How to insert -10dB Pad circuit

[abbey road d enfer]

It's the link posted by damien in post #13.
But really I based my onclusion on the electrical specs.
A FET-less capsule should not mention 1.5V and 2.2kohm.
It's like mentioning the max speed and fuel consumption of a car engine.

 

[MicMaven]

So it means the buyer knows only when he receives the capsule...? Very deceptive.

Ahem ... I do not follow this. I believe the schematic diagram indicates what is inside the capsule with dotted lines, and the rest of the circuit outside the dotted box is a minimum circuit used for testing. N'est ce pas? Or, do I misunderstand the diagram? Thanks for clarification.

Parenthetically, I presume, without knowing (ie., I am asking) one could use the capsule with just the test circuit? Are there reasons why one would not do that?

- James -

 

[k brown]

Ahem ... I do not follow this. I believe the schematic diagram indicates what is inside the capsule with dotted lines, and the rest of the circuit outside the dotted box is a minimum circuit used for testing. N'est ce pas? Or, do I misunderstand the diagram? Thanks for clarification.

Parenthetically, I presume, without knowing (ie., I am asking) one could use the capsule with just the test circuit? Are there reasons why one would not do that?

- James -

An optimum circuit would have the FET source resistor value adjusted for the actual FET in any one example of the capsule. Plus I imagine headroom would be improved with a higher operating voltage.

 

[abbey road d enfer]

Ahem ... I do not follow this. I believe the schematic diagram indicates what is inside the capsule with dotted lines, and the rest of the circuit outside the dotted box is a minimum circuit used for testing.

It seems you're correct, and k brown too.

N'est ce pas? Or, do I misunderstand the diagram? Thanks for clarification.

I misunderstood the diagram. However, I maintain that it's quite ambiguous. See my answer in post #21.

Parenthetically, I presume, without knowing (ie., I am asking) one could use the capsule with just the test circuit? Are there reasons why one would not do that?

The diagram shows a triangle representing a "FET impedance converter". It's a concept, not a circuit. It may be as simple as an FET with two or three resistors, or a FET input opamp, with a few associated parts, or a complex circuit à la AKG C414.

 

[k brown]

It seems you're correct, and k brown too.


I misunderstood the diagram. However, I maintain that it's quite ambiguous. See my answer in post #21.

The diagram shows a triangle representing a "FET impedance converter". It's a concept, not a circuit. It may be as simple as an FET with two or three resistors, or a FET input opamp, with a few associated parts, or a complex circuit à la AKG C414.

You're right - I was thinking in terms of the circuits Primo always provides for their capsules that do have built-in FETs; those certainly work, but are not optimized for any given example.

 

[abbey road d enfer]

The people at Primo should return to school for a make over regarding drafting schematics. If the triangle represents some kind of amplifier, it's point should be towards East.
If it's an FET, there is a standard symbol for it.
In conjunction with the dubious specs, it just adds confusion.

 

[MicMaven]

An optimum circuit would have . . . . .

Right. I have long understood data sheet schematics merely depict a simple, minimal test circuit, not one that is optimized for any serious or real world application.

I agree with Mr. @abbey road d enfer - it is far from obvious. Burying clues in the data sheet schematic is neither convenient nor up front. Vendors should indicate capsule type at the top of the product description. It is an onerous inconvenience to have to examine data sheet schema to determine whether it is an internal FET type or not.

Just MY take. Thanks for sharing yours. James

 

[k brown]

The people at Primo should return to school for a make over regarding drafting schematics. If the triangle represents some kind of amplifier, it's point should be towards East.
If it's an FET, there is a standard symbol for it.
In conjunction with the dubious specs, it just adds confusion.

Not mention that a single FET coould hardly be called a 'IC'.

 

[Barry Farmer]

It's just a horribly inaccurate drawing! Take pin 1 as supply to the amplifier, and pin 2 as the OUTPUT from the amplifier, with pin3 the common ground. School? If they're that daft, I'd suggest they take up knitting.

 

[k brown]

It's just a horribly inaccurate drawing! Take pin 1 as supply to the amplifier, and pin 2 as the OUTPUT from the amplifier, with pin3 the common ground. School? If they're that daft, I'd suggest they take up knitting.

The pinouts are all fine; it's just that they call the FET an IC, and don't use the universal circular symbol for it.