R3) and place a 330pf 1kv ceramic cap across it. This will beef up the mids and lows and make the entire amp feel more "meaty" and "thick".
2. Locate the 10K cathode resistor (R6 found on V1B) and replace it with a 4.7K resistor. This will beef up the gain. This seems to be the "sweet-spot" on these amps. If you want insane gain use a 1.5K.
3. Locate the 820ohm cathode resistor (R9 found on V2A) and place a .68uf cap across it. This will increase the gain a little, and give you a nice "Plexi" midrange boost.
4. Locate the 33K "slope resistor" which is in the EQ section (R15) and replace it with a 47K resistor. This bumps the amp's entire midrange frequencies up a notch. The result is a very "fat", "thick" or "beefy" tone that is really awsome.
5. Locate the 22K Midrange knob (VR4) and replace it with a 50K Liner or Log pot. This is for those who are seeking more flexibilty out of the midrange knob.
6. Locate the .68uf cap (C1) which is found on V1A and replace it with a .47uf cap. This alters the midrange response and adds a "heavier" tonal quality to the amp.
Note: All resistors are 1/2watt unless otherwise specified and caps/resistors are marked according to the Marshall schematics.
----------
Marshall Model 2203 JCM800's are notorious for having a very bright normal channel. This is due to an input series resistance which is very different from the Classic Marshall circuit. (470k Ohms vs. 68k Ohm). The following mod details a method of warming up the tone on these amps.
1. Replace the 470k Ohm resistor that is tied to the input tube grid with either a 68k Ohm, 34k Ohm or 10k Ohm resistor. The lower the resistance, the darker the tone, but 68k is the "classic" value. (Don't be tempted to remove this resistor altogether). It has to be there to attenuate the grid circuit and prevent excessive overload conditions.
2. Remove the 470pF cap which bridges the 470k Ohm resistor you just removed.
The combination of these two quick mods should return the normal channel of your JCM800 to a more classic and warmer Marshall tone.
ik wil dus een vetter geluid zonder de bas volledig te hoeven openzetten (dan gaat hij soms wat modderig klinken) en zonder de treble volledig te moeten wegdraaien
dit vond ik:
Marshall JCM800 2203/2204 Mod(s)-
1. Locate the 68K input resistor (R3) and place a 330pf 1kv ceramic cap across it. This will beef up the mids and lows and make the entire amp feel more "meaty" and "thick".
2. Locate the 10K cathode resistor (R6 found on V1B) and replace it with a 4.7K resistor. This will beef up the gain. This seems to be the "sweet-spot" on these amps. If you want insane gain use a 1.5K.
3. Locate the 820ohm cathode resistor (R9 found on V2A) and place a .68uf cap across it. This will increase the gain a little, and give you a nice "Plexi" midrange boost.
4. Locate the 33K "slope resistor" which is in the EQ section (R15) and replace it with a 47K resistor. This bumps the amp's entire midrange frequencies up a notch. The result is a very "fat", "thick" or "beefy" tone that is really awsome.
5. Locate the 22K Midrange knob (VR4) and replace it with a 50K Liner or Log pot. This is for those who are seeking more flexibilty out of the midrange knob.
6. Locate the .68uf cap (C1) which is found on V1A and replace it with a .47uf cap. This alters the midrange response and adds a "heavier" tonal quality to the amp.
Note: All resistors are 1/2watt unless otherwise specified and caps/resistors are marked according to the Marshall schematics.
----------
Marshall Model 2203 JCM800's are notorious for having a very bright normal channel. This is due to an input series resistance which is very different from the Classic Marshall circuit. (470k Ohms vs. 68k Ohm). The following mod details a method of warming up the tone on these amps.
1. Replace the 470k Ohm resistor that is tied to the input tube grid with either a 68k Ohm, 34k Ohm or 10k Ohm resistor. The lower the resistance, the darker the tone, but 68k is the "classic" value. (Don't be tempted to remove this resistor altogether). It has to be there to attenuate the grid circuit and prevent excessive overload conditions.
2. Remove the 470pF cap which bridges the 470k Ohm resistor you just removed.
The combination of these two quick mods should return the normal channel of your JCM800 to a more classic and warmer Marshall tone.
ik wil dus een vetter geluid zonder de bas volledig te hoeven openzetten (dan gaat hij soms wat modderig klinken) en zonder de treble volledig te moeten wegdraaien