Twin Reverb - Changed speakers WTF!!!!

lamf68

I picked this amp up last week, got rid of my other twin to replace it, I knew one of the speakers in this was frigged as it had a hole in it, replaced them with Jensen C12K's 100wt 8ohm...can't really say if the amp was doing this before as it was a hell of a racket with the broken speaker. I have uploaded a video to youtube to show the problem which is doing my head in, but have no idea what's causing it, could I have Funked up the installation of the speakers? or is there a Tube/Capacitor/Transformer issue.

Aside from the strange row it starts off sounding like a microphone in  gale force wind

https://www.youtube.com/watch?v=MMc_JaPQwxA

ICBM

That sounds like a blown power valve.

Have a look round the back while it's doing that, and see if you can see anything that looks odd. If not, try tapping on each one with your knuckle and see if it does it - although they're often so sensitive that even tapping another one can make the bad one make the noise.

Richardj

I thought the 'hmmm' was very restrained.  If it were me it would have been 'f*ckin' thing!'.

Bad valve(s)?

lamf68

ICBM said:

That sounds like a blown power valve.

Have a look round the back while it's doing that, and see if you can see anything that looks odd. If not, try tapping on each one with your knuckle and see if it does it - although they're often so sensitive that even tapping another one can make the bad one make the noise.

Power Valve!...you're talking to me now mate. I wouldn't know a power valve from a power-ranger.

lamf68

Richardj said:

I thought the 'hmmm' was very restrained.  If it were me it would have been 'f*ckin' thing!'.

Bad valve(s)?

hmmm!...was preceded by many an expletive, it's a strange one because it can play sweet for 20 minutes then this crap happens, it's intermittent and sometimes it's there from the off and other times it doesn't start playing up for 5-10 minutes!

meltedbuzzbox

lamf68 said:

Richardj said:

I thought the 'hmmm' was very restrained.  If it were me it would have been 'f*ckin' thing!'.

Bad valve(s)?

hmmm!...was preceded by many an expletive, it's a strange one because it can play sweet for 20 minutes then this crap happens, it's intermittent and sometimes it's there from the off and other times it doesn't start playing up for 5-10 minutes!

have you checked everything is seated nice and tight? Cables, valves etc?

Is it only lower frequencies that trigger the noise?

lamf68

I couldn't say if that's what triggers it mate, it comes and goes. When I was fannying around with it this morning I flicked to the neck pickup on the les paul and it started then, so maybe that's what started it off, but it happens when there's nothing plugged in, and when on the bridge pickup too. I was hoping it was a lead issue but it happens when nothings plugged in either.

ICBM

Power valves: the four large glowy glass things in the back, left-hand side as you look at it from behind.

When a power valves goes badly microphonic (a techy word for vibration-sensitive ) it tends to make that sort of noise, which can be triggered either by bassy sounds or just by vibration in the room, and once it starts it can be self-sustaining because the speakers are in the same box.

lamf68

Cheers again man. I've just dropped it off at a local(15 miles away) amp tech, Wynne Jenkins of Gowerton , dunno if anyone from Wales -Land has heard of him, anyway, seemed a nice fella sounded like he knew what he was talking about and he's assured me it'll either be fixed or Fu**ed by Saturday evening which is when I need it back. The complete irony of it all is I have just sold my Orange gear and My other twin leaving me amp-less for a gig on Sunday. Once again, I appreciate the input, I'll let you know how it pans out on Saturday evening, hopefully it's just the output Tubes as mentioned.

dandl

@lamf68 just to put your mind at ease. I've used Wynne tons of times and will do so in the future. He's done plenty of work on guitars and amps for me and has always done a first class job. Oh and he's a lovely bloke too!

lamf68

@dandl , yeah he was a lovely fella, He recently repaired a mates Artisan and he gave me his number, I'd have never known he existed otherwise. Kinda felt for him knowing he was gonna have to lug that beast of mine around his workshop though!

lamf68

Wynne, the man has saved my bacon. Dead Capacitor and two valves Frigged...cleaned it all up in there re-biased the power tubes all for the measly fee of £130.00....delighted aint the word. Thanks for your input lads. And if any of you in the South Wales area need an amp or guitar tech just give this fella a shout. he showed me half a dozen of his creations and I was blown away with all the weird switches he'd installed on them, but the shit those switches could do were incredible. Gonna have him potch around with a couple of mine when I finish spraying them. absolute Genius of a bloke, he's invented something for Gibson Recently too, some freaky deaky 5 way switch thing, or was it 8 way!!!!