HELP! My amp is behaving strangely… Can it be fixed?

waltschwarzkopf

waltschwarzkopf

New member
HELP! My amp is behaving strangely… Can it be fixed?

Hi guys,

I have a small practice amp that I bought back in the year 2000. It has served me well at home, studio and garage practice; sadly, now is behaving strangely.

It is a 15W solid-state Marshall combo model G15RCD, in case you have not heard of it, here are some links:

Reviews: https://www.ultimate-guitar.com/reviews/guitar_amplifiers/marshall/g15rcd/

Manual: https://www.manualslib.com/manual/99221/Marshall-Amplification-G15rcd.html#manual

Although it is a small amp, the volume stays on 2-3 for home practice. It has only one channel, so I set it to crunch and change the gain with the volume controls of the guitar.

The problem is that after playing it for a short while the sound starts to go on and off, then the gain goes until it the sound disappears completely. I have to crank it up all the way to 11 to be able to hear a clean sound at low volume. If I stop playing it for a while, it goes back to normal. This does not happen every time I play it, but it does happen with all of my guitars, so it is not a guitar nor a cable problem.

What do you think? Can it be fixed? I am quite handy with electronics and I like rewiring my guitars, but I have never worked on an amp before. I have heard on other amps that you can replace the OP amps, capacitors, and other parts, but I do not know where to start! I have checked the connection to the speaker and it seems fine, although I will disconnect it and clean the contacts just to be sure.

I hope that you can help me on this, I really like the sound of the amp and would be very sad to let it go.

Cheers!
Walter

P.S. If you live in Zürich and want to get together and jam, send me a PM and bring two amps!
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

Have you tried changing the tubes?
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

(Kidding. Sorry. I don't know what's wrong with your amp.)
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

Seems like I'm wanting to remember that SS Marshall's around that age had some sort of issue with a switch built into the input sockets that gets out of spec or corrodes and kills the volume.

First thing to try is some deoxit to clean those inputs (FX Loop sockets too) and see if that helps.
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?


Watch these and read the comments, I know it's not your exact amp but may help. Good luck and be careful if you open the thing up and don't juice yourself.
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

Hi guys,

Merry Xmas and Happy New Year to all of you. Here's an update on the status of the amp.

After letting it rest for a week, I plugged it in again to have a jam. I was very sad to find out that it did not work at all, even with the volume cranked to 11 no sound came out of it. To make things worse, it makes a horrible high-pitched noise that can be "controlled" with the Gain1 knob, at 10 is loudest and below 5 is almost unnoticeable.

I opened it up to have a look and the board and all the elements seem ok, I'm not an expert but there were no loose wires, exploded capacitors or burned components. All the knobs turn smoothly and everything else is tightly in place. The Gain2 knob was a bit darker on the back, but that was not the problem with the high-pitche noise nor with the volume issue. I put it back together and reconnected the speaker and it was still the same, no guitar sound, only the horrible pitch.

I'll appreciate all the help you can give me. Otherwise, I'd have to declare it legally dead and find a used equivalent or go for a new amp (Bassbreaker 007 comes to mind).

Cheers,
Walter
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

I was going to suggest maybe replacing your cables, but then I read your second post. I am not an expert on amp wiring, but I sounds to me as if your connection between the power amp and speaker may be bad. If that is not the problem, I have no idea what is, it might be junk.
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

If you are looking for a new amp her are some recommendations:
Orange Crush/Crush Pro series
Orange rocker series
Boss katana
Fender hot rod deluxe
Bassbraker series
Vox ac15
Marshall DSL40
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

Good excuse to buy a new amp. If you cant track the problem down yourself, spending money on a tech is false economy on an amp like that.
Plenty of excellent amps out there for not a lot of money these days.
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

^ good point.

If you still like combos and don't mind tubes you can't go wrong with this 12" beauty
https://marshallamps.com/products/amplifiers/mini-jubilee-series/2525c-mini-jubilee/

Or this...
https://peavey.com/products/index.cfm/item/658/118120

The Marshall uses a greenback speaker, which I think is great for cleans, rock and blues. I wouldn't recommend it for metal.

I had the Peavey and it was very versatile plus it has reverb. Very durable too.

This one looks like it can do it all and it has a great, versatile speaker, 12" as well.

http://hughes-and-kettner.com/products/tubemeister/tubemeister-36/tubemeister-36-combo/
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

PierceOkken said:
If you are looking for a new amp her are some recommendations:
Orange Crush/Crush Pro series
Orange rocker series
Boss katana
Fender hot rod deluxe
Bassbraker series
Vox ac15
Marshall DSL40
Click to expand...

I have my eyes on a Bassbreaker 007, I used it on a store to try a Gibson Les Paul and I loved it. I'm gonna try it again with one of my guitars and see if I buy it.
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

I saw a used Hughes & Kettner Blue Edition 15R for 90CHF. It's pretty much the same as mine and according to the reviews it looks to be a good sounding amp. What do you think?
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

BREAKING NEWS!!!

Hi guys, I haven’t given up on my old friend yet. I brought some tools and other components home and I think I’ve managed to track down the problem.

Hear me out:

If I connect my phone to the CD input, it sounds great. I control the volume from the phone and there is no hum or annoying pitch. Which means that the speaker works.

If I connect the phone to the guitar input it also works AND I can change the volume, gain and EQ settings from the amp. Which means that the amp controls work too!

If I connect my guitars (all of them passive) to the amp input, no sound comes out (hence the thread). BUT if I connect the guitar to an amp app on my phone and then the phone to the guitar input, it works!! And all the controls too.

I wouldn’t like to run the amp like that, because it’s a bit annoying with all the cables. But it makes me think that the Voltage from the guitar is too low to drive the amp, as the phone output does drive it well. Since the output of the guitars is the same as always, it must be something between the guitar input and the amp itself.

Could be a loose connector somewhere? The OC amp?

Come on guys! I’m really close on this one and I know that the problem is simple and there is still live in the old amp.


Sent from my iPhone using Tapatalk
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

Are you using the same cables to connect your guitars to your phone that you use to connect them to your amp?
It sure sounds like a bad cable to me.
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

Dave Locher said:
Are you using the same cables to connect your guitars to your phone that you use to connect them to your amp?
It sure sounds like a bad cable to me.
Click to expand...

I checked the cable when the problem first occurred. I checked the cable visually and its fine, I also measured resistance and continuity on the tip and jacket and it’s also fine. I don’t have another cable, but I will try hooking up the guitar directly with the wires I use for measuring and if I still don’t get good results I’ll buy or borrow a cable just to try.


Sent from my iPhone using Tapatalk
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

Definitely sounds like a bad cable, might be worth buying a new one, never hurts to have an extra or two around.

Other than that, you might try taking a soldering iron and reflowing the solder joints on the PCB, sometimes they get intermittent.
 
Re: HELP! My amp is behaving strangely… Can it be fixed?

Re: HELP! My amp is behaving strangely… Can it be fixed?

Walter I think your relentless Malmsteen-like shredding and power chording made your amp give up its ghost. Shell out some of those franks for something better than a beginners amp.
 
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