4BSST and 4BSST 2sq

rob80b · « **on:** 9 Jan 2010, 04:05 am »

(Jan 11th, sorry this tread has led us down the garden path, the clue is in the first photo, thanks to Ian)

Doing my yearly house cleaning (dust removal, dead flies etc.) and took a pick or two of my 4BSST (2002) and thought I'd post a comparison of the current SST 2 from a photo on the net ( http://www.soundstage.com/equipment/bryston_4b_sst2.htm ). Looks like Bryston did a bit of house cleaning also. Maybe what's not obvious is that my 4B has an extra 8"to 10" or more of cable folded up against the transformers, I've been told is necessary to allow rotation of the transformers for the best signal to noise.

Robert

rob80b · « **Reply #1 on:** 9 Jan 2010, 04:24 am »

Actual here's a better shot of my spaghetti western.

So no doubt the better layout, circuit board/components and point to point wiring help improve the performance of the SST2 of which we are hearing about.

Robert

rob80b · « **Reply #2 on:** 9 Jan 2010, 04:29 am »

Although here's another shot of what looks like a later model 4BSST.

vegasdave · « **Reply #3 on:** 10 Jan 2010, 04:07 am »

Awesome. Thanks for the visuals. Very interesting. I see the differences too. Particularly in the wiring.

rob80b · « **Reply #4 on:** 10 Jan 2010, 04:33 am »

Quote from: vegasdave on 10 Jan 2010, 04:07 am

Awesome. Thanks for the visuals. Very interesting. I see the differences too. Particularly in the wiring.

When I first acquired my 4BSST I had quite and obvious hum/buzz ( http://www.audiocircle.com/index.php?topic=54870.0 ) and sent the unit in to Bryston where they apparently "reset noise wiredress" and reduced most but not all of the noise and was curious if more could have been eliminated by reducing the cable lengths. I contacted service about this and was told other problems could arise if done so, but must admit I'm not totally convinced.

Robert

rob80b · « **Reply #5 on:** 10 Jan 2010, 04:51 am »

Quote from: vegasdave on 10 Jan 2010, 04:07 am

Awesome. Thanks for the visuals. Very interesting. I see the differences too. Particularly in the wiring.

There appear quite a few changes under the hood, more than i expected, don't you hate that.

Robert

Levi · « **Reply #6 on:** 10 Jan 2010, 06:04 am »

Interesting findings there. I have the 7BSST and looks like it is similar to the 4BSST layout?

7BSST

7BSST2

Mad Mr H · « **Reply #7 on:** 10 Jan 2010, 08:07 am »

The 7B is a 4B set full time to be a monoblock amp.

Think 4B set to bridge mode.

There is a very subtle AUDIO differance between a 4B in bridge and a 7B, but in 'general' answer to you post that is why they look so smilar...........

Andy.

rob80b · « **Reply #8 on:** 10 Jan 2010, 01:13 pm »

Looking at the picks it's looks like the 4B had the bigger makeover in terms of cable layout! Cables are more prone to pick up RF and other interference the most, which was my concern when looking at the innards of my 4BSST.

Robert

1oldguy · « **Reply #9 on:** 10 Jan 2010, 02:14 pm »

I agree there is quite the difference now.Much less wiring has to be a benefit in this case.

rob80b · « **Reply #10 on:** 10 Jan 2010, 03:02 pm »

If it wasn't for the warranty I'd be in there with the clippers, but seeing that the transformers (which have the most excess cable) make up the largest expenditure of the amp I'm inclined to leave well enough alone.

Robert

rollo · « **Reply #11 on:** 10 Jan 2010, 05:20 pm »

Could it be possible the new wire arrangement uses shielded wire as well. Changing the internal wiring in my amp made a difference for the good. Just curious.

charles

werd · « **Reply #12 on:** 10 Jan 2010, 05:38 pm »

Quote from: Mad Mr H on 10 Jan 2010, 08:07 am

The 7B is a 4B set full time to be a monoblock amp.

Think 4B set to bridge mode.

There is a very subtle AUDIO differance between a 4B in bridge and a 7B, but in 'general' answer to you post that is why they look so smilar...........

Andy.

Hello Andy

Apparently the new 7Bsq have the new transformer while there was no change in the transformer in 4Bsq.
It makes me think though if a 14B in bridged is the same as a 28B, or similar sounding.Can you even bridge a 14B?

vegasdave · « **Reply #13 on:** 10 Jan 2010, 11:40 pm »

Quote from: rob80b on 10 Jan 2010, 04:51 am

There appear quite a few changes under the hood, more than i expected, don't you hate that.

Robert

Yep, but that's progress! I'd love to have a squared amp, but I'm content with my regular old SST amp.

95Dyna · « **Reply #14 on:** 11 Jan 2010, 03:53 pm »

Quote from: Mad Mr H on 10 Jan 2010, 08:07 am

The 7B is a 4B set full time to be a monoblock amp.

Think 4B set to bridge mode.

There is a very subtle AUDIO differance between a 4B in bridge and a 7B, but in 'general' answer to you post that is why they look so smilar...........

Andy.

Andy,

There is a difference in the way the 7B sees impedence compared to a 4B in bridged mono. I think the 7 sees the impedence as it is and the bridged 4 sees half of the impedence, somebody correct me if I'm wrong or have it backwards. Wouldn't there be a difference in power supply capacitance as well? I wouldn't buy a 4B for the flexibility of using it as a stereo or mono amp thinking I would have the equivalent of a 7B when it is in bridged mono mode. Otherwise why would anybody buy a 7 and box himself into a corner.

Bill

1oldguy · « **Reply #15 on:** 11 Jan 2010, 05:19 pm »

Quote from: 95Dyna on 11 Jan 2010, 03:53 pm

Andy,

There is a difference in the way the 7B sees impedance compared to a 4B in bridged mono. I think the 7 sees the impedance as it is and the bridged 4 sees half of the impedance, somebody correct me if I'm wrong or have it backwards. Wouldn't there be a difference in power supply capacitance as well? I wouldn't buy a 4B for the flexibility of using it as a stereo or mono amp thinking I would have the equivalent of a 7B when it is in bridged mono mode. Otherwise why would anybody buy a 7 and box himself into a corner.

Bill

Agreed,there must be a reason why a 7B is preferred.Perhaps someone can answer this.

rob80b · « **Reply #16 on:** 11 Jan 2010, 06:54 pm »

Obviously the 7B has been optimized for single channel playback, but for those who are technically inclined you just need to look at the schematics which are shared between the 4B and 7B
http://www.bryston.com/BrystonSite05/pdfs/SSTAmplifiers/4b+7bSST-SSB-SCH-6_20041013.pdf
and we may have the answer.

Robert

ian.ameline · « **Reply #17 on:** 11 Jan 2010, 07:28 pm »

None of the pictures in this thread claiming to be a 4B-SST2 are actually of a 4B -- they are of a 7B SST2.
This is the guts of a 4B-SST2;

Notice the difference? (2 transformers, two XLR inputs vs 1)

-- Ian.

Mad Mr H · « **Reply #18 on:** 11 Jan 2010, 08:10 pm »

Quote from: werd on 10 Jan 2010, 05:38 pm

Hello Andy

Apparently the new 7Bsq have the new transformer while there was no change in the transformer in 4Bsq.
It makes me think though if a 14B in bridged is the same as a 28B, or similar sounding.Can you even bridge a 14B?

I am fairly sure the 4bsq has a new version transfomer, as the cost to change this shot up from the old SST price.

ALSO you can bridge 2ch to create 1ch so the 4b into 7b. What you CANT then do is bridge two bridged ch - So you CANT use a 14b to create a 28b and that is NOT how that is done. so no a 14b cant run in bridge mode.

rob80b · « **Reply #19 on:** 11 Jan 2010, 08:11 pm »

Good one Ian, you're right!
Should have caught that, I pulled the pic from a 4bSST 2 review ( http://www.soundstage.com/equipment/bryston_4b_sst2.htm ) and hadn't noticed there is only one set of binding posts.
Look closely at the left hand photo.

Robert