Hi, in cathode follower circuit with 12ay7/6072 tube C7 and C6 are not necessary.
Stock circuit comes with flaw in design removing those caps plus new tube takes down distortion and helps mic sound more transparent.
UTM INDUSTRY audio transformers - from Poland - EU
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Stock circuit comes with flaw in design removing those caps plus new tube takes down distortion and helps mic sound more transparent.
commanderberti
Well-known member
whats your favorite 6072 tube ?
Selected Electro Harmonix.
In Europe you can get it from TAD.
TillM
Well-known member
Anyone do a c12 build with UTM output transformer yet?
Think @mihi_fuchs does it with his PCB's
thomasdf
Well-known member
mihi_fuchs
Well-known member
yes i do have boards fitting the utm transformer for c12 and elam251. worked very nice. i plan doing a comparisson of the two transformers. just was quite busy these days …
ElaM 251
C12
BR
Michael
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Yes, it's the UTM3503. A quadfilar, 600 Ohm, line output transformer, 1:1 or 1:2 ratio.
zamproject
Well-known member
- Joined
- May 11, 2010
- Messages
- 1,616
I believe there's something that doesn't fit.
With 7H, the 10kohm mark is achieved at 230 Hz, which makes a quite high LF cut-off.
How do you measure inductance?
With 7H, the 10kohm mark is achieved at 230 Hz, which makes a quite high LF cut-off.
How do you measure inductance?
Hello friends!
I have heard good things about Igor's transformers (igs member here on the group), UTM Transformers, from many DIY enthusiasts. I became curious.
After testing different transformers (neutrik, cinemag, beyer or even custom, modified by me from those found in the DI-box for a suitable ratio) I decided to try the UTM brand as well.
I ordered 4 pieces of UTM0587. Easy order, excellent communication, fast delivery.
The transformers are very well built, consistent (they all measure the same), with a large and quality core.
Impatiently I quickly ran tests in a U87ai-inspired clone, cardioid only, with a 797 CY002 capsule in a B2-Pro headbasket,2N3819Motorola IDSS=8.1 point-to-point construction, on the workbench, partially shielded. The feedback capacitor between 330pF...750pF, gave me a nice Neumann-ish character, varying between U87ai and U87i. The truth is that I can't decide on a specific flavor, so I'll use a multi-position switch. Clear sound, great headroom.
I am convinced that with another capsule I would get a U67fet(?) sound
I am glad for the decision to test these truly professional transformers.
Comparisons with other brands and sound samples I will post later.
I recommend with all sincerity
UTMtransformers.
Thank you Igor for your kindness and professionalism!
Micolas
I have heard good things about Igor's transformers (igs member here on the group), UTM Transformers, from many DIY enthusiasts. I became curious.
After testing different transformers (neutrik, cinemag, beyer or even custom, modified by me from those found in the DI-box for a suitable ratio) I decided to try the UTM brand as well.
I ordered 4 pieces of UTM0587. Easy order, excellent communication, fast delivery.
The transformers are very well built, consistent (they all measure the same), with a large and quality core.
Impatiently I quickly ran tests in a U87ai-inspired clone, cardioid only, with a 797 CY002 capsule in a B2-Pro headbasket,2N3819Motorola IDSS=8.1 point-to-point construction, on the workbench, partially shielded. The feedback capacitor between 330pF...750pF, gave me a nice Neumann-ish character, varying between U87ai and U87i. The truth is that I can't decide on a specific flavor, so I'll use a multi-position switch. Clear sound, great headroom.
I am convinced that with another capsule I would get a U67fet(?) sound
I am glad for the decision to test these truly professional transformers.
Comparisons with other brands and sound samples I will post later.
I recommend with all sincerity
UTMtransformers.
Thank you Igor for your kindness and professionalism!
Micolas
zamproject
Well-known member
- Joined
- May 11, 2010
- Messages
- 1,616
I already corrected some values.
Primary Inductance Ls@100Hz: 47H
Secondary Inductance Ls@100Hz: 5H
Please find the measuring setup we use and the frequency response at 600 Ohm load (AP).
TwentyTrees
Well-known member
Looking for any available data on the UTM2582 beyond what’s on the web shop (also FYI the PDF link isn’t working for me). Strikes me as a handy tube mic pre input trafo, like a 10468 et al but +17 instead of +12. Nickel, high headroom, looks good.
I’ve started designing a front end around it that takes advantage of its 1:7.07 and 1:1.77 capabilities, assuming typical 50-250 ohm mics and phantom via two 6K8s up front. Two relays make the changeover, and the load is just a grid with a high value leak. Cool guy way to avoid a U pad.
With an example primary termination of 1K2, parallel/series works out to 60K on the secondary, and series/parallel works out to 3K75 on the secondary. Is there a preferred zorbel across the resultant secondary in either scenario? Any need for a particular ohmic termination?
What’s insertion loss like? I’ve been using +16dBu and +4dBu voltage gain for downstream calcs, assuming a healthy fraction of a dB will go away.
Another question is reversal, a la the 10468 flip used in the Lola (and countless 30267 applications), but that’s more of a curiosity than a need-to-know. Seems like plenty of inductance is available on the back end if one were to flip it to take a line or instrument input 1:0.141 series/parallel.
I’ve started designing a front end around it that takes advantage of its 1:7.07 and 1:1.77 capabilities, assuming typical 50-250 ohm mics and phantom via two 6K8s up front. Two relays make the changeover, and the load is just a grid with a high value leak. Cool guy way to avoid a U pad.
With an example primary termination of 1K2, parallel/series works out to 60K on the secondary, and series/parallel works out to 3K75 on the secondary. Is there a preferred zorbel across the resultant secondary in either scenario? Any need for a particular ohmic termination?
What’s insertion loss like? I’ve been using +16dBu and +4dBu voltage gain for downstream calcs, assuming a healthy fraction of a dB will go away.
Another question is reversal, a la the 10468 flip used in the Lola (and countless 30267 applications), but that’s more of a curiosity than a need-to-know. Seems like plenty of inductance is available on the back end if one were to flip it to take a line or instrument input 1:0.141 series/parallel.
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thomasdf
Well-known member
Hello
Maybe it has been asked before, but would the UTM3547 work for a BA283 output instead of a Marinair LO1166 ? Anybody tried it ?
What levels can it handle ?
Does it fit in a 1U rack space ?
Cheers
Thomas
Maybe it has been asked before, but would the UTM3547 work for a BA283 output instead of a Marinair LO1166 ? Anybody tried it ?
What levels can it handle ?
Does it fit in a 1U rack space ?
Cheers
Thomas
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The UTM3548 is the equivalent and a bit cheaper too. (their numbering is similar to the carnhill ones 1148 for the output).
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