BV08 transformer capacitance, comparable to mic cable capacitance?

[Moby]

I would like to help but I don't understand exactly what you mean by "primary winding capacitance of the BV08 transformer?". If you want to achieve the HF low-pass filter, why don't you put the capacitor and measure-listen and trim to taste? Whatever value you choose it will not sound like Bv.08 but maybe you will like the sound.

 

[abbey road d enfer]

Or you can use an anode follower-ish circuit, an anode follower is a regular gain stage with unity feedback, it has comparable impedance to a CF, but the output is inverted. and the input impedance is low.

Usually called "unity-gain inverter", not anode follower. What would be the point about doing that? Higher distortion, higher noise...

I believe I gave you a pretty good resumé of the points you should take into consideration, but you don't seem interested...
I don't claim to be a guru, but I was trained to solve problems by stating them clearly.

 

[abbey road d enfer]

I would like to help but I don't understand exactly what you mean by "primary winding capacitance of the BV08 transformer?". If you want to achieve the HF low-pass filter, why don't you put the capacitor and measure-listen and trim to taste? Whatever value you choose it will not sound like Bv.08 but maybe you will like the sound.

The low-pass effect depends not only on the capacitance, but also on the load. removing teh xfmr will necessarily result in a change of load.

 

[ELS]

Why would the capacitive load on the tube be so crucial then?

I promise i'm not being facetious or anything, just trying to get you to justify (at least to yourself) WHY you consider these details so crucial (when noone else does, or seem to do).

Some version of the M49 (M49b, by the looks of things) has a 600pF capacitor from plate to ground. You think the capacitance of the primary winding matters much there?

Point being, if wiser people than either of us assert that it's the leakage inductance that limits the high-frequency extension... What good reason would you have to insist on that difficult-to-measure (or even estimate) parameter?

Have I not answered that already like 5 times? Because I don't know what that capacitance IS, if I did I could tell if it is or isn't.

 

[ELS]

Usually called "unity-gain inverter", not anode follower. What would be the point about doing that? Higher distortion, higher noise...

I believe I gave you a pretty good resumé of the points you should take into consideration, but you don't seem interested...
I don't claim to be a guru, but I was trained to solve problems by stating them clearly.

It is called an anode follower very often.
"Unity gain inverter" is what solid-state gurus call it, anode follower is an old term for the tube type circuit.
The point of that is lower distortion, lower noise, lower output impedance. same traits as the cathode follower, but it's inverted, and you can get more gain by reducing the feedback, at which point it becomes just a inverting gain stage with negative feedback.
Yeah but the question was about the capacitance across the primary.
See this is the problem with going by the XY problem idea, you answer something that the original question wasn't about. I didn't need to make a thread to see the flaws in my circuit, I needed to make a thread to find out the primary capacitance of the transformer so I could judge for myself if it was of any importance.
As I even mentioned, even an estimate would be all I need.

 

[Khron]

Have I not answered that already like 5 times? Because I don't know what that capacitance IS, if I did I could tell if it is or isn't.

Point being, if wiser people than either of us assert that it's the leakage inductance that limits the high-frequency extension... What good reason would you have to insist on that difficult-to-measure (or even estimate) parameter?

But fine, the primary capacitance is the be-all-end-all... What do i know?

 

[ELS]

But fine, the primary capacitance is the be-all-end-all... What do i know?

Can you not read? I said like 7 times now, If you'd just give me an estimate of the primary capacitance then my question would've been answered, period.

 

[Khron]

My view is that nobody knows, nobody cares, and it's close enough to being irrelevant that it doesn't matter. But once again, what do i know?

And the XY problem thing was more about you clinging on to this primary capacitance idea (the "Y"), while your actual concern is (or should be)... i'm not even sure what, but that's the "X".

 

[Lampie519]

How can anyone know what Your transformer does ?

If you really want to know measure it !!!!

If you order 2 the same transformers from the same company built the same day they measure differently, that is what we call tolerances.

 

[abbey road d enfer]

See this is the problem with going by the XY problem idea, you answer something that the original question wasn't about. I didn't need to make a thread to see the flaws in my circuit, I needed to make a thread to find out the primary capacitance of the transformer so I could judge for myself if it was of any importance.

In order to "judge for yourself", the capacitance itself means nothing. It must be put in perspective with the rest of the circuit, including tube output Z, xfmr ratio, load... My post was not about "see the flaws in your circuit", but a more holistic approach. If you don't like that, find for yourself, nobody owes you anything here.

As I even mentioned, even an estimate would be all I need.

As far as I know, no manufacturer cares to document that.

 

[ELS]

In order to "judge for yourself", the capacitance itself means nothing. It must be put in perspective with the rest of the circuit, including tube output Z, xfmr ratio, load... My post was not about "see the flaws in your circuit", but a more holistic approach. If you don't like that, find for yourself, nobody owes you anything here.

As far as I know, no manufacturer cares to document that.

Can you read the title of the thread, "BV08 Transformer Capacitance".
The XY problem is BS because I didn't ask you to re-engineer my circuit.
I could put the capacitance value in perspective with the rest of the circuit IF I KNEW WHAT IT WAS. the U47 circuit schematic is easy to obtain.
So far the best answer I've gotten has been that it's less than 750pF

How can anyone know what Your transformer does ?

If you really want to know measure it !!!!

If you order 2 the same transformers from the same company built the same day they measure differently, that is what we call tolerances.

again, not my transformer, BV08 Transformer, as the thread title would hopefully suggest.

My view is that nobody knows, nobody cares, and it's close enough to being irrelevant that it doesn't matter. But once again, what do i know?

And the XY problem thing was more about you clinging on to this primary capacitance idea (the "Y"), while your actual concern is (or should be)... i'm not even sure what, but that's the "X".

"I'm not even sure what, but that's the "X"" It's because I haven't yet designed my microphone circuit, I cannot because I'm lacking details on a different microphone desing that I want to use as a rough guideline for performance, so I know how far my circuit's performance would be from that.
While the response of the U47 has been messured and can be found, I couldn't know how much of that is impacted by the winding capacitance of the primary.
Think of guitar pickups how the type of wire insulation on that strongly affects the response of them, they are usually wound with 42AWG wire with around 8000 turns.
The BV08 is wound with 41AWG wire with around 2600 turns.
So saying "It DOESNT MATTER", is most likely entirely false just by comparing the transformer to guitar pickups for which at least the fact that the capacitance DOES matter is clearly known.

 

[Lampie519]

I think you could estimate the capacitance using the data sheet. Here you see the measurements with its input and output loads.

https://www.don-audio.com/Haufe-BV-08-BV8-microphone-audio-transformer

 

[Moby]

I think you could estimate the capacitance using the data sheet. Here you see the measurements with its input and output loads.

https://www.don-audio.com/Haufe-BV-08-BV8-microphone-audio-transformer

Datasheet you attached is not Bv.08 but some modern replacement part. Bv.08 has 4 chambered bobbins and has no shield.

 

[Moby]

The low-pass effect depends not only on the capacitance, but also on the load. removing teh xfmr will necessarily result in a change of load.

I never said that LPF depends just from the capacitor. Thread question was about the capacitance.

 

[abbey road d enfer]

Can you read the title of the thread, "BV08 Transformer Capacitance".

I believe I can.

The XY problem is BS because I didn't ask you to re-engineer my circuit.

Neither did I suggest I would.

I could put the capacitance value in perspective with the rest of the circuit IF I KNEW WHAT IT WAS. the U47 circuit schematic is easy to obtain.
So far the best answer I've gotten has been that it's less than 750pF

Apparently, no one has a better answer, because, as I already mentioned, its not publicized by manufacturers, so instead of badmouthing us, why don't you take your fingers and do the measurements?

Think of guitar pickups how the type of wire insulation on that strongly affects the response of them,

Typical BS invented by pickup manufaturers for justifying their prices and trying to create mystiism.

 

[Lampie519]

Typical BS invented by pickup manufaturers for justifying tehir preices and trying to create mystiism.

Isn’t this the same with this trafo or any vintage stuff ?
Mystify it and prices go up.
Now the asking price of a vintage transformer is higher then it was new at the time.

 

[ELS]

I believe I can.

Neither did I suggest I would.

Apparently, no one has a better answer, because, as I already mentioned, its not publicized by manufacturers, so instead of badmouthing us, why don't you take your fingers and do the measurements?

Typical BS invented by pickup manufaturers for justifying tehir preices and trying to create mystiism.

1. nc
2. it really seems that way when you need details about my mic design when I'm asking details about another mic
3. because I don't have a U47, nor a BV08 transformer, not even a replica, because of that I'd have better luck asking here for measurements instead of measuring that which I don't have. See the problem?
4. you must be joking right?
and you know there are cheap pickups that use vintage style wire, plain enamel with thicker insulation.
Only ones that jack up their prices a ton are the ones that are making replicas of old pickups.
Pickups range from 30$ to 150$ for the usable yet not 1:1replica-price. It requires about a kilometer of magnet wire which for PE costs around 50$, for Poly it's 15$
So you say it's overpriced BS when the pickup costs not even twice the material costs?
Doesnt the saying go that for a profitable business you have to price products at over twice the material costs? doesn't seem like they're profiting much here.
Meanwhile I'm guessing you're the type that want 0.00001%THD from his hifi, and doesn't dare to even think of using an EQ for nothing else than flattening the room response.

 

[abbey road d enfer]

Isn’t this the same with this trafo or any vintage stuff ?

Indeed!

 

[abbey road d enfer]

2. it really seems that way when you need details about my mic design when I'm asking details about another mic

Did I ask details? You expressed your "problem" in ways that showed you don't understand all you need to know to solve it.

4. you must be joking right?
and you know there are cheap pickups that use vintage style wire, plain enamel with thicker insulation.
Only ones that jack up their prices a ton are the ones that are making replicas of old pickups.
Pickups range from 30$ to 150$ for the usable yet not 1:1replica-price. It requires about a kilometer of magnet wire which for PE costs around 50$, for Poly it's 15$
So you say it's overpriced BS when the pickup costs not even twice the material costs?
Doesnt the saying go that for a profitable business you have to price products at over twice the material costs? doesn't seem like they're profiting much here.

I know a lot about manufacturing and cost building, and I know about science.
Leo Fender was a very pragmatic guy. He made sure the BOM was the thriftiest he could go away with.

Meanwhile I'm guessing you're the type that want 0.00001%THD from his hifi, and doesn't dare to even think of using an EQ for nothing else than flattening the room response.

You're ASSumming a lot. You don't know me, your crystal ball needs maintenance.

 

[Lampie519]

Datasheet you attached is not Bv.08

Maybe so (but it is mentioned like so on the datasheet).
I guess you want to say that the original is/was better then the copy.
That is fine as well as the value can then also only be better/lower ( if it is true that the original is better)
So it is a good starting point anyway as it is closest to the original i guess.

I had a broken transformer once in a Oktava mic and replaced it with a tiny mains transformer and could’t hear any difference at all (no dc flowing through the transformer).
I had a matched pair and it still sounds as matched ( no measurements done yet)
Maybe that says something about my hearing or that all the talk about transformers is just talk. Now i did not overdrive it so here the difference maybe noticed.