I have really been having a lot of fun listening to various capacitors in my vintage McIntosh MX110Z tuner-preamplifier.
Vintage McIntosh MX110Z Tuner-Preamplifier
At the moment the vintage Sprague Bumblebees are at the top of my list for capacitors in the C93 & C95 and C94 & C96 positions for my MX110Z for their sheer musical prowess.
Vintage 0.22uF Bumblebee caps in the MX110.
The half a century old Bumblebees have a ravishingly beautiful combination of sonics & musicality that no modern capacitor has been able to match in my MX110Z capacitor adventure, but as I noted in my last post, you need to be very careful in your use of such ancient devices to protect both yourself & your audio gear, as they can pose a significant risk if they are not up to snuff. To be on the safe side you should test them to make sure their capacitance & ESR have not drifted up, and also you should test the Bumblebees for DC leakage current to make sure they won't turn your cherished audio gear into a fireworks display.
Eric Clapton playing Blackie in 1978. Photo courtesy of Wikipedia Commons.
I've been hanging out at electric guitar sites reading up on what is favored in vintage & modern guitars and guitar amplifiers, and you probably wouldn't be surprised to know there is as much diversity of opinion on the merits of various tubes, wire, capacitors, and resistors, as there are for enthusiast audio.
However, the electric guitar guys are way ahead of audio guys in their appreciation & understanding of vintage tone, which is an established genre in the guitar world, whereas in audio it still resides in an under-appreciated realm of sonic & musical performance.
They realize that substituting a tonally incorrect resistor or capacitor for an original vintage one in a cherished guitar or amplifier will completely destroy its tone, and thus destroying its musical character.
0.22uF Red Astron style of capacitor by Jupiter Condenser.
One capacitor that kept popping up in recommendations for restoring vintage guitar amplifiers was the Red "Astron" style capacitors offered by Jupiter Condenser Co.
Guitar guys say they sound articulate & warm, and that they come closer to the vintage Black Beauty / Bumblebee capacitor tone than any other contemporary capacitor.
As you can imagine, I was intrigued by this assertion, and I wanted to try a pair of these vintage tone Red Astron style of 'guitar capacitors' in my MX110Z to see how they compared to my actual pair of vintage Sprague Bumblebee capacitors.
It would be very newsworthy if there was a new production capacitor that had vintage tone that rivaled the vintage Sprague Bumblebee capacitors.
Top to bottom: Sprague Bumblebee, Jupiter Red Astron, and AZ capacitor.
If you consider the materials that vintage Sprague Black Beauty / Bumblebee capacitors are constructed of, kraft paper & mylar & aluminum foil, you would think that they would be very similar sonically & musically to the Blue & Green Cactus Arizona Capacitors, which are also constructed out of those materials, but they're not, they sound quite different.
Red Astron by Jupiter Condenser.
The Red Astron style of capacitor by Jupiter Condenser are constructed of mylar & tin foil instead of mylar & aluminum foil. Here's how the Jupiter Condenser website describes them:
"Tinfoil and Mylar 1950’s construction, warmer tone. Modeled after the legendary Red Astron Capacitors, our capacitors have similar style to the vintage capacitors to give a very authentic tone and look, yet with a high reliability and longevity. This phenolic case potted tinfoil and mylar capacitor yields a uniquely vintage tone perfect for guitar amplifiers and vintage audio amplifiers alike."
Now notice that Jupiter is not saying that the Red Astron style of capacitors have similar tone to Black Beauty's & Bumblebee's, they're comparing them to the original vintage Red Astron capacitors. However, the builders in the field are saying they have similar tone to Black Beauty's & Bumblebee's.
Jupiter Condenser 'Red Astron' style of capacitor.
I want to listen to the Sprague Bumblebees for a while longer before I swap them out for the Jupiter Condenser Red Astron capacitors, but you should be reading about that experiment here in the not too distant future.
It is my hope that one of these days I'll find a current production capacitor that I can recommend that will have as good as tone as a vintage Sprague Black Beauty or Bumblebee. Could the Jupiter Condenser Red Astron be the one?
Stay tuned, there will be much more to come!
