ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

Crackled sound with Marshall-clone

10/16/2000 8:08 PM
Dion	Crackled sound with Marshall-clone Hi, I've been working on an old 100w non-NMV Marshall-clone to get rid the hum and hiss, which was mainly caused by a bad layout. I picked it up quite cheap. Recently I was crancking up the amp, and (to me) the amp in combination with a standard 4x12 cab (Celestion 75W) was making strange crackling sounds. With the volume set at 5, the amp was bringing up some nice distorted sounds. At 9 nice, smoother distortion, but when the low E is hit hard and is muted, sometimes the amp/cab crackles. At 10 it occurs with every power chord. It sounds somewhat similar when an audio speaker can't handle the wattage of it's amp. Now I'm wondering: what is this? The cab is rated at 300W and the amps output may even exceed 100W when fully crancked. I've built an DIY 5E3 Deluxe which is driving a greenback. I can hear the speaker break up, but this is not what the 100-watter is doing. Is this cross-over distortion? I haven't tried yet to lower the bias current of both my DIY 5E3 and JCM combo to hear if it really is cross-over distortion. Has anybody an idea? Dion

10/16/2000 8:08 PM

Dion

Crackled sound with Marshall-clone

Hi,

I've been working on an old 100w non-NMV Marshall-clone to get rid the hum and hiss, which was mainly caused by a bad layout. I picked it up quite cheap.

Recently I was crancking up the amp, and (to me) the amp in combination with a standard 4x12 cab (Celestion 75W) was making strange crackling sounds.

With the volume set at 5, the amp was bringing up some nice distorted sounds. At 9 nice, smoother distortion, but when the low E is hit hard and is muted, sometimes the amp/cab crackles. At 10 it occurs with every power chord.
It sounds somewhat similar when an audio speaker can't handle the wattage of it's amp.

Now I'm wondering: what is this? The cab is rated at 300W and the amps output may even exceed 100W when fully crancked.

I've built an DIY 5E3 Deluxe which is driving a greenback. I can hear the speaker break up, but this is not what the 100-watter is doing. Is this cross-over distortion? I haven't tried yet to lower the bias current of both my DIY 5E3 and JCM combo to hear if it really is cross-over distortion.

Has anybody an idea?

Dion

Replies:

K BULL This may not be your problem but I ... -- 10/16/2000 9:44 PM
Rebel420 I've also heard bad output transfor... -- 10/17/2000 4:24 AM