Sunn Concert Bass not working--Help

[Seedy]

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.

[dubkitty]

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.

[Seedy]

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.

[dubkitty]

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

[metalmariachi]

This should help a bit.

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

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

MM

[Seedy]

Thanks all.