Newcomb TR-91 Input Transformer

[rock soderstrom]

what do you consider the best mic input transformer available that won't cost me a kidney?

Peerless k 241 d = a real bargain. You can still live with one kidney!

https://reverb.com/item/12997772-pa...nsformers-in-excellent-condition-pultec-mavec
Joking aside, I would also be interested in what are the "best" microphone to grid transformers that are still affordable?

 

[sahib]

Peerless k 241 d = a real bargain. You can still live with one kidney!

 

[CJ]

Jensen JT 115 is real nice and the price is very reasonable. At one time they were like 89 bucks.

 

[C12VR]

now they are nearly double that, sadly. And given their small size, won't they reach saturation early like the ouncers?

 

[CJ]

0.7746 v-rms at 20 hz,

Plug a 57 into a transformer like they use at hoover dam. Will not saturate but how much signal do you think will come out the other side?

 

[C12VR]

Ok so the saturation point at the input is high enough for most apps. Jensen specs at minimum 1% THD @20hz for -4DBU, which I think is close enough to the quoted .77V. How much better is one of those big old UTC LS or Triad HS type transformers anyway? Is there any point to using them nowadays? Besides the nether mind's philosophy that bigger is better?

 

[rock soderstrom]

How much better is one of those big old UTC LS or Triad HS type transformers anyway? Is there any point to using them nowadays? Besides the nether mind's philosophy that bigger is better?

I have been asking myself similar questions for a long time. Why are American vintage mic to grid transformers so big? They look like output transformers of tube power amps from the 15W class. Historically comparable transformers from European products like V72 or V76 are much smaller and also not known for constant overdriving, right?

I'd love to give these classics a try but the asking prices and transport costs to my side of the pond don't make it easy.

Tiny Telefunken/ Haufe 1:20 in front of a Mini SA70

 

[C12VR]

Oh my god you have the EXACT same handwriting as me!
And that is a microscopic transformer, wow. That thing definitely will have a "sound."
It looks like one of those Beyer peanuts, except even more extreme turns ratio

 

[rock soderstrom]

Oh my god you have the EXACT same handwriting as me!

I feel sorry for you!

And that is a microscopic transformer, wow. That thing definitely will have a "sound."
It looks like one of those Beyer peanuts, except even more extreme turns ratio

Yeah, it is really tiny but one size bigger (height and diameter) than the standard beyer peanut.
I cannibalized it from a broken (semi pro) Telefunken M24 tape recorder.
This will be my first test, I am very curious how this guy sounds!

 

[C12VR]

I wonder how thick the shielding can is on that Haufe. It may be the case the actual transformer is even smaller than it appears.
I'm interested in the sound of that pre; I'm looking into the old Gates stuff as well.

 

[rock soderstrom]

I wonder how thick the shielding can is on that Haufe. It may be the case the actual transformer is even smaller than it appears.
I'm interested in the sound of that pre; I'm looking into the old Gates stuff as well.

Same here. One day I'm going to saw open one of these Haufe transformers, I'm very interested in the inside.
First I'll see how it sounds. I am curious whether the Haufe transformer, despite its high step up factor, transmits high frequencies? 20KHz??

The whole project is also a circuit test with the 5654/6AK5w tubes instead of the US steel tubes.
The intended transformer for further preamps with this PCB is this UTM type, which looks very promising.

https://utmindustry.com/utm2572

 

[C12VR]

Same here. One day I'm going to saw open one of these Haufe transformers, I'm very interested in the inside.
First I'll see how it sounds. I am curious whether the Haufe transformer, despite its high step up factor, transmits high frequencies? 20KHz??

The whole project is also a circuit test with the 5654/6AK5w tubes instead of the US steel tubes.
The intended transformer for further preamps with this PCB is this UTM type, which looks very promising.

https://utmindustry.com/utm2572

I also wanted to use this transformer, but there are two different winding ratios listed, and all Igor did when I asked which was correct was like my post. I have a feeling this is just another 1:8 but I hope not, because then I can use it in my current project, cutting TFMR costs by a few hundred.

 

[CJ]

I think you just pull the yellow tape off and the cans come apart. Might be a toroid in there.

UTC LS cans often have the same size transformer as say, an A-22, the big can needed because of the three nested shield cans inside.

Jensen will sound more like a piece of wire. Vintage UTC will have more rolloff and therefore sound more "vintage."