rackmonkey

A-10 clone from Crimson Transformers
« on: June 10, 2020, 06:22:11 PM »
Came across this randomly on ebay. An A-10 reproduction from Crimson.

https://www.ebay.com/itm/Crimson-Audio-Transformers-CT-A10-UTC-A-10-equivalent/124186059462?hash=item1cea10e2c6:g:srIAAOSwGPdeuxyD

Crimson have been around forever, and I own a couple of the SM-57 bodies w/different transformers in them they've made for ages. I also own a couple of DI transformers from them. All are good products.

I sent a message to John, the owner, asking how he went about it without the original lams (or if he managed to find some old stock). This was his response:

Hi Bryan,

The original lamination is certainly not available to me (and I don't think anyone else and I've been making transformers since 1978) and that has always been a huge problem in making a clone. The physical size and shape of the lamination is inextricably tied to the resistance and inductance in any transformer. In my mind and experience, the relationship between those 2 define the sonic nature of a transformer more than anything else outside of the actual turns ratio.

We found a way to modify a standard lamination, and together with a custom winding form, create a "package" that has almost exactly the same length per individual turn as the original. With that in hand, we needed to combine it with the other inhabitants of transformer world - materials and manufacturing techniques - in the right mix to come up with something that could duplicate the original. It took a lot of calculations and too many protos checked against the original to count, but we were finally able to match the T/R, FR curve, THD, inductance and resistance of the original.very, very closely. The A series contains elements of almost everything I have ever learned about transformers and transformer construction. I'm pretty sure it's one of those "I had to go there before I could get here" kind of things for me.

Now that we have cracked the "A" code, the A24 is ready for take off, to be followed by the A11 and A20.
.


The header they managed to source would seem to make it drop-in as a replacement, as the footprint is the same size as the A-series footprint.

Interesting development, with all the usual caveats about the difficulty of an endeavor like this. I went ahead and dropped the dime for one and will test it when it arrives.
« Last Edit: June 19, 2020, 10:48:51 PM by rackmonkey »
Whether you think you can or you think you can't, you're probably right.


scott2000

Re: A-10 "clone" from Crimson Transformers
« Reply #1 on: June 10, 2020, 06:26:57 PM »
Thanks for doing this... Very interesting..

I was curious about those as well..

EmRR

Re: A-10 "clone" from Crimson Transformers
« Reply #2 on: June 10, 2020, 09:05:07 PM »
interesting, hadn't heard
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

Re: A-10 "clone" from Crimson Transformers
« Reply #3 on: June 10, 2020, 10:05:16 PM »
Quote
but we were finally able to match the T/R, FR curve, THD, inductance and resistance of the original.very

It would be nice to see those numbers in their 3 pg PDF "data sheet" . . . . . . . after all, those numbers are data.

rackmonkey

Re: A-10 "clone" from Crimson Transformers
« Reply #4 on: June 10, 2020, 11:21:01 PM »
I sent an email asking about that. Will update.

This is interesting. They make a 5 lead version with the windings connected in series internally for 1:10 ratio (plus a shield ground), for $20 cheaper ($75). Looks like they'll do a custom ratio on the same platform for about the same price:


This 5 lead option also makes it much easier to generate custom variations. The A10 is historically significant, but it’s also a great mic input xfo package. It’s large size and hum bucking construction would produce great results as a 1:2, 1:8, or 1 to almost anything. FYI - most custom variations will cost about the same as the base CT-A10L
Whether you think you can or you think you can't, you're probably right.

Re: A-10 "clone" from Crimson Transformers
« Reply #5 on: June 11, 2020, 01:14:52 AM »
Hey, hadn't heard of those, thanks.  A-10 is a good one to be kicking off with.

Just out of interest, does anyone know if dear departed Oliver Archut's A series of transformers are  still being made.  I suppose I could/should just email TAB and ask now that I thought of it, doh  :-\

I'd like to try one of Crimson's as a mic in anyway.

Cheers
Jeffrey Toobin: "This is the most embarrassing week ever."

Rudy Giuliani: "Hold my pants..."

rackmonkey

Re: A-10 "clone" from Crimson Transformers
« Reply #6 on: June 11, 2020, 01:18:23 AM »
Last time I emailed Oliver's people, they said that the A series was still a work in progress. This was maybe 2 or 3 years ago. I never saw any for sale on their site. But I haven't checked in a while.
Whether you think you can or you think you can't, you're probably right.

Re: A-10 "clone" from Crimson Transformers
« Reply #7 on: June 11, 2020, 01:22:47 AM »
Last time I emailed Oliver's people, they said that the A series was still a work in progress. This was maybe 2 or 3 years ago. I never saw any for sale on their site. But I haven't checked in a while.

OK gotcha.  Yeah wasn't sure if they'd ever been completed or?  Thanks dude.
Jeffrey Toobin: "This is the most embarrassing week ever."

Rudy Giuliani: "Hold my pants..."

rackmonkey

Re: A-10 "clone" from Crimson Transformers
« Reply #8 on: June 11, 2020, 01:26:05 AM »
Just went back and looked on their site for the first time in a while, and whaddya know...they are selling an A-10, A-24 and A-26.

Minimum order 10 pcs.
Whether you think you can or you think you can't, you're probably right.

Re: A-10 "clone" from Crimson Transformers
« Reply #9 on: June 11, 2020, 06:55:11 AM »
Just went back and looked on their site for the first time in a while, and whaddya know...they are selling an A-10, A-24 and A-26.

Minimum order 10 pcs.

OK, good to know  Ollie finished the A24 too.  Can't remember what the A-26 is,  15K:600 ?   

10 pcs min is too rich for my blood but, I'll hold a thought for them being available at a fair premium in singles maybe.

Thanks again for the Crimson A-10  info
Jeffrey Toobin: "This is the most embarrassing week ever."

Rudy Giuliani: "Hold my pants..."


shabtek

Re: A-10 "clone" from Crimson Transformers
« Reply #10 on: June 11, 2020, 01:03:49 PM »
Jeff S sells an a-11 remake that is likely made by crimson and marketed for use as a DI "31.5:1 ratio to be used for some absolute blissful magic"

 anybody have one and care to do a sweep?
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

rackmonkey

Re: A-10 "clone" from Crimson Transformers
« Reply #11 on: June 11, 2020, 04:35:31 PM »
Looks like it's definitely made by Crimson. Good catch.

Maybe someone will have one and be willing to sweep it.
Whether you think you can or you think you can't, you're probably right.

Re: A-10 "clone" from Crimson Transformers
« Reply #12 on: June 11, 2020, 05:01:06 PM »
Yeah, good catch Shabtek.   
Check your P.M.'s :)
Jeffrey Toobin: "This is the most embarrassing week ever."

Rudy Giuliani: "Hold my pants..."

Re: A-10 "clone" from Crimson Transformers
« Reply #13 on: June 11, 2020, 10:31:28 PM »
Heya Shabtek,
got your message, cool, thanks.
Just letting ya know your inbox is full dude
See ya
Jeffrey Toobin: "This is the most embarrassing week ever."

Rudy Giuliani: "Hold my pants..."

shabtek

Re: A-10 "clone" from Crimson Transformers
« Reply #14 on: June 12, 2020, 01:42:39 AM »
Sweep of utc top, ct a10 bottom.
 .7dB difference in step up.
vert scale is 1dB
source 600 Ω
load 100k Ω
dcr of windings ≤10%
« Last Edit: June 12, 2020, 01:52:40 AM by shabtek »
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

shabtek

Re: A-10 "clone" from Crimson Transformers
« Reply #15 on: June 12, 2020, 01:55:40 AM »
utc has little more 'dirt' @ 0dBu 20Hz

.69% vs .263%. thd+n
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

EmRR

Re: A-10 "clone" from Crimson Transformers
« Reply #16 on: June 12, 2020, 10:31:51 AM »
I wonder what the UTC tolerance really is.  I had a pile of 10 once, and there were obvious sonic differences when comparing.   
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

rackmonkey

Re: A-10 "clone" from Crimson Transformers
« Reply #17 on: June 12, 2020, 12:29:20 PM »
Good question. I've had to sort A-11's for reasonable matches in a couple of different dual mic pres. Discernible differences even between units with the same can color.  And that was leaving the early black can units out.

The Crimson follows the shape of the high end well in the bode plot. Small-ish step up level differences are to be expected.

The "dirt" part is interesting. This is where core materials will make a difference. It'd be interesting to see numbers at several different levels.

But pretty promising so far, IMO, especially when you compare the differences to other vintage "clones". The Cinemag "equivalent" of the UTC O-12 and the Sowter version of the UA 175 OT for example. Quite a lot of sonic ground between the originals and the modern subs.

Thanks Shab.
Whether you think you can or you think you can't, you're probably right.

justinheronmusic

Re: A-10 "clone" from Crimson Transformers
« Reply #18 on: June 12, 2020, 02:23:58 PM »
How do these compare sonically to the Sowter 4383? Would it be worth swapping the Sowter for the CT-A10 in my DLA2A?
Justin Heron
Artist / Recording Engineer

CJ

Re: A-10 "clone" from Crimson Transformers
« Reply #19 on: June 12, 2020, 05:46:28 PM »
good news to hear!  nice pricepoint,  evilbay prices have become insane over the last few years,

If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html


 

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