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Roll Call: Who's building, built, or thinking of building a beta22? - Page 203

post #3031 of 3166

Cool thanks.

post #3032 of 3166

That's right.. up that bias.  Overkill is the way to go.  I want to push it to the limits biggrin.gif

post #3033 of 3166

strange situation in my beta: my builder changed the gain from 8X to 5X and the beta has more power.

the output level of my source is higher compared to my old source.

my builder say me that the beta gain is not like in the other amplifier, or rather is not in the input stage but the gain is in the feedback section.

my apologies if some word is incorrect but i´m ignorant in electronic stuffs

post #3034 of 3166
Quote:
Originally Posted by alota View Post

strange situation in my beta: my builder changed the gain from 8X to 5X and the beta has more power.

the output level of my source is higher compared to my old source.

my builder say me that the beta gain is not like in the other amplifier, or rather is not in the input stage but the gain is in the feedback section.

my apologies if some word is incorrect but i´m ignorant in electronic stuffs

 

The bold may will have a lot to do with it as well.

post #3035 of 3166
Quote:
Originally Posted by preproman View Post

 

The bold may will have a lot to do with it as well.

probably. i understood your message but what it means "bold"?blink.gif

post #3036 of 3166
Quote:
Originally Posted by alota View Post

strange situation in my beta: my builder changed the gain from 8X to 5X and the beta has more power.

the output level of my source is higher compared to my old source.

my builder say me that the beta gain is not like in the other amplifier, or rather is not in the input stage but the gain is in the feedback section.

my apologies if some word is incorrect but i´m ignorant in electronic stuffs

 

a higher gain means that it will get louder more quickly as you turn up the volume.  if your source is outputting more Vrms than your previous one, then the extra voltage gets multiplied with the gain.  even if you dropped the gain from 8x to 5x, differences in the voltage that the your two sources produce can offset this. 

 

assuming the O22 is configured to deliver +/-30V, you B22 will be able to swing 43Vp-p, or 15Vrms without a load connected.  with an unbalanced source that outputs a typical 2Vrms, you will need a gain of 8x to achieve the max total voltage swing that the B22 can produce.  if you reduce the gain to 5x with a source that outputs 2Vrms, the max Vswing is reduced to 10Vrms.  while the total Vswing is reduced, it's not entirely correct to say it has less power.  yes, it has less total watts it can produce due to limiting the total Vswing, but it has the same power into less voltage demanding loads.  much above 10Vrms is K1000 and HE6 territory.  assuming a source with 2Vrms, 5x gain is plenty for the marge majority of HPs.  if you can adjust the output from the source, this is a bonus to achieve a reasonable amount of play on the pot and still achieve quiet operation into sensitive HPs.


Edited by fishski13 - 8/4/13 at 3:41pm
post #3037 of 3166

Sorry for so many questions but do you know if it is possible to make a beta22 into a speaker amp and a headphone amp.  From what I understand with a little tinkering that I could get 50W per channel out of a balanced configuration.  Or is that either a headphone amp or a speaker amp?

post #3038 of 3166
Quote:
Originally Posted by Zashoomin View Post

Sorry for so many questions but do you know if it is possible to make a beta22 into a speaker amp and a headphone amp.  From what I understand with a little tinkering that I could get 50W per channel out of a balanced configuration.  Or is that either a headphone amp or a speaker amp?

 

yes you can, but you need to consider what speakers you're driving, near-field or far-field, and do some maths.  major considerations are TX VA and heat sinking for the extra current demands.  also, the gain required to deliver a decent Vswing for the speakers may be too much for sensitive HPs, resulting in not enough play on the pot or noise.  why don't you do some searching over at the amb.org website and join the forum.  there's plenty of info.

post #3039 of 3166
Quote:
Originally Posted by Zashoomin View Post

Sorry for so many questions but do you know if it is possible to make a beta22 into a speaker amp and a headphone amp.  From what I understand with a little tinkering that I could get 50W per channel out of a balanced configuration.  Or is that either a headphone amp or a speaker amp?

 

B24 for a DIY speaker amp.  Also lots of Nelson Pass amps can be DIY as well.

post #3040 of 3166

I'll second the Nelson amps line, got some boards for 3 model of the F series coming my way soon. 

post #3041 of 3166
Quote:
Originally Posted by fishski13 View Post

 

a higher gain means that it will get louder more quickly as you turn up the volume.  if your source is outputting more Vrms than your previous one, then the extra voltage gets multiplied with the gain.  even if you dropped the gain from 8x to 5x, differences in the voltage that the your two sources produce can offset this. 

 

assuming the O22 is configured to deliver +/-30V, you B22 will be able to swing 43Vp-p, or 15Vrms without a load connected.  with an unbalanced source that outputs a typical 2Vrms, you will need a gain of 8x to achieve the max total voltage swing that the B22 can produce.  if you reduce the gain to 5x with a source that outputs 2Vrms, the max Vswing is reduced to 10Vrms.  while the total Vswing is reduced, it's not entirely correct to say it has less power.  yes, it has less total watts it can produce due to limiting the total Vswing, but it has the same power into less voltage demanding loads.  much above 10Vrms is K1000 and HE6 territory.  assuming a source with 2Vrms, 5x gain is plenty for the marge majority of HPs.  if you can adjust the output from the source, this is a bonus to achieve a reasonable amount of play on the pot and still achieve quiet operation into sensitive HPs.

thank you for explanation

post #3042 of 3166
Quote:
Originally Posted by DefQon View Post

I'll second the Nelson amps line, got some boards for 3 model of the F series coming my way soon. 

 

3 different amps?  That's a lot of building..

post #3043 of 3166
Quote:
Originally Posted by preproman View Post

 

3 different amps?  That's a lot of building..

Yeah the thing is, along with the other boards I have lying around I will probably never get around to building it. My balanced b22 is on the bench just waiting to do case work but cbf, completed half of my KGSSHV off board version, got 3 tube amp's to finish restoring and rebuilding, 3 amps to re-cap and service...Sigh if only money grew on the trees and I could freeze time. 

post #3044 of 3166
Quote:
Originally Posted by DefQon View Post

Yeah the thing is, along with the other boards I have lying around I will probably never get around to building it. My balanced b22 is on the bench just waiting to do case work but cbf, completed half of my KGSSHV off board version, got 3 tube amp's to finish restoring and rebuilding, 3 amps to re-cap and service...Sigh if only money grew on the trees and I could freeze time. 

 

 

Looks like you need a lot of bothbiggrin.gif

post #3045 of 3166

Indeed. frown.gif

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