A Bryston by any other name..........................

WolfsongAudio · « **on:** 29 Nov 2010, 12:04 am »

Hello gang,

I just picked up what looks for all the world to be a Bryston 4B NRB but it has a faceplace with SONICS Power Amplifier 800X in the front. The internals look for all I can tell to be a 4B in the NRB era with dual toroids and what look to be the normal 4B NRB output transistors (although they have 6B on the outside boards ( the ones attached with the 4 purple wires )).

There is a pair of RCA ins and a single XLR in ( bridged mono ?) and a really loud fan.

This look like an OEM for a Pro Sound rig? Does anybody have any idea what this thing is?

James Tanner · « **Reply #1 on:** 29 Nov 2010, 01:41 am »

Hi

Yes Sonics were the American company that supplied the audio systems for the OmniMax Theaters and we built the amplifiers for them. They added the rear panel and input circuitry that interfaced with their front end.

I think the 800 was a 7B?

James

WolfsongAudio · « **Reply #2 on:** 29 Nov 2010, 03:43 am »

James,

Thanks for the info. I am a bit new to the Bryston world. Is the 7B a stereo unit? Is this amp as stereo model or am I getting summed mono from both channels?

Mike

WolfsongAudio · « **Reply #3 on:** 29 Nov 2010, 03:45 am »

James,

Thanks for the info. I am a bit new to the Bryston world. Is the 7B a stereo unit? Is this amp as stereo model or am I getting summed mono from both channels?

Mike

James Tanner · « **Reply #4 on:** 29 Nov 2010, 11:45 am »

Hi,

If it is a 7B it will be MONO - I will check today for you what the 800 model was.

james

James Tanner · « **Reply #5 on:** 29 Nov 2010, 08:49 pm »

Hi WolfsongAudio,

Yes the 800 was a 7B so it is MONO.

james

WolfsongAudio · « **Reply #6 on:** 1 Dec 2010, 01:59 pm »

James,

I did a two channel test by connecting one input only and got sound from one channel only, then the other channel input only and got sound on the other channel only. Then I played a stereo disc with wide left and right info into both channels and got left and right separation. Also the speaker outs are labels for both stereo and mono operation. Could I be missing something? Using a pre with a stereo/mono switch and there is a definite difference in sound when that switch is changed.

James Tanner · « **Reply #7 on:** 1 Dec 2010, 02:02 pm »

Hi WolfsongAudio,

It may have been modified from the original 7B version by some one at Sonics and that could explain why it is behaving as a stereo amp.

james

KeithA · « **Reply #8 on:** 1 Dec 2010, 10:24 pm »

Quote from: James Tanner on 1 Dec 2010, 02:02 pm

Hi WolfsongAudio,

It may have been modified from the original 7B version by some one at Sonics and that could explain why it is behaving as a stereo amp.

james

I guess someone could have put a SONICS faceplate on a 4B, eh? The faceplates would be the sam size, I think??

Keith

bobbysdad · « **Reply #9 on:** 10 Jun 2013, 05:29 pm »

Quote from: WolfsongAudio on 1 Dec 2010, 01:59 pm

James,

I did a two channel test by connecting one input only and got sound from one channel only, then the other channel input only and got sound on the other channel only. Then I played a stereo disc with wide left and right info into both channels and got left and right separation. Also the speaker outs are labels for both stereo and mono operation. Could I be missing something? Using a pre with a stereo/mono switch and there is a definite difference in sound when that switch is changed.

I realise it's been a while since this thread was last commented on, but as I've only just acquired a pair of these very amplifiers, Sonics 800x, I've since found that they are indeed Bryston 7B, but with some modifications to the rear panel, as per Sonics spec and manufacture.
Firstly, it is set up as a monoblock amp, (two mono channels within set up in push-pull configuration) and there are no switches to change from series or parallel.

I'm extremely interested to know what the final findings were when they were run in stereo.
Was this done with the mono module disconnected/removed, as I believe this amp is permanently set to run in series bridged mode, therefore are the two -(ve) speaker terminals bridged in the module by any chance?

How necessary is the rear module to the operation of this amplifier if NOT being run with balanced inputs?

In Wolfsong's case, was the module disconnected/unplugged and then the two inputs to the amplifiers wired up as in an unbalanced configuration by just simply adding a line input to them, and just have the speakers connected to the speaker outs as per normal? +(ve) to red, and -(ve) to black left and right etc?

If not Wolfsong, is there anybody who can shed some light as to what is necessary to get one of the Sonics versions of a 7B running in stereo.

I would be so grateful for any insight and help in getting at least one of mine converted to stereo.

Cheers to all.....

Habs Fan · « **Reply #10 on:** 11 Jun 2013, 01:05 am »

Disconnecting the harness from the input board and then connecting a pair of RCA's to the correct places on the harness(grey coax) should allow you to feed an unbalnced signal to each channel.

bobbysdad · « **Reply #11 on:** 11 Jun 2013, 02:37 pm »

Quote from: Habs Fan on 11 Jun 2013, 01:05 am

Disconnecting the harness from the input board and then connecting a pair of RCA's to the correct places on the harness(grey coax) should allow you to feed an unbalnced signal to each channel.

Yes, that's what I was thinking/hoping.

I have just been informed that it's also just a matter of adding another IC to the signal paths and take the non-inverted signal from it to maintain a balanced configuration, but unbalanced for now will do.
I'll try it in the next day or so.

bobbysdad · « **Reply #12 on:** 12 Jun 2013, 08:52 am »

UPDATE:

Well I'm happy to report, yes, it really was as simple as that.
Disconnect and disregard the rear module plug-in, and wire up some RCA's to a 4-pin plug, and plug into the left side of the 'loom's' plug, (which is where the two signal leads terminate) and your away.
The rear connectors then act as normal speaker outs.

A 'standard' 7B Monoblock for my JBL B380 sub, and a 'Stereo' 7B for my JBL 4313B's

All working quite happily.

Thank you for the inspiration of this thread.

Habs Fan · « **Reply #13 on:** 12 Jun 2013, 11:24 pm »

Quote from: bobbysdad on 12 Jun 2013, 08:52 am

... and a 'Stereo' 7B for my JBL 4313B's

Think of that one more as a 3B with better low impedance drive capability.

bobbysdad · « **Reply #14 on:** 15 Jun 2013, 03:09 pm »

Quote from: Habs Fan on 12 Jun 2013, 11:24 pm

Think of that one more as a 3B with better low impedance drive capability.

Wouldn't the 7B's output power (in stereo mode) be considerably more than a 3B?

Habs Fan · « **Reply #15 on:** 15 Jun 2013, 03:20 pm »

Quote from: bobbysdad on 15 Jun 2013, 03:09 pm

Wouldn't the 7B's output power (in stereo mode) be considerably more than a 3B?

Since the two channels are working separately (no longer operating differentially/bridged) the output per ch will be considerably less.(approx120-150w per ch. @8 ohms).The additional paralelled output transistors vs a standard 3B will allow it to drive lower impedances better.

bobbysdad · « **Reply #16 on:** 15 Jun 2013, 03:33 pm »

Quote from: Habs Fan on 15 Jun 2013, 03:20 pm

Since the two channels are working separately (no longer operating differentially/bridged) the output per ch will be considerably less.(approx120-150w per ch. @8 ohms).The additional paralelled output transistors vs a standard 3B will allow it to drive lower impedances better.

Anything to help me understand these amps a little better is always welcomed.

I've been Googling away, but sometimes you can get a little swamped, and at times quite lost with the hundreds of pages browsed......
I've still yet to find a definitive User Guide or Manual or a Service Manual, with all the specs.

Thank you for that extra bit of info.

Cheers lots.

Habs Fan · « **Reply #17 on:** 15 Jun 2013, 03:38 pm »

Spec wise this will be very close.http://bryston.com/PDF/Manuals/7B_NRBNPB_MANUAL.pdf

bobbysdad · « **Reply #18 on:** 15 Jun 2013, 03:59 pm »

Huge "thanx" for that.

I kept making the mistake earlier of looking for the ST version. It wasn't until the other day, I found I should be looking for the NRB version.
Being a Sonics, has made things confusing for a while, until I got a bit more familiar with the Bryston models and their differences. The Mono Module back panel is vastly simplified on the Sonics is one example.

There are also the Sonics 600x monoblocks which I'll have to research eventually as well (once I get one home).
I still don't have a clue of what they are or their specs, but they came with the 800x's, along with 4x IMAX boxes and 5 (so far) 18" subs.

Hopefully the 600x will also be able to run in stereo as my 800x/7B now is.

Habs Fan · « **Reply #19 on:** 15 Jun 2013, 05:08 pm »

IIRC the 600x is a 3ch (3x120w @8 ohm's) with the ability to bridge two of the channels together for approx 400w @8 ohm mono.