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[Covers4Christ]

Ok, so I was at Church, I play on Saturday Nights AND Sunday Mornings.

Long story short my am broke, I'd like to know what direction to go about fixing it, It's a WAY old marshall 50 watt, like, 20 years old. I don't know much besides that, the model says G50CD.

So here's what happened.

I got to church, and from 4:20ish to 7:30ish, my solid state amp was on, played through service, no problem.

THE NEXT MORNING. I go to church, turn everything on, play 3 songs to warm up with the worship band, Cut my signal with my tuner (to.........you know.......tune) and when I brought up my volume pedal it was like no sound would come out. The amp like would cut back in with a lot of speaker distortion, but then be fine for like 10 seconds, then die the same way again. I went direct in guitar to amp with two different cables, and two different guitars. So It's the amp Im assuming........

What's wrong, Can it be fixed, and how much would it end up costing to be fixed?

Thanks so much to any help that can be offered.

[J M Fahey]

You have 2 "direct" inputs, bypassing the preamp.
1 ) the "power amp input" jack.
2) the "CD In" jack.
Plug your guitar straight into one of them.
Any sound? Clean/Dorty/noisy?
Now into the other. Do the same.
Results?

[Covers4Christ]

Thanks so much for helpn out.

To start of, I dont have a power amp input jack, but I did try the cd input.

The thing that happened worries me, I played through both the input and cd input, both worked as if nothing is wrong..........

So all I have is it worked one night, I came in and it worked, cut the volume to tune, and it kept cutting in and out, when it cut back it it would distort the speaker terribly. Im sorry if that doesn't help......I almost wish it'd have problems....Im scared to rely on it, but I don't want to buy a new amp I can't afford yet when I don't have to.

I will say this.....I had a noise suppresor in the effects loop, I KNOW it wasn't the noise gate that did it, because it was turned off. but could it be a problem in the effects loop perhaps?

[J M Fahey]

1)

So all I have is it worked one night, I came in and it worked, cut the volume to tune, and it kept cutting in and out, when it cut back it it would distort the speaker terribly. Im sorry if that doesn't help......I almost wish it'd have problems....

Don't understand a word, please rewrite.
2) take that noise gate away. I don't care it's turned off. I only want your guitar/cable/amp.
Retest and post results.

[mexicanyella]

Thanks so much for helpn out.

To start of, I dont have a power amp input jack, but I did try the cd input.

The thing that happened worries me, I played through both the input and cd input, both worked as if nothing is wrong..........

So all I have is it worked one night, I came in and it worked, cut the volume to tune, and it kept cutting in and out, when it cut back it it would distort the speaker terribly. Im sorry if that doesn't help......I almost wish it'd have problems....Im scared to rely on it, but I don't want to buy a new amp I can't afford yet when I don't have to.

I will say this.....I had a noise suppresor in the effects loop, I KNOW it wasn't the noise gate that did it, because it was turned off. but could it be a problem in the effects loop perhaps?

You do have a power amp input jack; you mentioned having a noise supressor in the effects loop. The power amp input is the return side of the effects loop.

Try plugging your guitar in there, or some other signal source, and see what happens.

[joecool85]

I vote that the noise gate was messing with things.

[Covers4Christ]

So all I have is it worked one night, I came in and it worked, cut the volume to tune, and it kept cutting in and out, when it cut back it it would distort the speaker terribly. Im sorry if that doesn't help......I almost wish it'd have problems....

So here's what I meant here.......


The issue is that the amp didn't just die, It faded in and out; When it faded out it was extremely quiet, when it faded back in the speaker would distort alot, then the guitar would play through just fine. This happened  Sunday at church when the problem first occurred,  I first checked the guitar/cable, then just when straight Guitar-Cable-amp and this continued to happen.

As for the testing........
I tried with JUST the guitar to the cable, to the amp, no noise gate. Plugged it into the CD input, Regular input, AND the effects loop return, and had no problems, I played with it for almost an hour and not once did I have the problem.

So what I worry about is the fact that as of right now; My amp works perfectly, no problems.

But it had a very real problem on Sunday morning. So I'd almost rather it have problems so I could troubleshoot better, then wait for it to happen again.

I'm gonna hook my pedal board back up today and see if the problem happens or not, the noise gate was off, so I don't think that was the problem, but the cables may have had problems......

THANK YOU ALL SO MUCH FOR HELPING, I had no clue what I was gonna do haha

[J M Fahey]

It was very probably the noise gate. Or its connection.
Many pedals are *always* in the signal path.
The footswitch turns *the effect* on and off (distortion/phase/delay/gate/whatever) but you are still passing through it.
And if it dies or has contact problems, *you* have problems.
Or the gate itself may be fine, but some of the send/return cables may be bad.
Good luck.

[phatt]

Someone once noted that 90% of electrical problems are found in connections.
Not active devices. I tend to agree

ANY Modern Guitar Amplifier that has and Efx Send Return Setup, (sometimes labeled Preamp out Poweramp In) Will at some stage give problems.  Unless I get to them first,,  .

The loop idea is valid except most amps use 3rd rate el-cheapo sockets which are prone to failure or intermittent connection which is the most likely issue.

In your case (as mentioned already) Totally REMOVE ANY gizmo using that loop AND I ADD,,

Go find a short cable and insert it in that loop as this bypasses the  often Pathetic internal Switch inside the Amp which is possibly causing you this grief.
Cheers,, Phil.

[Covers4Christ]

Thanks to everyone.

I hooked up my pedalboard today, no problems.......but when I checked the cables connecting the noise suppressor to the effects loop, I got the same distorting sound along with the extremely quiet volume when I jiggled them around.

I have no clue how the cable kept fading like it did, but that would explain why when I bypassed my pedal board the problem still occured, I forgot to take out my noise suppressor.

Thank you all so much to everyone who helped! I was ready to assume the amp had given up and have to buy a new amp.

You've all been such a help. God bless all of you!

[phatt]

Be very aware that fancy named guitar cables with thick outer sheathing (often claiming insane specs) means little in terms of REAL quality.

The outer braiding in some is worse than my ability to knit,,, which of course is close to zero. 

Not the best pics I could find but might help you understand the difference between good guitar cable and the inferior cheap stuff that is often sold as good quality.

Loose wound braiding will break easier and likely the cable will induce more noise that a tightly woven braid.

I've seen some audio cable with the outer screen so badly made that no braiding actually exists (often just strands twisting around the inner core) you only need to kink it a few times and the outer strands start to break causing a drop in output.

Yes and it was purchased as high quality brand name cable. go figure??

Sadly you will only find this out AFTER purchase.
The only way to tell is by stripping the insulation and I doubt most shops will do that
before you buy

No matter to me cause I make my own up from scratch ,, keeps you soldering skills up as well.

Phil.

[Roly]

Someone once noted that 90% of electrical problems are found in connections.
Not active devices. I tend to agree

 

I dunno about "90%" but it sure is a very high percentage, and this sounds to me more like a dirty connection problem than the noise gate itself.

@Covers4Christ when did you last clean all your plugs and sockets?  Never?  I carry a small bottle of metho and a packet of (smoking) pipe cleaners with a plastic twill.  Folded in half and dipped in the alcohol, then scrubbed into your sockets, and finally used to give the plug stems a good wipe over too.  Almost always fixes these mysterious problems.

If the problem persists after a good cleaning, start taking your plug covers off and looking for stray strands of shield or broken solder joints.