4bsst question

Eric · « **on:** 1 Apr 2005, 01:01 am »

Is there an AC fuse in the Bryston 4BSST. What is its value, and is it replacable by the user?

Mike Pickett · « **Reply #1 on:** 1 Apr 2005, 02:18 pm »

Hi Eric;

There is an internal fuse in the 4BSST, located on the softstart board, next to the power inlet. It should be replaced with a 12 Amp fast blow fuse, if blown. Usually, the external breaker (large switch on rear) should blow before this fuse, so it isn't considered a user servicable part.

However, fuses do eventually weaken over time, so this doesn't necessarily mean the amp is damaged. If you want to try replacing this fuse, just make sure the amp is unplugged first. If a new fuse blows as well, then there is something wrong with the amp, and it should be serviced.

Mike

Eric · « **Reply #2 on:** 1 Apr 2005, 03:37 pm »

Mike,

Thanks. I did not blow a fuse. I was just going to try to use an esoteric fuse form Isoclean to see if it added to the already great sound. But they only use slo-blo fuses. My guess is that will not be acceptable?

saea501 · « **Reply #3 on:** 3 Apr 2005, 01:01 pm »

Eric: Please don't fall for that Isoclean crap. That is pure snakeoil. In fact, those fuses were the source of a lot of humor on many of the other forums recently. Goes right along with the magic rocks that you set on top of your pre amp to make it sound more "open".

Eric · « **Reply #4 on:** 3 Apr 2005, 01:39 pm »

Hee Hee

Mike Pickett · « **Reply #5 on:** 4 Apr 2005, 07:04 pm »

Exotic aftermarket fuses, eh? I thought I'd seen everything.

Be very careful with slow blow fuses. They are capable of passing several times the rated current for much longer than they should, and are designed to accomodate inrush current on products that don't "ramp up" the power supply on turn on.

I'm usually pretty supportive of trying esoteric tweaks and trusting your ears, but I'd have to draw the line at replacing fuses, unless you can find exactly the same type. Sorry if I offend anyone, but this is a safety issue.

Mike

Eric · « **Reply #6 on:** 5 Apr 2005, 12:18 am »

Mike,

Thanks, I will listen to the experts on this one and err on the side of safety

Eric

Skyhawk · « **Reply #7 on:** 12 Apr 2005, 12:33 am »

I am curious.

I could not help but notice all the similarities between the 7B and the 4B. Cosmetically, and that the 7B is 2 amps in series that nets twice the power of a 4B. They seem to cost the same too. a pair of 4Bs is the same retail as a pair of 7Bs

My question is are they the same amp, just bridged internally?

Mike Pickett · « **Reply #8 on:** 12 Apr 2005, 08:19 pm »

Hi Skyhawk;

The 7B and the 4B share most of their metalwork, and are similar electrically, but differ considerably in voltage and current capability.
A bridged 4B will deliver 1000 Watts into an 8 Ohm load, while the 7B only delivers 600. However, the 7B is designed to work into loads below 4 Ohms, whle the bridged 4B shouldn't drive any speaker less than 8 Ohms, and is really intended to be used in stereo.

Therefore, the two amps will put out around the same amount of power, just into different impedances/#'s of speakers.

Mike