Quality of vintage Neumann tube mic cables?

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Zebra_PD

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Complete vintage tables for old German tube mics like Neumann, Gefell or Telefunken usually cost A LOT on evilbay and reverb. But it's still possible to get hold of 7 lead tube cables for a decent price per meter from Outlaw and similar dealer of scaped audio gear here in Europe.

For example Neumann tube mic cables is about 5€ per meter at Outlaw.

Sommer cable is about 4€ per meter so pretty much the same. The Gotham about the same as well.

But that raised the question  if the old German cables has stood the test of time?

Anyone that have made some test or measurement of original german cables vs modern quality cables?
 
EmRR said:
See Klaus Heyne commentary.....

Tried to google and also search in the REP forum. Did not find any Heyne commentary or test. Bet it's out there though.

Would you be kind to point me in the right direction  or give me the short version?
 
Polish your golden ear or get the aluminium hat on, depending on which side of the debate you stand :eek:. Halfway down the page: http://germanmasterworks.com/u67reissue.html

Personally I can't see the point of vintage cable. Newer cable usually handles better, less handling noise, possibly better shielding. DCR and capacitance are low enough to not be relevant anyway.
 
I've never tested nor compared them, but I have some old but we'll stored EMT tube mic cables and the specs (capacitance) in the specsheet were better than the GAC 7 from Gotham.
Whether you can hear the difference or not is another question...
 
Modern cables generally have better shielding, and this can be very important. I was using some AG C60 for a session  and someone keyed up a  cell phone a few feet away on the other side of the studio wall, and the C60s picked up cellphone interference. Ruined the take, and required an insert to fix it. So, while there might be some ephemeral reasons why old cables will sound different, preventing modern RF problems is IMHO much more important to the overall value of a cable.

Old cable and how it attaches to the connector and mike were worked out in a simpler time where there was far less RF, so it makes sense to me to re-visit this. Unless you record away from the city, which some people do, it's worth considering new cable with the original connectors. IIRC, Mogami made a few types of tube mike cables which are basically good quality cable. The choice was largely how many and what size of additional conductors are offered for heater, pattern voltage, plate voltage and the like.
 
The AKG C-60 does NOT have an output transformer inside the mic.  The audio output is taken off the cathode of the AC701 and is transmitted UNBALANCED to the power supply where the output transformer (and some rudimentary bass cut off filtering) is.  The unbalanced audio is a RF entry point.

Depending on the frequency of the RF source, any microphone (especially condenser) can be susceptible to RF.  Even the venerable Neumann U67 is susceptible to RF.  Found out the hard way with a MIDI interface to a pipe organ.  The spectrum analyzer indicated a strong clock signal around 2.15 MHz which got into other equipment as well.  A test with a calibrated field intensity meter (FIM) pegged the scale inside the venue where mics were placed....  May build a TNF inside a Switchcraft S3FM barrel connector... The Hum-X filter works well on conducted RF on the AC line, but won't touch radiated RF.  The interference mode most likely is rectification of the RF signal inside the mic or other equipment.

Fortunately, the Schoeps M221 pair didn't pick up RF.  Didn't have any FET mics.  The FET probably acts like a crystal diode detector and rectifies RF (from the offending cell phone or other RF source) easily...

Some venue people are completely oblivious to RF problems.  Including churches.  Sometimes the only way a church realizes there is a problem when a nearby truck driver hollers "Break 19 for some commercial.." on the CB radio and it comes through loud and clear on the church system during the sermon....
 
rmburrow said:
The AKG C-60 does NOT have an output transformer inside the mic.  The audio output is taken off the cathode of the AC701 and is transmitted UNBALANCED to the power supply where the output transformer (and some rudimentary bass cut off filtering) is.  The unbalanced audio is a RF entry point.
Is it really? Analysis of how interference builds up is necessary.
Assuming the shield is adequate and properly connected at both ends, electrostatic interference is eliminated.
Only magnetic interference remains. Since the mic is floating, the parasitic voltages developped along the conductors are cancelled.
In terms of susceptibility to interference, it is equivalent to a balanced connection, but with a higher nominal impedance.
 
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