The Audio Gods are tough but fair-Have you had the "Curse of the 300B" ?


These amps can really pull you in to hear the singer. The voice instrument is so spot on it can provide moments of disillusionment. For example, I've always preferred Sam Cooke's Live at the Harlem Square Club over Live at the Coppa.  The former is way more free and pushes the R&B needle.  It's musical and soulful.  On my 300B setup I agree with that but I also can put Live at the Copa on and be drawn in... in so much that I start enjoying that album as much as Harlem Square. My attention gets focused on the music and not that this isn't my favorite Sam Cooke album.  And I start hearing and feeling things in the vocals that weren't present before. It's wonderful in the truest sense. 

The 300B SET also delivers smaller group instrumentals like no other.  Drums in the jazz, acoustic/folk settings are sublime.  You really identify the drum skins. You do this sonically more than viscerally.  It is, however, intoxicating.  

When done right these amps can be captivating.  But the 300B mistress is not without its issues.  

-You have to mate it with more sensitive speakers.  This is huge.  You are no longer looking at the lion's share of state of the art loudspeaker reviews.  No. You are searching for sensitive, efficient speakers because the 300B runs out of gas real quickly. 
-You have few choices in amps, 
-You have few choices in tubes and they get really expensive for the 'premium' makes.
-You are likely listening at below moderate to moderate volumes. 
-You may keep a second system to use outside of 300B time. 

When I go back to push pull, or even solid state, I immediately appreciate the power and increased visceral impact.  My attention, however, gets more easily lost, and while they don't sound "bad", I lose the clear window into pieces of the performance.  Subtle nuances of how the singer's voice has personality arising out of the phrasing and tone of the vocal.  Instruments with the 300B sound more "instrumenty".  I don't consider any of what's lost when switching to push pull to be hyper detail or analytic.  Instead, it's characteristics of the sound that aren't there leaving less of the inherent personality of whatever sound is being reproduced--vocal, instrument, or the room in which the performance is taking place.

And so I've done things with my system to help it when it's in 300B mode and push pull mode.  For 300B, I added an REL subwoofer and a second Sumiko I had laying around.  I use those to load the room and expand low end but increase soundstage and make things sound bigger with few watts.  For the push pull setup, I've got the input source all tube whether digital or vinyl.  

This leaves me with the feeling that the Audio Gods are tough but fair.  It's hard to have it all with SET or PP.  Nonetheless, my mind seems made up that it seems easier to work within the 300B setup to make it better as opposed to the push pull. 

As a total aside, I am not the audiophile sage that many are on this forum or out in the audiophile-wild.  I will say with confidence though that if you love hifi you owe it to yourself to spend a month with a SET amp coupled with efficient speakers. 
jbhiller

Showing 10 responses by charles1dad

Jbhiller,
Yes I do certainly understand. I’m not an engineer or technician, All of my comments and observations are the result of much listening over the years of recorded music and many hours spent in live music venues. SETs do things that seemingly counter conventional wisdom 😊.
Charles 
In the High End community/sector there are certain numbers often and proudly presented to presumably impress audiophiles.
Very high amplifier output wattage
Very high current (amperage) peak capacity
Very low output impedance of amplifiers
Very low THD i.e. 0.001range
Very high damping factor i.e. 1000 and higher.

When it comes to actual sound quality and listening to music I don’t believe that the above stated parameters are necessarily shown to be beneficial.
Charles

+2 jburidan.
Higher sensitivity ’and’ also  higher/easy speaker load impedance (8 to 16 ohms nominal range). The High End ndustry norm seems to be 85 to 88 db sensitivity and a 4 ohm nominal speaker impedance.
Charles
Facten 
 Those engraved W.E. 300bs are the epitome of a cult following product. 
Charles 
Facten,
Canary audio has made a 50 W 300b amplifier for quite a few years now. Allnic I believe alSo currently builds a 50 W 300b. At one time VAC produced  140 watt 300b mono blocks with eight of these tubes per channel (16 300bs total !!!). I am glad that I have found much contentment with a single tube 300b per channel SET 😊. Replacing multiple 300bs can get expensive in a hurry.
Charles
Facten,
Thanks for providing the link regarding the Thrax 300b amplifier, this needless to say is a beast as it weighs 120 pounds. I suspect that the transformers, chokes and power supply are massive and yet of outstanding quality. This is an (it seems) all out state of the art effort. 50 watts pure class A push poll topology. I wonder how much nuance, inner detail and intimacy of a SET (single 300b) it will capture/preserve? No doubt it will have impressive authority, dynamics and musical power with an appropriate speaker. I look forward to the review. IMHO what SET does best and sets it apart from other topologies is tone, purity, intimacy and emotional connection with music listening.
Charles
I’ll be the friendly dissenter as I do not accept the premise that 99% of speakers available are incompatible with a 300b SET amplifier. That ’may be true for the 1 watt 45 tube . A friend uses 3.5 watt 2A3 SET mono blocks and the list of speakers he has found to pair with his amplifier is surprisingly impressive. Wilson,Magico, Vandersteen and Maggie’s? No. However there are ample choices that are suitable. Many are from high quality but small/lesser known companies. The 300b SET isn’t an universal amplifier for any and all aplications. Nor is it as narrowly limited as some suggest.
Charles
-i would definitely agree with "subjectivity" and "to each his own". I find the 300b has a few limitations but by no means debilitating. In regard to speaker selection the sensitivity and probably more so the load impedance curves are necessary considerations. . In my experience there are a good number of viable candidates. One can find them with the proper (and motivated) search.
Charles
Hi Gary,
You raised a point I forgot to mention, you re right, there is no shortage of 300b tubes available. Through a combination of buying and getting generous loans of tubes I've heard 10 or 11 different 300bs in my SET amplifier. Also there is no shortage of good quality 300b amplifiers currently available. The SET circuits are quite simple the major keys for sucess are output transformer and power supply quality. 
Charles  
Hi jbhiller,
Thanks for posting your happy 300b experiences. As you can see from the replies you aren’t alone. As noted, no amplifier type, design or topology is without some inherent compromise or shortcoming. In the end we choose what suits us best. "Instrumenty" I know just what you mean 😊. There are for certain very fine sounding solid state and push pull tube amplifiers and I have owned some myself.

When I acquired my Coincident Frankenstein 300b mono blocks and powered them up it took about 10 seconds to realize this was the sound I’d been yearning for. Things only improved as the amplifier burned_in. This was 9 1/2 years ago and my admiration and happiness has only grown. It does many things well but reproduction of human vocals and instruments was the best I’ve heard. Just so pure, connecting and realistic. It has been an absolute joy and now going on 10 years of ownership these amplifiers are a permanent fixture in my system.Needless to say all 300b SET amplifiers aren’t created equally. However if one gets a well implemented good quality amp you’ll be rewarded with music reproduced with strong emotional involvement, excellent tonality, beautiful nuance and realism. This is my listening experience.
Charles