UTM INDUSTRY audio transformers - from Poland - EU

[jhaell]

I ordered transformers for a Vari-Mu a month ago, fedex are slow though… no transformers yet

 

[solkatten]

Please let us know what you think of it when you have it, it will be my next order as well

I will try it out in my 4in1 mic pre here at groupdiy I will post measurments

 

[warpie]

I ordered transformers for a Vari-Mu a month ago, fedex are slow though… no transformers yet

Over a month from Poland to Sweden? Wow!

 

[jhaell]

Over a month from Poland to Sweden? Wow!

It really has to be a new record.. I think I'll have to call them again on monday. Parcel has not moved since Dec 10th. Thankfully Its not for a customers project but for myself.

 

[igs]

I ordered transformers for a Vari-Mu a month ago, fedex are slow though… no transformers yet

I checked the FedEx status. They were trying to deliver your package on Friday, 10 December 2021. 3 days after we ship them.
But the reason was: "Customer not available or business closed".
Probably I have to contact FedEx add ask to try again.

 

[jhaell]

I checked the FedEx status. They were trying to deliver your package on Friday, 10 December 2021. 3 days after we ship them.
But the reason was: "Customer not available or business closed".
Probably I have to contact FedEx add ask to try again.

Yeah.. I contacted them shortly after the 10th, however I never got a response or even a note that they had tried to deliver it.
That said, I appreciate your support and Im really excited to put these transformers to good use.

 

[Whoops]

Yeah.. I contacted them shortly after the 10th, however I never got a response or even a note that they had tried to deliver it.

Those companies are fast but I had the same problem with DHL, they didn’t left a note, call or warning they tried to deliver it so I couldn’t know and the parcel was sent back, I really dislike those companies and prefer regular mail, they always leave a Note

 

[ruffrecords]

How do you measure freq response. Ex UTM3515 Has primary inductance of 19 H and is -0,2 dB at 15Hz with 15K source, it dont add up for me? The source z is way lower? Otherwise you need like a 1000H

I agree these inductances are too low. For comparison the Carnhill VRB2291 ( 9K6:600) has a measured primary inductance of 106H.

Cheers

 

[igs]

I agree these inductances are too low. For comparison the Carnhill VRB2291 ( 9K6:600) has a measured primary inductance of 106H.

Cheers

VTB2291 has an EI57 core, while UTM3515 has an EI41. This could be a reason.

 

[abbey road d enfer]

Those companies are fast but I had the same problem with DHL, they didn’t left a note, call or warning they tried to deliver it so I couldn’t know and the parcel was sent back, I really dislike those companies and prefer regular mail, they always leave a Note

I had a similar problem recently. I needed urgently a USB extender, so ordered via Amazon, for overnight delivery..
2 days later I got a message from Amazon saying the driver had tried to deliver the parcel at 1.06 AM and there was nobody! Of course I was home.
The guy had just lied so he could be paid normally. They don't if they deliver late.
I know these guys have a harrassing job, but I hate it when they lie. They also do it often when they don't find the address, they just say they found nobody home.

 

[ruffrecords]

VTB2291 has an EI57 core, while UTM3515 has an EI41. This could be a reason.

Core size will make a difference but so will the number of turns. Maybe you need more turns of thinner wire.

Cheers

Ian

 

[igs]

Core size will make a difference but so will the number of turns. Maybe you need more turns of thinner wire.

Cheers

Ian

The UTM3515 winding is PRI: 1260+1260, SEC: 252+252. Serial 2 serial connection. DNE=0.13mm.
What do you think?

 

[Whoops]

Hi igs,
thanks for joining this thread, it's great to be able to have more info on the UTM transformers.

I was doing a list with the UTM parts and equivalence to other known transformers so that I know what is available and I can choose that depending on the project.

This is the list I was able to do with the help of IGS also:

MIC input	Equivalent
UTM2545	Carnhil VTB9045	Neve L10468
UTM2546	Carnhil VTB9046	Neve L31267
Line input
UTM2571	Carnhil VTB9071
Line Level Out
UTM3502	UA-5002	1176, rev A-D circuit
UTM3504	UA-5002	1176, rev A-D circuit low-profile for 500 series (EI-41 core)
UTM2510	Teletronix LA2A and UA175	UTC A-10 replacement
UTM3523	API 2623 output	75:300
UTM3503	API 2503 output	300:300
UMT3507	B11148	1176 - Rev E-H e Gyraf
UTM3505	B11148	1176 - Rev E-H e Gyraf
UTM3515		LA2A or REDD output transforme
UTM3501		Recommended for any kind of API-ish style output amplifiers
UTM3556		Carnhill VTB9056 direct replacement
UTM3580		Altec 436 and many other vari-mu, push-pull circuits
UTM3547	Carnhill VTB1148 (PCB mounted, 8 wires)	LO1166
UTM3548	Carnhill VTB1148 (clamped, 4 wires)	LO1166
UTM3501	Edcor PCW, 1/2W, 600Ω to 150Ω, low profile, for 500-series modules
UTM2555	VTB9045 but 1:7 ratio
UTM2571	Carnhill VTB9071
UTM2581	Carnhill VTB2381
UTM2582	Similar to Carnhill VTB2381 but 1:7 stepup possible
UTM1543	Carnhill VTB9043
UTM1544	Carnhill VTB9044
UTM1550	Carnhill VTB9050

UTM3580 = Sowter 9745

Best Regards

 

[igs]

Thanks for the clear table. It's a good idea.

UTM3547 - Carnhill VTB1148 (PCB mounted, 8 wires),
UTM3548 - Carnhill VTB1148 (clamped, 4 wires),
UTM3501 - Edcor PCW, 1/2W, 600Ω to 150Ω, low profile, for 500-series modules,
UTM2545 - Carnhill VTB9045,
UTM2546 - Carnhill VTB9046,
UTM2555 - Similar to VTB9045, stepup 1:7,
UTM2571 - Carnhill VTB9071,
UTM2581 - Carnhill VTB2381 (not listed on the Carnhill's Design Guide - Issue 1e),
UTM2582 - Similar to Carnhill VTB2381 but 1:7 stepup possible.

UTM3504 and UTM3505 are low-profile, suitable 500-series modules transformers, (30mm high) dedicated for 1176 DIY modules. The parameters are slightly different, coz the core is smaller (EI-41).

You can update your table and I'll delete this post to keep this thread clear now.

 

[abbey road d enfer]

Also I though the UTM3502 and UTM3504 were the same transformer with the only difference being the frame and both have in the description "Useful for 1176, rev A-D circuit" , but when checking the specs they have different specs, so what's the difference between the 3502 and the 3504?

Do you know that adding a frame to a xfmr slightly increases the inductance? Just because the lams are more compressed. Not huge difference , about a few %.

 

[Whoops]

Do you know that adding a frame to a xfmr slightly increases the inductance? Just because the lams are more compressed. Not huge difference , about a few %.

I didn't know that, thanks you so much for the info.

But the core is smaller also (EI-41) in this case like igs said, so it makes sense now.

Thank you both

 

[TwentyTrees]

Do you know that adding a frame to a xfmr slightly increases the inductance? Just because the lams are more compressed. Not huge difference , about a few %.

That's definitely worth knowing, thanks! Have been removing the frames from a load of Jensen quadfilar outputs recently without even thinking about it, I'll try measuring L before and after next time.

Anyway, back on topic it's great to see a new EU source for iron and hats off to UTM and IGS for opening their wares up to the DIY crew. Wonder if there's anything in the catalogue similar to a UTC A-25, that would do for an RCA BA-2C preamp output... (9:1, gapped for 5 or so mA DC).

 

[Whoops]

Hi igd,
I forgot the UTM2555 mic input tx in the list...

Whats that one?

Thank you

 

[abbey road d enfer]

That's definitely worth knowing, thanks! Have been removing the frames from a load of Jensen quadfilar outputs recently without even thinking about it, I'll try measuring L before and after next time.

For transformers, it doesn't really make a difference, but for filters it does, shifts frequency by a few %.

 

[ruffrecords]

The UTM3515 winding is PRI: 1260+1260, SEC: 252+252. Serial 2 serial connection. DNE=0.13mm.
What do you think?

Whether that is enough turns depends on the permeance of the core material. Do you have an Al figure for it?
To put this into context, inductance = Al x N x N so Al = inductance / (N x N). With primaries in series you have 2500 turns and a measured inductance of 19H which means Al is about 3uH/turn^2.

So if you doubles the turns to 2500 per winding for a total of 5000, the inductance would increase to 75H which at 20Hz has an impedance of about 10k ohms.

Cheers

Ian