Speaker Swap kills V15G. Help

[AcroCaster]

From a new SS amp with no frills and (theoretically) little to go wrong? Really, really poor build quality.

Honestly, I know you don't want to hear this, especially since you seem to have sunk a lot of time into this already, but all this time spent trying to diagnose something that was never meant to be serviceable is time not spent playing guitar. This is why as a teacher it always pains me when beginners or parents ask for gear recommendations and then totally disregard it and buy something junky just because it had a few good reviews on amazon and they figure it's better to play it safe in case they or their kid quits.

So you voided the warranty. Ok, lesson learned. At least it was only a $70 lesson instead of a $700 one. I commend your persistence, but I would suggest setting a time limit, after which you throw your hands in the air, say "I'm done" and then scrape together a couple hundred bucks for something that was made with decent quality control, even if it's used.

I've already got a brand new Fender Champion 20 in the box, awaiting the timewhen I can make use of it.

What I want is to get the 15 watt tweed 8 in speaker running so I can begin at the beginning.

What I need is advice on how to trouble shoot a cheap amp, not advice on how to spend more money.

But thanks for the concern,

 

[DanglingNutslots]

What’s wrong with some of you guys? The OP bought something, made a change, it stopped working. He’s asking for some help. No need to put down his purchase.

 

[Old Verle Miller]

From the audio spectrum view those second and third tonal components look to me like harmonics and something tells me there's a signal somewhere in there that's leaking and getting fed back into the system.

Without a service manual and schematic and an O'scope, tracing down the component(s) that are causing it is all but impossible. I don't know if the amp is modular enough to be able to swap out a preamp board but you could start with that.

 

[schmee]

Well, seems weird and like you were careful.
I wondered about the shielding touching a wire or something, but that doesn't seem the case.
Be sure to test the new speaker.
My guess is it was a bad amp from the get go.

Buy another, you now have the baffle you need anyway.
I doubt you'll have an issue returning a brand new 'bad out of the box' amp with the seal broken. (at least not from a reliable seller)
If amp #2 works, put it in your modified cab. Re assemble the bad amp in the new cab etc. Return it for refund.
They often refund on new items once the shipper shows you shipped it.
Fender will likely never inspect the amp.
My local GC had 3 brand new defective Blues Jr's for sale cheap, "as is".
They were all defective from the factory and Fender didn't want to mess with them to repair at all.

 

[schmee]

What’s wrong with some of you guys? The OP bought something, made a change, it stopped working. He’s asking for some help. No need to put down his purchase.

Yeah, there's room for them over on the Gear Page.

 

[DanglingNutslots]

Yeah, there's room for them over on the Gear Page.

Hehe. Yeah. It’s why I don’t go there anymore.