Ela-M 251 Body from Aliexpress

[Lowfreq]

Also, there was some discussion in other threads with the 6s6b tube in an M251 circuit, about the R1 plate resistor.
Is it best to work off the 200k value like the ac701 schematic? or stick with the 100k like the 6072a schematic?
What is the 6s6b closest to?

 

[Papa Tango Charly]

Hello guys thank you for your help. I hope i got this right! Do i still need C3? Best!

 

[Khron]

Why wouldn't you?

 

[Papa Tango Charly]

Yes sorry i was busy drawing the new schematic and i didn't see all the comments and your schematic Sparklebear thank you so much. C3 (10,000 pf) there just to filter noise off of the rail? Different than the role of c6 (600pf) in the m49 to shunt HF from plate out (to reduce hf response) yes? I got it now! Thank you all. Best

 

[Papa Tango Charly]

Where does the capsule get the polarization from? What's the voltage applied to it?

I didn't check the voltage! the Jules Op microphone can be use with or without dc hex inverter. the amp circuit is meant to work with an electret capsule. To my surprise the C12 cap was sounding pretty well without the dc hex inverter...

 

[paulcheeba]

View attachment 123441

Well worth waiting for. I wonder if they are the same length as the unmarked body? Oops just seen your previous post.

 

[Jim50hertz]

Well worth waiting for. I wonder if they are the same length as the unmarked body? Oops just seen your previous post.

I’m hoping so! Do those measurements seem to match up with your bodies?

 

[Papa Tango Charly]

10meg & 100nF (instead of 10nF) - no reason to need to go all that "exotic"...

If you see any changes to improve thi schematic let me know please. Thank you again! Sincerely yours.

 

[Drosselmeier]

 

[paulcheeba]

I’m hoping so! Do those measurements seem to match up with your bodies?

I'll measure mine and let you know. I have a sneaking suspicion they are very similar though.

 

[Jim50hertz]

I'll measure mine and let you know. I have a sneaking suspicion they are very similar though.

Thanks Paul, yup, going by eye and the pics in the forum here I’m betting it’s the same body finished a little differently.

My capsules have shipped so I’m now just waiting on a PCB restock.

 

[chrispbass]

Thanks Paul, yup, going by eye and the pics in the forum here I’m betting it’s the same body finished a little differently.

My capsules have shipped so I’m now just waiting on a PCB restock.

What capsules will you be using?

 

[Jim50hertz]

What capsules will you be using?

Beeznees, Danny just restocked the D251 boards so I’m more or less set.

 

[chrispbass]

Beeznees, Danny just restocked the D251 boards so I’m more or less set.

Thanks Jim. I’m helping a friend who’s new to diy build up an 1176 and he’s got the bug, so would really like to build one of these mics. I’m trying to compile ‘a kit’ that would be reasonably ‘plug and play’ so with all the capsule options, it’s useful to know. I was going to suggest the BZ as that seems to be a popular choice, but tbh, I don’t have a benchmark.

Those aliex bodies look great, so that’s that sorted and I’m aware of the mechanical mods needed for Danny’s pcb. Was going to suggest nodding the Thomann retro psu to speed things up.

Reg, the BZ capsule, is the supplied mount useable or too big for the body?

Is it just a case of stripping down a 7 pin male XlR plug to use the connector part for the body?

Any help would be gratefully received and look forward to seeing your progress.

Cheers
Chris

 

[Papa Tango Charly]

Hello Thank you all for you help. I guess i could add a 560pf or lower between anode and ground to tame the brightness of the capsule if needed right?

 

[Jim50hertz]

Hi @chrispbass

I'm standing on the shoulders of giants here but...

Some links here for you.

7 pin insert
https://www.aliexpress.com/item/100...o.order_list.order_list_main.5.4e521802A25s4c

Capsule holder (I thinkg the BN one will be too big)
https://www.aliexpress.com/item/100....order_list.order_list_main.10.4e521802A25s4c

Shockmount (these are ok, I might replace with the Rycote USM)
https://www.aliexpress.com/item/100....order_list.order_list_main.12.4e521802A25s4c

Washers to extend body (the inner diameter of the mic body is 49mm so I'm hopeful these will work, plus being conductive they'll help with shielding), I ordered 4.
https://www.ebay.co.uk/itm/294067528860?var=592756403381

If you hit me up with an email I can send you my BOM and some tuning notes gleaned from the build thread and other places. There are minor parts changes from Dany's BOM and I've ordered some alternative values for key components.

The relays are out of stock but I got the same part from Futurlec.

 

[chrispbass]

Hi @chrispbass

I'm standing on the shoulders of giants here but...

Some links here for you.

7 pin insert
https://www.aliexpress.com/item/100...o.order_list.order_list_main.5.4e521802A25s4c

Capsule holder (I thinkg the BN one will be too big)
https://www.aliexpress.com/item/100....order_list.order_list_main.10.4e521802A25s4c

Shockmount (these are ok, I might replace with the Rycote USM)
https://www.aliexpress.com/item/100....order_list.order_list_main.12.4e521802A25s4c

Washers to extend body (the inner diameter of the mic body is 49mm so I'm hopeful these will work, plus being conductive they'll help with shielding), I ordered 4.
https://www.ebay.co.uk/itm/294067528860?var=592756403381

If you hit me up with an email I can send you my BOM and some tuning notes gleaned from the build thread and other places. There are minor parts changes from Dany's BOM and I've ordered some alternative values for key components.

The relays are out of stock but I got the same part from Futurlec.

You’re a star Jim…thank you. I’ve been gleaning as much info from the thread as I can, but that would be great. I’ll Pm you later

 

[Khron]

guess i could add a 560pf or lower between anode and ground to tame the brightness of the capsule if needed right?

... Or in parallel with R1.

 

[Jim50hertz]

Washers linked to above fit perfectly

 

[HerbertR]

These look great in person, much more cream coloured than yellow. Nicely finished and heavy.

If anyone can chime in and suggest how these dimensions might compare to the other version and the fit of the D251 pcbs that would be great, @HerbertR ?

Dimensions

Inner rails Length 124.5mm
Distance between outer edge of rails 40.5mm
Distance between screw holes 26.8mm

Body tube

Outer diameter 49mm
Inner diameter 43.65mm
Length 135mm

Headbasket

Length 65mm
Diameter front to back 50.8mm
Diameter side to side 50.8mm

Sorry, I did not read your post. Here are the measuments for a comparison
Post in thread 'Ela-M 251 Body from Aliexpress' https://groupdiy.com/threads/ela-m-251-body-from-aliexpress.84513/post-1097464
I think they are the same size....

The Beesneez capsule holder can be mounted directly in the microphone. It fits. Inside it is close to the top of the basket but offers enough space.
It becomes more difficult to optimize the mic for as little noise as possible. As easy as this microphone appears to be to build, a lot of optimization was necessary to make it quieter imo. Very good Tube, higher Grid to Ground Resistorvalue,...