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Author Topic: Poor Man's ELA M...?  (Read 32371 times)

Tricatel

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Re: Poor Man's ELA M...?
« Reply #15 on: July 12, 2008, 12:50:07 PM »

Nice forum, first post for me!

Reading your answer about the 6072/AC701 that there is only a minute difference, so I can used a 6072 in a M49 with the same
slight audible differences after I jack up the heater to 6.3V.?

Jacques
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dofo

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Re: Poor Man's ELA M...?
« Reply #16 on: July 12, 2008, 02:41:31 PM »

I don't think there is room in an M49 for the 6072.  It's a bigger tube.
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Aaron Zeller

Tricatel

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Re: Poor Man's ELA M...?
« Reply #17 on: July 13, 2008, 03:19:07 PM »

Sure with tube base it will not fit, but spot welding
leads on the tube will make it fit. With regards to Klauses comparation to the Elam the M49 should sound nearly or as close to AC701.

There are several subminiature tube that are nearly identical to the 6072a too.

Any thoughts?
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CHANCE

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Re: Poor Man's ELA M...?
« Reply #18 on: July 13, 2008, 03:27:09 PM »

Tricatel wrote on Sun, 13 July 2008 12:19


There are several subminiature tube that are nearly identical to the 6072a too.
Any thoughts?



Could you post those subminiature tube numbers?

I don't recall ever seeing a subminiature tube with a socket. They all seem to be soldered.
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Chance Pataki
The Musicians Workshop
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A person is a biological signal processor--EQ mag

Klaus Heyne

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Re: Poor Man's ELA M...?
« Reply #19 on: July 13, 2008, 03:27:32 PM »

Tricatel wrote on Sat, 12 July 2008 09:50

Nice forum, first post for me!
Reading your answer about the 6072/AC701 that there is only a minute difference, so I can used a 6072 in a M49 with the same
slight audible differences after I jack up the heater to 6.3V.?


Tricate: Thanks for the compliments, but I don't get your post. Do you have an M49? Do you want to save money by using another tube than AC701 in that mic? If not, let's skip this analogy, and let's not spend any more time on this train of thought, because your idea cannot be tested in an M49, for space reasons alone.

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Klaus Heyne
German Masterworks
www.GermanMasterworks.com

Tricatel

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Re: Poor Man's ELA M...?
« Reply #20 on: July 13, 2008, 05:22:47 PM »

Klaus,


given the current prices of an AC701(k), $350 to 450 and given the fact that the ratio of useable is about 1 in 3 makes a retubing for my M49 about $1050 to 1350, then a suitable replacement tube is definite worth to try.

Then when you say that the difference AC701K to 6072a Elam is minute, so the same statement should subscribe to the M49 if only the tube gets exchanged. Right?

Jacques

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Klaus Heyne

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Re: Poor Man's ELA M...?
« Reply #21 on: July 13, 2008, 05:41:44 PM »

No, not necessarily right. We have no idea how Neumann's BV 11 transformer would dynamically behave with a 6072 tube and the mic's different input impedance.

Again, this issue will remain academic, because the tube does not fit, and its much higher heat output, compared to the AC 701, could not be cooled sufficiently, given the lack of air circulation under the tight fitting cap over the amp.
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Klaus Heyne
German Masterworks
www.GermanMasterworks.com

Barry Hufker

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Re: Poor Man's ELA M...?
« Reply #22 on: July 13, 2008, 05:47:40 PM »

It's not academic if he tests the mic with the body cover off.  The tube "doesn't work" because it can't fit in the body.  Test the tube without the body cover on and then worry about whether it "doesn't fit".

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Klaus Heyne

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Re: Poor Man's ELA M...?
« Reply #23 on: July 13, 2008, 06:17:18 PM »

Barry,  
Let's look at this one more time, and I'd promise to try to stay logical and rational:

How do you test the 6072 tube in an M49, when you cannot mount a capsule, because the amp cover contains the capsule mount?
With other words, how do you want to get audio out of this contraption, so you can compare tube functions and sound?  

And have you thought about the financial implications of such a modification? What's a new 6.3V. power supply going to cost you, compared to just getting the only tube for which this mic was designed?  And what about the depreciation in value for this frankensteined mic? And remind me again, what the purpose for this exercise was supposed to be? To trash a highly collectible vintage mic? No, it was to  try to save money, but I submit, the poster will only lose money in the process.

I'd say, what I said before: If you cannot afford an original tube or other vital parts for your vintage mic, and you have start to hemorrhaging value by severely altering it, sell it, and buy a mic whose maintenance you can afford. This may sound hard and cold, but I cannot see any rational reason for proceeding like the poster was considering.


P.S.: another argument against: have you thought of how to heatsink the tube pins of the 6072 when connecting wires to them, and how to mount the tube without socket?
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Klaus Heyne
German Masterworks
www.GermanMasterworks.com

Extreme Mixing

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Re: Poor Man's ELA M...?
« Reply #24 on: July 13, 2008, 09:10:40 PM »

Klaus,

Your post points to many of the reasons why I am afraid to buy a vintage microphone.  I don't have the technical expertise to determine whether a mic is "clean", inside,or not.  Lots of bad things can happen to them in 50, or so years.  Some done with good intention, and some just to save money.

Designing great microphones is hard work.  If it weren't, then everyone would be doing it.  Clearly they are not.

Steve

Barry Hufker

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Re: Poor Man's ELA M...?
« Reply #25 on: July 13, 2008, 11:57:03 PM »

Klaus, everything you say is quite reasonable.  You certainly present a great case (pun intended) if all a person wants to do is save money.

If they want to get an education, or want to experiment in the hope of creating something better then I encourage them.  "Cost" is in the wallet of the owner.  Education always requires some cost from the student.  Each person must weigh the odds of success, the value of the information learned and the cost of the education/result.

I don't advocate recklessness or stupidity, but I always encourage someone who wants to explore away from the well-marked trail provided they understand what is involved.
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aamicrophones

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Re: Poor Man's ELA M...?
« Reply #26 on: July 14, 2008, 01:04:03 AM »

Hi Barry, you can get an AC701 from http://www.bavodekker.com/equip.html

They are $275 well worth the price to keep you Vintage M49 stock.

I am sure you could rent out the M49 once it repaired for $100 a week and re-coup your investment very quickly.

Cheers, Dave Thomas www.aamicrophones.com
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aamicrophones

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Re: Poor Man's Elam....
« Reply #27 on: July 14, 2008, 01:21:28 AM »

Why not just buy a P12 for John Peluso or check out our CM12 with the Peluso capsule fitted.   They are definitely a poor mans ELAM 251 or C12.

John's microphone uses an original C12 type circuit while ours uses the same 6072a front end circuit as the ELAM 251 with a cathode follower output stage which can deliver +20dbv of level with less than 1% distortion from a 5:1 (BV11 like) dual bobbin transformer.  

The Peluso is a hand tuned brass edge fed capsule with 6 micron diaphragms.

The only time I use figure-eight is with a Blumlein pair.  I much prefer to record acoustic guitar in OMNI.

The best Classical recordings I have heard were three U47 microphones across the front of the orchestra in OMNI for the Mercury Living Presence series.  I believe the late great Bill Putnam had something to do with these recordings.

Cheers, Dave Thomas

www.aamicrophones.com
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Klaus Heyne

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Re: Poor Man's ELA M...?
« Reply #28 on: July 14, 2008, 01:23:25 AM »

Not quite sure what to think of that site of Mr.Dekker in Holland. Certain items for sale where pictures are available are highlighted, but when I click on the items, the pictures either don't show the right mic, or are stock photography of that model. They sell an M249, but the picture shows an M49, for example.

The prices on the site also seem too good to be true. I would love to buy many of the mics sold at these prices myself (you cite, for example, AC701s at less than half the current going rate!)

So, what to think?
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Klaus Heyne
German Masterworks
www.GermanMasterworks.com

aamicrophones

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Re: Poor Man's ELA M...?
« Reply #29 on: July 14, 2008, 01:35:08 AM »

Hi Klaus, I am in Canada but a bought some Telefunken V72 modules from him a few years ago and was very happy with the quality and price.


Maybe there is someone else around who has dealt with him lately or lives closer than me and has visited them.

Still even for $350 the investment could be re-couped very quickly if the capsule is good.  It might a good idea to test the capsule first.  Especially if its an original M7.

My other thought is that maybe the tube works and there is a problem with the circuit, cable or power supply.  I have not had much experience with the M49 as the only ones I have seen have been working.  However, I have serviced 2-3 U47 microphones that the client was convinced had a bad tube that turned out to be a "baked" capacitor or broken wire in the connector.

Dave

www.aamicrophones.com


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