Fender champ 25 se amp diagnostics

[Wildefalcon]

I've had this little amp for decades, and am using it with my bass at low volume.

Recently it's started really distorting for periods of time and then crackling before settling down back to the warm tones I like. It then pops and crackles occasionally.

Anyone got any ideas as to where I should start? Are new valves a good idea? It's got three, probably original since new.

It's a hybrid valve amp if that makes any difference.

 

[voipio]

Is the distortion altered by mechanical movement, or tapping the cabinet? Check for bad contacts on valve bases and other parts of the signal chain, including the input jack!! I've had one of those go on a fairly high end keyboard. A bit of contact cleaner sorted that out. Also take a look at the electrolytic capacitors.

 

[gaz1]

old parts die with age so you will have to go through each one to find the issue

the ceramic pots and capacitors are known to fail

as goes for joints they dont go as bad as the new soldered joints as they was properly soldered

only tvs as they was high power with heat involved with them

 

[Wildefalcon]

Well, tapping on the cabinet does nothing much, so I think it's time to find a tech to look at it.

 

[voipio]

Might it be the guitar or cable that's the problem?

 

[Wildefalcon]

Good point. I'll try both in the big bass stack.

 

[Wildefalcon]

I hate this, but it might be cheaper to get a new amp than to get this one fixed up, madness.

 

[Hotstuff]

You’ve done it now wildefalcon; challenge extended.

 

[m_c]

Could be a valve starting to die, but there are far more knowledgeable people on these things than me.
I'd highly recommend posting on thefretboard.co.uk , as there are a couple guys there who know most amps inside out.

 

[Misterg]

Recently it's started really distorting for periods of time and then crackling before settling down back to the warm tones I like. It then pops and crackles occasionally.

Input jack is a likely culprit - I think it's soldered to the PCB (ISTR fixing one with a similar sounding fault for a mate a few years ago.)

As above - ask on thefretboard.co.uk and you will get very knowledgeable answers, and guidance on repair. (Same username, but not very active these days.)

Amps Discussions on theFretBoard

www.thefretboard.co.uk

ETA: Rule out things like the guitar and (especially) jack leads by swapping them if possible before delving into the amp.

ETA2: No disrespect intended to this forum or anybody on it - if somebody 'over there' was asking about welding, I'd send them here.

 

[Wildefalcon]

I'll do that.

 

[Wildefalcon]

Well, that's a decent website: there's a tech in Hereford that I think I'll drop it into for a repair.