[James Tanner]

This kind of thing happens quite often when you have been building amplifiers as long as we have and sometimes the new ideas work (rarely though) but when they do we are more than happy to investigate - after all the purpose is to make the amplifiers as transparent as possible and any and all possibilities should be explored.

james

[James Tanner]

another testimonial at http://www.canuckaudiomart.com/forum/viewtopic.php?f=33&t=21060
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"Back in '06, there was a rather vigorous debate in this forum about the wisdom of modifying Bryston amps by Pure Sound in North Vancouver.
I have a 3B ST that has been owned for the past 14 years, and decided to give this upgrade a try. The cost was certainly reasonable ($200 plus tax), and the service was quite prompt as well.

Suffice to say, I'm very happy with the result. There's a lot more detail, while the musicality of this amp has been maintained. If you own a Bryston amp in the Lower Mainland, give this serious consideration! "

Bryston uses two diff-amps, (long-tailed pairs), at the input.

We deliberately do not use constant-current sources for the emitters because it is not necessary to reduce second harmonic as it is automatically cancelled anyway.

However, constant-current sources introduce higher-order harmonics due to the junction capacitance in the active components.

cwr

[minbean]

Bryston uses two diff-amps, (long-tailed pairs), at the input.

We deliberately do not use constant-current sources for the emitters because it is not necessary to reduce second harmonic as it is automatically cancelled anyway.

However, constant-current sources introduce higher-order harmonics due to the junction capacitance in the active components.

cwr

I am afraid the result was from the limitation of the particular CCS used in the Bryton lab.
There are variety of CCS designs, hence different characteristics.
Different implementation produces different result.
The listeners testimonials are pointing different direction than the Bryston's.

[brucek]

The listeners testimonials are pointing different direction than the Bryston's.

It would be great if you could publish your THD+N figure that you measured after the modification. Listener testimonials are great but don't tell us a lot. Amplifiers are linear systems and are not supposed to alter the spectral characteristics of the signal that passes through them. This characteristic is specified by the THD+N number. It tells you everything you need to know about the device, especially if its measured over the full audio range and power levels involved. The THD+N test is the golden rule for a linear system and cannot be debated. It simply measures the amount of signal degradation as it passes from input to output.

Could you tell us the results of your testing?

brucek

[*Scotty*]

More might be learned from a blind,level matched listening test. We are after all allegedly building these circuits to listen to music with.
Scotty

[rmurray]

 This mod was aimed at the ST series ( I thought). My ST has never sounded so good since I went to the balanced circuit . I would have to think long and hard before I let an outsider screw with a fantastic amp.such as  this. If there was a better way I'm sure Bryston would have said so a long time ago.

[minbean]

A religion brings comfort for sure if it is believed in!   

[James Tanner]

A religion brings comfort for sure if it is believed in!   

There is an easy solution to all this rat a tat  - send us an amp with the mods done and I will let you know how it fairs.

james

[Phil A]

There is an easy solution to all this rat a tat  - send us an amp with the mods done and I will let you know how it fairs.

james

I concur with that. After all this is a Bryston forum with many satisfied Bryston owners and one would expect they would view claims would a degree of skepticism.  I'm certainly curious and as I noted I have a 3BST which I got for a secondary system.  For a relatively inexpensive mod cost as presented, it is certainly something I could be interested in.  While for a secondary system, I'm always for better sound.  No better way to show your stuff.

[minbean]

There is an easy solution to all this rat a tat  - send us an amp with the mods done and I will let you know how it fairs.

james

Easier and surer is for you to do the mod with my kit and do A/B. The mod will be done by your tech and there will be no tricks. Sure you have 2 exactly same units to compare side by side. Isn't that fair enough? 

[Phil A]

If you're talking about a unit/model that is not current you are also making the assumption that there will be multiple units available sitting at Bryston

[minbean]

If you're talking about a unit/model that is not current you are also making the assumption that there will be multiple units available sitting at Bryston

The mod will effectively work for all ST, SST and SST2. No worries!

[minbean]

If you're talking about a unit/model that is not current you are also making the assumption that there will be multiple units available sitting at Bryston

Dear Phil,
if a modified one is sent to Bryston, your concern becomes more significant.
How can Bryston find an exactly same condition of unit as the modified one for reliable A/B?

[Phil A]

I assumed you were talking about prior models as there was no mention of what the mod would work with up until a few minutes ago.

[minbean]

I assumed you were talking about prior models as there was no mention of what the mod would work with up until a few minutes ago.

The front end of SST2 is not much different than SST and there is no constant current source.

http://bryston.com/pages/technical.html

I thought I explained but it was not very clear. Sorry about that!

[James Tanner]

Dear Phil,
if a modified one is sent to Bryston, your concern becomes more significant.
How can Bryston find an exactly same condition of unit as the modified one for reliable A/B?

Hi

I don't think so because if we do it it is a different level of expertise as opposed to the person who is offering the mod and how they implement it.  Also I think if you do it there can be no concern or question that it was done exactly as you required.

james

[rmurray]

This mod was aimed at the ST series ( I thought). My ST has never sounded so good since I went to the balanced circuit . I would have to think long and hard before I let an outsider screw with a fantastic amp.such as  this. If there was a better way I'm sure Bryston would have said so a long time ago.

  Sorry, I realize now this referring to sst models and not the earlier ST

[minbean]

Hi

I don't think so because if we do it it is a different level of expertise as opposed to the person who is offering the mod and how they implement it.  Also I think if you do it there can be no concern or question that it was done exactly as you required.

james

If that is the real reason, I will give you a second option.

Send me one of your amps and I will have it modded.
You cover the cost of mod and shipping, and declare you will not copy the mod. for your product.

[James Tanner]

If that is the real reason, I will give you a second option.

Send me one of your amps and I will have it modded.
You cover the cost of mod and shipping, and declare you will not copy the mod. for your product.

Hi

It seems like you have a real concern about trusting us so I think we will pass on this and I will close the thread.

james