hitchhiker

old high impedance type mics
« on: January 04, 2017, 12:40:25 PM »
Are any of these older high z mics good for recording?  Does anybody here use them?


JohnRoberts

Re: old high impedance type mics
« Reply #1 on: January 04, 2017, 02:21:20 PM »
The hi-Z 600 ohm mics were generally supplied with inexpensive gear because the higher Z mics had more output level so preamps for them could be made simpler/cheaper.

They may sound bad in a useful way for a sound effect, but unlikely to be musically useful (subjective). They will also be more affected by cable capacitance, but probably not an issue for modest length cables.

 The one karaoke unit I designed (last century) could accept either Hi Z or Low Z mics, because they were still common in that market.

As I recall Neutric sold molded transformers that would step down a 600 ohm mic for use with low Z input electronics (150-200 ohm mics).  A 2:1 transformer would transform the impedance to 1/4th.

There are probably some good 600 ohm mics somewhere but not common in my experience.

JR
John Roberts
http://circularscience.com
Tune it, or don't play it...

ruffrecords

Re: old high impedance type mics
« Reply #2 on: January 04, 2017, 03:09:14 PM »
A lot of HI-Z mics had a built in 600:50K step up transformer. You can sometimes convert them the 600 ohms just by removing it. This not only makes it easier to interface to regular mic pres but also removes the distortion and poor frequency response these transformesr often caused.

Cheers

Ian

hitchhiker

Re: old high impedance type mics
« Reply #3 on: January 04, 2017, 05:09:13 PM »
WOW! 50k output! What would the input impedance be on the hi z mic preamps?

Lance

ruffrecords

Re: old high impedance type mics
« Reply #4 on: January 04, 2017, 05:48:32 PM »
WOW! 50k output! What would the input impedance be on the hi z mic preamps?

Lance

In the old days when they were tube based they would have been 10 times that.

Cheers

Ian

hitchhiker

Re: old high impedance type mics
« Reply #5 on: January 04, 2017, 11:06:49 PM »
Right, that makes sense that they started with hi z mics into tubes.

Cheers!
Lance


ln76d

Re: old high impedance type mics
« Reply #6 on: January 05, 2017, 08:50:36 AM »
It all depends on the capsule :D
There's a lot of crap (cheap Japanese high impedance dynamics from 60's-80's for example - never found any usable) but there's  alot of good microphones.
Some really bad sounding can be well used as effect microphones, especially for vocals. Pretty good for overdub of vocal mixed to the main clean vox.
German/Austrian microphones - Uher M534 which from what i remember is 750ohm, works pretty good on many sources with standard 2k input preamp. It has some coloration due to higher impednace. It's the same type of capsule which you can find in many other AKG mikes like D119 etc. but the rest is usual 200ohm.
There was a lot of high impedance microphones which had step up transformer. D9 akg have really great large diaphragm capsule (same type as D14) but there was a lot of different impedance versions like 15ohm, 60ohm, 150ohm, 200ohm etc. All were used with additional transformer for ...kohm output.  The other models sold as AKG/Telefunken/Uher had similar capsules but some had direct 500ohm from the capsule for example.
Similar with some grundig mikes (usual sennheiser made).
MD417 from sennheiser use 800ohm version of the capsule which you can find in MD419 and MD441. It's also very usable microphone even if it's high impedance.
My favourite snare microphone is Revox M3500 which is ca. 600ohm version of Beyer M201.
Definately worth to test some.

emrr

Re: old high impedance type mics
« Reply #7 on: January 05, 2017, 10:02:15 AM »
Various American mics made in both Hi-Z and low Z models too, some RCA lower line ribbons.  Change the transformer for low-Z and better sound. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

ruffrecords

Re: old high impedance type mics
« Reply #8 on: January 05, 2017, 12:38:58 PM »
Various American mics made in both Hi-Z and low Z models too, some RCA lower line ribbons.  Change the transformer for low-Z and better sound.

Ditto Europe, especially dynamic types which were available in both impedance and sometimes both.

Cheers

Ian

ELM

Re: old high impedance type mics
« Reply #9 on: February 13, 2017, 04:46:43 PM »
I bought a pair of lustraphone vr64 high z last week and tested them today thru my classic solo pre (It works perfect btv, Ian)
The mics sounded crap thru mic input but quite good thru DI even if the signal was weak. Any suggestions on good transformer ratio for these mics?

Thanks!


ln76d

Re: old high impedance type mics
« Reply #10 on: February 13, 2017, 05:37:29 PM »
Xaudia :D

Send it to Stewart he will make it great sounding ;)

ELM

Re: old high impedance type mics
« Reply #11 on: February 14, 2017, 12:37:21 PM »
Thanks, he must to be the right guy to contact!

Rob Flinn

Re: old high impedance type mics
« Reply #12 on: February 22, 2017, 09:15:18 AM »
Stewart is just breathing life into a stereo Lustraphone ribbon for me at the moment.   Part of the job is rewinding the output transformers to the spec of the medium range version.  Originally they were wound for high impedance.
regards Rob

Capital letters.  The difference between helping your uncle Jack off his horse, & helping your uncle jack off his horse ........

Whoops

Re: old high impedance type mics
« Reply #13 on: October 06, 2017, 09:22:55 PM »
Are any of these older high z mics good for recording?  Does anybody here use them?

Most older Ribbons are High z mics and they are still being used and praised

abbey road d enfer

Re: old high impedance type mics
« Reply #14 on: November 01, 2017, 07:08:54 PM »
600 ohms is not really high-Z.
Hi-Z mics were quite popular for use with tube tape recorders and PA systems; because it made the design of their preamps simpler and less costly. They have a built-in step-up xfmr, with a typical secondary Z of about 20-50k.
When solid-state became the norm, designers saw an opportunity to use directly low-Z mics, of a typical impedance of 150-200r. Most of the preamps were not really optimized for such low-Z. Typically, the circuits used at the same  had an OSI (optimum source impedance) of about 2k. Some manufacturers chose to take advantage and created transformerless mics with an impedance of about 600r. These offered higher level and better noise factor with consumer equipment.
Used in conjunction with a period "pro" mic pre (xfmr input with about 1.5-2k input Z) , their impedance is not very well suited, resulting in level loss and frequency response and noise issues.
With a modern transformerless mic pre, and preferrably a higher input Z (4-5k), there is no reason for them to sound bad, but anyway, they were relatively  low-budget types, so their performance is not stellar.
Ribbon mics are a slightly different issue, since they need a xfmr anyway; the high-Z transformers (ratio of about 1:100+!) almost invariably alter performance significantly. Replacing the xfmr with a low-Z type may sometimes reveal jewels.
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