300B or 845?

We tried both 15 wpc 300B and 16 wpc 211 SET amplifiers with Merlin VSM-ME, in my buddy Spencer's (Sbank) system, Pubul57.

The 300B was a parallel single-ended amplifier, with 2 TJ mesh plate 300B output tubes. The 211 featured a single output tube. I have my 211 amp modded to run 845 tubes as well, but we didn't get to it that day.

You'll be able to drive the Merlins like crazy with any of these tubes, as we did that day. In my opinion, the midrange/treble of the 300B cannot be approached by a 211 (or 845, especially) amplifier. However, there is a lack of low-end with the 300B amp in comparison to the 211 (and, again, especially, the 845 which has tons and tons of bass) that may leave some audiophiles wanting.

For me, it's a closer race as to which I prefer, but Spencer (hopefully, he'll chime in here) was most emphatic in his feeling that the 211 was the way to go because of the paucity of low frequency performance via the 300B. Again, you can listen at very high volumes with either amp, and that is probably where the two of us will agree most.

DISCLAIMER: I am the North American importer/distributor for Opera Audio/Consonance high-end audio components - which the aforementioned amplifiers were

Spencer, if you chime in, I'd like to know what you think of the SET performance versus your Atmaspheres.

Where is Spencer?

Been waiting over 10 years!

As an importer and re-seller for a manufacturer of 845 and 300B amps they are both amazing tubes.  One of the most important questions in terms of soundprofile and overall amp quality is going to be in regard to the transformers.  They are key to an amazing SET

The 300B is going to be your most linear and musical tube but is going to be limited in the amount of power it can deliver.  The soundstage is gorgeous and lush and the midrange/treble shines like the sun.  Bass can be a hair flabby, especially compared to an 845. A good 300B SET is going to be ~10w.  With a 96dB SPL Speaker though, that is a max output of over 102dB. Plenty for any normal person. 

An 845 SET is going to give you tighter bass but is going to be less lush.  Compared to a SS or even a 6550 or KT-88 based amp you are going to get much better PRAT and spectacular midrange/treble but not quite what a 300B delivers.  You get a bit more power out of an 845 and they do tend to be slightly less expensive amplifiers.

The Art Audio Diavolo is 10w and my Carissa is 18w.  

Tube costs vary wildly for both tubes.  A good pair of 845s range from <$200 a pair to $1900 and 300Bs can be had for $200 a pair to $1600.  Quality of the tubes will make a difference and it matters 

A 2A3 or a PX25 (similar tubes) are arguably as linear as a 300B with tighter bass and the same lush soundstage.  They tend to be lower in power output and usually are 5w or less.  This would still have you 99dB of output at full power 10' from the speaker.  

I am re-introducing a PX25.  The advantage again is that it is a bit cheaper than a 300B though you have a lot less tube choice but the two that are available new (Sophia and KR) are spectacular.  

One other note - What speaker are you running?  There are a couple high efficiency speaker manufacturers who are notorious for over-rating the SPL on their speakers.   I would hate for you to get a 10w amp when you really need something more powerful because the speaker is really 91dB instead of 96dB.