[FEELER] C12 Clone Project

[chunger]

Cool, I'll was thinking of trying this surgery myself.  I'm curious to see how much of a difference it makes sonically.  How did you end up doing it?  Did you bake the entire thing or use a torch?

For colors, I always switch to black solder mask with yellow silkscreen for final versions of projects.

No, I didn't use heat.  That would probably make everything loosen up including the vertical support bars and I suspect you would end up with a pile of deformed mess.  From the bottom of the headbasket, you can observe 2 prominent "blogs" of solder paste holding the vertical bars and 3 layers of mesh together.  One side has the end-joint of all mesh layers.  Starting there, I simply cut around the solder paste blob with cutters on the inner layer of mesh.  After a little cutting, I was able to pry the inner layer free at the corner with a fine screwdriver and continue cutting around the solder paste blob freeing the inner mesh layer.  Then, I progressed to pliers and just kept prying/cutting along the perimeter.  Some rather vigorous pulling was required.

The entire process took about 10 minutes and at some point, when I pulled, the 2nd mesh layer came with, so I just went with it.  Note:  This method only removes mesh layers on the sides of the headbasket and not on the top section.  I couldn't squeeze my cutters all the way down into the top portion and have any sort of control.

This is a VERY tight meshing setup.  I suspect the stock setup was so sibilant they used tight mesh and lots of layers to try and contain it.

Regarding the solder mask color. . . please don't to black.  I know, it's the flavor of the month and many new CAPI as well as IJ Research kits currently use it.  I am well familiar with shooting these.  No disrespect for these brilliant designers and their kits, but it is HARD to shoot black (matte and glossy).  Every little spec of dust, flux, and fingerprint shows up and it generally pisses me off probably because I have obsessive compulsive disorder.  Also, the black is, well, dark. . . makes it a little more difficult to light all the parts.  So far, my happiest shoot (visually) has been the VC528 with it's dark blue, yellow, and red pcb's contrasted with the slew of red WIMA caps.  Assuming our final C12 cap will be yellow like the prototype, I vote dark blue (or stay green) if we go muted to go complimentary color to the cap, but I'm partial to yellow on the PCB.  Maybe I'm nostalgic for my first DIY project.

 

[Enchilada]

No, I didn't use heat.  That would probably make everything loosen up including the vertical support bars and I suspect you would end up with a pile of deformed mess.  From the bottom of the headbasket, you can observe 2 prominent "blogs" of solder paste holding the vertical bars and 3 layers of mesh together.  One side has the end-joint of all mesh layers.  Starting there, I simply cut around the solder paste blob with cutters on the inner layer of mesh.  After a little cutting, I was able to pry the inner layer free at the corner with a fine screwdriver and continue cutting around the solder paste blob freeing the inner mesh layer.  Then, I progressed to pliers and just kept prying/cutting along the perimeter.  Some rather vigorous pulling was required.

That's exactly how I did mine. Easy job and sounds much better now.

 

[alexc]

Click!

Thanks also - I may give it a go and rip that mesh out too.

Cheers

 

[Matador]

Regarding the solder mask color. . . please don't to black.  I know, it's the flavor of the month and many new CAPI as well as IJ Research kits currently use it.  I am well familiar with shooting these.  No disrespect for these brilliant designers and their kits, but it is HARD to shoot black (matte and glossy).  Every little spec of dust, flux, and fingerprint shows up and it generally pisses me off probably because I have obsessive compulsive disorder.

For board color, I can do:  Blue, Red, Black, Yellow, White
For silkscreen:  Blue, Red, Black

Any other votes?  How about yellow boards with blue silkscreen?

 

[manulaudic]

I'm in for a PCB in any color 

 

[micaddict]

How is it that many here shoot fantastic photo's of every aspect of DIY, but come time mesh removing, the shutters get closed?

Otherwise still a happy guy, mind. 

 

[tonycamp]

May be difficult for pics, but the darkness of a black or blue pcb gives good contrast to id markers and is easier on the eyes for extended periods of time  in my view. Matador and Chung should do as they please though. i could always wear  8)

 

[MicDaddy]

I agree with tonycamp, black pcbs with white or other contrasting designators make it easy on the eyes.

 

[Matador]

Well, we can split the difference:  how about blue PCB's with yellow lettering? 

Hopefully Jeff Steiger doesn't get angry and sue me.

 

[funkymonksf]

I like the blue idea with yellow font! Im very excited about this. Has anyone had a chance to compare the ami t-14 to haufe t-14? I understand the haufe was the original manufacture for the originals.. Also I do recall there being a larger output transformer for a time as well.. Just curious on opinions before I think of ordering a t-14 type transformer.

Thanks,
Brice

 

[Scrappersa]

My AMI T-14 is absolutely incredible in my 250 clone. I love it. I already bought two for my C12's.

 

[micaddict]

Has anyone had a chance to compare the ami t-14 to haufe t-14? I understand the haufe was the original manufacture for the originals.. Also I do recall there being a larger output transformer for a time as well.. Just curious on opinions before I think of ordering a t-14 type transformer.

Historically, the first version was the big Hiller T14. The AMI T14 is a copy of this one.
Then came the similar Henry Radio V 2148.
The tird version tranny was the much smaller T14/1 by Haufe. Still made today.

Numbers two and three in this picture:

The big ones have extended bass.

That's the short story.

 

[chunger]

I rather enjoy arguing about pcb color rather than getting the prototype working right  ;D  I stick to my original assertion that yellow is sonically superior.  Yellow with blue lettering would be quite legible I believe and photos of the PSU would work better in this color scheme due to the black case.  Blue with yellow lettering would work well assuming the blue is the dark navy-ish blue in contrast with the yellow cap assuming that will be the final configuration.  I actually think the retro no solder mask look with be kindof cool on the mic, but that would somewhat compromise function.

I bet this all goes back to green in the end

prototyping for custom headbasket has commenced.  Hopefully, a sample will be produced soon.

Regarding the headbasket that I modified.  I didn't think it was that important of a piece given new retrofit headbaskets are on the way.  I bought this extra one with intention of shipping it back to the motherland for the factory to get detailed measurements of the base piece to manufacture the custom headbaskets, but ended up sending a complete microphone instead.  So, this piece was really inconsequential to the overall picture. . . kindof like in Star Trek when Spock, Kurk, Dr. McCoy, and a nameless ensign beam down to the planet surface.  Expendable.  I was bored and figured if I didn't succeed in removing the inner grill layer, I'd remove the 2 inner grill layers, and if I mucked up the entire thing, I'd take the entire top off and verify my measurements of the base piece.

 

[funkymonksf]

On that note is anyone digging the fact Netflix has all the star trek series! Im on series 7 of ds9. Sisko is badass (Avery brooks), I think any one with an imagination loves star trek! Any ways back to the topic yellow with blue is cool as well. However how has the consideration of the tube placement evolved? And does anyone have reviews or experience using other than the 6072 in this type of circuit? The cheapest most consistent option is the ehx 6072a, which i doubt, or a nos five star GE 6072a, which is about $60-$150 depending on manufacture source and quality.. Ive read the AC701 is useable. And ami found a source of equivalent tubes but only uses them for their designs, FYI is based on using a 6072 type...
Blah blah

 

[Matador]

And does anyone have reviews or experience using other than the 6072 in this type of circuit? The cheapest most consistent option is the ehx 6072a, which i doubt, or a nos five star GE 6072a, which is about $60-$150 depending on manufacture source and quality.. Ive read the AC701 is useable. And ami found a source of equivalent tubes but only uses them for their designs, FYI is based on using a 6072 type...
Blah blah

There's no reason a 12AT7 wouldn't work well in this circuit.  I think 12AV7 would also work well.

 

[chunger]

And does anyone have reviews or experience using other than the 6072 in this type of circuit? The cheapest most consistent option is the ehx 6072a, which i doubt, or a nos five star GE 6072a, which is about $60-$150 depending on manufacture source and quality.. Ive read the AC701 is useable. And ami found a source of equivalent tubes but only uses them for their designs, FYI is based on using a 6072 type...
Blah blah

There's no reason a 12AT7 wouldn't work well in this circuit.  I think 12AV7 would also work well.

Mullard and Siemens 12AT7's also seem to be NOS options that would work well.  They are more available than the GE6072a in low-noise non-microphonic copies.

 

[Rob Flinn]

a 12AY7 is actually the equivalent valve to a 6072.

 

[kidvybes]

...I have found the GE 6201 (military grade 12AT7WA) to be an excellent alternate option to the 6072 in tube mic applications...slightly different sounding but still very nice...these are becoming more popular (David Bock recently switched from the 6072 to the 6201 as his tube of choice in his 251 clone) so prices have been climbing, but they are much more accessible then the dwindling 6072 inventories...like the 6072, there are 2 and 3-mica versions, black and grey plates, 5-stars, etc...versions of these have extra thick mica wafers to help eliminate microphonics, and some have extra support rods which give even more stability...

...the Sylvania Gold Label 12AT7WA (the "WA" denotes higher-grade military/industrial low noise version...there are also "WB" and "WC", but the WAs are earlier vintages) also get high marks of the many 12AT7 variations...Mullard's version of this tube is the CV4024, also excellent...

...the high-grade ECC801/ECC801S were Telefunken's supreme grade 12AT7 variations...more costly and rarely available as NOS...

 

[micaddict]

How about the current production Electro-Harmonix 12AY7-EH / 6072 Gold(pin)?

 

[kidvybes]

How about the current production Electro-Harmonix 12AY7-EH / 6072 Gold(pin)?

...IMHO, these are very useable in ccda circuits (where both triodes are active in the two-stage circuit)...tube selection tends not to be as critical as in single-stage plate-follower circuits (Dave Thomas chooses EH 6072 as the stock tube in all of his ccda-based tube microphones)...

...in a plate-follower, where only a single triode is active, and swapping tubes will more readily reveal sonic variation, I find quality NOS tubes to be worth the extra effort and expense...of course, YMMV...