300B SET Amp driving Wilson Sabrinas

Certainly not the first pairing that would come to my mind.. (qualifying as a thought)

Your listening levels and musical taste make this less than a universal pairing, but done right 300B SET can be very musical.  Sabrina Impedance Curve

I would think that the impedance at 139Hz would demand more power than your SET would be able to provide, but in real life, listening to your music and your listening levels, this isn’t an issue.

No surprise at all. Now, turn it up and see what happens. IMHO music should be listen to at realistic levels, but kept below ear damage levels. Many people listen quietly for a number of reasons and might get away with a SET amp. If you really want to hear what glorious sounds like, put a Pass XA 200.8 in there. Any thoughts of set amps will immediately dissipate, even at low volumes.

👍

Pairing of low powered tube amps can be incredibly informative. First that speakers are far less sensitive to tube amp power… way more than you would think. You put a low power solid state amp in there like a Pass kit and it would sound dead and completely underpowered. Also, the midrange produced by a 300b tube amp can be pretty intoxicating. I had done this recently.

My ARC tube amp can be run in triode mode 70wpc or linear, 140wpc. Virtually no difference in volume or dynamics (my speakers 90db efficient).

@mijostyn +1. Pass XA200… or even better an ARC 160 amp.

The volume control being at the same position means nothing really. It only means that the two amps have similar gain and input sensitivity. If you had increased the listening level, the shortcoming of the SET amp would have been easily noticed.

Normally I’d guess not enough power, glad it worked out.

@mijostyn +1: A 7 watt SET amp has a really limited dynamic range unless you have Klipschorns (100db sensitivity). To hear an appreciable increase in loudness with the Sabrina's an amplifier of at least 70wpc is required. 10 x the wpc = twice the perceived loudness.

Most people that say that won’t work have never hooked up SET to non efficient speakers. I have hooked up my Magnepans to my  807 monoblocks at 13 watts and because the Maggies are a stable 4 ohms for some reason it just works. Right now I’ve loaned my 807’s to a friend that has very inefficient Ryan speakers. He has several higher powered amps and the 807’s have not left his system. 
I do realize that they are not optimal to play super loud but for playing at around 85 db they sound amazing. 
I now have a pair of 838 single ended amps that power my custom newform research speakers and it’s a perfect match. 

 

This is another good example of how a mismatched amplifier and speaker "will work" and even sound OK but you are not hearing the speaker sound the way the designer intended.

Looking at the impedance curve (thanks @vonhelmholtz ) the Sabrina is a very difficult speaker to drive. It is a classic example of a speaker that needs a robust amplifier to sound its best. It should be driven by an amp that can double its output with each halving of the impedance - a feat that your 300B amp cannot do. The result of this mismatch is that the speaker will sound weak in the bass. In other words, you are introducing an unintended tone control into your system. Your Modwright isn't specified into 2 ohms but it does provide good power into 4 ohms. However, it doesn't look like it was designed to power a difficult speaker like the Sabrina. BTW, you never see a pair of Wilsons at an audio show being driven by a low wattage tube amp. Most often it's a D'Agostino amp that puts out huge current at low impedances.

Apparently this setup sounds OK to you and the altered frequency response may be a better fit for your room acoustics or perhaps it better conforms with your taste in sound. If possible I would recommend that you try an amp that is rated to 2 ohms (something like a Krell, Pass, or Levinson) and see what it sounds like. Maybe you won't like it but at least you could hear your speakers sound the way the designer voiced them.

It's baffling that in this hobby so few people understand what speaker sensitivity actually means. They just take what's fed to them by reviewers or other opinions and regurgitate it when talking about speakers and how sensitive they are or are not. Someone once said something along the lines of, better to keep your mouth shut and be thought the fool than to open it and confirm the thought. Then again, those that continue to spread the nonsense, think they're right. 

@roadcykler 

What, specifically are you referencing.  Please provide us with guidance.

@audioaholic1 

I’m not saying it won’t work. But with speakers under 90 db efficiency, you will be limited on sheer volume and dynamics. If you have a small to medium sized room and listen at moderate levels, it could “work”. But ideal? No.

@carlsbad2  @jasonbourne71 is exactly right. Live music is extremely dynamic. Have you ever been 15 feet from a drum set?  85 dB is for apartment dwellers. Real men listen at 95dB and piss off their wives.  Sabrinas will do this easily, but that amp will choke.  @8th-note 1++ Even with Klipschhorns that amp is not enough. We use to bottom out Stereo 70's on K horns. Marantz Model 9s did the trick. Sounding OK and performing realistically are two separate issues. I do not want "sounding OK" I want the band in my media room. I want to close my eyes and FEEL like I am at a live performance. I is that feeling that makes people want to jump up and dance. "Working" is not good enough. People are entitled to have whatever goal they like with their systems. If listening to a table radio is their goal then a SET amp is perfect and so simple they could easily build one themselves. @ozzy62 is on the path to success. 

@roadcykler ​

@vonhelmholtz has a valid point. Speaker sensitivity is the volume a speaker reaches with a given power at 1 meter. Have you ever seen people listen to their system at 1 meter from the speakers? Volume drops off rapidly with distance especially with point source speakers. This is why larger rooms require bigger more powerful systems. SET amps are for closets and headphones

Hearing damage can result in less than an hour at 95db. CDC

@ghdprentice The CDC is a totally lost cause. All of these silly studies are assumptions taken by people who hate loud music. Think about it. How do you do a study like that. Are you going to subject people to 95 dB for years to see what happens? How do you know what a person was exposed to, take a history? Do you carry a sound pressure level meter around with you all the time? These are the same people that told us pot makes you sterile and shoved a dangerous and ineffective vaccine down our throats. For 40 years I did comprehensive hearing tests on individuals from every walk of life as a family physician (Not a modern primary car provider) I followed them through decades. Not one of my musicians, who played electric music on stage had hearing loss beyond normal presbycusis. The ones that wound up with hearing aids either had a family history of hearing loss or were subject to a lot of impulse noise from machines and guns. My 72 year old dead head friend still hears fine and I still hear to 16 kHz at last check. I have been listening at 95 dB (when the music calls for it) as long as I can remember. My 95 dB is as measured, dBSPL , not dBFS. Remember dB is a relative scale.

@carlsbad2 I can understand your position. Most systems at 95 dB sound like sh-t. They hurt my ears. But, not because they are inherently bad systems. They are not tuned for louder levels. Mine is tuned for louder levels with the high end being rolled off. Our ears are much more sensitive to high frequencies as volume increases. If your system is balanced at 85 dB it will hurt at 95 dB  Even my wife was vacuuming along to Poco at 95 dB yesterday. 95 dB is not that loud. Many concerts hit 105 dB, twice as loud. Now that makes my ears ring, in go the plugs. At the range I wear 30 dB attenuators made by Etymotic. We saw Mark Lettieri two weeks ago in a theater setting. I would estimate it was around 95 dB most of the time and the sound was wonderful. I did not see anyone wearing hearing protection. What 95 dB does is it gets people up and dancing. 85 dB does not. 

Wow something made of good parts

sounded better than a more powerful amp made with not as good parts! Shocking 

@ghdprentice 

Actually OSHA specifies a 4 hour limit for 95 db SPL. I would rather trust them than the lying CDC.

The CDC is a totally lost cause.

To this day I listen to music wearing a mask and staying six foot from others.  The issue here is separating the agenda from the objective.

@vonhelmholtz or taking out the poster's bias.

I totally agree with you.

I have heard SET with Maggies, and it sounded OK. Bass control is bad on SET's and that is why they were just OK.

People, this is a hobby, it isn't life and death. 

I find listening to a good system between 65 and 80db is more than satisfying. The times I have needed higher volumes was when the sound quality was terrible. 

 If blasting your self silly makes you happy, go for it.

The surprise, not only did the Elekit drive the Sabrinas very well (improved clarity and tonality), but at the same volume with the same input level as the Modwright! Using a passive preamp, when I set the volume knob on the preamp to the same point for both the Modwright and the Elekit it results in essentially the same volume from the speakers.

@gareents There is more to this than just power. The reason the SET seems to keep up with the more powerful Modwright is due to the distortion it makes. As you push it harder, higher ordered harmonics show up (the amp lacks feedback so this is normal) which convince your ear that the sound is louder than it really is. A sound level pressure meter (which is available as an app for most phones) will reveal the truth of the matter.

Put another way, the mark of a good system is that it doesn't sound loud, even when it is. This is because it makes less of the artifacts that the ear uses to sense sound pressure, so sounds more relaxed.

@atmasphere - actually I did measure the dBA with a sound level app. The measurements between the two amps were essentially equal at the same volume setting. However, I also understand what you are saying because the SET amp "sounds" louder at the same setting. Interesting. Thanks.

I have a Korneff 45 SET w/EML Meshplates (3.5 w/ch) that are driving 40 year old Snell Type K bookshelf speakers. I’m amazed at how engaging the music is, although it’s by no means concert level SPL. The speakers are only rated at 90db efficiency and 6 ohm nominal impedance with frequency response of 70 - 20kHz. Of course I need a sub to fill in the low end, but this is the most fulfilling system I’ve had in 40 years of home audio. I have a pair of Coincident Invictus bookshelf speakers ordered. It will be interesting to see how they compare to the Snells.

mijostyn ignoring your sexist comment for the moment since when does loud = good? I have that Elekit amp and can say for certain there is a magic in that tube I have very very rarely heard with big muscle SS amps. Its a trade off, will you get all that Sabrina has to offer? No but you can get something that else you wont with SS.

@mootsdude If you used that amp with a speaker of 10dB greater sensitivity, you'd find that amp more spacious and more detailed, also smoother sounding all for the same reason: its making less distortion.

The Coincident, being designed to be easy to drive, points you in that direction.

OTOH, you might also be surprised how well a lower power PP amp would do on your Snells. Decades ago Dynaco used to make a small power amp called the ST35 which made 17 Watt/channel using a pair of EL84s per channel. If one of those is refurbished properly it gives you pause when compared to a good SET.

@atmasphere Prior to the Snells I had Tekton Lores and Klipsch Fortes, both driven by the Korneff amp. Considering both are rated at 98db and 8 ohms, I was shocked when the Snells sounded better, even before I added a sub. I never imagined an amp of such low wattage could drive 90db bookshelf speakers with such authority. If this is distortion I’m hearing, it’s never sounded so good. I’ve had a number of professional musicians listen to my system and they are VERY impressed by how it sounds. I can’t wait for the Coincidents to arrive!

I’m wondering if the Korneff amp delivers exceptionally high current and can handle lower impedances better than most other SET amps. I corresponded with Jeff Korneff many years ago and he indicated his amps are overbuilt with the highest quality transformers and power supplies. Makes me think not all SET amps are created equally…or all watts for that matter.

Makes me think not all SET amps are created equally…or all watts for that matter.

@mootsdude They aren't! It makes a big difference how the power tube is loaded. Some try to get more power, but really if you want the amp to handle more difficult loads, its better to sacrifice a bit of power so that when the speaker impedance dips down, there is in fact a bit of current available.

But Watts are Watts and a sound level pressure meter always shows wut up in that regard. When it sounds loud but the meter is saying its not all that loud, that tells you distortion is making it seem loud.

@ghdprentice The CDC is a totally lost cause. All of these silly studies are assumptions taken by people who hate loud music. Think about it. How do you do a study like that. Are you going to subject people to 95 dB for years to see what happens? How do you know what a person was exposed to, take a history? Do you carry a sound pressure level meter around with you all the time? These are the same people that told us pot makes you sterile and shoved a dangerous and ineffective vaccine down our throats. For 40 years I did comprehensive hearing tests on individuals from every walk of life as a family physician (Not a modern primary car provider) I followed them through decades. Not one of my musicians, who played electric music on stage had hearing loss beyond normal presbycusis. The ones that wound up with hearing aids either had a family history of hearing loss or were subject to a lot of impulse noise from machines and guns. My 72 year old dead head friend still hears fine and I still hear to 16 kHz at last check. I have been listening at 95 dB (when the music calls for it) as long as I can remember. My 95 dB is as measured, dBSPL , not dBFS. Remember dB is a relative scale.

@carlsbad2 I can understand your position. Most systems at 95 dB sound like sh-t. They hurt my ears. But, not because they are inherently bad systems. They are not tuned for louder levels. Mine is tuned for louder levels with the high end being rolled off. Our ears are much more sensitive to high frequencies as volume increases. If your system is balanced at 85 dB it will hurt at 95 dB Even my wife was vacuuming along to Poco at 95 dB yesterday. 95 dB is not that loud. Many concerts hit 105 dB, twice as loud. Now that makes my ears ring, in go the plugs. At the range I wear 30 dB attenuators made by Etymotic. We saw Mark Lettieri two weeks ago in a theater setting. I would estimate it was around 95 dB most of the time and the sound was wonderful. I did not see anyone wearing hearing protection. What 95 dB does is it gets people up and dancing. 85 dB does not.

@mijostyn +10

I think a lot of the resilience over time is genetics, if relatively harmful exposure did occur at some point. I still have the same ears as when i was a young adult (nothing has gone south apparently).

If we went by Agon standards, every musician i know should be deaf. Guys listening to Diana Krall @60db have no idea perhaps of the spl levels associated with live music. If Diana Krall sang a bit too loud in real life, they might just drop their blonde bombshell and run away back to their wives! 😁

I do have a fear of nearfield, headphones, in-ear monitors, etc (i don't use them), i.e., wondered if the fields produced in a smaller space around the ear causes more harm at even lower measured avg spl levels. It could be that spl levels are a lot more forgiving for the ear at more farfield distances, larger rooms, venues, etc.

I find my system completely satisfying at 70 - 80 or below. Additionally safety standards are guidance and I would prefer to be no where near the limits, they easily could be too high as well as low. I would not want to put my hearing in jeopardy. Also, standards virtually never go up they go down as more studies come in and more folks with compromised hearing are sampled. I love the way some folks see conspiracies everywhere. Common sense… a worthwhile thing to have. 

@ghdprentice Experience tells you what is acceptable and what is not. Ears ringing is never acceptable. That is natures way of warning you, you have gone to far. Most of us music lover, concert goer types have made the mistake of going to a concert without hearing protection that turned out to be too loud and our ears rang for a day or two. Peter Gabriel did that to me back in 1982. I have carried hearing protection with me ever since. That concert had to be in the 110 dB range. I am very use to 95 dB and will not tolerate much louder before the hearing protection goes in. You do not want to get close to ear ringing levels. Etymotic makes musician hearing protection plugs that are excellent once you get your ears use to them. They attenuate sound without changing the frequency balance. 

IMHO at 70 - 80 dB you can't even do string quartets justice and you are missing a lot of the joy in music. Get an SPL meter so you have a reference, they are not very expensive at all and $50 gets you a very serviceable one. If your system is balanced at 80 dB it will not be comfortable at 90 dB and this is the main reason people shy away from volume. The analog folks have no good way to deal with it, but with digital signal processing you can make a system balanced at any volume by adjusting bass and treble levels to mirror Fletcher Munson curves. 95 dB becomes perfectly comfortable for anyone not trying to hold a conversation. 

@mijostyn --

What’s the weighting used relative to your SPL-measurements? 

A question aimed at everyone, really, just to get a bearing. Many if not most may use A-weighting "default," but with B or C-weighting and substantially less LF-attenuation here the dB numbers will of course be somewhat higher. 

I find my system completely satisfying at 70 - 80 or below. Additionally safety standards are guidance and I would prefer to be no where near the limits, they easily could be too high as well as low. I would not want to put my hearing in jeopardy. Also, standards virtually never go up they go down as more studies come in and more folks with compromised hearing are sampled. I love the way some folks see conspiracies everywhere. Common sense… a worthwhile thing to have.

I was at a small venue with a small gig last night. I was consistently measuring 88 to 90db and it was quite enjoyable. Throw a drummer in there and all 60db Diana Krall fans would have gone deaf in a hurry. The 3 guys who are fairly advanced in age should all be totally deaf too by now. It in indeed a "conspiracy" (facepalm).