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louloomis

110 RD-50 Goes Silent with 8.7 Ohm External Speaker?

Hi Everyone,

Please excuse this question if it is naive in some way:

Background:
1. I have a 110 RD-50 combo. It sounds great - no known issues.
2. Today, I unplugged the internal speaker jack from the back panel. In its place I plugged in an external 2x12 cabinet (which I just got) which on my meter reads 8.7 ohms.
3. I played through this cab for about 3-5 minutes and the amp went silent all of a sudden (power light was still on). I turned the amp off immediately.
4. I then unplugged the 2x12 and plugged in the internal speaker again, powered up the amp and the amp sounded fine.
5. I then unplugged the internal speaker again and plugged the amp this time into a different external speaker I have (1x12) which reads something like 6.7 ohms on my meter. I turned the amp on again.
6. The amp sounded fine through this external 1x12 speaker.
7. I used the same speaker cable for each external cabinet cited above.

Question:
Is the amp turning itself off because the load for the 2x12 is greater than 8 ohms? Or am I jumping to conclusions here or something else? I thought that ohm load was still within acceptable tolerances, but I could be wrong.

Thanks for any input and let me know if you need more info please.

Regards,
LL

mgriffin155

What's going on inside?

Hi, What was the ohms reading on the 2x12 after it quit working? Did it change? Open it up and check the wiring. There could be a loose wire, bad solder joint or poorly crimped connector inside. Good Luck, -mgriffin

louloomis

Cabinet Speaker Output Jack Cleaned w/De-Oxit / Amp Works Fine!

Hi. Thanks very much for the input. Apologies for not thinking of that myself.

I did the following:
1. I measured the cabinet ohms using my multimeter and it was fluctuating and mostly showing a 3 digit number - something was very wrong here.
2. I removed the jack plate and sprayed deoxit on the contacts.
3. I used a Q-Tip with De-Oxit on it to clean inside the opening through which the jack plug travels itself and the contact where the tip touches.
4. I then sprayed the tip of a 1/4" jack with De-Oxit and plugged it in and out of the speaker output jack several times.
5. I then measured the ohms of the cabinet and saw that it was now 5.1 ohms, which appears to be in the "acceptable range" for an 8 ohm cabinet, based on my research.
6. I then screwed the jack plate back into the cabinet, re-checked the ohms and it was still reading 5.1 ohms (i.e. no wires pinched or pulled loose from the jack plate installation - it was tight in there).
7. I plugged in the speaker cable to the main output of the amp (where the amp's internal speaker is plugged in - same as discussed in my original post).
8. I tested this amp-to-external 2x12 setup for about 25 minutes of playing time and there was no issue this time.

Seems like the issue was with the cabinet rather than the amp as you implied might be the case.

Thanks again for the advice. I really appreciate it.

Regards,
LL

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