Do you have an alternative speaker pair and / or amp build you’d recommend? A quick google search, it looks like Klipsch 600m have pretty great reviews, 96db sensitivity, and sell for around $599 new.
For an amp I recommend you get a board from George (tubelab) for the SSE. It rocks. I built it with EL34, but there are many options. KT88 seems popular. Contact/order through tubelab.com. There is a dedicated forum here at DIYaudio if you look under vendor/tubelab. As for speakers, I always built my own so I'm not familiar with any current commercial offerings. There are many ways to skin that cat.
For a tube amp to handle low frequencies you need big and expensive output transformers. If you consider using a solid-state sub woofer a lot of the strain is taken off the system. That also makes the fullrange speaker option much more appealing IMHO.
For a tube amp to handle low frequencies you need big and expensive output transformers. If you consider using a solid-state sub woofer a lot of the strain is taken off the system. That also makes the fullrange speaker option much more appealing IMHO.
@fidel1890 just buy the kef ls50 they sound Great. I have them in my home theater setup( 5 pieces and subwoofer) drive them with class D amp because these sound good and are cheaper then tube amps. My listen setup is dynaudio 86db speakers with 20watt se tube amp in 50m2 room. It plays loud and good.
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@fidel1890 just my 2 cents , build a gremlin class D amp with linear power supply and put it in a case with glowing tubes on it.🙂
Then you never spend more money on a amp and concentrate on sources and speakers.
Do you have a class D amp kit / plans that you’d recommend?
Thanks
No that's the FR within +/-3 dB. It is not the cut off. In fact the -3 dB point is somewhere around 55 Hz. However they are only 83 dB/1W/1m being basically a 5 ohm loudspeaker. In pairing with tube amps one should take this into account in order to pick the right output transformer and get the desired primary load. A short-cut might be to use the 4 ohm secondary if the OT has got one but will get a bit less power than expected.
A 25-50 W amp is enough for these to play really loud. EL34's or some 18-19W sweep pentode in push-pull would do the job rather easily. Otherwise 15-20 W are already good for most occasions.
Here is one example of LS50 with 50W EL34 amp:
YouTube
That's a rather classic pentode circuit by Hiraga and relatively easy to build. Needs good quality output transformers. Can also be found in the used marked for about 1500-2000 euros....in immaculate conditions of course.
Not according to the datasheet... http://www2.kef.com/uploads/files/en/LS50/LS50_brochure_EN_preview_230412.pdf
It says +-3db 79Hz - 28kHz, -6db 47Hz - 45kHz, 85db 2.83V/1m.
I know a lot of people say these are amazing speakers, but on paper they look like rubbish without a subwoofer IMHO.
Then again, I use Energy RC-70 which is a much larger, more efficient design with far better frequency response... 31Hz-23 kHz +/-3dB, 95db 1W/1m in room, 92db anechoic...
Energy Reference Connoisseur RC-70 Surround Speaker System Specifications | Sound & Vision
It says +-3db 79Hz - 28kHz, -6db 47Hz - 45kHz, 85db 2.83V/1m.
I know a lot of people say these are amazing speakers, but on paper they look like rubbish without a subwoofer IMHO.
Then again, I use Energy RC-70 which is a much larger, more efficient design with far better frequency response... 31Hz-23 kHz +/-3dB, 95db 1W/1m in room, 92db anechoic...
Energy Reference Connoisseur RC-70 Surround Speaker System Specifications | Sound & Vision
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The datasheet says frequency response +/- 3 db which does NOT mean the -3 dB is at 79 Hz. It a different definition where +/- 3 dB is the max variation of FR across the full frequency range.
On top of that because it rolls off as a 3rd order in the best case (in reality more like a 4th order) if 79 Hz were at -3 dB it would be very unlikely that 47 Hz were at -6 dB. That doesn't happen even with the 2nd order roll off of a typical closed box!
If you can find some review where they take measurements I am sure you will see that FR rolls off around 55 Hz.
85 dB is the sensitivity which is referred to 8R. Because the speaker is effectively 5 R on average then the efficiency is about 2 dB less. Sensitivity doesn't make much sense with constant or nearly constant power sources like tube amps.
I really doubt your large floor stander can compete for imaging and definition with the little KEF. It's a matter of what one is looking for. Building a properly good 40-50W EL34 amp is not difficult or too expensive....
On top of that because it rolls off as a 3rd order in the best case (in reality more like a 4th order) if 79 Hz were at -3 dB it would be very unlikely that 47 Hz were at -6 dB. That doesn't happen even with the 2nd order roll off of a typical closed box!
If you can find some review where they take measurements I am sure you will see that FR rolls off around 55 Hz.
85 dB is the sensitivity which is referred to 8R. Because the speaker is effectively 5 R on average then the efficiency is about 2 dB less. Sensitivity doesn't make much sense with constant or nearly constant power sources like tube amps.
I really doubt your large floor stander can compete for imaging and definition with the little KEF. It's a matter of what one is looking for. Building a properly good 40-50W EL34 amp is not difficult or too expensive....
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Fair points... Still, I've never seen a speaker where the lowest frequency quoted wasn't the -3db point.
Why would they lie on their own datasheet?
If only I had a pair to hear... It would be interesting to hear a full range system without a +8" speaker with a wheezer cone that still had bass...
Why would they lie on their own datasheet?
If only I had a pair to hear... It would be interesting to hear a full range system without a +8" speaker with a wheezer cone that still had bass...
They give the lower useful frequency as -6 dB which is 47Hz. They have quite some bass for such tiny size. What they can't do is play at concert levels of course. It's a great monitor. No question about it.
I use wondom aa-ab32313 amp pcb WONDOM AA-AB32313 Amplifier Board T-AMP Class D 2 x 400 Watts 3 Ohms 48V - Audiophonics
You can also buy in china at sure electronics. With simple 500va toroid linear supply(33v), just rectifyer and 50000uf filtering caps. And chinese remote 6 channel controll. There is also 2 channel passive remote volume and 4 input controll.
But we are in the tube section, about aa-ab32313 you can read a lot in the class-d section.
I have also 100 Watt SE tube amp building cost are € 1200 a channel. And it uses 500watt/houre.
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It's not strange. When trying to achieve a response until 30Hz with 6.5" drivers that also have to be efficient this is quite typical. The Fs of your woofers is more likely in the region of 45 Hz otherwise they would not be so efficient with reasonable parameters for reflex enclosure. The reflex is tuned very low but it is also becomes quickly inefficient as you move from the F3. There is no free lunch.
Anyway when I read that a speaker like the RC-70 is defined as 8R with 4R minimum impedance then the actual efficiency for the tube amp user is typically 2-3 dB less than the rated sensitivity. It's a rule of thumb but generally works and if it's wrong the better!
A nice full range loudspeaker with good efficiency around 89 dB/1W/1m, smooth impedance, very good imaging, dynamics and deep bass is the highly overlooked Vandersteen 1Ci. A loudspeaker that has been around in its various versions for some 20-30 years has surely something good....and the latest version is best!😉
Very interesting speaker.
I've designed the amplifiers that drive the RC70s for an Ra-a of 650R to 1300R or so. Don't try these impedance ratios with audio tubes 🙂 but triode connected sweep tubes are excellent into such a low load due to their high peak current capability from my experiences. I get almost ~180W into the 650Ra-a set up with 320V B+.
I've designed the amplifiers that drive the RC70s for an Ra-a of 650R to 1300R or so. Don't try these impedance ratios with audio tubes 🙂 but triode connected sweep tubes are excellent into such a low load due to their high peak current capability from my experiences. I get almost ~180W into the 650Ra-a set up with 320V B+.
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The +/- 2 ohms in the impedance specifications is mostly due to the possibility of changing the tweeter emission from +1 db to -2 dB respect to the factory flat response. Otherwise in the woofer range impedance is between 6.5 and 9 ohm, except for the two peaks resulting from the woofer resonance and the transmission line tuning (the lowe one is actually quite modest). The TL alignment is very close to the sealed box roll-off.
I have done something similar with the 6C33C. They can deliver 85W class AB1 into 750R pl-pl with just 250V anode voltage. Peak current at the primary is just under 1A! 😀
Why use the sweep pentode in triode when you get full efficiency with pentode + local feedback? They usually have good gm and sensitivity and thus respond very well to cathode feedback, Schade etc...
In my living room I get away with about 1 watt but with a large speaker. 10 watts is only twice as loud as 1 watt as ear is logarithmic.
I think it was Babani used to do a book on high power valve amplifiers. Some were as high as 10,000 watts !
To my ears 3 dB difference is small but surely audible even at louder volumes. 10 dB is quite a lot of difference!
Logarithmic or not if I have 10W amp with 87 dB/1W/1m speakers to achieve the same or similar result with 1W I need 97 dB/1W/1m speakers. The difference in cost, convenience and compromises is MASSIVE. Easier and cheaper to make a more powerful amp. Up to 50W there are no real problems for sure.
Logarithmic or not if I have 10W amp with 87 dB/1W/1m speakers to achieve the same or similar result with 1W I need 97 dB/1W/1m speakers. The difference in cost, convenience and compromises is MASSIVE. Easier and cheaper to make a more powerful amp. Up to 50W there are no real problems for sure.
I respectfully disagree. In my opinion, the cheapest way to go (best value) is to:
1) build a modest sized amp (say around 10W) using relatively inexpensive transformers
2) have satellite speakers with full range drivers that are fairly efficient (Fostex for instance), no filter parts except an optional zobel to flatten impedance.
3) A solid-state subwoofer for LF to take that requirement off the tube amp
1) build a modest sized amp (say around 10W) using relatively inexpensive transformers
2) have satellite speakers with full range drivers that are fairly efficient (Fostex for instance), no filter parts except an optional zobel to flatten impedance.
3) A solid-state subwoofer for LF to take that requirement off the tube amp
Sub-woofer(s) is (are) good for HT. No thanks. 🙂
One can build a simple TABAQ with a good 4" full-range and get the FR flat down to 50-55 Hz with efficiency around 86-87 dB. Then 10 W will be enough for most cases....and anyway that's a more or less as much as a small driver can take at low frequency without running out of displacement. No zobels, no equalizations, no random positioning.
A classic 2-way sealed box with 8" woofer + tw in the same fashion as the old good Snell K can be even bit more efficient. Better if the tw allows no compromise x-over at or below 2 KHz. There are plenty nowadays without spending a fortune or it can be achieved using a suitable wave-guide which also allows time alignment! In the end it's more about effort, patience and time in building something really good than money.
P.S.
Last but not least one can build an unconventional 2-way with 7-8" woofer + 3.5-4" full range crossed-over around 500-600 Hz. with right drives it might even allow simple 1st order x-over....so to speak....
One can build a simple TABAQ with a good 4" full-range and get the FR flat down to 50-55 Hz with efficiency around 86-87 dB. Then 10 W will be enough for most cases....and anyway that's a more or less as much as a small driver can take at low frequency without running out of displacement. No zobels, no equalizations, no random positioning.
A classic 2-way sealed box with 8" woofer + tw in the same fashion as the old good Snell K can be even bit more efficient. Better if the tw allows no compromise x-over at or below 2 KHz. There are plenty nowadays without spending a fortune or it can be achieved using a suitable wave-guide which also allows time alignment! In the end it's more about effort, patience and time in building something really good than money.
P.S.
Last but not least one can build an unconventional 2-way with 7-8" woofer + 3.5-4" full range crossed-over around 500-600 Hz. with right drives it might even allow simple 1st order x-over....so to speak....
I prefer triode. They work better with toroidal PTs as OPTs, they have lower distortion, and the design is simpler.
In my monoblocs which are PPP, I get over 130W of power at max output, the peak current is "only" 450mA or so per tube, and there is almost 20W of class A before class B takes over. 🙂
I've never heard a single subwoofer setup that sounded as clean as a pair of good speakers. I do have a pair of 12" subs in the trunk of my car. I rarely turn them on anymore though.
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