OPEN SOURCE DIY Mic Project - ORS 87 - Stripped Down u87

[Wordsushi]

t13 transformer from ali is not the best choice

Definitely not the best choice. I wanted to try it because I hadn't heard it. I don't hate it. I don't love it. More importantly, can you explain other transformers are shown in your graph, in comparison?

 

[Khron]

More importantly, can you explain other transformers are shown in your graph, in comparison?

And especially the exact level of the test signal used...

 

[Drosselmeier]

Definitely not the best choice. I wanted to try it because I hadn't heard it. I don't hate it. I don't love it. More importantly, can you explain other transformers are shown in your graph, in comparison?

I have a lot of different transformer tests, for example the bv8 from aliexpress is completely flat or the toroidal Terrapin which has treble and bass dips

 

[Khron]

I have a lot of different transformer tests, for example the bv8 from aliexpress is completely flat or the toroidal Terrapin which has treble and bass dips

Some text labels would be helpful (so we know what we're looking at).

 

[Drosselmeier]

Definitely not the best choice. I wanted to try it because I hadn't heard it. I don't hate it. I don't love it. More importantly, can you explain other transformers are shown in your graph, in comparison?

I tried many different transformers from Ali and literally everything is better than T13, only T8 is worse,

the best is bv8, but it is very big

 

[Drosselmeier]

And especially the exact level of the test signal used...

the topmost line is the frequency response, the next line is the 2nd harmonic that comes from the circuit, we ignore this harmonic, and all other lines are other harmonics due to the transformer, we also ignore the fundamental noise

 

[Khron]

And especially the exact level of the test signal used...

the topmost line is the frequency response, the next line is the 2nd harmonic that comes from the circuit, we ignore this harmonic, and all other lines are other harmonics due to the transformer, we also ignore the fundamental noise

Where did i ask "what line is what"? I thought i pretty clearly asked about the level of the test signal used.

Or are you implying that no transformer ever saturates (especially in the low frequencies), regardless if you're putting 1Vrms or 50Vrms into it?

 

[micolas]

Okay, so far... when it comes to stuff I've built, I have found that once I switched to the superior HL-95 body, the UTM 5087 with the Fuchs and Arienne k87 v1 is the best match for the u87ai on me. Now that I've had time to listen to a number of different transformers in the ORS 87, just not the UTM, I'm probably calling the GZT-87 my next favorite choice as it also sounds close in my Holy Fuchs mic, but the UTM is closer.

I just want to make a remark:
In U87i with a polarized voltage of the capsule of maximum 46v, the signal that will pass through the transformer is significantly lower than in the case of U87ai with a polarized voltage of the capsule of 60v.
With a small signal, the transformers (I would say the tubes too) are more neutral, but when they are attacked with a larger signal, they reveal their true character, the saturation, the harmonics stand out. Depending on the size of the magnetic core, the type of lamination, the material of the core alloy, possible thermo-chemical treatments, the quality of the winding wire, inductances, DC resistivity, parasitic capacities, resonances, etc.
So I noticed the bigger differences in transformers in U87ai, in general in circuits with high gain.
As a joke, I recall an extreme combination tested a few years ago:
Rode NT1a capsule that produces a large signal (stock is polarized at about 70v, I gave it 85..90v)
Jfet with small Idss, so higher circuit amplification
Audio power supply over 29v recommended, 31..32v
jFet Bias for maximum output.
Transformer: the little Neutrik10/3 !!!
The result: very high output signal, saturation, high harmonics.
But on spoken voice, moderate level, I was delighted. I had an amazing DJ voice and a surprising compression.
Radio-ready voice!!

 

[Drosselmeier]

Where did i ask "what line is what"? I thought i pretty clearly asked about the level of the test signal used.

Or are you implying that no transformer ever saturates (especially in the low frequencies), regardless if you're putting 1Vrms or 50Vrms into it?

T13 show the same picture in terms of harmonics and frequency response at both 1mV and 300mV, I tried taking measurements at different AC levels

 

[Papa Tango Charly]

Transformer are really surprising, i had great experience with UTM transfomer same with 3u, great sound with most tube and fet microphone. I have often read that people are very happy with the NT3 Neutrik


i have read somewhere on Groupdiy that the millenium DI transformer is 10:1.

Millenium DI thoman 13€ is a 1:10 . has anybody tried this one is it a 10:1.​

https://www.epanorama.net/newepa/2022/01/15/millenium-di-e-teardown/
https://www.thomann.de/fr/millenium_die_dibox_passiv.htm

There is also the Monacor 10:1

https://www.ltt-versand.de/fr/son/o...ansformateur-audio-di-10-1-pour-signaux-micro​

has anybody tried the monacor.
I'm always looking for new transformer.

This looks interesting


https://fr.aliexpress.com/item/32949260514.html?gatewayAdapt=glo2fra

https://fr.aliexpress.com/item/1005002001613663.html?gatewayAdapt=glo2fra



Best Charly

 

[micolas]

i have read somewhere on Groupdiy that the millenium DI transformer is 10:1.

Millenium DI thoman 13€ is a 1:10 . has anybody tried this one is it a 10:1.​

https://www.epanorama.net/newepa/2022/01/15/millenium-di-e-teardown/
https://www.thomann.de/fr/millenium_die_dibox_passiv.htm

I'm sorry, but the transformer in the Millenium DI-E box sounds bad.
Stock has over 10:1 ratio
I have bought several DI-Es but they sound non-linear, an unnatural, ugly sound.
I took turns from the primary and made it 9.5:1
The same unmusical, strange, muddy, dull sound.
In the picture is the modified one.
I think the material used for the magnetic core is of poor quality.

 

[Wordsushi]

Ok, just for comparison, u87ai and ORS 87 with that Ali T-13 and generic, possibly Transound capsule.
View attachment 87ai vs ORS87 with T-13.wav

 

[Papa Tango Charly]

I'm sorry, but the transformer in the Millenium DI-E box sounds bad.
Stock has over 10:1 ratio
I have bought several DI-Es but they sound non-linear, an unnatural, ugly sound.
I took turns from the primary and made it 9.5:1
The same unmusical, strange, muddy, dull sound.
In the picture is the modified one.
I think the material used for the magnetic core is of poor quality.

Thank you good to know

 

[Papa Tango Charly]

Yes good Transound
https://a.aliexpress.com/_mscSM4A
Km84 (t84) can handle a Transound and an Ali express t13. Thank you Mark!

 

[micolas]

Thank you good to know

I also tested one of the transformers from
DI PAN 04 Palmer Stereo
Sounds Lo-Fi, very vintage
(stock)
Probably Low-tech transformers in cheap DI-Boxes do not give good results used in microphones.

 

[Papa Tango Charly]

You had a good experience with the Neutrik 10/3 haven’t you?

 

[micolas]

Yes good Transound
https://a.aliexpress.com/_mscSM4A

I think it's just a scam

 

[micolas]

You had a good experience with the Neutrik 10/3 haven’t you?

Yes I like
And it can be used in 7:1 configuration for km84, if you connect blue wire

 

[Wordsushi]

Yes good Transound
https://a.aliexpress.com/_mscSM4A
Km84 (t84) can handle a Transound and an Ali express t13. Thank you Mark!

The one I have in here looks more like this one, but single sided.
https://www.jlielectronics.com/microphone-capsules/tsc-2/
It's probably not a Transound cap, just some $20 Ali cheapie.

And I"ve tried the Neutrik 10/3 in this circuit, wired backwards, and while I haven't really put that one through its paces, it has a bit more color than the Ali T-13.

 

[micolas]

The one I have in here looks more like this one, but single sided.
https://www.jlielectronics.com/microphone-capsules/tsc-2/
It's probably not a Transound cap, just some $20 Ali cheapie

JLI's TSC-2 appears to actually be Takstar's CTS-2, and is found in the AKG Perception Series 420 and P420. Possibly the best Chinese k67 capsule available, closest to the original.
The single-sided capsule appears to be the one from the 220 model

https://en.takstar.com/product/type/75.html

http://recordinghacks.com/microphones/AKG-Acoustics/P220