SOLD
Really hate to part with this but a deadbeat seller has forced me to sell some of my treasured (keep for life) items.
Sean Casper's Version Is 4 Watts Dual Triode Hand Built With Vintage 1950's Siemens German Gold Coupling Capacitors, Edcor Transformer and NOS Tung Sol Output Tube. I have not broken it in yet and must sell it. Sounds fantastic!!
In a never-ending search to find just the right amp I’ve been able to put together a rotation of amps that meets most of my varying listening moods. Each amp has a distinguishing character that keeps drawing me back to it like a spirit familiar. The latest addition is an unassuming 5998 SE amp built by Sean Casper from Oshkosh, WI. It’s about 4.5 watts of power but sounds much bigger than that. It consists of a 5998/421a output tube, 6SL7 or 6SN7 input and 5U4 rectifier. There are more tube swaps that can be made in the rectifier and input tubes. I’ve found the best sound thus far consists of a WE421a, Tung-Sol VT-229 and RCA 5U4GB. As you can see from the picture, it’s inspired by Don Garber’s 421a, which I’ve not had the good fortune to hear.
The amp has a deceptively petite footprint with a single dual triode 421a doing stereo duty. The biggest surprise was how well this little amp did in lower-mid to bottom-end music. The highs and mid-range are similar to the clarity of a 45 but the 421a has more body in the lower-mid to bottom than any of the other amps. Although the WE 91a (300B) goes lower with greater force and articulation at the bottom end, the sense of body in the 421a paradoxically can often seem greater.
I almost exclusively listen to classical chamber and solo instrumental music so I don’t need head-banging decibels or orchestral cascades of sounds. However, when I put on Scelsi’s Kho Ta for double bass or Xenakis’s Rebonds B for percussion, the palpability of the instruments is astounding. Both the drum head and body of Rebonds B come through with a timbral fidelity that I haven’t heard with most of my other amps. The woody resonance of the double bass on Kho Ta is clearly articulated and sustained.
The mid-range and treble have an amazing clarity without graininess. This is much closer to my prized Korneff 45 but whereas the 2w 45 doesn’t have enough power to drive my Ikonoklast HO (~95db) into the lower depths or tends to simplify complex sound waves by highlighting a single character, the extra power of the 421a makes the Ikonoklasts go deeper with a combination of tonal body and resolution I’ve not been able to get before. As others have said, the 421a gives the power of 300B with the clarity of 45.
The 421a is the first amp in a while that I can listen to any instrumental combination and not feel like another amp is just clearly superior to it. Like the Korneff 45 the piano strings vibrate against the soundboard with amazing overtones of sustain. However, unlike the Korneff the wooden body of the piano mingles more with the vibrating strings. Also, like the Korneff, the 421a captures the delicate, diminutive beauty of the vihuela. Hopkinson Smith fingering his way through a de Visee suite on theorbo sounds with the deep majesty. String quartet, solo violin, viola, all sound right.
My speakers just aren’t efficient enough to showcase all that the Korneff can probably do with complex music. However, the Korneff amp plays solo plucked instrument with a splendor unparalleled. The WE91a has more rhythmic snap and agility than the 421a and even more of the 45 tonal purity or cleanness than perhaps the 421a. There’s a slight blur or porousness to the 421a sound but this I think gives the music a bit more of body and harmonics than the WE91a.
The 421a can really resolve the music, take you deep into the counterpoint and overtones of sustains. At the same time it has a believable dynamic and scale. It does a great job of placing the instruments in relation to one another and placing the listener in the performance/recording space. The detail is not at all clinical. It has a naturalness to it, a tonal splendor without being bloated or overly textural. Groping for an analogy from the visual arts between the WE 91a and 421a, I’d say the 421a has the ability to sculpt musical details more in the manner of Bernini’s marble portraits than Michelangelo’s. The latter molds the figure into a marble monument, whereas Bernini sculpts the marble into the fluidity of the moment, the history and future of the moment suspended in the space within and around the figure.
The difference between the Sun 300B PP and 420a is that the weight is more embodied in the instrument than in the recorded space around them. Whereas the Suns distribute the weight into a more uniform palate, the 420a concentrates the weight into more distinct spatial presentation of instruments (for example, in the Lagos Ensemble’s recent recording of Kagel’s 4th string quartet). However, compared to the Sun 300B there is some roll off at the bottom end. The cello solo of the Kagel string quartet doesn’t come through quite as well on the 420a. The overall PRAT of the 420a is, however, superior.
My friend was mighty impressed with the amp’s punchiness, clarity and directness playing it through Audio Physic Virgos (90db) so its meager 4.5watts can be astounding even with less efficient speakers than the Ikonoklasts. As you can tell, I’m very impressed by the overall musical presentation of the 421a.
Price is $1050 plus shipping, via paypal or US postal money order and add 3% if using paypal to total, USA shipping addresses only. Price is 850 less the Western Electric 421A tube (tests strong and sounds wonderful.) Email me at
apt_one@yahoo.com. Please no trade offers or overseas buyers.
