300B Tube Amps with 15/16 Watts Per Channel?

@debjit_g

Sorry for the delay, issues with getting Agon to load and login.

I am a Big proponent of tubes and over the years have owned some of the best SS Class A Amps but they have really not connected me to the music like tube equipment...

I have owned a plethora of tube amplifiers and have 2 additional units on hand, 1 is a customized KT88 with 65 Watts and the other another KT88 but Class A @ 12 Watts and 100 Watts A/B.

I knew I wanted to eventually try a 300b amp as the possibility of squeezing out 15-20 Watts in PP with Zero NFB was within reach, so I reached back out to Ken Uesugi of Otoman Labs, Japan and he confirmed that he could build me mono’s that would fit my rack and the power requirements I was wanting.

Ken had my Mono’s built in about a month and shipped after the holiday rush to minimize shipping damages but they arrived flawlessly and packing and build quality was outstanding...

Amps are as quiet as a mouse and they exudes all of the audiophile terminology but it’s without question that these 300b are more transparent yet with warmth than Any KT88 amp I have ever owned and the bass is much tighter and the top end is more refined, detailed and airy. The power supplies and transformers are massive and quality Tango and Luxman iron...

My Pre Amp was built my another tube guru designer and builder, Radu Tarta... It’s a 4P1L direct coupled, filament bias, line output transformer coupled pre amp. It has that 2A3/45 tube sound but with more transparency and dynamics.

I’m extremely happy with this combo and feel as I’m at a live event each night I sit down to listen 🎶

4P1L Line stage | simplepleasuretubeamps
https://simplepleasuretubeamps.com/products/

Wig

For everyone here who is considering a zero feedback 300b amplifier, something you should know which has to do with the loudspeakers you plan to use: http://www.atma-sphere.com/en/resources-paradigms-in-amplifier-design.html

The short explanation is this: tube amplifiers with no feedback don’t adhere to the Voltage drive principles of about 99% of all loudspeakers made. That 1% left over are nearly all made by high end audio loudspeaker manufacturers. Zero feedback tube amps try to make constant power with respect to the speaker impedance rather than constant Voltage. This means if you mix the two technologies you’ll get some sort of tonal aberration.

In particular if the amp in question is also an SET, plan on having a speaker that is a bit more efficient! This is because all SETs that are zero feedback only have about 20-25% usable power- above that power level distortion causes the amp to sound ’dynamic’.

You might think that ’7 Watts is enough’; here’s a tip: Its the mark of the best systems that they do not sound loud even when they are. If a system sounds loud when a sound level pressure meter (available as an app for any phone) shows that it really isn’t, what is happening is distortion is being interpreted by the ear as sound pressure.

Put another way, if your speakers are efficient enough that the SET never needs to make more than about 25% of full power you’ll really start to hear the best of what that amp can do. In case there’s any doubt, this is part of why horns were so common in the 1950s and prior.

@wig appreciate the feedback. The Luxman iron was a custom order in your case ? I don't see it mentioned on their website.

@debjit_g 

The type of iron is dependent on what he have on hand but it will be very good with whatever iron he uses 😊

Wig

@atmasphere thanks for the info. Wonderful explanation. Yes, my speakers Cube Audio Nenuphar is a single wide band driver. The manufacturer recommends amps with 0 or low feedback design, which will also have low damping factor. I have gone through some amps, and fine these recommendation matter a lot when it comes to the bass performance.