Can anyone ID this old microphone?

[Resonator Guy]

No, I did my spending on an Electromuse amp cabinet that will fit a chassis I restored a couple of years back. That did cost me 45 bucks, but I will still have fun.
I watched that mic and decided I might not get one.

[km6xz]

I remember seeing the Astatic 600 in a ham shack in the mid 50s, it was old then. Crystal or "Salt" mics were not very good for consistency, because they were fragile, heat sensitive, the salts were hydroscopic and no two left the factory sounding alike or having the same output level or bandwidth. They were obsolete for any practical use by the introduction of ceramic elements and by the advent of reasonably priced dynamics that did not suffer from all the negative traits of crystal elements. Ceramic elements were much better, more consistent, more rugged, less sensitive to temperature and moisture etc yet sounded alike. Their biggest advantage was very high output impedance which allowed them to generate a pretty good level directly applied to the grid of the first amplifier stage. They were usually spec'd at 50k but measured much higher so they were only used with short cables if any high frequency response was expected. Shielded mic cables were often 20-50pfd/foot back in the cloth covered cable days or when using the highly flexible metalized fiber wires that permitted high flexibility.
A lot of radio amateurs used crystal phono cartridges to make crystal microphones and those often were more stable than the purpose build larger elements for mics. The bright high-end of the crystal mics which people liked for PA and radio, and later, harp, actually was easier to get by using the smaller, lower mass phono-cartridge elements. My sister probably still wonders what happened to her portable record player;>) I used my home made mic to drive a 12AU7 speech amp, as preamps were called then, that did not need that much gain to use the second half as a screen modulator for a 6146 tube with plate input of about 60watts. Not terribly efficient but no modulation transformer was needed which was out of my 9year old's budget anyway.
So those old mics bring back some memories of 9 year old hacking and building. By the time i was 10, i had graduated to a real dynamic mic, a plate modulator and 3 6146's in parallel running 275watts input. Many years later tried using a crystal mic on a big budget recording project but the old , long forgotten problems with them being so inconsistent prevented them from keeping continuity between tracks or between basics and overdubs with the harp player. Switched to a more rugged ceramic mic element from a vintage Turner. Also used Shure 520's for harp but those were mostly dynamics(they were available at different times in crystal, ceramic and mostly dynamic) for harp. The dynamics were really rugged and consistent, plus matched balanced lines well for use in recording. With radical EQ, the same sounds could be gotten from any of them but the dynamic 520's had a damped, controlled ringing which sounded better on disc. Another problem with the crystal mic was their very high output impedance made it their cables highly microphonic, acting like condenser mics but without the good sound. Loading them a bit reducing the microphonics but killed the sparkle. Another problem with the old ones, was their being more efficient in rectifying RF than picking up sound. An AM radio station nearby usually meant the amplifier was getting more station program content than sound capture.

[Martin Pedder]

Another mic for you experts to identify

I have been given a couple of mics to sell by a retired BBC engineer. At first, I thought they were both Reslo mics. One is (it says Reslosound on it!), but I am far from sure about the other. The connector is different to the Reslo one and there is no identification anywhere that I can see on the mic or stand. Does anyone know anything about the non Reslo mic? Both will be hitting eBay soon, so an accurate description would be great.

The links are to my high res photos for any mic photo collectors. They show the mics from different angles with close-ups of the connectors.

Reslo Ribbon

http://www.boomerangsounds.co.uk/BB034.html

Unknown Mic

http://www.boomerangsounds.co.uk/BB035.html