SWR Trouble

[Rumblejohn]

I have been using a little SWR Workingman 10 with my EUB. At the last rehearsal it would crackle just a bit on F2 and Bb2 sporadically. It quit the crackle, but volume went way down. It it is not distorted, just much lower volume. Is it time to send it to the tech, or is there anything I can check first.I have another amp to use, Eden WT550, with a XLT210, sounds great, but not nearly as portable.


Thanks for any advice

John

[fdeck]

Here is the universal first thing to try: Does the amp have an effects loop? Sometimes the contacts in the FX loop connector, particularly on the "return" side, corrode with time. You can see if this is happening by sticking a patch cord into the FX loop and seeing if it revives the amp. You can exercise those jacks by plugging and unplugging into them several times, and see if that helps. You can also see if the amp basically works when feeding a signal directly into the FX return, which would tell you if the problem is in the preamp or power amp.

I've repaired a lot of amps. Based on experience, most amp problems are mechanical in nature, rather than electronic. High on the list of prime suspects are connectors, pots, and the solder joints between those components and the printed circuit board. If you can do this safely, it is often possible to find mechanical problems such as cracked solder joints or cracked circuit boards by visual inspection with a bright flashlight and magnifying glass.

Last but not least, there's the connection and wiring to the speaker, and your cables. I hate to admit the number of times that I have fussed with an amp, only to discover that I had been using a damaged cable.

[Rumblejohn]

I think you may be onto something with the effects circuit. I'll attempt to clean up the pot and contacts later this week. I wish I could find a way to make the little SWR sound as good as the Eden, of course there is a significant difference in price.

Thanks for the tip,

John

[tornadobass]

Some of the SWR combos use a 1/4" plug to connect the speaker to the head. I had a Workingman 12 that needed the plug sprayed with DeOxit occasionally.

[Rumblejohn]

I'll try by-passing the speaker to another cab. No luck with the effects loop. If all else fails I'll take a look at the solder joints, eyes aren't what they used to be, and they weren't that great then.

John