blown amp - vintage speaker the culprit?

Calling on the collective experience/ knowledge, here:

A while ago, i was given a pair of vintage speakers. They appeared to be working without issue at the gentleman's house and seemed to work fine for a while at home as well.

After a bit of listening a couple of nights ago, I noticed some distortion in the right channel. It seemed intermittent at first, but gradually worsened.

In an attempt to determine if it was the speaker or the amp that was the problem, i powered down and unplugged the unit to swap speakers left and right (to see if the problem stayed in the right channel, which would make it an amp or source problem - or if it moved to the left - speaker problem). When i connected everything and powered up again,I heard a loud buzz come from the amp for about 4-5 seconds, after which it clicked on to 'ready'. However, now the right channel was dead. I tested the left channel; working fine with both speakers.

While at an audio store in Toronto today, the owner of the store suggested that it could have potentially blown because of a faulty speaker (eg. caps are toast/ issues with crossover etc).

Although I understand that a speaker's sound quality can diminish over time, I was never under any impression that a speaker can blow an amp (provided the amp and speaker were a good match in the first place and in proper working order).

Is this true? can speakers that are out of spec cause an amp to blow?

NOTE: the amp in question appeared to have a slight problem developing with the power-on safety relay even before connecting the vintage speakers, whereupon it began to develop a loud hum/ buzz (emanating from the amp itself) before clicking into 'ready' mode. I mention this b/c I believe the blown channel likely does not have anything to do with the speaker, but i would like to hear what you guys have to say on the subject.

(pairing is Sugden A48B amp with epi100's)
Highly unlikely the speaker caused the problem unless the crossover/caps were out of spec to the point the impedance of the speaker dropped to 1 ohm or less, essentially shorting out the channel in question.

This looks like a boutique or DIY type solid state amp? I'm not familiar with the model. Either way does the amp have overload protection in the topology to protect the amp from the conditions mentioned.

Hi Apache,

It's possible that the caps are that out of spec, i suppose, since they are about forty years old or so, if i'm not mistaken.

The amp is not a DIY or boutique amp; it's an old british amp that's been modified (better caps, point to point wiring etc).
I'm not sure if there's any protection for it aside from four fuses (which didn't blow when the channel went).
Swapping speakers and blowing a channel is a short in the wires which the op created.
No matter what else, that fact the op swapped the speakers and immediately had the failure is CLEAR it is a wiring issue the op caused.
I would bet 100% that a short in the wiring is the cause.
Check you amp rail fuse.
If it has them, you are saved, just replace the rail fuse in the amp on the blown channel. If the amp does not have them, then your amp is toast.
Elizabeth, there was no short in the wiring at all. Everything was powered down, the amp unplugged from the wall. The speakers were the only things swapped (and i have pin connectors, so no bare/ frayed wires were crossing over). Not to mention, that's the first thing i always check (been around the block a few times)

The fuses in the amp are not blown - I checked them already.

As mentioned in the latter part of my original post, i HAD noticed a problem with the amp already. Further, the problem started becoming apparent during extended listening (before anything was swapped in the first place).

So, no, it was not a short that i created by crossing wires at the speaker or amp connection point - I'll bet YOU 100%.
Not the loudspeakers faulty seems more like user error or amp issues not related to loudspeakers
amp problem, yes. User error? No.

The amp was just sent in for service. Faulty output transistor as well as a problem with the power relay.

thanks for your input, guys (even from the finger-pointers ;) )