Power preamp
I mean that why not make the preamp like a power amplifier, it would be more allround as it can drive headphones and also small speakers the voltage gain needed to drive an ordinary power amplifier may be enough.
Specs
~8W/8Ohm = 8 Volt
THD 0.01 or better
S/N -100dB or better
IM and TIM as an good preamp/buffer
How much voltage can an amplifier like that give when it is running as an preamp/buffer.
I mean that why not make the preamp like a power amplifier, it would be more allround as it can drive headphones and also small speakers the voltage gain needed to drive an ordinary power amplifier may be enough.
Specs
~8W/8Ohm = 8 Volt
THD 0.01 or better
S/N -100dB or better
IM and TIM as an good preamp/buffer
How much voltage can an amplifier like that give when it is running as an preamp/buffer.
I see what you mean. Sure you can do a preamp with a little bit more output current capability.
If those who dare will look at my stuff (forget the extreme word) you can see an example of how you can do. Take my headphone amps, adjust the emitter/source resistors to a lower value and also remove the 100 ohm res at the output. Then you will get a little bit more power out. The amps have already heatsinks.
Notice, It's wise to have some overcurrent/overvoltage protection if you connect headphones (100 ohms res at the output). I prefer also to have the feedback with the 100 ohms res inside the loop, but this is just my kind of taste.
If you have +-15-18 V supply voltage it's possible to get out 7-10 Vrms, = some power!
Still, I wonder though about the use of this preamp?
If those who dare will look at my stuff (forget the extreme word) you can see an example of how you can do. Take my headphone amps, adjust the emitter/source resistors to a lower value and also remove the 100 ohm res at the output. Then you will get a little bit more power out. The amps have already heatsinks.
Notice, It's wise to have some overcurrent/overvoltage protection if you connect headphones (100 ohms res at the output). I prefer also to have the feedback with the 100 ohms res inside the loop, but this is just my kind of taste.
If you have +-15-18 V supply voltage it's possible to get out 7-10 Vrms, = some power!
Still, I wonder though about the use of this preamp?
Power preamp
It seems that a preamp with power utility like your amp may have better specs from very low signal to rather high signal output it will remain almost the same regardless of output level, now it comes like the BLOWTORCH from CTC.
NB
and maybe all other specs may be much better ofcource the amplifier have to be a SOTA design what do you think am on wrong track or...
It seems that a preamp with power utility like your amp may have better specs from very low signal to rather high signal output it will remain almost the same regardless of output level, now it comes like the BLOWTORCH from CTC.
NB
and maybe all other specs may be much better ofcource the amplifier have to be a SOTA design what do you think am on wrong track or...
Headphone Amp as a preamp
[If those who dare will look at my stuff (forget the extreme word) you can see an example of how you can do. Take my headphone amps, adjust the emitter/source resistors to a lower value and also remove the 100 ohm res at the output. Then you will get a little bit more power out. The amps have already heatsinks.
Hi,
If you go on like this maybe the Linn Company are interested in your design knowledge they also use a lot of components in their designs I'm not very sure about this concept I think that the best way to make circuits for Audio is to use very few components.
[If those who dare will look at my stuff (forget the extreme word) you can see an example of how you can do. Take my headphone amps, adjust the emitter/source resistors to a lower value and also remove the 100 ohm res at the output. Then you will get a little bit more power out. The amps have already heatsinks.
Hi,
If you go on like this maybe the Linn Company are interested in your design knowledge they also use a lot of components in their designs I'm not very sure about this concept I think that the best way to make circuits for Audio is to use very few components.
Re: Headphone Amp as a preamp
Focus only towards the output transistors, forget the overkill stuff before that. You can drive the output transistors "minimalistic" or "maximalistic" if you know what I mean? You must consider how much current you need the feed the output transistors.
leiade said:If you go on like this maybe the Linn Company are interested in your design knowledge they also use a lot of components in their designs I'm not very sure about this concept I think that the best way to make circuits for Audio is to use very few components.
Focus only towards the output transistors, forget the overkill stuff before that. You can drive the output transistors "minimalistic" or "maximalistic" if you know what I mean? You must consider how much current you need the feed the output transistors.
Power preamp
Ok!,
I can understand what you mean and I will try this ciruit as well,
but... I also noticed that you use fet transistors i this output stage.
Have you converted to the "Gang of FET"or have I missed something.
I have designed an BJT output for the JC-2 I just hooked on two transistors I used the old BD139/140 seems to be very good devices is there any other esoteric devices that I can use.
I will post this scheme tonight and I'm indeed very curious for the comments.
I have used the Multisim "pspice type of simulator" it has very good schematic drawing utility and the simulator "state of the art".
Am I right with the idea of power preamp that the specs is often much better then an ordinary coventional preamp like the old JC-2.
One big problem that you have mentioned erlier is to remember to check the availibility of semiconductors I'm now realize that this is a good "rule of thumb".
Ok!,
I can understand what you mean and I will try this ciruit as well,
but... I also noticed that you use fet transistors i this output stage.
Have you converted to the "Gang of FET"or have I missed something.
I have designed an BJT output for the JC-2 I just hooked on two transistors I used the old BD139/140 seems to be very good devices is there any other esoteric devices that I can use.
I will post this scheme tonight and I'm indeed very curious for the comments.
I have used the Multisim "pspice type of simulator" it has very good schematic drawing utility and the simulator "state of the art".
Am I right with the idea of power preamp that the specs is often much better then an ordinary coventional preamp like the old JC-2.
One big problem that you have mentioned erlier is to remember to check the availibility of semiconductors I'm now realize that this is a good "rule of thumb".
Re: Power preamp
You don't know me. I have never been against JFET's or MOSFET's. My old 2 x 500 W 2SK135/2SJ50 amp has JET's as input transistors and my sub has also JFET's. Those are from the 80's.
ELFA http://www.elfa.se/ did recently stop selling OK JFET's for audio, made me .
leiade said:
You don't know me. I have never been against JFET's or MOSFET's. My old 2 x 500 W 2SK135/2SJ50 amp has JET's as input transistors and my sub has also JFET's. Those are from the 80's.
ELFA http://www.elfa.se/ did recently stop selling OK JFET's for audio, made me
.
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