ilovefuzz.com

I use a Sunn Concert bass head that stopped working. Other than some scratchy pots it worked wonderfully before I just had to record a bass line in the wee hours. I took a chance and plugged the line-out direct to my board but didn't connect anything to the speaker outs to bear the load. The recording came off without a hitch but the next time I plugged the amp in I got no sound. I would add that the lighted switch also didn't come on, but it never did even when it was working.

Is it just a fuse? And can I fix that myself? Despite playing for 22 years I've never taken an amp apart.

it could be several things ranging from minor to catastrophic, but when you aren't getting an amp that's correctly connected to power and a known-working cabinet to light up, the first thing is always check the fuse(s). some amps have more than one fuse; look for a manual, schematic, or other info online to find out. most amps are made with the fuses in little spring-loaded clips or round sockets with spring-loaded caps located on the back panel, often helpfully labelled "FUSE" which i always appreciate; fuses can also be placed near the power cord connection in a similar clip or, like my Laney, in a difficult-to-see little battery-style compartment. fuse placement on the amp's front/control panel is rarer, but i've seen this, especially on old (pre-1970) amps. sometimes fuses are placed inside an amp on the chassis, but most amps have the fuses in immediately accessible positions.

Thanks dubkitty. I did look for an easily accessible fuse port but to no avail. On the back there is a circuit breaker button that didn't appear to do anything, a polarity switch (i know what that does), and the ol' "no user serviceable parts inside" label. I'll try to find a manual on-line to start.

search on TalkBass also...they seem to have a number of threads about this amp there. and on the Sunn amp forum: http://sunn.ampage.org/sdp/index.php

This should help a bit.

http://www.schematics.ca/modules/PDdown ... 8&lid=1411

http://sunn.ampage.org/site/schematics/concertbass.gif

MM

Thanks all.