Kara Chaffee (deHavilland Electric Amplifier Company) was over visiting Pete Riggle (Pete Riggle Audio Engineering) for an impromptu audio fest, and brought along her prototype Super 40 monaural power amplifiers for a little listening.

I didn't have a camera along with me so I didn't get any photos of the Super 40 prototypes (sorry about that), but I was very impressed with what I was hearing from them via Pete's vintage Altec A7 loudspeaker based system.

I had never heard Pete's A7's sound better. Pete's system is always very impressive sounding, and is one of my favorite systems to hear because it is so musically natural and engaging to listen to music over.

Pete's using restored vintage McIntosh MC30 monaural amplifiers in his system, in fact most of us around here are using MC30's these days.

The MC30 monaural amplifiers are somewhat overlooked wonder amp's, and if you've never heard a pair they'll really take you by surprise at what they're capable of from a musical & sonic standpoint, because they are like so different (dramatic) sounding compared to pretty much everything else.

I like the MC30's better than any new or old vacuum tube amplifier that I've heard to date in my system.

Like the MC30's, Kara's prototype amps took me by surprise too, and Kara told me that I could consider the prototype deHavilland Super 40 monaural amplifiers to be refined versions of the vintage MC30's, and after hearing them I was very impressed - they really are super!

Kara said she'd let me give the production versions a listen when they're all done, so I'll be looking forward to that.

Also, you'll be able to pick up a pair of the deHavilland Super 40 monaural amplifiers for about the same price as a nicely restored pair of vintage MC30's.

You can reach Kara here if you want to find out more about this emerging Super 40 story.

The other part of the story I want to tell you about is the NOS Tung-Sol 5AW4 rectifiers that Kara uses in the Super 40.

We did most of our listening with 5AW4 rectifiers in the Super 40's, but then we took a brief listen to another pair of new production rectifiers that are well regarded, and I was impressed with how smooth, rich, and natural high-frequencies sound with the 5AW4's sounded in comparison.

I was impressed enough by the demo of the 5AW4 rectifiers at Pete's that I ordered some vintage NOS Tung-Sol 5AW4 "V" plate rectifiers to try in my MC30's.

It was dark when I was shooting the photos, so it's a little hard to clearly see the internal structure of the 5AW4 rectifier, but I'll follow up with some more photos in better light.

I couldn't find a data sheet for the Tung-Sol 5AW4 rectifiers, but I did find it for the RCA 5AW4 here.

The 5AW4 full-wave rectifier can directly replace the typical 5U4G full-wave rectifier as they have similar characteristics (the 5AW4 draws a bit more filament current than the 5U4G).

I put a pair of the 5AW4's in my MC30's and gave them a listen, and my impressions of them in the prototype deHavilland Super 40's were replicated in my MC30's, with the 5AW4's providing an effortless, smooth, rich, and natural mid-range and high-frequency presentation that matches the best I've heard from my MC30's with the exotic and impressive Sophia Electric Aqua 274B rectifiers, which I have been immensely impressed with.

I was so impressed with the NOS Tung-Sol 5AW4 "V" plate rectifiers I ordered 5 pairs (!) of them for my tube stash. The NOS Tung-Sol 5AW4 "V" plate rectifiers are really, really, superb in my vintage MC30's. Fantastic overall tone!

You're probably wondering how expensive the NOS Tung-Sol 5AW4 "V" plate rectifiers are, given the cost of vintage tubes these days.

I bought mine from Radio Electric Supply for $8 USD each.

I'll try to get some more photos up for the NOS Tung-Sol 5AW4 "V" plate rectifiers when the light gets a little better.

As always, thanks for stopping by, and may the tone be with you!