What you write makes no sense.
As i said before, it’s a pain in the *** for output transformers. And if you thinking about blocking DC with a capacitor it will add a nasty resonance circuit not making it better.
But if you have other ideas….i am listening.
Btw having high permeability is not a + , it needs an airgap even more.
As i said before, it’s a pain in the *** for output transformers. And if you thinking about blocking DC with a capacitor it will add a nasty resonance circuit not making it better.
But if you have other ideas….i am listening.
Btw having high permeability is not a + , it needs an airgap even more.
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Agreed! In reality these cores will result in lower permeability once you use the correct airgap for the job in SE output transformers. I think that it will need more likely 4500-5000 turns to get decent inductance and so larger gap, more leakage inductance etc....it looks more like a cat chasing his tail.
These Metalglass cores for SE use with DC current are only good for IT application with relatively small DC current (5-15 mA) using slightly oversized core. This won't be a problem as will have limited impact on overall weight and size.
Their lower core loss is of little benefit because the airgap in SE output transformers takes care of it. Instead high perm cores are useful for PP where lower core loss is an advantage.
@tubes4all:
no ideas, but enough experience.
Of course air gapping lowers permeability, but it's only part of the complete picture.
You seem to wind? OK, wind a coil for a DHT SE triode output transformer, and get yourself the appropriate HiB silicon steel c-cores, as well as a set of nanocrystalline (Finemet) c-cores with the same dimensions (yes you could get them). Do the proper airgapping; maybe it's not quite the same for the HiB and nano cores but perfectly doable. When you don't hear a difference in sound quality, stick with HiB cores. If you do (and I bet you will prefer the nano cores...) decide if you find the extra cost worth.
@ 45,
Don't confuse amorphous with nanocrystalline cores, they behave quite differently. The EL300B Finemet (nanocrystalline) transformers in the picture I sent you are 5k prim Z, have ~15 cm2 Afe, proper airgapping, 40H inductance, 68R primary DCR with 2240 primary turns of 0.4 mm silver wire. You might call them "boutique" and/or "unnecessary", but that's up to the judgment of the customer willing to pay for his preferred sound don't you think?
no ideas, but enough experience.
Of course air gapping lowers permeability, but it's only part of the complete picture.
You seem to wind? OK, wind a coil for a DHT SE triode output transformer, and get yourself the appropriate HiB silicon steel c-cores, as well as a set of nanocrystalline (Finemet) c-cores with the same dimensions (yes you could get them). Do the proper airgapping; maybe it's not quite the same for the HiB and nano cores but perfectly doable. When you don't hear a difference in sound quality, stick with HiB cores. If you do (and I bet you will prefer the nano cores...) decide if you find the extra cost worth.
@ 45,
Don't confuse amorphous with nanocrystalline cores, they behave quite differently. The EL300B Finemet (nanocrystalline) transformers in the picture I sent you are 5k prim Z, have ~15 cm2 Afe, proper airgapping, 40H inductance, 68R primary DCR with 2240 primary turns of 0.4 mm silver wire. You might call them "boutique" and/or "unnecessary", but that's up to the judgment of the customer willing to pay for his preferred sound don't you think?
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I see no problem airgapping a high permeability core when necessary. What's the fuzz about that? Some people prefer nanocrystalline cores due to their characteristic sound.
I think you are confused. Have a look at the Hitachi DC permeability curves with airgap. Definitely need more turns respect to GOSS core of the same size. I see Monolith Magnetics transformers as well. Same size, same turns, same insertion loss, less inductance.
@50AE, it's not a problem but it's not a better solution. Higher cost with worse performance (for the same size) is just hard to justify unless we are talking about boutique gear. That is. If you have to increase the size and even more the cost to get the same low frequency performance, very likely you have to trade-off something else. Likely high frequency performance. A cat chasing his tail, indeed.
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@45,
Not confused 😀.
The Monolith 3k3 and 5k SE transformers apparently have the same core size (Afe) and coil / winding scheme (same DCR's; HF bandwidth).
Amorphous and nano transformers have lower inductance because the airgap needs to be wider to prevent core saturation.
With a bit larger nano core it is not difficult to have the same inductance as the GOSS core before core saturation; checking Monolith HF bandwidth there is enough margin to loose a bit on HF bandwidth with a larger core and a bit more winding capacitance (where do we need 150.000 Hz minus 3 dB for??).
I don't quite understand their 5k series: over 300 ohm primary DCR is IMO too much for a high grade output transformer for 300B, no matter the core material.
Not confused 😀.
The Monolith 3k3 and 5k SE transformers apparently have the same core size (Afe) and coil / winding scheme (same DCR's; HF bandwidth).
Amorphous and nano transformers have lower inductance because the airgap needs to be wider to prevent core saturation.
With a bit larger nano core it is not difficult to have the same inductance as the GOSS core before core saturation; checking Monolith HF bandwidth there is enough margin to loose a bit on HF bandwidth with a larger core and a bit more winding capacitance (where do we need 150.000 Hz minus 3 dB for??).
I don't quite understand their 5k series: over 300 ohm primary DCR is IMO too much for a high grade output transformer for 300B, no matter the core material.
That's way I say. No real advantage for 3 times the price. Everyone is free to do as he likes of course but the (potential) different sound is not a good reason. The sound of an amplifier, and more importantly of a HiFi system, can be tweaked to taste without spending extra money.
To be honest and with due respect: 3 times the price is ridiculous. Winders are free to charge for their transformers what they want, but these prices do not reflect the difference in production cost.
When I pay 20 USD for a SU60b HiB GOSS c-core with 0.23mm tape thickness, a nano core with the same dimension (yes I had them made with SU60b dimensions like I had them made with SU75b dimensions) costs some 30 USD, no more....unless you don't know where to order/buy.
Major part of production cost is labour, so, once more, 3 times the price for the transformer ....😡 🤢
IMO prices for socalled high end hifi gear and components are not funny anymore.
When I pay 20 USD for a SU60b HiB GOSS c-core with 0.23mm tape thickness, a nano core with the same dimension (yes I had them made with SU60b dimensions like I had them made with SU75b dimensions) costs some 30 USD, no more....unless you don't know where to order/buy.
Major part of production cost is labour, so, once more, 3 times the price for the transformer ....😡 🤢
IMO prices for socalled high end hifi gear and components are not funny anymore.
you seem to wind….. do you? I guess not. I am not that stupid to swap cores.
What picture you sended @45? The difference between amorphous cores and nanocrystalline cores are not that big if you understand the real physics of the cores
True. In practice, you need approximately 1.7 times bigger core when going for amorphous or nano instead of HiB. I calculate this "thumb" value by multiplying the difference in stacking factor times the difference in flux density.
Stacking factor for GOSS is usually 92-95%. Nanocrystalline and amorphous cut cores reach 78%.
Knee start region 1T for amorphous and nanocrystalline, where 1.4T for HiB.
So 95/78 * 1.4/1 makes 1.7
If you look better at the technical performance at the site of MM the you would have noticed that there are many mistakes about this data.
https://www.datasheets.com/en/part-details/amcc-400-hitachi-metals--ltd-57613349#datasheet
As you can see, the high quality GOSS core 3% Si-Fe for a given H field (ampere-Turn) can use a significantly smaller airgap without causing any drop in permeability. Hence will have more inductance, all the rest being the same.
As you can see, the high quality GOSS core 3% Si-Fe for a given H field (ampere-Turn) can use a significantly smaller airgap without causing any drop in permeability. Hence will have more inductance, all the rest being the same.
Tribute never had dealers.
Re-reading the last couple of pages of this thread, it is time to leave and put my energy elsewhere🙂
Re-reading the last couple of pages of this thread, it is time to leave and put my energy elsewhere🙂
About nanocrystalline core. This is not about permability, core losses ect. but about B-H curve which nonlinearity directly affects distorsions.
Here is comparsion of B-H curves of:
- annealed cold-rolled transformer steel steel (0,3 mm)
- amorphous iron-based alloy
- nano-crystalline alloy AMAG-200S series MSTAN (russian 🙄 flat foop type nanocrystalline material)
without and with gap accordingly:
also it is about (but only regarding PP OPT - the "first watt efect"):
* Source auto-translated in attachement
Attachments
Slightly offtopic, but nanocrystalline cores are the only material I can trust on low-excitation measurements, usually giving 10% to 15% lower inductance values than high excitation tests, for example 30mT compared to 0.5T. No other material I know, even armorphous, cannot give such high inductance values at low B.
Apart the topic of the ambivalent domain of high-end audio, I find it useful to have a few nanoinductors around to check on the accuracy and performance of your L meters.
Apart the topic of the ambivalent domain of high-end audio, I find it useful to have a few nanoinductors around to check on the accuracy and performance of your L meters.
@50AE exactly, this is result of this:
the percentage permability drop near zero B is the smallest compared to amorph and silicon steel. IMHO this is critical in PP OPT in which there is no Bdc. In case of silicon steel it drops to almost zero! This results with loss of low level detail (like some TVs looses details in near-black region).
the percentage permability drop near zero B is the smallest compared to amorph and silicon steel. IMHO this is critical in PP OPT in which there is no Bdc. In case of silicon steel it drops to almost zero! This results with loss of low level detail (like some TVs looses details in near-black region).
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This is what i got recently from daanve, a picture from the site of Thomas Mayer with some tribute transformers.
And this he wrote here on diyaudio: “The EL300B Finemet (nanocrystalline) transformers in the picture I sent you are 5k prim Z, have ~15 cm2 Afe, proper airgapping, 40H inductance, 68R primary DCR with 2240 primary turns of 0.4 mm silver wire”
But if i look at the picture there is written primary current 120mA. Is this a joke or a mistake? Parallel 300B?
Something is wrong……
[
Picture redacted by moderation]
And this he wrote here on diyaudio: “The EL300B Finemet (nanocrystalline) transformers in the picture I sent you are 5k prim Z, have ~15 cm2 Afe, proper airgapping, 40H inductance, 68R primary DCR with 2240 primary turns of 0.4 mm silver wire”
But if i look at the picture there is written primary current 120mA. Is this a joke or a mistake? Parallel 300B?
Something is wrong……
[
Picture redacted by moderation]
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