"It doesn't make much sense to use single transistor input (why? to save 50 cents over op-amp?),
and then put op-amp as a servo..."
This structure gives great room for creativity, including applying singleton input. Someone prefer the sound of single tranistor over LTP and opamp, this is why I mentioned that. Two drawbacks need to be solved: low PSRR and offset fluctuations.
and then put op-amp as a servo..."
This structure gives great room for creativity, including applying singleton input. Someone prefer the sound of single tranistor over LTP and opamp, this is why I mentioned that. Two drawbacks need to be solved: low PSRR and offset fluctuations.
Last edited:
If that's the profile you like - why not..Q2 only for 2SA1381C, leave Q3 as MJE340
If that's the profile you like - why not..
come on.. this looks OK... Honestly it is the best setup so far..
12 hours later, minek built it
Last edited:
Here is sim file for Lomakin/Parshin + LatFets from post #358
Very simple amp - at the cost of LatFets from Exicon.
I happen to have a stash of ECW20N20/ECW20P20 - dual die Exicon Latfets, rated at 200W each (at 25 degrees).
So I guess just 1 pair of these devices should be good for an honest 100W amp, given that proper cooling is used.
Very simple amp - at the cost of LatFets from Exicon.
I happen to have a stash of ECW20N20/ECW20P20 - dual die Exicon Latfets, rated at 200W each (at 25 degrees).
So I guess just 1 pair of these devices should be good for an honest 100W amp, given that proper cooling is used.
Attachments
What for?Then turn on the second transistor with a common base
Then turn on the second transistor with a common base
As wish.But this is standard LMK, as built from Radio magazine.
The only change is BJTs => LatFets.
DC at the output of the amp is 0V in the one I built.
Then turn on the second transistor with a common base
Then it will become Wiederhold amp
As wish.
Maxim, are you saying, LMK amp as described in Radio magazine (as in build from post #87), DOES need this emitter repeater?
If, as you say, output DC voltage on the op-amp is "skewed", what problems it is going to cause?
I don't see why this LMK amp (with latfets) would have better simulated results than Wiederhold amp?
Last edited:
What is 'correct' DC voltage at the output of the amp?
What is 'skewed' DC voltage at the output of the amp?
The one I built (LMK) has 1.1 V at the output of the opamp.
Wiederhold I built, has -1.56 V at the output of the opamp.
In those ancient times, the output stages oramp were mostly low-power and with very low quiescent current, so due to the skew of the ramps, the operational amplifier switched to single-stroke amplification mode.And with a modern oramp, why do you need a constant voltage at the output ?
It will be even better. Anti-clip at least a decent make, and then in the clip at the output of the OU is a very large signal.
Here is a picture, an illustration.
This is the effect of nested OOS.
Anti-clip operation
Here is a picture, an illustration.
This is the effect of nested OOS.
Anti-clip operation
Attachments
Last edited:
- Home
- Amplifiers
- Solid State
- Unusual amp from 1987