I have an old stereo speaker cab rated at 8 ohms and 25 watts, it has like a 1/8 jack hole, can I safely use say for a temporary fix, a little pedal jumper cable with a 1/8 inch converter on one side or, a 1/8 inch cable with a 1/4" converter?
I guess so, as long as you're using speaker cable and aren't mismatching ohms or using too much wattage.
I'll be playing with a guitar cable from joining pedals not a speaker cable, so it will be about 6 inches long, I will be using a 200 (160 at 8 ohms) watt bass amp turned to like 1 (light test)
Don't do it without a speaker cable, you could seriously damage something.
What I mean is don't connect the amp to the speaker without a speaker cable. I also would not connect a 200w bass amp to a 25w speaker. The speaker will blow.
all I needed to know, I have one actually, now that I think about it, 1/4 on both sides, can I plug a 1/8 inch adaptor into it without any reprocussions?
I'd be playing it at low levels if at all
Again, I can't think of any reason you'd run into problems.
I've never seen any decent speaker cab with an 1/8" connector. Low powered computer speakers have them. That 25watts may be peak or peak to peak watts, which really means a few watts. The 6" instrument/pedal cable probably won't burn up before the speaker blows so you could use it. Go for it, just keep the vol low.