The High End ndustry norm seems to be 85 to 88 db sensitivity and a 4 ohm nominal speaker impedance.Yeah- I don't get that. It doesn't matter what kind of amp you have, if you make it work hard its going to make more distortion, and with **any** amplifier tube or solid state the distortion is always higher driving 4 ohms as opposed to 8 or 16. Speaker cables are more critical on 4 ohms too. I always thought high end audio was about making the playback sound like it was real, but so often it sounds like being able to weld with your amplifier is more important.
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.
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.
Showing 5 responses by atmasphere
If only we could have 200 watt 300b SETs...why oh why not!?Its the output transformer- with SETs its very difficult to get bandwidth as power is increased. This is true of push-pull too, but you don't run into problems until you have about an order of magnitude more power (+70 watts or so). What gives SETs a lot of that magic is the ultra low distortion at lower power levels. Most push pull amps can't do that- they have a minimum distortion at a certain low power level and below that power the distortion actually increases. It is possible to build a push pull amp that has a very low distortion signature at low power like an SET but to do that the amplifier must be fully differential from input to output. If the amp has a single-ended input combined with a phase splitter circuit its common to run into problems. |
My listening level is never more than 65-70db in a room measuring 15’D x 25’W. That’s plenty loud for me 😊96dB is at the upper end of moderate efficiency. You might think its playing loud enough, but if you ran an amplifier that was making less higher ordered harmonic distortion, you might not think so. If you really want to hear what a 300b can do, try a speaker with +101 dB sometime! |
Question: would 300b amplifiers work with my ~93dB efficient JBL 4430 studio monitors? Or do I need something more efficient than that?Unless you are playing the speakers nearfield you either will need more power or more efficient speakers. Again, an SET is best used when the maximum volume attained does not used more than about 20-25% of full power. Otherwise the amplifier starts making more higher ordered harmonics. If you've ever wondered why SETs are known for being so much more 'dynamic' than their low power would suggest, this is why: Those higher ordered harmonics are used by the ear to sense sound pressure and since music has a great deal of transients, the loudness cues (distortion harmonics) initially show up on the transients as you turn up the volume. This sounds to the ear is if its more dynamic but in reality its just distortion. Once you are aware of this fact, its also easier to hear that such is the case, so I may have ruinied it for you if this is how you use your SET. |
Here is another link you all may find interesting. Eddy's article covered a good deal of the basics, but one thing he really didn't go into is how the amplifier interacts with the loudspeaker. Since SETs run zero feedback for the most part, this is pretty important! So here's the link:http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php Also FWIW, Eddy didn't cover the issue of distortion completely. One important thing he left out is that SETs have distortion that linearly decreases to measurable at lower power levels- this is the source of that 'inner detail' you read about in them so often. Most push pull amps don't do that; below a certain power level their distortion actually increases. But this is not true of **all** push pull amps; it is possible to build a push pull amp that shares the character of decreasing distortion to measurable just like SETs have. |