[Raiderone]

...is this normal?  The heat sink fins are too hot to leave your hand on for more than a second.  I'm using the single ended inputs (set on 2V gain) with a Marchand electronic crossover to power my bass cabinets.  I acquired the amp a couple of years ago and never used it until a few days ago.  I just noticed how hot the amp got tonight when I was about to move it into my stereo cabinet.  I read the manual and it recommends 3.5" of space above the unit, but if this heat is normal then shouldn't more space be required?

Also, the date code is 0531, is this the SST2 version?

Thanks for looking.

[James Tanner]

...is this normal?  The heat sink fins are too hot to leave your hand on for more than a second.  I'm using the single ended inputs (set on 2V gain) with a Marchand electronic crossover to power my bass cabinets.  I acquired the amp a couple of years ago and never used it until a few days ago.  I just noticed how hot the amp got tonight when I was about to move it into my stereo cabinet.  I read the manual and it recommends 3.5" of space above the unit, but if this heat is normal then shouldn't more space be required?

Also, the date code is 0531, is this the SST2 version?

Thanks for looking.

No it should not be that hot.  Leave it on with no input or speaker connections and see if it gets hot.  if so its a bias problem if not either your source or your speakers are causing it to overheat.  It is a 2005 model so it is most likely an ST no an SST.

james

[Raiderone]

Thanks for the prompt response.  I disconnected everything turned it on and it is barely luke warm.  Nothing like last night.  My bass towers are Scan Speak 32W/4878 in sealed enclosures, which are rated at 8 ohms, but they are actively crossed over by the Marchand.  And I was playing the system at a moderate level for several hours.  Could the Marchand be the culprit?

Under normal listening levels how warm/hot should the amp get?  Should I be able to put my hand on it for 5-10 seconds?

The back reads:  3B-SST-PRO-120.  When did the SST version go into production?

[sfraser]

I would check your speaker cable connectors carefully for stray wires which may be shorting.

Also  I quickly checked the drivers you mentioned (Scan Speak 32W/4878) the driver spec sheet rates them @ 4ohms. if there is more than one are they configured in Series or parallel ? The spec sheet graph shows a little impedance dip around 80hz, where about is  your external crossover low freq. cut off at?  Depending on your music content, there could be a lot of music information in and around 80hz which could be giving the 3B a little workout. Are you clipping at all?

Cheers,

[Raiderone]

Connections are secure (but I'll check under the plastic coverings).  One driver per channel, so 4 ohm load.  Marchand crossed at 160Hz, 24db slope.  When I touch the driver I can feel very little cone movement; no wild excursions like rumble.  "Clipping" is not audible and the amp never shut down.  Perhaps, I should hook the 3B to a full range speaker to if it will overheat.  It could be that the combination of the SS driver and Marchand and jazz music is the cause.