Anyone want to help me fixing/modding my JCM800? Clip Added!

[duesentrieb]

It all depends on your taste. If you keep the gain level pretty much as it is, keep the 68k. If you increase the gain and you get annoyed by the hiss when the amp is idle, just use a smaller value. Easy fix, just decide . . .

 

[JakeAC5253]

What causes idle bias current to vary so wildly? At first when I biased my amp it was at 41mA. I used it without checking it for a week or so, then I checked it again and it was at 43mA. Then I set it to 38mA and used it for a while without checking, checked it again tonight and it's stable at 33mA... Why such extreme drift in stable bias current?

 

[duesentrieb]

smaller variations can be caused by the primary source. Your wall voltage may go up/down 5% easily.
Depending on current consuming devices in your house even more than 5%.
Be careful when you want to check your wall volts with a DMM.
Other than that either the tubes or the electrolytic caps for filtering (all of them incl bias circuitry) would be my next step to check.

 

[JakeAC5253]

Very quick phone recording of my mod progress so far.

At first is 100% stock JCM800, halfway through the clip, the gain switch is set to high gain mode.

 

[HilltopExplosion]

Very quick phone recording of my mod progress so far.

At first is 100% stock JCM800, halfway through the clip, the gain switch is set to high gain mode.

Dude...

 

[JakeAC5253]

Very quick phone recording of my mod progress so far.

At first is 100% stock JCM800, halfway through the clip, the gain switch is set to high gain mode.

Dude...

 

[mchn13]

Very quick phone recording of my mod progress so far.

At first is 100% stock JCM800, halfway through the clip, the gain switch is set to high gain mode.

Dude...

That sounds killer! Didn't remove what was killer about an 800. Still would benefit from a boost to sound tight, but didn't make it sound like something else.

 

[MetalHeadMike]

Very quick phone recording of my mod progress so far.

At first is 100% stock JCM800, halfway through the clip, the gain switch is set to high gain mode.

Dude...

Freezing moon?

 

[JakeAC5253]

Very quick phone recording of my mod progress so far.

At first is 100% stock JCM800, halfway through the clip, the gain switch is set to high gain mode.

Dude...

That sounds killer! Didn't remove what was killer about an 800. Still would benefit from a boost to sound tight, but didn't make it sound like something else.

Thanks man! Yeah, def didn't want to change the character too much. This song doesn't really display it too well, but the amp has a great grind to it in high gain mode. Hit a chord and it just grinds away. Pretty nice for a classic Marshall with no boost.

Very quick phone recording of my mod progress so far.

At first is 100% stock JCM800, halfway through the clip, the gain switch is set to high gain mode.

Dude...

Freezing moon?

Yupp lol. I'm that guy who brings Norwegian black metal to an 80s hair forum

 

[MetalHeadMike]

^^^
Good stuff. Vader s

Can't remember, do you own a Savage120?
I might be thinking of somebody else.

 

[JakeAC5253]

^^^
Good stuff. Vader s

Can't remember, do you own a Savage120?
I might be thinking of somebody else.

No sir, not me. A friend of mine had one a few years ago, but I've never owned one.

BTW, the Vader version was a tribute cover. The original song is Mayhem.

 

[MetalHeadMike]

^^^
Good stuff. Vader s

Can't remember, do you own a Savage120?
I might be thinking of somebody else.

No sir, not me. A friend of mine had one a few years ago, but I've never owned one.

BTW, the Vader version was a tribute cover. The original song is Mayhem.

Thinking of someone else.

Ah! Didn't realize they covered that song. When you said Norwegian black metal I was scratching my head thinking well IDK I always considered Vader DM.