[rob80b]

Hey Guys,

I used to know this,  but, anyway I've replaced my Dynaudio 1.3MKII's with a pair of Dynaudio Special 25's, which happen to be a lot more efficient and therefore the dial on the BP25 now averages around 8 or 9 o'clock (but I'll still crank them up there) instead of 10 or 11.
I seem to remember that the volume control on the preamp actual works as a resister, attenuating the signal which has been increased by the preamp, meaning that the boosted signal is already maxed in the preamp and the volume control is just acting as a faucet to control the amount of current leaving the outputs, which would let one to believe that the more open it is the better.
Now the question is, am I better off to lower the gain on the 4BSST using the gain switches (which also introduces a resistance) and have less attenuation of the signal through the BP25.
I may have answered my own question but looking at the posts there does not appear to be a general consensus of which is best, the Special 25's appear to be quite linear and apparently do not deviate a lot from their nominal impedance. 

Also with Dynaudio's Esotar tweeter, whatever is happening down stream is a lot more apparent.

(I know, I can just use my ears, but sometimes there is a lot more going on with signal between the pre-amp, amp and speakers)

Robert

[Dilbert]

I have no experience with the Bryston BP series preamps, but if they use a potentiometer as a volume control, they usually have the best channel to channel tracking between 10:00 and 2:00 o'clock.

I would set the power amp sensitivity switches to whatever gets you in that range, most of the time.

[rob80b]

I have no experience with the Bryston BP series preamps, but if they use a potentiometer as a volume control, they usually have the best channel to channel tracking between 10:00 and 2:00 o'clock.

I would set the power amp sensitivity switches to whatever gets you in that range, most of the time.

Hi Dilbert

This afternoon I tried to do some critical listening between the two variables, under normal recording and playback we try to get the best compromise from the source between the original input and the master potentiometer.
With regards to the preamp we have a variable resistor and hard wired resistor on the amp end, so yes we would conclude that the volume control should on the pre should be as open as possible.
During the listening session I felt there was a touch less tension with the 4BSST (2V) attenuating the signal and the BP25 turned up to about 12 o'clock, the music appeared to be slightly laid back and natural.
With the 1V setting there was more immediacy to the sound, I tried as best as possible to match levels as a difference of a few dBs can make a significant difference, usually louder appears better.
My finding are not conclusive but what I'm trying to find out if indeed the amp will behave differently depending on the strength of the original input and it's interaction with the speaker load.
The main reason I've been looking at this is that is that I've currently replaced my Dynaudio Contour 1.3MKII's, which really only came alive at higher volumes, with the Dynaudio Special 25's which are more linear and are satisfying to listen at low and high volumes, the Esotar tweeter is a lot more revealing and changes up stream are  more noticeable.
If anyone wants to chime in on the perceived differences when sending more or less gain to the amp depending on the voltage input selector I'd be interested.
I should point out that my connection to the 4BSST was with unbalanced connectors as I'm using the crossover in the Velodyne, I'll try the balanced connectors once I have a bit more time.

Robert

[rob80b]

I'd like to add that either way, 1V or 2 the Bryton's sound superb and that the BCD-1 continues to impress even more now that more nuances are revealed, especially in the higher frequencies.

Robert

[Robert D]

Robert I?m not 100% sure but I believe that the 1v setting will give you 6db more over the 2v setting.

How many 4bsst?s are you running?

I?m running 2 x 4Bsst2 1 for the left channel 1 for the right channel.
My 2 4Bsst 2 are both set at 2v setting. I prefer the sound at the 2v setting.
I would highly suggest that you go Balanced from your Bp25 to your 4Bsst?.

As well you can connect your BCD-1 Balanced to your BP25  you will gain 3db using Balanced cables from the BCD-1 ?.
 As well you can use the RCA connections to your BP25.

Robert do you have a BDA-1 planned for your future B- Day Gift??? Or Xmas- Gift????
If you do well all the better cause then you can use the Digital out puts of the BCD-1 to
BDA-1 and then Balanced to your Bp25 ?

The Balanced connections will clean your sound Quality. So saying that, they best thing to do is borrow a few pairs of Balanced cables you amp to Bp25 your BCD-1 to BP25?
I?m not saying go out and buy them? Try them and you see 
 

Good luck

Robert D

[rob80b]

Hi Robert

I'm only running one 4BSST, that's all I need.
The Velodyne only accepts single ended but I've been running balanced when available for years, but I still have both connections available to the 4BSST at the flick of a switch if I wish to bypass the crossover.
When switching between balanced or unbalanced I hear absolutely do difference and find the sound quality excellent either way so that's not the issue.
What I'm curious about without doing hours of critical listening, and this question probably falls in the realm of the amp designers, is there a difference with how the amplifier behaves, in this case the 4BSST (regardless of using single ended or balanced connections) if you feed the amp a higher signal from the preamp when using the 2V input or lower signal with the 1V setting to get the same level of playback volume.
Common sense would dictate that the amp would deal better with the STRONGER signal, therefore the gain on the preamp is higher than a weaker signal from the preamp with the 1V setting.
Not that I can hear any distortion or noise from either setting, but does the signal, the way it is received by being reduced at the preamp  or reduced by the use of a resistor at the amp affect the overall way the amp reacts to dynamic changes when amplifying the sound to the desired volume level. (does this make sense?)
As I said, just curious, part of being in this hobby and nothing I'm about to loose sleep over

Robert

[rabpaul]

An SE amplifier input expects 1V while a Balanced amplifier input expects 2V so that's what the 4BSST gain switches are there for. I also vaguely recall James saying you could (and I believe he does) set balanced connections to 1V to get the extra 6dB gain.

[Daniel Datchev]

Hi
I am not expert ,but according to my knowledge one of the reasons to have these options is
that there are different gain in preamplifier, so you have to know the gain stage of preamplifier and sum with the desirable gain of power amplifier. In most cases the sum is around 40dB gain.
daniel

[rob80b]

There are many variables but the 1v and 2V simplify matching the levels of multi channel setups and in theory all the amps should increase in volume accordingly. The pro models come with an adjustable gain for each channel and makes it easier when you're dealing with stacks of amps.
Again the question is,(and only because we can adjust the incoming signal on the Brystons) does the input affect the character of the amp if it receives a higher or lower signal from the pre amp in relation to the 1v or 2v setting or do they just negate each other when adjusting the volume to the same level.( 1+3=4 and 2+2=4)
This is in relation to a two channel setup, bearing in mind that in both cases the volume control is higher than 9 o'clock, in extreme cases were the speakers are extremely sensitive (2V setting) or the opposite of being very inefficient (1V setting) one may not have a choice.

Robert

[Levi]

I find the higher gain setting better for my ears.

[James Tanner]

Hi All,

The 1V and 2V sensitivity settings on the amplifiers are just to allow for a different total 'gain' throughout the system. Most preamp volume controls are more linear, (left to right channel balance accuracy), between about 9 and 5 o'clock.

The sensitivity switch changes the feedback loop to allow for the different voltage settings so there is not an issue where one setting has more circuitry than another. Also some preamps have difficulty delivering high voltages at their outputs.

Go with what sounds best in your system.  In most cases, if your preamp has sufficient output headroom, you will derive the lowest noise floor overall from the lower-gain, (2 Volt), setting.  We find that most people prefer their system to reach room-shaking levels with the volume control setting at 12:00-2:00 on the dial, but in fact the theoretical 'ideal' is when your amp just reaches clipping when the volume control is at maximum rotation.

james

[drummermitchell]

If I'm reading this right,then I would think the 26 has sufficiant headroom,so perhaps then the amps should be on the 2v setting.
For sure it's all about what we like to hear.My problem is AS I HAVE A NASTY TIME GETTING BEHIND MY AMPS(no room)I can only turn the pre up to 8:45 am
and she pins me to the wall ,especially with some meaty kick drum ,I am using the 1v setting,so it sounds like the 2v setting will give out
 more overall satisfaction ,correct.We do like more .

[Dilbert]

I use the 2V setting with balanced inputs even though my preamp has selectable 0, 6, 12 or 18 db overall gain. It improves the s/n with my 96db/1m medium-high efficiency speakers.

[drummermitchell]

Hi Dilbert,my 50as are 88db,sooooo.I don't know if it'll help using the 2v setting.
Maybe James will have an answer for me .

[Dilbert]

Yes, but it will get your volume control into a better operating area.

[James Tanner]

Hi Dilbert,my 50as are 88db,sooooo.I don't know if it'll help using the 2v setting.
Maybe James will have an answer for me .

Hi Don,

88 is low/medium efficiency so 1 volt is Ok - try the 2 volts and see what you think.  The problem most people have is it has been indoctrinated into their brains that less movement of the volume control means more power!

james

[werd]

Hi Rob80b

I think i know what you are asking. No i don't think the amp behaves or pre behaves any differently. If you dial the volume in to match both settings i find that the resistor in the 2v setting nerfs the dynamics (headroom) and this is what you hearing. So the 1 volt is unbridled in that respect. This is even more evident now that you have more efficient speakers.

I like both settings and go back and forth every couple months. If i am into listening loud i normally engage the 2v. The 4B just presents itself with too much jam in the 1v with my speaks.

I think it`s time to try a 4bsq with those new speaks. The change in gain at lower volumes is more apparent... beware though the amp wont the leave the house if you try one...

[drummermitchell]

Thanks James,I'll give her a shot later today when I have more .

[werd]

Thanks James,I'll give her a shot later today when I have more .

  it costs you 80bucks in chiro fees every time you turn up the volume.

[rob80b]

Hi All,

The 1V and 2V sensitivity settings on the amplifiers are just to allow for a different total 'gain' throughout the system. Most preamp volume controls are more linear, (left to right channel balance accuracy), between about 9 and 5 o'clock.

The sensitivity switch changes the feedback loop to allow for the different voltage settings so there is not an issue where one setting has more circuitry than another. Also some preamps have difficulty delivering high voltages at their outputs.

Go with what sounds best in your system.  In most cases, if your preamp has sufficient output headroom, you will derive the lowest noise floor overall from the lower-gain, (2 Volt), setting.  We find that most people prefer their system to reach room-shaking levels with the volume control setting at 12:00-2:00 on the dial, but in fact the theoretical 'ideal' is when your amp just reaches clipping when the volume control is at maximum rotation.

james

Bingo, you've just won a prepaid trip for 2 to Peterborough  , oh sorry you're already there, oh well.

Thanks for chipping in James.
As I said earlier the differences were not so apparent with my 1.3MKII's, but after putting the Dynaudio Special 25's in their place I'd thought I'd play around to see if indeed there was a difference.
Even with these aging ears I felt that higher gain from the BP25 achieved a slightly more relaxed presentation,while the 1v was a bit more forward, not night and day but still there.
But as you mentioned the preamp needs sufficent headroom, and we all have Bryston preamps,right, so no problem.

Robert