[Raimo]

Wrong adress again.
http://faktiskt.se/modules.php?name=Forums&file=viewtopic&t=18569

[Ron D]

OK James - thanks for the details.

If one felt the alteration was worth the effort of shipping Bryston one's 14B amp have you kicked around the anticipated cost of this venture to the amp's owner?

Tx
Ron

[amdan]

Hi All,

OK – I checked with Chris and Engineering and here are the facts on the changes to the 14B SST after and including serial number 506.

The updated 14B SST that was sent to Sweden was modified by reducing the output filter choke on each channel to ½ of the previous value. This change reduces the roll-off of very high frequencies into low impedances.

The frequency response of the 14B SST’s into 4 ohm loads prior to SN 506 was down .25dB at 20KHz.

The frequency response of 14B SST’s into 4 ohm loads after SN 506 is down .1dB at 20KHz.

The frequency response at 10KHz is not affected in either amplifier.

Hope this helps clarify the situation.

james

Hi James,

Three questions:

1. Are these the only differences between my 14 B ST and the 14 B SST with serial number greater than 00505? (Aside from the difference in power that we already knew about). There was some mention previously about other improvements being made by Chris.

2. Those measured differences seem very small to my layman's mind. Is the audible difference large? I realise that is a subjective question but would appreciate some comment.

3. What is the cost to upgrade my amp to the new specifications (assuming that is possible)?

Thanks.

[James Tanner]

Hi All,

OK – I checked with Chris and Engineering and here are the facts on the changes to the 14B SST after and including serial number 506.

The updated 14B SST that was sent to Sweden was modified by reducing the output filter choke on each channel to ½ of the previous value. This change reduces the roll-off of very high frequencies into low impedance's.

The frequency response of the 14B SST’s into 4 ohm loads prior to SN 506 was down .25dB at 20KHz.

The frequency response of 14B SST’s into 4 ohm loads after SN 506 is down .1dB at 20KHz.

The frequency response at 10KHz is not affected in either amplifier.

Hope this helps clarify the situation.

james

Hi James,

Three questions:

1. Are these the only differences between my 14 B ST and the 14 B SST with serial number greater than 00505? (Aside from the difference in power that we already knew about). There was some mention previously about other improvements being made by Chris.

2. Those measured differences seem very small to my layman's mind. Is the audible difference large? I realise that is a subjective question but would appreciate some comment.

3. What is the cost to upgrade my amp to the new specifications (assuming that is possible)?

Thanks.

Yes the only difference is the filter change. The cost to change the filters would be about $200 including parts and labour.

james

[Baard]

Hello
Are the 7B and 14B identical – only different is stereo and mono chassis?

I have a 3 year old Bryston 7B SST - do the same fix apply to these amplifiers? Is this why LG in Stereophile found that the old ST was slightly brighter and more forward?

http://stereophile.com/solidpoweramps/1093bryston/index9.html

If so, can the fix be implemented by the Bryston dealer in Oslo/Norway?

Baard

[James Tanner]

Hello
Are the 7B and 14B identical – only different is stereo and mono chassis?

I have a 3 year old Bryston 7B SST - do the same fix apply to these amplifiers? Is this why LG in Stereophile found that the old ST was slightly brighter and more forward?

http://stereophile.com/solidpoweramps/1093bryston/index9.html

If so, can the fix be implemented by the Bryston dealer in Oslo/Norway?

Baard

Hi Baard,

Yes the 7B SST has the same output circuit as the 14B SST.  We made the change to the 7B SST output filters a few months back - I will see if I can get an exact serial number for you. It should be able to be modified by our distributors in the field but I will have to check with engineering on that one.

In my discussions with Larry Greenhill he felt the new 7B SST was more "NEUTRAL" but liked the sound of the more upfront ST even though he realized it was more 'coloured'. I think a lot of that preference had to do with his system at the time. He currently has a pair of 28B SST's and a Torus Power Isolation unit and you will see the review on those in the December issues of Stereophile- wait till you see his comments!

james

[Baard]

Hi James

Thanks – I didn’t expect you to replay so fast, after all its weekend.

I will appreciate if you can check with engineering if this “fix” is obtainable in the field – you know how it works. Its like maintains on a PC, just have too have the latest drivers for peak performance

Baard

[James Tanner]

Hi James,

Three questions:

1. Are these the only differences between my 14 B ST and the 14 B SST with serial number greater than 00505? (Aside from the difference in power that we already knew about). There was some mention previously about other improvements being made by Chris.

2. Those measured differences seem very small to my layman's mind. Is the audible difference large? I realise that is a subjective question but would appreciate some comment.

3. What is the cost to upgrade my amp to the new specifications (assuming that is possible)?

Thanks.
[/quote]




Hi amdan,

Sorry I just realized I did not answer your second question.

Your correct, it is subjective but I have always found that what seems like very small changes in the 'spec' of a component can have larger consequences than one would expect.  Certainly in this case the frequency response roll-off changing from 1/4dB to .1dB at 20K seems minuscule to say the least but obviously Ingvar heard the difference in his bypass test.

Two things we have found over the many years we have been developing amplifiers is 'noise floor' and '1/10th power output' produce very audible differences. Every time we have been able to lower the noise floor even a few dB positive audible differences become apparent. Also how the amplifier performs at 1 watt is as critical as how it performs at full power.

The assumption is that once you are below the accepted standards of 'audibility' future improvements are unnecessary. My experience over the years has taught me that continuing to push the performance envelope is a worthwhile and rewarding task.

james

[amdan]

Hi James,

Thanks very much for you responses. Ingvar also said ....

Secondly:
According to the info I've got from Chris Russel the modification includes 12 components (tree on each halve of each
channel of the amplifier - i.e. it includes changes in the whole output filter, L, C and R in four places).

However - compared to the first amplifier I had for test (much older) there are also changes made to parts of the rest
of the amplifier, reducing the bandwith, and improving the intrinsic output impedance properties (output filter not
included).
But if I understood Chris right, these changes was done by Bryston before I suggested them / before I did the test,
but after the time where my first amplifier on test, was produced!

Amazingly enough, these other (non output filter) changes are exactly what I suggested to be changed after having
experience of the older model only (don't remember the serial number of it, but I think it was a bit over 000 100).
I'd like to think of it, as an indication that great minds think alike! But probably a truer way to describe it, is that
my thought, was thoughts already old, when I had them...

Are these other changes also included in your $200 estimate. Also, I am in Sydney. Will your Australian distributor be able to make the modification?

Regards,
amdan

[James Tanner]

Hi James,

Thanks very much for you responses. Ingvar also said ....

Secondly:
According to the info I've got from Chris Russel the modification includes 12 components (tree on each halve of each
channel of the amplifier - i.e. it includes changes in the whole output filter, L, C and R in four places).

However - compared to the first amplifier I had for test (much older) there are also changes made to parts of the rest
of the amplifier, reducing the bandwith, and improving the intrinsic output impedance properties (output filter not
included).
But if I understood Chris right, these changes was done by Bryston before I suggested them / before I did the test,
but after the time where my first amplifier on test, was produced!

Amazingly enough, these other (non output filter) changes are exactly what I suggested to be changed after having
experience of the older model only (don't remember the serial number of it, but I think it was a bit over 000 100).
I'd like to think of it, as an indication that great minds think alike! But probably a truer way to describe it, is that
my thought, was thoughts already old, when I had them...

Are these other changes also included in your $200 estimate. Also, I am in Sydney. Will your Australian distributor be able to make the modification?

Regards,
amdan

Hi amdan,

The $200 will just be the filter networks.

I am looking into this further - it seems to be taking on a life of its own. I have a meeting with Stuart Taylor the design engineer behind the 14B and will be going over with him exactly what if any other changes were made on the 14B that went to Ingvar. There appears to be some misunderstandings of the communications between the parties involved.

james

[Phil A]

Hi James,

Thanks very much for you responses. Ingvar also said ....

Secondly:
According to the info I've got from Chris Russel the modification includes 12 components (tree on each halve of each
channel of the amplifier - i.e. it includes changes in the whole output filter, L, C and R in four places).

However - compared to the first amplifier I had for test (much older) there are also changes made to parts of the rest
of the amplifier, reducing the bandwith, and improving the intrinsic output impedance properties (output filter not
included).
But if I understood Chris right, these changes was done by Bryston before I suggested them / before I did the test,
but after the time where my first amplifier on test, was produced!

Amazingly enough, these other (non output filter) changes are exactly what I suggested to be changed after having
experience of the older model only (don't remember the serial number of it, but I think it was a bit over 000 100).
I'd like to think of it, as an indication that great minds think alike! But probably a truer way to describe it, is that
my thought, was thoughts already old, when I had them...

Are these other changes also included in your $200 estimate. Also, I am in Sydney. Will your Australian distributor be able to make the modification?

Regards,
amdan

Hi amdan,

The $200 will just be the filter networks.

I am looking into this further - it seems to be taking on a life of its own. I have a meeting with Stuart Taylor the design engineer behind the 14B and will be going over with him exactly what if any other changes were made on the 14B that went to Ingvar. There appears to be some misunderstandings of the communications between the parties involved.

james

James - do any of the changes result in the amp being able to handle low impedence loads a bit better?

[James Tanner]

Hi James,

Thanks very much for you responses. Ingvar also said ....

Secondly:
According to the info I've got from Chris Russel the modification includes 12 components (tree on each halve of each
channel of the amplifier - i.e. it includes changes in the whole output filter, L, C and R in four places).

However - compared to the first amplifier I had for test (much older) there are also changes made to parts of the rest
of the amplifier, reducing the bandwith, and improving the intrinsic output impedance properties (output filter not
included).
But if I understood Chris right, these changes was done by Bryston before I suggested them / before I did the test,
but after the time where my first amplifier on test, was produced!

Amazingly enough, these other (non output filter) changes are exactly what I suggested to be changed after having
experience of the older model only (don't remember the serial number of it, but I think it was a bit over 000 100).
I'd like to think of it, as an indication that great minds think alike! But probably a truer way to describe it, is that
my thought, was thoughts already old, when I had them...

Are these other changes also included in your $200 estimate. Also, I am in Sydney. Will your Australian distributor be able to make the modification?

Regards,
amdan

Hi amdan,

The $200 will just be the filter networks.

I am looking into this further - it seems to be taking on a life of its own. I have a meeting with Stuart Taylor the design engineer behind the 14B and will be going over with him exactly what if any other changes were made on the 14B that went to Ingvar. There appears to be some misunderstandings of the communications between the parties involved.

james

James - do any of the changes result in the amp being able to handle low impedence loads a bit better?

No changes on that front.

james

[James Tanner]

Hi All,

Ok, I think I can explain why the confusion on the 14B SST. It appears we had a number of people in the mix; Chris, Ingvar, Stuart and myself, and therefore information among the various parties sometimes got skewed.

The modified 14B SST that we sent to Ingvar in Sweden had the new output chokes as had been suggested by Ingvar when he listened to the first sample.  By the time he received it we had already made his suggested change to the regular production of the 14B SST.

None of the current 14B SST’s in the field, as of April 2007, have any changes other than the output chokes as mentioned above.   There is no modification concerning an additional 12 output components. That seems to have been a miscommunication on Chris Russell’s part, in speaking to Ingvar.  Amplifiers up to the FIRST sample Ingvar tried, (borrowed from a customer), may have had a wider unloaded bandwidth, but that was changed quite early in production. 

If we decide to offer a retrofit program for the 14B SST, it would include new lower-value chokes, and any necessary changes to the input bandwidth to bring it to current practices, (though the latter should not be necessary on the vast majority of the amplifiers out there).

[amdan]

Hi All,

Ok, I think I can explain why the confusion on the 14B SST. It appears we had a number of people in the mix; Chris, Ingvar, Stuart and myself, and therefore information among the various parties sometimes got skewed.

The modified 14B SST that we sent to Ingvar in Sweden had the new output chokes as had been suggested by Ingvar when he listened to the first sample.  By the time he received it we had already made his suggested change to the regular production of the 14B SST.

None of the current 14B SST’s in the field, as of April 2007, have any changes other than the output chokes as mentioned above.   There is no modification concerning an additional 12 output components. That seems to have been a miscommunication on Chris Russell’s part, in speaking to Ingvar.  Amplifiers up to the FIRST sample Ingvar tried, (borrowed from a customer), may have had a wider unloaded bandwidth, but that was changed quite early in production. 

If we decide to offer a retrofit program for the 14B SST, it would include new lower-value chokes, and any necessary changes to the input bandwidth to bring it to current practices, (though the latter should not be necessary on the vast majority of the amplifiers out there).

Hi James,

I was wondering if you will be offering a retrofit program. Any idea on when a decision will be made. Of course I am very keen that there is a retrofit option and am hoping that it is not too expensive.

Thanks.

[James Tanner]

Hi All,

Ok, I think I can explain why the confusion on the 14B SST. It appears we had a number of people in the mix; Chris, Ingvar, Stuart and myself, and therefore information among the various parties sometimes got skewed.

The modified 14B SST that we sent to Ingvar in Sweden had the new output chokes as had been suggested by Ingvar when he listened to the first sample.  By the time he received it we had already made his suggested change to the regular production of the 14B SST.

None of the current 14B SST’s in the field, as of April 2007, have any changes other than the output chokes as mentioned above.   There is no modification concerning an additional 12 output components. That seems to have been a miscommunication on Chris Russell’s part, in speaking to Ingvar.  Amplifiers up to the FIRST sample Ingvar tried, (borrowed from a customer), may have had a wider unloaded bandwidth, but that was changed quite early in production. 

If we decide to offer a retrofit program for the 14B SST, it would include new lower-value chokes, and any necessary changes to the input bandwidth to bring it to current practices, (though the latter should not be necessary on the vast majority of the amplifiers out there).

Hi James,

I was wondering if you will be offering a retrofit program. Any idea on when a decision will be made. Of course I am very keen that there is a retrofit option and am hoping that it is not too expensive.

Thanks.

Hi amdan,

I am going to have to go over it with engineering and see what is involved. Also want to see if it can be done by our distributor rather than having to be shipped to Bryston.
We would need the serial number of the amplifier and where purchased.

james

[amdan]

Hi James,

Sorry for the slow reply. The SN is 140006 and the Date is 0025. The unit was purchased in Singapore and is a 240V unit.

BTW does the date mean that it was manufactured in Feb 05?

Thanks.

[Ron D]

I believe that your amp was built in the 25th week of 2000 and your amp may have been the 6th amp built? My amp's build date is 0316 which if correct that it was built in the 16th week of 2003 that coincides with the time frame as to when I acquired it a month or so past that date...

James will confirm but I'm quite sure I'm correct.

BTW James - any update on Engineering's thoughts on an upgrade/retrofit program???

Ron

[amdan]

James,

Any news on the upgrade for the 14B ST?

Thanks.

[James Tanner]

James,

Any news on the upgrade for the 14B ST?

Thanks.

Spoke to engineering and it looks like it will cost about $250 plus shipping.
Problem is it can not be done in the field and must come back to the factory.

james

[Ron D]

James - please advise on how to proceed if one wants to ship their amp to Peterborough. Obviously a tech's abililty to turn things around will depend on your build schedule. No point in having one's amp sit on the bench/staging area for weeks on end while Bryston completes products currently committed for delivery to their dealers & distributors.

In other words, I don't expect Bryston to drop everything to modify my amp upon its arrival but I'd rather not be without it for an extended period of time...

Tx
Ron