Mastersound 300b Compact-thoughts???

@mmcgill829 

The brand does seem like it's fairly well-respected (though not very well known still outside of Europe).

Yes, I’m pretty sure the Mastersound has greater presence in the European audio market compared with North America. Although Allnic and Mastersound differ in their approach to building 300b SET amplifiers I believe both of these would sound terrific with the Coherent speakers you’re having built.

Charles

@mmcgill829 

it appears 8-10wpc is expected on 120v US power, which is more in line with what would be expected

That is reassuring particularly the comment addressing tube lifespan. Their in-house built transformers are universally acknowledged to be very high quality. 
​​​​​​​Charles

@mmcgill829 

Your budget range will allow you to purchase an excellent quality amplifier. I’m much more familiar with the 300b genre than the 2A3 but I believe that either would work in wonderful fashion with your Coherent Audio speakers. Triode Lab uses Hashimoto transformers and chokes. I know that Allnic goes a different route with “permalloy “ iron in their amplifiers.

Allnic also believes a “bit” of NFB is desirable (Lower output impedance thus higher damping factor/DF).  I’m pretty certain that the Triode Lab is purist zero NFB. Does Frank feel the added NFB is necessary or a factor with his speakers? Allnic utilizes 6 db NFB. Anyway both of these brands are well thought of. With those speakers get the best amplifier you can afford. You’ll have superb sound quality for many satisfying years.

Charles

@mmcgill829 

I'm having Coherent Audio 18s made currently, so investigating amp options that'll take advantage of their high efficiency (102dB

In my opinion based upon what I have learned about the Coherent Audio speakers you’re going to be exceedingly happy!! You are on the right course with regard to pursuing lower power but high quality built tube amplifiers. Stick with your plans as your speakers will allow this to come to fruition.

Mastersound is a very reputable manufacturer that’s been around for years and I believe that they build their own very high quality transformers. My only concern is that 15 watts per channel rating is unusually high for the 300b tube. The good news for you is that there are no shortage of other low power SET (Or push-pull) tube amplifiers to consider. You are “not “ going about this in a wrong manner.

Frank has explicitly designed and implemented his speakers to be superb partners with these types of fantastic sounding amplifiers. Have you determined a particular budget range for your amplifier? Take your time and you’ll have a splendid high efficiency speaker/low power tube amplifier audio system. My system is posted on this site. I went this route 14 years ago and there’s been no looking back.

Charles

@mmcgill829 

I've been considering this amp since it was recommended to me by the speaker-maker of my speakers, but I have some concerns - notably the 15wpc rating on it. As a SET 300b amp, that seems quite high. I'm used to seeing half that in SET applications for 300b, so I'm a little wary as this may negatively impact tube life - which, considering the cost of these 300b tubes, would be a dealbreaker.

These are valid concerns. 15 watts from a single 300b is very high and certainly suggests that the chosen operational points are very aggressive and pushing the 300b quite hard. In this scenario a shortened tube lifespan is very likely. The sweet spot for SET 300b is usually 6 to 8 watts per channel. Now there could be some innovative circuit that can achieve this level of power without stressing the 300b. If so I’m unfamiliar with such.

Charles