Thank you, Ian. We'll do the prototype and post the results asap.
UTM INDUSTRY audio transformers - from Poland - EU
- Thread starter Whoops
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Ricardus
WILL SOLDER FOR FOOD
Wow. I love this conversation!
Ricardus
WILL SOLDER FOR FOOD
igs,
Have you considered making a 2622 API style input transformer using the modern JT-110K-HPC footprint (round with 2 rows of 4 pins)?
You know the one. Jeff at CAPI typically offers the CA2622 and the EA2622 in that footprint (when supply chains are going well).
It would be amazing to have another source for those.
I am in the process of building 4 channels of API clone using CAPI's iron, but I wanted to build another 4 channel unit using someone else's iron (and opamps) for a slightly different flavor.
Have you considered making a 2622 API style input transformer using the modern JT-110K-HPC footprint (round with 2 rows of 4 pins)?
You know the one. Jeff at CAPI typically offers the CA2622 and the EA2622 in that footprint (when supply chains are going well).
It would be amazing to have another source for those.
I am in the process of building 4 channels of API clone using CAPI's iron, but I wanted to build another 4 channel unit using someone else's iron (and opamps) for a slightly different flavor.
ruffrecords
Well-known member
A trafo with higher primary inductance would be great for tube preamp projects... simular to carnhills 2290, 2291 trafos... 
3515 Trafo:
Ratio: 5:1
Impedance: 15k:600Ω
Frequency response @15kΩ source, 600 load: +/- 0.2 dB 15 Hz to 80 kHz (Ap)
Primary Inductance: 19H
Secondary Inductance: 2.5H
Total DC Rezistance PIR: 280Ω
Total DC Rezistance SEC: 53Ω
Max Level: @50Hz: +30 dBu
If sec inductance is 2H5 then the pri inductance should be 2,5x 25= 62H (wich is a decent number). 2H5 is probably a 100Hz measurment and and 19H is a 1KHz measurment or one of the two are wrongly stated?
If the secondary value is correct you probably only need to increase the turns by ca. 35% to hit 100H pri inductance....
3515 Trafo:
Ratio: 5:1
Impedance: 15k:600Ω
Frequency response @15kΩ source, 600 load: +/- 0.2 dB 15 Hz to 80 kHz (Ap)
Primary Inductance: 19H
Secondary Inductance: 2.5H
Total DC Rezistance PIR: 280Ω
Total DC Rezistance SEC: 53Ω
Max Level: @50Hz: +30 dBu
If sec inductance is 2H5 then the pri inductance should be 2,5x 25= 62H (wich is a decent number). 2H5 is probably a 100Hz measurment and and 19H is a 1KHz measurment or one of the two are wrongly stated?
If the secondary value is correct you probably only need to increase the turns by ca. 35% to hit 100H pri inductance....
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..if the inductance value of a transformer winding is where we expect low-frequency response to be impacted, than that inductance should (off course) be measured somewhere close to the low-cutoff frequency - or at least at 100Hz. Wouldn't make sense to measure at 1kHz and expect figure to predict behavior at 20Hz...
And before just expanding on the wish list, remember that these designs all comes with very carefully planned trade-offs between several parameters that are all severely limited by physics. It's not about just winding a calculated number of wire turns on a core..
/Jakob E.
And before just expanding on the wish list, remember that these designs all comes with very carefully planned trade-offs between several parameters that are all severely limited by physics. It's not about just winding a calculated number of wire turns on a core..
/Jakob E.
As I promised, we did new prototypes and measurements today:
UTM3515 Standard (2500turns:500turns, EI41): PRI: 75H, SEC: 4,6H @100Hz
UTM3515 Plus (5000turns:1000turns, EI41): PRI: 180H, SEC: 22H @100Hz
UTM3515 Max (5000turns:1000turns, EI57): PRI: 205H, SEC: 26H @100Hz
UTM3515 Standard (2500turns:500turns, EI41): PRI: 75H, SEC: 4,6H @100Hz
UTM3515 Plus (5000turns:1000turns, EI41): PRI: 180H, SEC: 22H @100Hz
UTM3515 Max (5000turns:1000turns, EI57): PRI: 205H, SEC: 26H @100Hz
All measurements (Pri and Sec) were done at 100Hz using the Uni-T UT612.What freq. is the pri inductance measured at?
Ex. If sec inductance is 26H at 100Hz the pri inductance should be around 650H at 100Hz
That would put pri inductance of the standard version at 115H at 100Hz
Maybe we can send you some free samples of our transformers for verification? Please PM me.
..just measure -3dB point at exact-known-source-impedance..
...at nominal level.
The frequency response graph is attached. -3dB of the gain is out of the AudioPrecision measure range.
What is the output (drive) impedance of that system? If e.g. 50 Ohms, just add another 950 Ohms to get it to e.g. 1K Ohm and try it there. That will give much clearer info.
If output impedance is unknown, load it with a variable resistor until it gets dragged down to half it's initial level. Measure resistor - this is your source impedance.
/Jakob E.
If output impedance is unknown, load it with a variable resistor until it gets dragged down to half it's initial level. Measure resistor - this is your source impedance.
/Jakob E.
Source impedance = 600R or 10k (can't remember), Load impedance = 600R.
I'm on winter vacation now. Can't do more measurements at the moment.
I don't think so my guys can operate AP but they can do really nice transformers for sure.
I'm on winter vacation now. Can't do more measurements at the moment.
I don't think so my guys can operate AP
but they can do really nice transformers for sure.
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Sorry, I don't understand your question.16H or 265H…
soapfoot
Well-known member
I love watching this exchange between manufacturer and end user.
