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Post by malkit on Aug 1, 2017 8:46:13 GMT -6
Hi Folks,
I've got a u47 clone (audio-scape build) that - once warmed up- gets quite hot. It's enough heat that I woulnd't want to hold it for more than a few seconds.
Anything unusual about that? None of my other tube mics are like this...not even close.
Thanks for the input.
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Post by svart on Aug 1, 2017 8:48:37 GMT -6
It should never get that hot..
None of my tube mics get more than slightly warm to the touch. My U47 doesn't get more than lukewarm, that's for sure.
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Post by malkit on Aug 1, 2017 8:56:05 GMT -6
Thanks for the reply, Svart. I wonder what on earth could be causing this...will be getting in touch with the builder!
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Post by Ward on Aug 1, 2017 9:32:40 GMT -6
Get the danged thing serviced and/or repaired ASAP before it's a worthless pile of metal and glass.
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Post by svart on Aug 1, 2017 9:37:29 GMT -6
They could be dropping too much voltage through the dropping resistor, and producing the heat.. That's about all I can think of that would heat up the mic and it still work.
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Post by Ward on Aug 1, 2017 9:50:18 GMT -6
svart a bad cap or a bad transformer could do that too, don't you think? Especially if there's chassis/shielding or housing connection to the heat source.
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Post by malkit on Aug 1, 2017 10:41:52 GMT -6
Gents,
I just heard back from the builder (he's been very helpful and communicative).
He's saying that the mic body gets hot due to resistor in the heatsink, mounted at the bottom of the mic. He's offered to reach out to Dany - who designed the capsule and board- for some tips on dropping the heat.
I noticed that the power supply housing also gets pretty warm- I'd almost say hot. Seems to point to what you guys are saying.
I'm having to max out my gain around 70db to get a decent signal out of this puppy. Is that normal, too? No shouting vocals, but a solid pop voice.
Thanks again, gents.
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Post by bluegrassdan on Aug 1, 2017 11:12:06 GMT -6
Most 47-style mics have pretty high output. Sounds like something ain't right.
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Post by EmRR on Aug 1, 2017 11:16:56 GMT -6
I find the mk47 output is comparable to my Gefell UMT70S, pretty much dead on. For speech that will be 60-65dB gain to get a hot level into a +24dBu converter. Mine hasn't been on long enough in one go to assess heat, but it does get pretty warm at the base near the resistor mount.
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Post by svart on Aug 1, 2017 11:25:08 GMT -6
Gents, I just heard back from the builder (he's been very helpful and communicative). He's saying that the mic body gets hot due to resistor in the heatsink, mounted at the bottom of the mic. He's offered to reach out to Dany - who designed the capsule and board- for some tips on dropping the heat. I noticed that the power supply housing also gets pretty warm- I'd almost say hot. Seems to point to what you guys are saying. I'm having to max out my gain around 70db to get a decent signal out of this puppy. Is that normal, too? No shouting vocals, but a solid pop voice. Thanks again, gents. My resistor is also mounted to the bottom piece and it doesn't get that hot. Maybe a few watts of heat. I don't need more than maybe 30-40dB when talking normally. Sounds like something is definitely wrong. |
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Post by malkit on Aug 1, 2017 11:32:13 GMT -6
Sheesh. That's a world of difference.
Very helpful to know this- something is definitely wrong, then!
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Post by EmRR on Aug 5, 2017 9:43:01 GMT -6
My MK47 was on about 8 hours yesterday, end bell where the resistor is mounted was pretty warm, but not hot. You could hold hold that spot forever without feeling cooked.
Levels are right in the same zone as the Gefell UMT70S and a Max U67, also the TLM67 guts.
This MK47 is a Thiersch Blue capsule, and the capsule sound signature is remarkably similar to the UMT70S. The Gefell is thinner on the bottom and smoother up top. The MK47 is fatter/bigger on the bottom, and the top has a touch of a grainy edge to it in comparison to the Gefell.
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Post by rowmat on Aug 6, 2017 5:54:49 GMT -6
Our Flea 47 barely gets lukewarm at best.
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Post by jakeharris on Aug 6, 2017 6:42:48 GMT -6
Our Flea 47 barely gets lukewarm at best. EF12 build, with no heat-sinked resistor; very different schematic compared to a real U47. |
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