indeed, in general, yes
and shows even more how much credit Nelson Pass really deserves, when he choosing to stay and support us
no doubt a dilemma, and a 'challenge'
members have walked away fore much much less than that
just a silly 'reminder'
jims audio sucks period.
It was not my intension to "start" something. but I'we read so mutch about other members finnished their amps.... I want to... me to
And CUDOS to Mr Pass himself. for all his exelent work. You other guys.. deserves the best of thanks to.
BTW: bt is glowing nice and dim for now
It was not my intension to "start" something. but I'we read so mutch about other members finnished their amps.... I want to... me to
And CUDOS to Mr Pass himself. for all his exelent work. You other guys.. deserves the best of thanks to.
BTW: bt is glowing nice and dim for now
its a 50w spotligh bulb, gu10socket. as to mainsvoltage in wall socket 228.9vac after bulb 226.8vac
and the deep six is connected aswell as the biasboard
and the deep six is connected aswell as the biasboard
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biasing problems
so I started to bias today and got in problems right away...
seems I'm not able to get bias over 84,8mVDC or once I turn trimpot to lowest value it jumps to approx 150mV but falls to stable 84,8mV... checked all resistors and they are the right ones. 3x15Kohms and 1x4,75Kohm trimpot are 5k and 1k... on the bias bord.
btw I get the output dc to 0.06v or so.. any ideas?? where do I start to look, what do I meassure?? Could it be that r28 should have lower value?
HELP!
could it be pirated tl431?? ebay
orded new TL431ACL TL431 PRECISION SHUNT REGULATOR - TEXAS now...... just in case
so I started to bias today and got in problems right away...
seems I'm not able to get bias over 84,8mVDC or once I turn trimpot to lowest value it jumps to approx 150mV but falls to stable 84,8mV... checked all resistors and they are the right ones. 3x15Kohms and 1x4,75Kohm trimpot are 5k and 1k... on the bias bord.
btw I get the output dc to 0.06v or so.. any ideas?? where do I start to look, what do I meassure?? Could it be that r28 should have lower value?
HELP!
could it be pirated tl431?? ebay
orded new TL431ACL TL431 PRECISION SHUNT REGULATOR - TEXAS now...... just in case
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nevermind...removed the lb tester then it's ok
so I started to bias today and got in problems right away...
seems I'm not able to get bias over 84,8mVDC or once I turn trimpot to lowest value it jumps to approx 150mV but falls to stable 84,8mV... checked all resistors and they are the right ones. 3x15Kohms and 1x4,75Kohm trimpot are 5k and 1k... on the bias bord.
btw I get the output dc to 0.06v or so.. any ideas?? where do I start to look, what do I meassure?? Could it be that r28 should have lower value?
HELP!
could it be pirated tl431?? ebay
orded new TL431ACL TL431 PRECISION SHUNT REGULATOR - TEXAS now...... just in case
haha bias stable at 258mV
Finaly got it right.... bias stable at 258mv
however the heatsink is bearly getting warm.... could I bias it higher?? like 500mv like nelson speaks about in ba2 initial turn on and adjustment? What is the differens in sound and so on? anyone got any ideas for a newbe
Thanks to zen man for elping out the other day.
stig
Finaly got it right.... bias stable at 258mv
however the heatsink is bearly getting warm.... could I bias it higher?? like 500mv like nelson speaks about in ba2 initial turn on and adjustment? What is the differens in sound and so on? anyone got any ideas for a newbe
Thanks to zen man for elping out the other day.
stig
amp has been on for 24 hours in the livingroom ambient temp is 22Celsius. The heatsink is around 30C. so I will try to up the bias. However.. is this going to affect the sound in a good way? The higher bias the better sound?
thanks
be careful.
Higher bias in the output stage also pulls higher bias in the preceding stages.
Changing the bias of these transistors can/will move them to a different operating point where their parameters are different.
I think these changes can change the stability margins of the standard amplifier.
One that shows no oscillation during any testing, may now show damped oscillation on a part of a signal waveform.
Higher bias in the output stage also pulls higher bias in the preceding stages.
Changing the bias of these transistors can/will move them to a different operating point where their parameters are different.
I think these changes can change the stability margins of the standard amplifier.
One that shows no oscillation during any testing, may now show damped oscillation on a part of a signal waveform.
so for now its probably better to leave bias at 250mA and finnish the BA3 merge them and listen?
When you say osilate what exactly do you mean? is this what I'm seeing on output as it moves a little round +- some mV? this normal?
as I've said earlier I'm a newbee....so please have patience with me.
When you say osilate what exactly do you mean? is this what I'm seeing on output as it moves a little round +- some mV? this normal?
as I've said earlier I'm a newbee....so please have patience with me.
I have the bias set at 400mV. At this bias the heatsinks stay within the temp suggested by Mr. Pass. Nelson has written that the mosfets do benefit from running at a higher bias if the heatsinks are up to it and all I can say is that the amp sounds very good at 400mV.
What is your DC offset?
What is your DC offset?
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Zobel networks.
I have been using a Zobel across the loudspeaker wires for some years. If values and components are chosen properly one can get tighter bass, less brittle and hard upper frequencies. Since I took out the RC components of the BA-2 board for the Salas reg I have noted an immense clarity to the sound but also some hardness creeping in to the upper mid frequencies and perhaps a little too much upper frequency energy. After scratching my head a little I reversed the Zobel so that the cap made contact with ground and the resistor on the +ve terminal. This has abolished the hardness and over bright upper fequencies whilst retaining the overall clarity.
I have been using a Zobel across the loudspeaker wires for some years. If values and components are chosen properly one can get tighter bass, less brittle and hard upper frequencies. Since I took out the RC components of the BA-2 board for the Salas reg I have noted an immense clarity to the sound but also some hardness creeping in to the upper mid frequencies and perhaps a little too much upper frequency energy. After scratching my head a little I reversed the Zobel so that the cap made contact with ground and the resistor on the +ve terminal. This has abolished the hardness and over bright upper fequencies whilst retaining the overall clarity.
That's good. Why don't you listen to the amps at this bias and then if you want to at a later date turn up the bias and let us know what differences you can hear.
can you imagine amount of head-scratching if someone , during the night , again rotate position of cap and resistor in Boucherot , and you don't spot any difference ..........
block cap and resistor pretty much don't care where their head is , only ppl take too much care of it
...someone , during the night , again rotate position of cap and resistor in Boucherot , and you don't spot any difference ..........
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But who would do a thing like that?
But who would do a thing like that?
RC chain is R and C series connected - between two nodes ;
it's irrelevant is it RC or CR