Ela-M 251 Body from Aliexpress

[paulcheeba]

Got Poctops 251 PCBs today. It was easy to integrate the board into the AliEx case. It fits well. I mounted the board holder profiles to the capsule holder plate from below, not from above like the manufacturer does. The four washers used between the screw and this holder plate are used to lengthen the holder by a few mm. Then I used a 50mm PCV tube and cut 3-4mm thin pieces as insert lining to fill the space/length of the powder coated MicBody outer tube. Very easy!. Then the bottom screw cap of the mic body holds everything together as before, with a few mm more length to allow for Poctop's 251 circuit boards to fit. There is enough space on the top to easily accommodate a thick, fat axial 3.3uF 20mm DC block filmcap. There is enough space behind this fat axial film cap to accommodate the microphone electron tube. Holes for screws are usable to mount the PCB and there is also enough space under the tube for mounting a UTM0512 transformer, cutting the lower unused screwnoses on both sides away. Only the solder-side of the 7-pin connector has to be cut shorter and well insulated, otherwise 1-2 mm would protrude into the PCB area. And checks for shorting soldering connection with the frame.... are also necessary to check before finishing carefully....for sure -file.....That's it. No milling machine or the like is required.... I like it very much in this way... 30min work and you have a good solution for using these super looking Micbodies

I don't know how you did this but you’re a genius Dude! I had basically thrown mine away until I understood how you subtly extended yours. It’s so good we have problem solvers like yourself or we would never get anywhere. Thank you so much, I have almost sorted it. Just waiting for some 50mm pipe as a washer.
Can I use my TBone Retro Tube PSU transformer with 115v & 115v primary and 175v and 9.5v secondary? Micparts use the same. Cheers Paul.
P.S. what size bolts for the holder plate.

 

[Whoops]

This thing is serious business! Seems to have the original dimensions. Just took it out of the box, and had to share. The only "flaw" i find at first glance is unnecessarily heavy sleeve. Looks like brass. It seems to be built like a rock. I have large hands so it might look smaller than it really is.
It weights 800 grams!

https://a.aliexpress.com/_mOUon8y

Hi mate,
thank you so much for showing us this body.

How to you find the head-basket and grille of this body when compared to a 251 original one?

 

[HerbertR]

I don't know how you did this but you’re a genius Dude! I had basically thrown mine away until I understood how you subtly extended yours. It’s so good we have problem solvers like yourself or we would never get anywhere. Thank you so much, I have almost sorted it. Just waiting for some 50mm pipe as a washer.
Can I use my TBone Retro Tube PSU transformer with 115v & 115v primary and 175v and 9.5v secondary? Micparts use the same. Cheers Paul.
P.S. what size bolts for the holder plate.

175V is perfectly, that should deliver about (x 1.41) 245V DC, not rippled. Theoretically you can use every transformer above 120V AC secondary for the plate Voltage. You have more than enough Voltage after the D1-D4 diode bridge for the ripple the B+Plate down to 120 V DC, what is needed as Plate Voltage for the Mic. Might be possible that you want to decrease the R1 and R2 75K Ohm Dropresistors to 50k Ohm used for 175V instead of a 200V AC secondary output Transformer. But not really necessary. There is B+ R4 trimmer with 250k is for adjusting properly the 120V DC. The secondary 9V AC is ideal for generating the LM317 regulated Tube Heater/Filment Voltage down to 6.3V DC. If Poctops included "L" PSU - PCB is too big / high or to broad for the Retro Case, mount it with two bottom mounted 45 degree bent metal angles, diagonal, no disadvantage.

 

[paulcheeba]

175V is perfectly, that should deliver about (x 1.41) 245V DC, not rippled. Theoretically you can use every transformer above 120V AC secondary for the plate Voltage. You have more than enough Voltage after the D1-D4 diode bridge for the ripple the B+Plate down to 120 V DC, what is needed as Plate Voltage for the Mic. Might be possible that you want to decrease the R1 and R2 75K Ohm Dropresistors to 50k Ohm used for 175V instead of a 200V AC secondary output Transformer. But not really necessary. There is B+ R4 trimmer with 250k is for adjusting properly the 120V DC. The secondary 9V AC is ideal for generating the LM317 regulated Tube Heater/Filment Voltage down to 6.3V DC. If Poctops included "L" PSU - PCB is too big / high or to broad for the Retro Case, mount it with two bottom mounted 45 degree bent metal angles, diagonal, no disadvantage.

Thanks again for your helpful words Herbert!

 

[kingkorg]

Hi mate,
thank you so much for showing us this body.

How to you find the head-basket and grille of this body when compared to a 251 original one?

Sadly, i haven't had a chance to compare to the original.

 

[Tim Campbell]

What are the dimensions of the headbasket? I have an original vintage Ela M 251E.
About 5.3cm diameter and 6.5 centimeters long

 

[paulcheeba]

Got Poctops 251 PCBs today. It was easy to integrate the board into the AliEx case. It fits well. I mounted the board holder profiles to the capsule holder plate from below, not from above like the manufacturer does. The four washers used between the screw and this holder plate are used to lengthen the holder by a few mm. Then I used a 50mm PCV tube and cut 3-4mm thin pieces as insert lining to fill the space/length of the powder coated MicBody outer tube. Very easy!. Then the bottom screw cap of the mic body holds everything together as before, with a few mm more length to allow for Poctop's 251 circuit boards to fit. There is enough space on the top to easily accommodate a thick, fat axial 3.3uF 20mm DC block filmcap. There is enough space behind this fat axial film cap to accommodate the microphone electron tube. Holes for screws are usable to mount the PCB and there is also enough space under the tube for mounting a UTM0512 transformer, cutting the lower unused screwnoses on both sides away. Only the solder-side of the 7-pin connector has to be cut shorter and well insulated, otherwise 1-2 mm would protrude into the PCB area. And checks for shorting soldering connection with the frame.... are also necessary to check before finishing carefully....for sure -file.....That's it. No milling machine or the like is required.... I like it very much in this way... 30min work and you have a good solution for using these super looking Micbodies

One more thing. I didn’t get washers or bolts. Am I right in thinking this is M1 sizing on the holder etc?

 

[kingkorg]

What are the dimensions of the headbasket? I have an original vintage Ela M 251E.
About 5.3cm diameter and 6.5 centimeters long

5.2cm, 6.4cm. Could be mine shrunk by a milimeter since i'm some 500km more North

6cm internally top of the grille to the base.

@Whoops seems to be spot on

 

[HerbertR]

One more thing. I didn’t get washers or bolts. Am I right in thinking this is M1 sizing on the holder etc?

I ve used four standard M3 Washers on each side. I think they have a hight of about 0.6-0.7mm or so.

 

[ElSmurf]

Just ordered mine. Looking forward to drawing out the acrylic parts.

And thank you @paulcheeba and @HerbertR for the info on the t.bone Retro PSU. It just looks so much cooler than the rectangular one you see everywhere, so I'm glad to know I can use it for my build.

 

[ElSmurf]

I received mine last week and it looks great and feels very heavy. I'll be curious to see what this'll do to a shock mount.

First order of business is drawing out the acrylic parts. Despite the body being a little wider than the HT11a, the wall thickness makes the internal frame the same width - at least at first glance.

I'll also be giving it the metal flake treatment, a process I'll share in an upcoming thread.

@kingkorg do you have any ideas how to create the dome? I've been thinking about getting some concentric circles with screw holes lasered in acrylic and stacking them into the dome shape.

 

[thomasdf]

I've received mine a few days ago. Nice overall finish. They seem artificially overly heavy to give a better quality feel ... so I am also wondering how they will behave in a shockmount.
I wanted to go 251 PTP style, so I am very interested in your acrilic / plexiglas experiments. Do you plan to do all the inner structure (hence the globe reference) or simply a plexi turret board ?
Only trouble is the polar patterns need to be switched with relays, so there I'd need some kind of PCB
I'll investigate too, to see if I can paint the rear mesh in black, that would help with mic placement / orientation since front and back sides are identical.

 

[cfanzalone]

For a shock mount I'd certailly recommend a Rycote USM. I wouldn't trust this in a spider type, and Rycotes vibration-rumble-insulate far better than spider-types.

 

[ElSmurf]

Do you plan to do all the inner structure (hence the globe reference) or simply a plexi turret board ?

Plexi turret board, tube suspension bridge and cutout for the transformer, and maybe use acrylic to create a dome like shape on top of the metal frame that would house the capsule mount. I'd also go for polar pattern control in the PSU.

For a shock mount I'd certailly recommend a Rycote USM.

I had a friend buy a Rycote for his vocal mic, and was very disappointed by the finish quality. Like they didn't even bother to deburr the plastic. Technically they are superior, but aesthetically not so much.

 

[cfanzalone]

H... Well, ugly is better than an inferior or makeshift shock mount...I'd hate to , because of an aesthetics choice, have to replace the headbasket or touch-up paint or XLR connectors should it fall...
...But let's focus on finishing the mic first, then deal with the mount.

 

[Barry Hufker]

I can strongly recommend these mounts from Enhanced Audio, Ireland…
http://www.enhancedaudio.ie/m600series.html

 

[thomasdf]

Plexi turret board, tube suspension bridge and cutout for the transformer, and maybe use acrylic to create a dome like shape on top of the metal frame that would house the capsule mount. I'd also go for polar pattern control in the PSU

Keep us posted And since im not very far away, I could be interested in buying you a pair of plexi turret board

 

[kingkorg]

I received mine last week and it looks great and feels very heavy. I'll be curious to see what this'll do to a shock mount.

First order of business is drawing out the acrylic parts. Despite the body being a little wider than the HT11a, the wall thickness makes the internal frame the same width - at least at first glance.

I'll also be giving it the metal flake treatment, a process I'll share in an upcoming thread.

@kingkorg do you have any ideas how to create the dome? I've been thinking about getting some concentric circles with screw holes lasered in acrylic and stacking them into the dome shape.

Not really, i kind of experiment with whatever i have. I have the benefit of measuring results so whatever works...

3d printing? Also this?

Post in thread 'My BRAUNER VM1 modification' My BRAUNER VM1 modification

 

[thomasdf]

Amazing work !

I suppose the dome is here for acoustic reasons and more interesting for that than a flat head basket bottom ?

 

[ElSmurf]

And since im not very far away, I could be interested in buying you a pair of plexi turret board

I will definitely share the files, if anyone's interested.

3d printing? Also this?

Post in thread 'My BRAUNER VM1 modification' My BRAUNER VM1 modification

3D printing is an option, which would be better than the acrylic option since this will produce a stepped dome, layer cake style. I'll see what is possible with this body.

Unfortunately I don't have access to a lathe, because that would probably deliver the smoothest and roundest results.