The sunn Forum

Other Musical Equipment => General Discussion => Topic started by: NsubUlysses on December 05, 2010, 03:09:59 pm

Title: Sneaking in an Acoustic 370 question!
Post by: NsubUlysses on December 05, 2010, 03:09:59 pm
Hey I know this isn't the right place for this but there's a lot more activity here than the Acoustic forum. ANY info is greatly appreciated, so here's the question:

Just got a 370 but it seems to be troubled. The volume doesn't really get louder past about 4 and it's almost impossible to get a totally clean sound, especially at higher volumes.

Other things I've noticed are my Sunn Concert Lead is LOUDER than the Acoustic 370. Seems like this should be the other way around, right? The Concert Lead is 100 watts solid state and the 370 is 270 watts (also I had an Acoustic 470 in the past that is 170 watts solid state and that thing was as loud, or louder than the Concert Lead). It also takes about 10 seconds to totally shut down after turning it off. If you play while it's powering down the sound is very crackley and sounds like destruction.

Is this an output transformer problem or a capacitor problem? I should be getting a lot more volume and clarity out of this thing than I am.
Title: Re: Sneaking in an Acoustic 370 question!
Post by: george on December 06, 2010, 07:06:54 am
There is no output transformer?? You need to take it to someone who will check out the power supply, driver and output transistors.
Title: Re: Sneaking in an Acoustic 370 question!
Post by: mckinnon audio on December 06, 2010, 08:04:05 am
   Hi there,the Acoustic is a Capacitivly Coupled amp at the output.There is a large electrolytic cap at the output which eventually fails,check this to see if it's leaky.There is also a small circuit breaker/test function sw. on the main board,check this for dirty contacts.Hope this is of some help,good luck,Mel.
Title: Re: Sneaking in an Acoustic 370 question!
Post by: NsubUlysses on December 07, 2010, 01:11:38 pm
I took the amp apart and found a broken solder that was connected to the smallest of the 3 caps. I reattached it and the amp definitely runs smoother but I still think it's not that loud. Maybe I am overestimating the potential of the Acoustic 370 but I really thought it would be much louder than the Concert Lead. Anyone have both of these amps??

I found this thread and am considering replacing the largest capacitor. Never had to swap parts like this before though. Is it ok to switch just one, or should I replace all 3 caps??


http://music-electronics-forum.com/t9987/
http://www.mouser.com/Pro...Xyht2qZHiDxA%252bQ%3d%3d

thanks for your help!
Title: Re: Sneaking in an Acoustic 370 question!
Post by: xsolarusx on December 07, 2010, 09:05:14 pm
I took the amp apart and found a broken solder that was connected to the smallest of the 3 caps. I reattached it and the amp definitely runs smoother but I still think it's not that loud. Maybe I am overestimating the potential of the Acoustic 370 but I really thought it would be much louder than the Concert Lead. Anyone have both of these amps??

I found this thread and am considering replacing the largest capacitor. Never had to swap parts like this before though. Is it ok to switch just one, or should I replace all 3 caps??


http://music-electronics-forum.com/t9987/
http://www.mouser.com/Pro...Xyht2qZHiDxA%252bQ%3d%3d

thanks for your help!


My bassist has the 370, and I have a silverface concert lead. I'd say they are pretty comparable, volume-wise, though I've never run them both through the same cabinet and measured it.
Title: Re: Sneaking in an Acoustic 370 question!
Post by: grimniggzy on December 08, 2010, 09:59:20 am
Pretty sure the 370 goes down to 2 ohms.
If you're using a 4 ohm cabinet I wouldn't imagine it would blow a Concert Lead out of the water but I would think it'd be a little louder.
Title: Re: Sneaking in an Acoustic 370 question!
Post by: NsubUlysses on December 08, 2010, 10:35:32 am
So basically you're saying I should run the 370 through a 2x15 AND a 4x12 for maximum volume and destruction?
Title: Re: Sneaking in an Acoustic 370 question!
Post by: grimniggzy on January 14, 2011, 07:30:46 am
So basically you're saying I should run the 370 through a 2x15 AND a 4x12 for maximum volume and destruction?

If they're both 4 ohms, then yes.

I always preferred a 2X15 paired with an 8X10 myself.

But you really can't compare anything to the sound of 12's and 15's kicking together, just listen to the Melvins these days.
Title: Re: Sneaking in an Acoustic 370 question!
Post by: stanner on January 14, 2011, 12:39:46 pm
Quote
But you really can't compare anything to the sound of 12's and 15's kicking together, just listen to the Melvins these days.



w o r d
Title: Re: Sneaking in an Acoustic 370 question!
Post by: Soundmasterg on January 15, 2011, 12:40:47 am
Hey I know this isn't the right place for this but there's a lot more activity here than the Acoustic forum. ANY info is greatly appreciated, so here's the question:

Just got a 370 but it seems to be troubled. The volume doesn't really get louder past about 4 and it's almost impossible to get a totally clean sound, especially at higher volumes.

Other things I've noticed are my Sunn Concert Lead is LOUDER than the Acoustic 370. Seems like this should be the other way around, right? The Concert Lead is 100 watts solid state and the 370 is 270 watts (also I had an Acoustic 470 in the past that is 170 watts solid state and that thing was as loud, or louder than the Concert Lead). It also takes about 10 seconds to totally shut down after turning it off. If you play while it's powering down the sound is very crackley and sounds like destruction.

Is this an output transformer problem or a capacitor problem? I should be getting a lot more volume and clarity out of this thing than I am.


This actually is the right place for this, because this section is for general discussion of non-Sunn amps.

Greg
Title: Re: Sneaking in an Acoustic 370 question!
Post by: NsubUlysses on January 16, 2011, 11:51:49 am
I'm getting the amp back sometime next week repaired. something about output transistors and 10V power loss
Title: Re: Sneaking in an Acoustic 370 question!
Post by: ZiggyDude on February 04, 2011, 06:36:19 am
Your 370 should be insanely loud before it reaches even 2 on the volume knob.  I have just gotten a 215B (the style you see the white wood through the black grill) and put a 370 on it.  Killer.

Taking a few seconds to get quiet after turning off is normal.

Finding good techs to fix these is hard - even though they are simple it requires someone that understands how they work rather than just replacing parts.