scott_humphrey
Well-known member
Here it is:
http://www.treblebooster.com/m251e/telefunken_ela_m251e_circuit.htm
Enjoy!
-Scott
http://www.treblebooster.com/m251e/telefunken_ela_m251e_circuit.htm
Enjoy!
-Scott
so, I finally finished my Telefunken Ela M251E project...
- Thread starter scott_humphrey
- Start date
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MikoKensington
Well-known member
Very cool. :shock:
Consul
Well-known member
Scott, that looks absolutely bee-yoo-ti-ful! Great work!
scott_humphrey
Well-known member
Hey, thanks to you guys for the nice comments! Also, thanks to Jakob for posting the G7 mic. The power supply that I ended up using is a cross between the original and Jakob's G7 power supply.
A pic for those seeking instant gratification:
I have not had a chance to try out a real C12 or M251E. It would be great to be able to compare, but I doubt that this will happen any time soon.
My impression so far is that I really like the cardioid setting. The omni setting seems fairly well balanced, and the figure of 8 setting has nice rejection from the sides. I think that I might have to increase the 1000pF cap in the head to balance the two sides of the capsule when using the figure of 8 setting. The one side seems to have a little bit less of a bass response than the other. The difference is subtle, though.
A pic for those seeking instant gratification:
I have not had a chance to try out a real C12 or M251E. It would be great to be able to compare, but I doubt that this will happen any time soon.
My impression so far is that I really like the cardioid setting. The omni setting seems fairly well balanced, and the figure of 8 setting has nice rejection from the sides. I think that I might have to increase the 1000pF cap in the head to balance the two sides of the capsule when using the figure of 8 setting. The one side seems to have a little bit less of a bass response than the other. The difference is subtle, though.
scott_humphrey
Well-known member
I haven't tried reversing the capsule. In the omni mode, though, the mic sounds the same on one side as on the other, so I believe that the capsule itself is probably matched fairly well.
My thought is that the 1000pF cap that is part of the switching circuit might be a bit too small. It might be acting as too much of a high pass filter for one side of the capsule (when in the figure-of-8 mode). I suppose that the right value of the capacitor would depend upon the properties of the actual capsule used. I doubt that the Peluso is an exact copy of an original C12, so the circuit may need to be adjusted to compensate. Any thoughts? (EDIT: here is the schematic http://www.treblebooster.com/m251e/m251e.pdf. Look at the capsule/kapsel labeled M251E. That is the switching circuit).
There isn't a huge difference from one side of the capsule to the other, though, so I really just consider this a bit of final tweaking.
My thought is that the 1000pF cap that is part of the switching circuit might be a bit too small. It might be acting as too much of a high pass filter for one side of the capsule (when in the figure-of-8 mode). I suppose that the right value of the capacitor would depend upon the properties of the actual capsule used. I doubt that the Peluso is an exact copy of an original C12, so the circuit may need to be adjusted to compensate. Any thoughts? (EDIT: here is the schematic http://www.treblebooster.com/m251e/m251e.pdf. Look at the capsule/kapsel labeled M251E. That is the switching circuit).
There isn't a huge difference from one side of the capsule to the other, though, so I really just consider this a bit of final tweaking.
pmroz
Well-known member
.
Scott, that is a sweet looking mic...
... when i click the 'schem' link, i get a series of sex xxx popups, hard to get out of the loop.... ? maybe worth a check?
Scott, that is a sweet looking mic...
... when i click the 'schem' link, i get a series of sex xxx popups, hard to get out of the loop.... ? maybe worth a check?
[quote author="scott_humphrey"]The one side seems to have a little bit less of a bass response than the other. The difference is subtle, though.[/quote]
If you're noticing this while monitoring with headphones, the decrease in bass from the rear capsule is likely bass cancellation from being out of phase with the headphones.
If you're noticing this while monitoring with headphones, the decrease in bass from the rear capsule is likely bass cancellation from being out of phase with the headphones.
scott_humphrey
Well-known member
[quote author="pmroz"].
Scott, that is a sweet looking mic...
... when i click the 'schem' link, i get a series of sex xxx popups, hard to get out of the loop.... ? maybe worth a check?[/quote]
I had problems like this before with the company that hosts my web site. I'll look into it. My apologies.
Scott, that is a sweet looking mic...
... when i click the 'schem' link, i get a series of sex xxx popups, hard to get out of the loop.... ? maybe worth a check?[/quote]
I had problems like this before with the company that hosts my web site. I'll look into it. My apologies.
scott_humphrey
Well-known member
[quote author="22busy"][quote author="scott_humphrey"]The one side seems to have a little bit less of a bass response than the other. The difference is subtle, though.[/quote]
If you're noticing this while monitoring with headphones, the decrease in bass from the rear capsule is likely bass cancellation from being out of phase with the headphones.[/quote]
Good point! I didn't think about that. I'll try switching the phase at the mic preamp and see what happens. THanks for the suggestion.
If you're noticing this while monitoring with headphones, the decrease in bass from the rear capsule is likely bass cancellation from being out of phase with the headphones.[/quote]
Good point! I didn't think about that. I'll try switching the phase at the mic preamp and see what happens. THanks for the suggestion.
dukasound
Well-known member
NICE :thumb:
Duka
Duka
Bryson
Well-known member
Woah!
You're not human!
I want to do that somewhere in my lifetime!
You're not human!
I want to do that somewhere in my lifetime!
scott_humphrey
Well-known member
[quote author="badger"]Very nice work Scott.
Am I right in assuming that the Peluso CK 12 is a plastic device ?
Andy.[/quote]
Yes, there is some plastic that is used in the construction. I'm assuming that this is to isolate the brass backplates of the capsule. Maybe Peluso could let us know... :wink:
Also, unfortunately someone has hacked into my site. If you try going there you may be linked to a porn site! Don't these losers have anything better to do?!! I can just picture some pimply-faced teenage hacker sitting in his room somewhere feeling like he has just conquered the world. I'll have to contact my web hosting company to have them investigate. I'm sorry if anyone was offended by anything.
The capsule:
Am I right in assuming that the Peluso CK 12 is a plastic device ?
Andy.[/quote]
Yes, there is some plastic that is used in the construction. I'm assuming that this is to isolate the brass backplates of the capsule. Maybe Peluso could let us know... :wink:
Also, unfortunately someone has hacked into my site. If you try going there you may be linked to a porn site! Don't these losers have anything better to do?!! I can just picture some pimply-faced teenage hacker sitting in his room somewhere feeling like he has just conquered the world. I'll have to contact my web hosting company to have them investigate. I'm sorry if anyone was offended by anything.
The capsule:
Consul
Well-known member
So did you place the capsule mount in some kind of silicone base for shock absorption?
That mic just looks so good. Someday, someday...
That mic just looks so good. Someday, someday...
T
tubejay
Guest
Wow, big props, that looks very well done. Very cool man! :thumb: :thumb: :thumb:
scott_humphrey
Well-known member
[quote author="Consul"]So did you place the capsule mount in some kind of silicone base for shock absorption?
That mic just looks so good. Someday, someday...[/quote]
Thanks.
The mount was purchased from Peluso. I found some grey foam that I shaped to sit at the base of the capsule mount. My thought was that this might absorb some of the reflections (though I don't really know that this is open cell foam).
I'm now experimenting with adding another layer of grill mesh. This seems to change the sound in a pleasant way. It is cutting some of the wooly, low mids and emphasizing the higher frequencies more. It seems to make my recorded voice sound more natural by reducing some of the unflattering frequencies.
That mic just looks so good. Someday, someday...[/quote]
Thanks.
The mount was purchased from Peluso. I found some grey foam that I shaped to sit at the base of the capsule mount. My thought was that this might absorb some of the reflections (though I don't really know that this is open cell foam).
I'm now experimenting with adding another layer of grill mesh. This seems to change the sound in a pleasant way. It is cutting some of the wooly, low mids and emphasizing the higher frequencies more. It seems to make my recorded voice sound more natural by reducing some of the unflattering frequencies.
scott_humphrey
Well-known member
[quote author="22busy"][quote author="scott_humphrey"]The one side seems to have a little bit less of a bass response than the other. The difference is subtle, though.[/quote]
If you're noticing this while monitoring with headphones, the decrease in bass from the rear capsule is likely bass cancellation from being out of phase with the headphones.[/quote]
Thanks 22busy. You're right about this. I tried switching the phase at the mic pre and this changed the sound in the headphones as you would expect.
I thought that I'd mention (in case anyone else is building something like this) that the metal casing around the polar pattern switch in the mic needs to be grounded, otherwise the mic will pick up radio signals. For this mic I used a ground buss wire that runs from the xlr connector, through the center of the body, and then to the grill area where it is again attached to the chassis. All of the mic's electronics are grounded to the buss wire, as is the metal casing for the polar pattern switch. The mic is very quiet in terms of self noise.
Someone asked about the construction of the grill. I basically bent some wire mesh over the end of a rolling pin and used plumbers solder to weld it. You may read about that and see pics if you follow the link on the first post in this thread.
Thanks to everyone for all of the kind words above. :grin:
-Scott
If you're noticing this while monitoring with headphones, the decrease in bass from the rear capsule is likely bass cancellation from being out of phase with the headphones.[/quote]
Thanks 22busy. You're right about this. I tried switching the phase at the mic pre and this changed the sound in the headphones as you would expect.
I thought that I'd mention (in case anyone else is building something like this) that the metal casing around the polar pattern switch in the mic needs to be grounded, otherwise the mic will pick up radio signals. For this mic I used a ground buss wire that runs from the xlr connector, through the center of the body, and then to the grill area where it is again attached to the chassis. All of the mic's electronics are grounded to the buss wire, as is the metal casing for the polar pattern switch. The mic is very quiet in terms of self noise.
Someone asked about the construction of the grill. I basically bent some wire mesh over the end of a rolling pin and used plumbers solder to weld it. You may read about that and see pics if you follow the link on the first post in this thread.
Thanks to everyone for all of the kind words above. :grin:
-Scott
