UTC revisions question

[LN]

Hello everyone,

I’m about to buy an UTC A-10 and I can choose between a dark gray and light gray one.

What are the differences (if any)?

What is the best sounding one of the two revisions?

Thanks for the help!

 

[emrr]

You can pick 4 of each and probably hear differences between all of them.

 

[LN]

You can pick 4 of each and probably hear differences between all of them.

Thanks for the info. I guess time and wear play a big role as to why they can sound different even if they’re from the same revision.

Let’s assume I can get NOS ones, are there technical differences that makes one revision sound better or worse than the other?


As I have the choice I would like to get the best sounding one for my LA2A (at least for my taste). I already have the black HA-100X but it sounds too dark, bass heavy and saturated for me (too vintage)

 

[emrr]

Inductance seems to be highest in the middle area, may make the cleanest low bass, may not. Usually inductance is fine in any of them. Treble will differ across the eras, that's a matter of taste. Differences in 2 from the same batch and same living environment are down to QC tolerances. I don't like the old saying "U Take a Chance", but it's the kind of thing that pops up with market saturated product criticism. FWIW. "U T C" really applies to anything old.

 

[LN]

That’s really interesting, thanks for your in depth explanation. As they’re old I guess it’s always a bet to find a good one.

As for the treble do you know the differences between the 2 eras (dark gray vs light gray - does one have less or more than the other etc) ?

 

[CJ]

Dark and Light Gray should all be good.

The really early Black vintage UTC A-10 i checked had lower primary inductance probably due to lower perm laminations.

As far as high end, it has never been that high, usually around 40 K IIRC.

But back then AM radio was still popular so like the Honey Badger, they didn't give a shit about high end.

 

[thomasdf]

Hello
Can anybody tell me what's the screw type these old UTC A Series use ? I am located in France, so I'll have to buy them online I suppose.
I just got a pair of A18 and the seller did not provide the screws.

Thanks in advance

Thomas

Edit : once again, I should have used the search function haha. Found the answer here (and I laughed, too) :
https://groupdiy.com/threads/mounting-an-utc-transformer.2789/

yes those are #4 screws with 40 threads per inch.
There are 4 litle threaded pipes that get welded to the inside of the case, so the holes on the base are actually on the same piece of metal as the holes on the top.
If you want, you could just tap out the old threads with a slightly bigger metric tap, or just tie wrap the darn thing down with some heavy tie wraps.