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In Reply to: RE: Am I correct that transmitter triodes never sound superb? posted by PaulF70 on May 22, 2025 at 19:47:33
I too am a fan of the likes of 45 and 2a3 amps. I've owned both. But, I have heard pretty good transmitter tube amps too. The best is the Audio Note Gaku-On amp (parallel 211 SET). An electrical engineer tried to explain to me the inherent difficulty in making a suitable output transformer for high powered SET amps, which might explain why good examples are rare. The Gaku-On is a crazy expensive example of a higher powered SET.
Yes; as I noted those uber-expensive models *must* sound top-rate (or they wouldn't sell).
It's hard to believe it actually takes $50K+ to make a 211 amp with the finesse of even an average 300B... but maybe it does.
The 300B can use a much simpler (i.e. cheaper) transformer for a good load line. Finding good transformers for 845 and 211 has never been easy, and none that I'm aware of are suitable for the power capabilities of these tubes in the first octave. A single-ended series feed transformer for 20W at 20Hz would be the size of a cinder block. I use Magnequest FS-100 OPTs, which are very large, but even these are limited to about 7W - 8W at 20Hz without NFB. This limitation aside, my 211 amps are extremely nuanced and transparent, and I wouldn't hesitate to put them up against any 300B.
You are actually reinforcing my suggesting. If a 211/845 is only good for 8W without a "cylinder block"-sized output tranny, then it would seem that virtually every commercial 211/845 amp is substandard compared to a decent 300B.
Unless you're only talking about bass issues.
But why run a transmitter triode to get 8W when any 300B will do that?
(SETs are so bad at low bass in general, IMO it's best to sidestep it with bi-amping.)
"But why run a transmitter triode to get 8W when any 300B will do that?"Because the additional midrange headroom of the larger triode produces sound that is more nuanced and effortless when paired with most speaker systems.
To be clear, the issue of limited bass I mentioned has nothing to do with load lines or inductance (although those parameters can certainly undermine amplifier performance). The more important issue is core flux, with the maximum that is permissible being directly related to core size. Core flux is inversely proportional to frequency, so the flux produced at 50Hz will be twice that produced at 100Hz, all else being equal. This is a critical concern for any full bandwidth amplifier, because it means transformer performance is declining at the same frequencies where most musical material requires more power from the amplifier.
There's a lot of misinformation in this thread on this subject. I would urge anyone who thinks the bass is tight and abundant in their high power SET to make a measurement. OTOH, maybe this is one of those things owners are better off not knowing. :)
Edits: 05/25/25
For example both B&W 801 and ProAc response three can go down 20Hz but the room can't. So that 20Hz is useless. On the other hand, my JBL dual 15" can go down 30Hz but it has a lot of more output than the tiny woofers on the ProAc.
I believe your woofers are JBL 2226Gs. Their free air resonance is 40Hz. In ported, tuned boxes you would be doing well to have a -3db point of 50Hz.
Tre'
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Key Features:
u Usable Response to 35 Hz
u 100 dB Sensitivity, 1 W, 1 m
u 1200 Watts Power Capacity
u Two 380 mm (15 in) Low Frequency
Transducers
u Direct Radiator Ported Enclosure
"Usable Response to 35 Hz"I'm sure you realize this is a meaningless number. The term "usable" has no scientific meaning, especially when discussing the frequency response of speakers.
"100 dB Sensitivity, 1 W, 1 m
"1200 Watts Power Capacity"By virtue of the physics of voice coils, gaps and excursion, these two specifications are mutually exclusive when applied to a woofer. The high power capacity implies relatively low sensitivity of the low frequency driver, more than likely at least 10dB less than the sensitivity spec. The latter is undoubtedly confined to midrange frequencies and higher, which is one reason bi-amping of SETs is so common.
Edits: 05/26/25
Have you looked at their specs?
Edits: 05/26/25
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Have Fun and Enjoy the Music
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If so, cool but you didn't say that.
Tre'
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Forget about EQ. The only place I used EQ is on B&W 801. They call it BAF (bass alignment filter).
are not usable to 35Hz. They are too quiet at 35Hz to add anything to the rest of the music.Tre'
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Edits: 05/26/25
Can you give me an example?
!
The Mind has No Firewall~ U.S. Army War College.
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It's difficult to give a single number because it depends heavily on the speaker's physical size and design.Small, highly sensitive speakers (e.g., bookshelf speakers): These might struggle to go much below 60-80Hz without a significant drop-off in output or increased distortion.
Larger, highly sensitive speakers (e.g., floorstanding speakers, horn-loaded designs): These can extend lower, perhaps down to 40-50Hz, and in some cases even lower. True horn-loaded speakers, known for their extreme efficiency, can achieve impressive bass extension, but they tend to be very large.
Edits: 05/26/25
Your JBL speakers have a free air resonance of 40Hz and are 3db down at 45Hz. 10db down at 35Hz.
Tre'
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That system is -10db at 35Hz. You can call that "usable if you want but that is not normally how we talk about speakers. The -3db point is 45Hz.
By the way, you said "On the other hand, my JBL dual 15" can go down 30Hz"
Again, you can say that your speakers "go down to 30Hz" if you like but that is not normally how we talk about speakers. We normally talk about the -3db point. Not the point that is further down than 10db.
Tre'
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This is the specs from ProAc. Could you please tell me how many dB at 20Hz?
Description: Two-way dynamic loudspeaker with 1" dome tweeter and two 6.5" polypropylene-cone midrange/woofers. Frequency range: 20Hz-25kHz (no limits given). Nominal impedance: 8 ohms. Sensitivity: 88dB/W/m.
JBL is an American brand. I don't think they lie.
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They show the speaker is 10db down at 35Hz
You can get 35Hz from that speaker but you would need a lot of EQ and a lot of watts. The speaker is far, far from flat to 35Hz.
JBL shows the speaker is 3db down at 45Hz so it might be flat down to 60Hz, (educated guess but I would bet I'm not far off)
I can't find the TS parameters for the woofers in the ProAc so I don't know for sure but a 6.5" woofer won't play low bass flat (vs. the midrange)
The ProAc 2.5 falls fast at 70Hz.
Tre'
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With a drawback, had some rather rare 4315 speakers and they confounded for a brief spate till listened and realized when driven by Good SS amps they sounded like a totally different speaker than using ANY tube amps (12 or 13) I owned. The impedance curve must have looked like the Andes mountains.
The Mind has No Firewall~ U.S. Army War College.
Can you explain how a typical room would attenuate the low frequency pressure waves from a speaker at the listening position? It's not clear to me that this is even a valid concept. That aside, my point is not whether you think it's appropriate for an amplifier to perform well in the lowest octave, but rather whether it has that capability.
You do this using multiple subs. If your main speakers are good into the 20s then you only need two to do the job.
They must be asymmetrically placed. In most rooms they must not reproduce anything above about 80Hz else they can draw attention to themselves.
Standing waves can cancel bass or reinforce it. If its being cancelled, no amount of room correction or bass traps can fix it since amplifier power is being cancelled in the standing wave.
At 80Hz the waveform is about 14 feet long. The ear needs the entire waveform to pass it so know the note is there; a few more iterations to know the frequency and nature of the note. By that time anything below 80Hz has bounced all over the room probably several times. Deep bass is thus 100% reverberant. So a mono bass signal for the subs works fine and you don't have to time-align anything.
At that point you can get smaller rooms, even ones that are square to play bass just fine.
In Texas, you have huge rooms so bass is not an issue. But here in NYC, we have medium size rooms which can accommodate about 30Hz. However we stay outside during spring/summer time and enjoy sun light.f = c / 2d
For example, if your room is 6 meters (about 19.7 feet) long, the lowest frequency axial mode related to its length would be:
f= 343 / 2*6 = 28.58Hz
Edits: 05/26/25
"But here in NYC, we have medium size rooms which can accommodate about 30Hz."
Sorry, no. The smaller the space, the better it supports the pressure waves. What you are stating is an urban myth that is entirely contradicted by the laws of physics. Having taken low frequency SPL readings in motor vehicles and compared them to the same speakers in larger rooms, I can tell you that empirical data also proves this assertion to be false.
!
The Mind has No Firewall~ U.S. Army War College.
By that logic, bass would be impossible in cars. Not to mention headphones ... :^)
It's hopeless, Paul. I studied speaker drivers and acoustics in great detail more than 40 years ago. Nowadays, too many people rely on the Internet knowledge base and simply don't know what they don't know. Newcomers will argue over nonsensical concepts till they turn purple, never bothering even to crack a book written by knowledgable experts. It's the way of the world, and one of the reasons there's so much junk on the market.
I'm in the middle of building a couple monoblocks at the moment, so I'll sign off for now. Take care and thanks again for sharing your considerable expertise through the years.
I have no interest in car audio. I have good headphones and may one day get a good tube headphone amp.
One can use a 5k transformer if they limit the bass to 200Hz or so and up-tap the transformer using the 4 ohm tap for an 8 ohm speaker.
I am not convinced that any gapped transformer has enough inductance to properly play bass.
I use SS for my JBL 2231s crossed at 200Hz. The load line for my SET 6b4gs (driving the mids and the tweeters) at 200Hz looks almost resistive.
Tre'
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My 805 SET driving JBL dual 15"s gives me great bass. Better than B&W 801 driven by very high power mono blocks.
An 805 SET is almost certainly operating in Class A2 with plenty of feedback. It's the feedback that makes the bass so good.
Thank you!
There are four selections of negative feedback. Each one has their own sound effect.
How much inductance does your output transformer have and what is the reflected impedance loading the 805?
Tre'
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I do not design SET amps for Line Magnetic. But my ears tell the truth. My wife also likes the bass from the 805 SET better.Dual 15" works. The 12" from B&W 801 doesn't have enough output in my house. I have a medium size room for B&W 801. But the room for JBL dual 15" is bigger.
Edits: 05/24/25 05/25/25
Sure, I can see it.
I loved the bass my Fi (RIP) 45 SET monos gave on my Lamhorns - all 1.5 watts of it.
And I loved the bass my Consonance 211 SET monos gave on Hyperion (RIP)bass-reflex speakers.
Bass meaning bass fundamentals and overtones of acoustic instruments.
Not <40 Hz, electronic, etc., material.
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Here's track 6 from Alison Krauss CD Lonely Runs Both Ways.
There's a lot going on below 40Hz and even if your speakers don't/can't reproduce it, in the presents of low frequency a lack of inductance will turn the load line into a beach ball and all the frequencies will follow that beach ball load line. A beach ball load line drives the tube into the non-linear regions.
View YouTube Video
Tre'
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I agree with Leo. My Shishido 805 (think Wavac 805 with original special order Hirata Tango) provides tight low bass on the Altec 604G based speakers (15"). Hirata Tango are known for their lovely transformers, and that is well earned and deserved.
It is accurate to say that virtually everything is only as good as its weakest component.
Do you know the reflected impedance and the inductance of that output transformer?
Tre'
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Here is a photo of the transformer specs from the Shishido book. You can google for more info (xformer # at bottom of picture).I base my opinion on sound rather than specs, which can be very misleading.
regards -- Roger
Edits: 05/25/25
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Bass is not an issue.
Hello,
They were both made in 2023, one in week 8 and the other in week 23. They both are as close as you can get to being identical considering they are two different parts. We manufacture to strict tolerances no matter what day a product is made. There is simply no way to order a transformer with matching date codes and the sound quality would be the same anyhow.
Regards,
xxx|Hammond Mfg. Co. Inc.
At only 1250 ohms you won't need much inductance at all but 1250 ohm will be a very low load impedance for most triodes leading to a vertical load line and getting into the non-linear part of the tubes operating curve even if the load line is straight (resistive looking).
Tre'
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This is for my DIY. 300B PSE. Summer is busy season. A lot of activities. I may start my project in the winter (may be never).
Edits: 05/25/25
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I was talking about the difference in the plate resistance between the 300b and the 805. The 300b has a much lower plate resistance than the 805 so the two need very different output transformer impedances.
Tre'
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For audio, the 805 usually runs in Class A2 with plenty of feedback. I have seen (and heard - it sounded great) an 805 amp that used a 3K transformer primary impedance. Very different from a 300B SET, but the transformer impedance is the same for both.
.
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For audio, the 805 usually runs in Class A2 with plenty of feedback. I have seen (and heard - it sounded great) an 805 amp that uses a 3K transformer primary impedance.
Are you sure it runs in A2? What is the reason that it has to use negative feedback? Damping factor is one reason. How about distortion?
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Yes, it is in A2. And the distortion is quite high w/o negative feedback.
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