Category 5

chunger, do you anticipate having the gt-2b's in stock by say the new year? I have a session coming up in jan that I would really love to use my (presently naked) mk47 on.

Hi Teacat,

Please email me.  I have a sample body solution in my inventory that might interest you but I am not planning to carry this particular mic.  If you are on a tight timeline, I can offer you one of these.

Are your upcoming GT-2B mics bodies only?  They will still fit the MK47, no?


chunger

chunger, do you anticipate having the gt-2b's in stock by say the new year? I have a session coming up in jan that I would really love to use my (presently naked) mk47 on.

Hi Teacat,

Please email me.  I have a sample body solution in my inventory that might interest you but I am not planning to carry this particular mic.  If you are on a tight timeline, I can offer you one of these.

Are your upcoming GT-2B mics bodies only?  They will still fit the MK47, no?

2nd gen gt-2b will fit the mk47 kit. . . I dont know if you noticed but it even has threades screw holes specified for the chassis mounted resistor in the build so no drilling.
DIY photo documentaries consolidated here:  http://studio939.blogspot.com

Category 5

2nd gen gt-2b will fit the mk47 kit. . . I dont know if you noticed but it even has threades screw holes specified for the chassis mounted resistor in the build so no drilling.

If only the factory in China were as with it as you are Chunger!  Thx for the update.

Steph.B

Hello there,

Just a silly idea I had when looking at some U47FET pictures.

Since you're doing what looks like a complete overhaul of the GT-2B design, why not include a swivel arm too ?

Or maybe just a screwing thread hole ?

I'm aware that it would make it more expensive and need a lot of more work from you on your CAD but it would look awesome.

Thanks,
Steph.

PS : it's not really clear to me, are you also designing a new headbasket too ? More "U47 like".
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chunger

Hello there,

Just a silly idea I had when looking at some U47FET pictures.

Since you're doing what looks like a complete overhaul of the GT-2B design, why not include a swivel arm too ?

Or maybe just a screwing thread hole ?

I'm aware that it would make it more expensive and need a lot of more work from you on your CAD but it would look awesome.

Thanks,
Steph.

PS : it's not really clear to me, are you also designing a new headbasket too ? More "U47 like".

The headbasket will be as exact as I can reasonably get to the original U47 dimensions.  It was a bit of a juggling match for dimensions.  In looking at the original U47FET, it seems they are using a casting for the body that integrates the side lug where the swivel mount attaches as well as an offset XLR connector at the base with a recessed switch.  Cost if implemented might escalate dramatically if I attempt this.

The other consideration on my part is ioaudio's mk47 kit that I felt was a really nice, streamlined package in the original GT-2B.  No space wasted.  I wanted to retain that internal feel.  Plus, if I continue on the current development path, it is an easy thing to make longer frame rails and a longer tube and create a  "short U47" offering that more closely tracks that vintage look.

In order to accomodate the current PCB's and associated transformers, i was not able to make the proportions short enough to track exactly with the U47FET though I am close.

Comes down to cost I guess.  On it's own merits, and based on final price, It think this will be a solid option for current designs and for people to adapt new projects to the "native" internal frame structure.  From this point, having hit the major design criteria, I'm seeking the path of least resistance to making it actually happen which is sharing the same M24 screw type shock mount as the gen 2 SYT-5 and making the tube simple and easy to manufacture.
DIY photo documentaries consolidated here:  http://studio939.blogspot.com

chunger

Our 34mm Edge Terminated capsules just went live.

DIY photo documentaries consolidated here:  http://studio939.blogspot.com

Our 34mm Edge Terminated capsules just went live.



...looking forward to hearing how these perform when paired with this C12 build...

Just gotta say, I've used my C12 clones on every session I've done since I made them and they just sound amazing! 
I'm hoping those STY-5 bodies are nearing finalization, I've got a DIY fever for 4 U67's in the new year!!!!!

chunger

Just gotta say, I've used my C12 clones on every session I've done since I made them and they just sound amazing! 
I'm hoping those STY-5 bodies are nearing finalization, I've got a DIY fever for 4 U67's in the new year!!!!!

Update on gen 2 SYT-5.  The factory continues to frustrate me, but we are getting closer logistically to our large production run.  Our final pricing is not as favorable as originally quoted to me by a large margin, so it does not look like I will be able to reduce cost any significant amount at least upon this initial production run.  I may be able to find some streamlining processes in subsequent runs, but for now, my priority is to get bodies in my hands as fast as reasonably possible.

So, after 2 samples, we appear to have the correct materials and 2 out of the 3 layers oriented properly. . .the outside and the inside.  Our middle layer in the latest sample is at 90 degrees instead of the correct 45 degrees.  I will take delivery of this sample to confirm that the materials used are indeed the same specification as the samples that I sent to the factory.





In order to show good faith in our dealings and not perpetually be the "overly-picky customer". . . I plan to move forward transfer the initial payment for the production run once I verify the materials are correct.  I have instructed my Chinese associate to confirm a change in our price agreement to reflect a discount if that center mesh layer is not adjusted to a 45 degree orientation in the production run.  I need to have that caveat official before moving forward with such a large deposit.  This moves the ball forward while still maintaining my insistence that the mesh layers must be executed exactly to specification.  But, we have a worst case scenario right now of the center mesh being 90 degrees.  Taking a step back, and looking at the project as a whole, it would not be the end of the world being as our external dimensions are significantly different from the vintage original sample anyways.

Due to the increased cost over my previous projections, I will not be able to make cases and other periphery accessories just yet.  I felt it was important to maintain my very large order quantity even with the higher cost per unit to show that this is a serious endeavor to the factory and to make it a priority.  We will see if the quality of this production is much better than the 1st gen bodies.  It should be given the other companies this factory OEM's for.

Another small development is I have located a producer of power transformers in the footprint that fits inside the popular Chinese PSU enclosures.  Matador seems to be in some sort of switch mode power supply development obsession so I felt it would be beneficial from an ease of build perspective to continue re-using our readily available and low-cost PSU enclosure.  The 12V power transformer will allow for a variety of voltages to be generated from his switch mode supply modules both + and -.  We should be able to make a nice, low-cost, compact 51X power supply for instance.



The 90V power transformer is targeted directly at adapting our existing passive B+ power supply PCB for use in the U47 type builds and generate a well filtered 105V B+ without producing the extreme heat the original topology generates.  I would need to consult with Matador to see if this same 90V transformer can be used in the upcoming regulated PCB as some theories point towards regulated supplies being quieter for high current applications (ie. where the heater supply is tapped off of the B+ as in U47).

DIY photo documentaries consolidated here:  http://studio939.blogspot.com

teacat

chunger, I'm not sure if my emails are getting through. I sent payment over two weeks ago for that mic body and have not heard back from you. I would have liked to have gotten it before the 1st. If need be I can pick it up. Let me know, thanks.


chunger

chunger, I'm not sure if my emails are getting through. I sent payment over two weeks ago for that mic body and have not heard back from you. I would have liked to have gotten it before the 1st. If need be I can pick it up. Let me know, thanks.

Hi teacat,

I am currently travelling and will resume shipping on the 2nd.   I apologize for the delay.  With the increased holiday flurry of.shipping. . .(not all diy), I thought I cleared the queue before departing but missed yours as.it was a manually generated invoice.  Please let me know at any time if you would like a refund.  I can process that immediately.  Also, local pickup will be fine if you want on or after the 2nd.
DIY photo documentaries consolidated here:  http://studio939.blogspot.com

teacat

Thanks, chunger. No refund, I am quite happy with the deal you gave me and stoked that you offered it up at all. Do you think you'll mail it on the 2nd? If so, I wouldn't need to pick it up. Safe travels.

chunger

Just had a nice conversation with Dave over at Cinemag regarding a large-core offering at 12:1 ratio suitable for the C12 kit.  This is the primary reason I did not extend the PCB for easier transformer mounting in our current revision 1.2.

It looks like he is willing and able to make the transformer for us.  Being as I do not have original samples in my hands, I do not think this will be as exact of a "vintage reproduction" unit as the AMI T14 is for the smaller late style transformers, but sonically, it will yield the overall characteristics of the larger core particularly in the bass response, and I have always been impressed with Cinemag's level of quality and development in their transformers.

More to come.

For now, CM-13114 is being spec'd in the budget kits and the cost reduced as appropriate.  Also,

CM-13114 (12:1)
CM-13113 (9.5:1)
CM-13101 (9.1:1 large core)

are being offering in the webstore.
DIY photo documentaries consolidated here:  http://studio939.blogspot.com

Can we talk some more about this transformer situation? The first transformer in the C12 was the Hiller, then the Henry Radio, and then the small Haufe. While Oliver's T14 is the smaller size of the Haufe, it is sonically modeled after the flatter Hiller.

What overall characteristics of the larger core are you looking for? I could seriously not imagine my C12 having any more bass than it does haha. It's bassier than my U47

micaddict

Quote
The first transformer in the C12 was the Hiller, then the Henry Radio, and then the small Haufe.

If I recall well, the Henry Radio was used before the Hiller.


Quote
While Oliver's T14 is the smaller size of the Haufe, it is sonically modeled after the flatter Hiller.

I don't have them side by side here, but I think the Haufe is considerably smaller.

micaddict,

I just meant that the AMI T14 was a smaller form factor, not that it was dimensionally the exact same as Haufe.

Here's a quote from Klaus:
"From my upcoming book "The Vintage Microphone Handbook":

"Three distinct generations of C12 can be identified, primarily by their visibly differing output transformers. The first one, from 1953 to about 1955, used the Hiller-made T14. A beefy looking affair, which, as mounted on the mic’s frame, barely clears the housing tube.

The next generation C12, including most ‘Siemens SM 204/23’-branded models, used the Henry Radio, model 2148, identified by that number on one side, and a black diamond painted on the opposite side onto lacquer-soaked brown cloth wrapping. These transformers can be found as early as 1954. Around 1958 the mic received its final transformer, the rather anemic looking T14/1, made by Haufe, near Frankfurt, Germany- the only transformer company that has been continuously supplying German mic manufacturers since post-war years through today. The last transformer version, by the way, was also used in AKG’s C24, ELA M 250/251, and C28A mic models." © Klaus Heyne, 2013 "

micaddict

Ha, ha, classic. Look at my own post here (reply #11):
http://groupdiy.com/index.php?topic=48996.0

Nice. The internet remembers better than the memory :p.

Also from that pic I would wager the AMI T14 is a little bigger than the Haufe, but smaller than the Henry. Regardless, I'm still curious about chunger's comment son the low end. I would actually be curious how to DECREASE the bass in my C12.

OPR

Quote
I would actually be curious how to DECREASE the bass in my C12
You could Use a smaller value grid resistor as used on the Ela-m-251 which uses a 30M to create a bass cut.
I tried recently in my 251 Build and it sounds great with my TC capsule but rubbish with the Chinese ck12 types
It's What's Inside That Matters!

Open Plan Recording

[email protected]

http://www.openplanrecording.com/

chrispsound

Do the 35mm K67 capsules you offer fit in the HT-11A custom head-baskets you offer?  The Cinemag cm-2510 is a great transformer  to use/experiment with submini's and fets, any chance of stocking those?  Thanks, chrisP