danieljw, thanks for the post, very informative.
That is what I was thought, to try the amplifier with batteries only first, as two 80AH batteries will last more. It is also a bit cheaper than aqcuiring these big caps.
I think the biggest problem with batteries is the voltage variations as the battery discharges, which will affect the bias setting, so one should continuously set the bias or should use the battery for less time before it descharges completely and have a voltage drop. Of course in such configurations only deep cycle batteries should be used.
Also voltage and amp meters must be used to contonuously monitor the voltage and the amp drawn. Since the PSU will be in another box changing the configurations won't be a problem.
I will let you know about the results, but I feel that appart from the time restriction factor of the batteries it won't dissapoint, as it is clean and straight forward. Anyway five hours a day continuously is very fine to me
That is what I was thought, to try the amplifier with batteries only first, as two 80AH batteries will last more. It is also a bit cheaper than aqcuiring these big caps.
I think the biggest problem with batteries is the voltage variations as the battery discharges, which will affect the bias setting, so one should continuously set the bias or should use the battery for less time before it descharges completely and have a voltage drop. Of course in such configurations only deep cycle batteries should be used.
Also voltage and amp meters must be used to contonuously monitor the voltage and the amp drawn. Since the PSU will be in another box changing the configurations won't be a problem.
I will let you know about the results, but I feel that appart from the time restriction factor of the batteries it won't dissapoint, as it is clean and straight forward. Anyway five hours a day continuously is very fine to me
woody said:
That sounds like a really good idea.
Lumba Ogir said:
do you mean they are deteriorating in terms of the sound or the high freq roll off... ??
neazoi said:danieljw, thanks for the post, very informative.
That is what I was thought, to try the amplifier with batteries only first, as two 80AH batteries will last more. It is also a bit cheaper than aqcuiring these big caps.
I think the biggest problem with batteries is the voltage variations as the battery discharges, which will affect the bias setting, so one should continuously set the bias or should use the battery for less time before it descharges completely and have a voltage drop. Of course in such configurations only deep cycle batteries should be used.
Also voltage and amp meters must be used to contonuously monitor the voltage and the amp drawn. Since the PSU will be in another box changing the configurations won't be a problem.
I will let you know about the results, but I feel that appart from the time restriction factor of the batteries it won't dissapoint, as it is clean and straight forward. Anyway five hours a day continuously is very fine to me
Yeah that is a good point Neazoi, 5 hours is pretty good. oh by the way are you planning to make a run of boards?
-Dan
I can make another pair too, no problem.
I do not see anything unusual with your PCBs, the same star GND as the original Hiragas PCBs but with a more modern tone. So I am going to go for them.
In such small PCBs you do not have long paths of GND so I believe a star topology wouldn't be necessary either way
One last thing, I am thinking of replacing the bias resistor on the base of the drivers with another trimmer, to easily adjust the bias for voltage differences in the battery, when discharged. I am not sure about the sound effect so this is a thought yet. but if I decide this I have to adapt the pcb accordingly.
I do not see anything unusual with your PCBs, the same star GND as the original Hiragas PCBs but with a more modern tone. So I am going to go for them.
In such small PCBs you do not have long paths of GND so I believe a star topology wouldn't be necessary either way
One last thing, I am thinking of replacing the bias resistor on the base of the drivers with another trimmer, to easily adjust the bias for voltage differences in the battery, when discharged. I am not sure about the sound effect so this is a thought yet. but if I decide this I have to adapt the pcb accordingly.
I am not sure i understand why Lumba,
can you add some info for me ??
by my calculations the 68pF only come into play in the HF region
and the 2200pF is there for a similar reason HF stability,
I understand the stance on audio being affected my how the amp performs many octaves higher, but it measures out to the hundreds of kHz,
Perhaps you can shed some light - i am open to hear your thoughts on this ?
-Dan
can you add some info for me ??
by my calculations the 68pF only come into play in the HF region
and the 2200pF is there for a similar reason HF stability,
I understand the stance on audio being affected my how the amp performs many octaves higher, but it measures out to the hundreds of kHz,
Perhaps you can shed some light - i am open to hear your thoughts on this ?
-Dan
i get what you are saying.... it is a valid point,
the Cob is 55-65 for 2SC1096/2SA634... perhaps i can remove them due to the input filter (and the amp seems stable....
i guess if you look at it as 68pF + 65pF that is 133pF
using 1/(2PiFC) at 20kHz that is 59832.7Ohms..... Hmmm
at 20Hz 59.8327 MOhm.... so HF could be affected....??
Perhaps it is time for these caps to go.....
What is the resoning behind the 2200pF being a problem ?
(if i do remove them i will do before and after listening and measurement tests.)
-Dan
the Cob is 55-65 for 2SC1096/2SA634... perhaps i can remove them due to the input filter (and the amp seems stable....
i guess if you look at it as 68pF + 65pF that is 133pF
using 1/(2PiFC) at 20kHz that is 59832.7Ohms..... Hmmm
at 20Hz 59.8327 MOhm.... so HF could be affected....??
Perhaps it is time for these caps to go.....
What is the resoning behind the 2200pF being a problem ?
(if i do remove them i will do before and after listening and measurement tests.)
-Dan
probably what i will do is keep the "Le class A" the same as it is currently because it was designed to "sound" a certain way and it does in fact sound very good in my opinion. I think the caps were added for stability and measured performance and listening is very good.
I think I will build another "Le monstre" with batteries this time.
Le class A is almost as good as Le monstre but there is somthing about this tiny power monstre amp that is special......
What (everyone) do you think about using newer devices - perhaps with better spec than the originals used in "Le monstre"
for example better JFETs with lower noise (if possible)
I would say the input devices in the Le monstre may be hard to better in terms of noise/Cob etc though
thoughts anyone?
-Dan
I think I will build another "Le monstre" with batteries this time.
Le class A is almost as good as Le monstre but there is somthing about this tiny power monstre amp that is special......
What (everyone) do you think about using newer devices - perhaps with better spec than the originals used in "Le monstre"
for example better JFETs with lower noise (if possible)
I would say the input devices in the Le monstre may be hard to better in terms of noise/Cob etc though
thoughts anyone?
-Dan
I am glad you wish to make the battery version, that makes two of us
Before I print the PCBs I am trying to add the option to accept a precision trimmer for 1K too, in order to set the bias correctly. Audiomanics, if you could provide the pcb file it would be much easier than trying to edit the image.
A good and cheap option for the batteries if someone lives in Greece: http://www.eshops.gr/index.php?act=viewCat&catId=589
Before I print the PCBs I am trying to add the option to accept a precision trimmer for 1K too, in order to set the bias correctly. Audiomanics, if you could provide the pcb file it would be much easier than trying to edit the image.
A good and cheap option for the batteries if someone lives in Greece: http://www.eshops.gr/index.php?act=viewCat&catId=589