Nelson Pass releases two low-powered amps, and jelt2359 is ready with his trusty Hifiman HE6
On Top: First Watt F7 Power Amp
Output: 20W into 8 Ohms, 30W into 4 Ohms
Damage: $3000 USD
Inputs: Single-ended only
Damping Factor: 100
Below: Pass Labs XA25 Power Amp
Output: 25W into 8 Ohms, 50W into 4 Ohms
Damage: $4900 USD
Inputs: Single-ended only
Damping Factor: 500
I own multiple speaker amps and do not have a single pair of speakers to my name. Instead, I use them solely to drive my headphones. After doing this for many years (I use a banana taps to XLR adaptor for this purpose), I’ve learnt that good amp is a good amp, whether it’s meant to be driving speakers or headphones. Make sure the gain and output power isn’t too much; look for quiet amps with low noise floors (a pitch black preamp helps a lot as well), and you’re in business.
In this context, the newest two amps from the legendary Nelson Pass seem tailor-made for me. Both are low-powered amps meant for high efficiency speakers, and are perfect for headphones. First Watt had in the past been Nelson’s ‘personal test-kitchen’ of sorts, with every amp hand-built by him, with limited runs, until he moved on to his next crazy invention. This has changed in recent times, with his other company Pass Labs now taking over distribution, manufacturing and support for all First Watt amps as well. First Watt has always had a philosophy of ‘less is more’, and the First Watt F7 is a refinement- a further simplification- of arguably Nelson Pass’s most popular amp, the First Watt F5. On top of having only four transistors and four resistors in the circuit- the bare minimum for a circuit of this type- it also employs a rare combination of both negative and positive feedback, working in combination. Nelson Pass akins this to a Tango dance.
On the other hand the Pass Labs XA25 adopts the ‘more is more’ philosophy of Pass Labs, but with some caveats. Taking on the immensely popular XA series design, the XA25 limits it to single-ended only. Instead of using multitudes of output devices under-driven in parallel ala the Point 8 architecture, the XA25 also uses only a single new-style output device per channel. The XA25 is stiff (it is stable up to ½ ohms!), it is powerful (it peaks at 200W), and Nelson Pass writes that this was an amp that was simple in its design but surprising in its performance. It is currently the only in-production amp of the “XA series” of amps from Pass Labs that’s not a Point 8 design, and speaking to the good folks over there they’re simply not sure if this new-style output device (affectionately named ‘Hockey Pucks’) can scale upwards towards more power. In short, this amp may only be possible as a low-powered design! Lucky me.