[fuzzboy]

I've been lurking in this wonderful forum for a few years now and have waited for the day that I could happily post as a proud Bryston owner, and when the time comes now I pretty much need some help in the form of technical expertise that a lot of posters no doubt have.

I have snagged the abovementioned amp on Ebay just now, being advertised as Brand New In Box (believe me it is, even smells new!). It's a 230V version for the Australian Market with a date of 02 26 and S/N: 000154. I've connected it up to my system to replace a Gryphon S100 Power amp, with a Mark Levinson 38S preamp feeding it - into Focal JMLabs Chorus 826S speakers. The problem is there is a distinct lack of volume. At a level that would normally have the walls shaking with my old amp I can hardly hear things and I can actually turn the preamp up to its max volume level of 94 without any problem. There's also a digital buzz or chirp when I turn the volume knob on the preamp that didn't exist with my old amp. It sounds, well . . kinda terrible.

Could there be a problem with an amp manufactured in 2002 sitting around being unused for so long? Absolutely stumped, I'm running Transparent Audio AES/EBU balanced interconnects into it and have even turned up both gain / level controls to full.

My next course of action is to get back in touch with the seller and request a receipt from the authorised dealer so I can get in touch with Syntec (the local distributor) for a warranty inspection

Any input would be much appreciated as I'm determined to have it a permanent part of my hifi rig.

[BrysTony]

Have you replaced your old amp and interconnects to see if everything is OK?  I'm thinking that you may have a problem with the preamp.  Are you using the same preamp outputs - if not change back to the single ended output.

[fuzzboy]

The problem is my old amp is in for a service so I don't have the opportunity to A/B the setup. Nothing has changed in my configuration though. Essentially I disconnected my speakers, interconnects and power and plugged the new 4B in.

I might try to dig up some RCA's to try out the single ended output and see if it is the same.

Little bit worried though I must admit.

[James Tanner]

The problem is my old amp is in for a service so I don't have the opportunity to A/B the setup. Nothing has changed in my configuration though. Essentially I disconnected my speakers, interconnects and power and plugged the new 4B in.

I might try to dig up some RCA's to try out the single ended output and see if it is the same.

Little bit worried though I must admit.

Hi Fuzzboy - sounds strange indeed - make sure the voltage switch on the back is in the 1V position and the balanced inputs are selected.  Also being a Pro unit make sure the 'gain' controls on the rear panel are turned up fully clockwise.

james

[werd]

Yah, you have to turn it up in the back .... buddy.

[srb]

Yah, you have to turn it up in the back .... buddy.

He has already done that, from his first post:
 

.... and have even turned up both gain / level controls to full.

But he did not mention the 1V/2V input sensitivity switch setting.
 
But the fact that  "There's also a digital buzz or chirp when I turn the volume knob on the preamp that didn't exist with my old amp. It sounds, well . . kinda terrible."  doesn't sound encouraging.
 
Good luck, fuzzboy!
 
Steve

[rob80b]

Hopefully you've just had one of those moments and overlooked switching the back switches to balanced and not RCA.

Robert

[fuzzboy]

Thanks for your thoughts everyone. I've most definitely set the amp to the balanced inputs (and tried every permutation of toggle as well).

Will drop it off at the distributor today and a big thank you to Bryston for the no-fuss attention in respect to warranty support, it's what attracted me to the brand in the first place. Had too many components go bung on me over the years and it's refreshing to have a company stand by their products so passionately.

[fuzzboy]

Just as an update, I dropped into my local Bryston dealer and tried the amp out with different components. The problem was not reproduced. The dealer seemed to think it is an impedance difference between the two power amps and I will need to adjust the output level in my pre-amp. The specs for the Gryphon S100 list input impedance as 50 kOhm and the 4BSST as 20kOhm.

I'm now looking through the documentation for my Mark Levinson 38S preamp and will endeavour to adjust the output level.

Will keep you all posted. Never experienced this kind of issue before in years of limited hi-fi tinkering.

[fuzzboy]

Bah, no go. The only adjustment I can make is to normalize the volume settings relevant to each input. The problem is my amp goes up to a max volume level of 92 and it needs to go a lot more than that for desirable sound levels. Even tried single ended unbalanced RCA interconnects and it was still the same.

I think I need an amp like in Spinal Tap 'that goes up to 11'.

Damn, lost from here. 

[Napalm]

Damn, lost from here. 

Nah. Get a BP6.

Or connect the CD player directly to the amp 

Nap. 

[Anonamemouse]

Interesting challenge...
In the manual (page 24) I saw that the ML also has a setting for maximum volume lock. I take it you have looked at that?
Another possible way to check (be VERY careful with this!!!) is to connect the 4B to the tape out of the ML, and play some SOFT music (better: if your cd player had an adjustable output, use that).
If the problem persists you may want to give a completely fresh set of (el cheapo, they are just for testing) cables a try.

[Anonamemouse]

The problem is my amp goes up to a max volume level of 92 and it needs to go a lot more than that for desirable sound levels.

Actually, not quite.
A pre amplifier doesn't amplify, it dampens a signal. So technically it goes from maximum dampening (silent) to minimum dampening (loud).

[srb]

Actually, not quite.
A pre amplifier doesn't amplify, it dampens a signal. So technically it goes from maximum dampening (silent) to minimum dampening (loud).

Actually, no.  A passive linestage or an active tube buffer with unity gain doesn't amplify.  Preamplifiers do amplify (voltage), and typically have a gain around 10dB, but may be higher or lower.
 
Steve

[Anonamemouse]

Actually, no.  A passive linestage or an active tube buffer with unity gain doesn't amplify.  Preamplifiers do amplify (voltage), and typically have a gain around 10dB, but may be higher or lower.
 
Steve

i stand (or actually, sit) corrected.

[rob80b]

Just as an update, I dropped into my local Bryston dealer and tried the amp out with different components. The problem was not reproduced. The dealer seemed to think it is an impedance difference between the two power amps and I will need to adjust the output level in my pre-amp. The specs for the Gryphon S100 list input impedance as 50 kOhm and the 4BSST as 20kOhm.

I'm now looking through the documentation for my Mark Levinson 38S preamp and will endeavour to adjust the output level.

Will keep you all posted. Never experienced this kind of issue before in years of limited hi-fi tinkering.

Just checking online and saw that each input on the 38 can also be have it's gain adjusted, so there maybe something there also. All in all it does not make much sense not to have enough gain with the 4B.

Robert

[fuzzboy]

Interesting challenge...
In the manual (page 24) I saw that the ML also has a setting for maximum volume lock. I take it you have looked at that?
Another possible way to check (be VERY careful with this!!!) is to connect the 4B to the tape out of the ML, and play some SOFT music (better: if your cd player had an adjustable output, use that).
If the problem persists you may want to give a completely fresh set of (el cheapo, they are just for testing) cables a try.

Yes, I have indeed looked at this. Basically, you turn your volume up to the max level and set it to limit there. Obviously, it's to prevent little urchins with grabby hands blowing your speakers. The volume still only goes up to 92 so it makes no difference.

Also, looking at the input offset function does not provide any solution. It adjusts the volume relative to your loudest input. For my purposes I only have one input, a WEISS Minerva DAC being fed by a Mac Mini and Mark Levinson 37 transport. Fiddling with this doesn't help at all. As I've already tried different cables via the single ended inputs I feel that base has been covered also.

I should have my Gryphon power amp back tomorrow and will check to see if it runs in my system as it did before with no problems. If so, as much as it pains me to say, if I can't get the 4B SST cranking as it should then off to the shop on consignment it goes.