Hi,
It's not about the size of the caps, it's about not needing one at all.
Maybe this one could be an alternative:
LL 2615/2616.
Cheers,😉
It's not about the size of the caps, it's about not needing one at all.
Maybe this one could be an alternative:
LL 2615/2616.
Cheers,😉
fdegrove said:
Whether you need one or not depends on how much DC (and subsequently how much performance degradation) you're willing to tolerate. Again, not every circuit is going to lend itself to a parafeed configuration.
Alternative to what exactly? What's the primary inductance? That's what will determine the size of any coupling caps if you're going to use them.
se
Hi,
Oh yeah? Such as?
I can think of some but they're not typical at al...
That's one you should explain...
Cheers,😉
Oh yeah? Such as?
I can think of some but they're not typical at al...
That's one you should explain...
Cheers,😉
fdegrove said:
Such as a typical opamp output.
The coupling capacitance and the primary indcutance of the transformer form an LC resonant circuit.
se
Hi,
I fail to see any particular problem coupling an OPA to an OPT.
Don't they always? But what has the size of the coupling cap have to do with that?
The tank resonance is typical of the xformer so a damping network should take care of it, the coupling cap determines the bandwith.
Cheers,😉
I fail to see any particular problem coupling an OPA to an OPT.
Don't they always? But what has the size of the coupling cap have to do with that?
The tank resonance is typical of the xformer so a damping network should take care of it, the coupling cap determines the bandwith.
Cheers,😉
fdegrove said:
It'll depend on the opamp used and again how much DC one is willing to tolerate.
Because as the size of the coupling capacitance decreases, the Q of the resulting resonance will increase. And if you use the typical 2-10 uF of coupling capacitance typically found in line level output stages with an output transformer such as the JT-11-DMCF/PF, you'll end up with a rather large peak in your low frequency response as a result.
In order to keep the Q of the resonance reasonably low (and subsequently the low frequency response from peaking), you need to increase the amount of capacitance to several hundred uF.
The RC damping networks you see across the secondaries are to address high frequency resonance. Not low frequency resonance.
The coupling cap not only determines the bandwidth, but also determines the peak of the resonance. A larger capacitance no only results in a lower frequency response, but also a lower resonance peak.
se
Hi,
Capacitively couled DC doesn't even enter the picture so OPAs aren't any different than any other device with DC on the output.
That's only due to the frequency the primary is being fed.
Bollocks...read on.
Whether the RC network is on the primary side or secundary side, the point of having it is to reduce self resonances of the OPT.
The DC coupling cap is not going to change any of it's behaviour.
provided the RC network is chosen to cover the entire bandwidth targeted.
If you don't have the RC network in place...maybe.
I already look forward to the sound of several hundreds of µFs into a resonating xformer....
Cheers,😉
Capacitively couled DC doesn't even enter the picture so OPAs aren't any different than any other device with DC on the output.
That's only due to the frequency the primary is being fed.
Bollocks...read on.
Whether the RC network is on the primary side or secundary side, the point of having it is to reduce self resonances of the OPT.
The DC coupling cap is not going to change any of it's behaviour.
provided the RC network is chosen to cover the entire bandwidth targeted.
If you don't have the RC network in place...maybe.
I already look forward to the sound of several hundreds of µFs into a resonating xformer....
Cheers,😉
fdegrove said:
Tell me, Frank, where do you propose placing this RC network in order to deal with the low frequency resonance caused by the output coupling capacitor and the the transformer's primary inductance?
se
Hi,
None of your business? Who cares?
Those were your replies to another member, right?
Without knowing the exact conditions how would anyone know?
One thing I do know is that you know very little about xformer coupling and I suggest we'd leave it at that.
Cheers, 😉
None of your business? Who cares?
Those were your replies to another member, right?
Without knowing the exact conditions how would anyone know?
One thing I do know is that you know very little about xformer coupling and I suggest we'd leave it at that.
Cheers, 😉
fdegrove said:
Sure. With regard to personal, subjective matters. Not objective matters as this.
Don't need to know the exact conditions to answer the question.
You've got a series capacitance and a shunt inductance creating a resonant circuit (as well as a high-pass filter). Where do you place the RC network to damp the resonance? I'm not asking you for any specific values of R and C.
That's possible. So let's see what you know.
se
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