[Edward4]

Hi everyone. So I was listening to my sound system a few weeks ago, and I realized it sounds absolutely awful! lol. After improving a few things, like dirty records and improperly shielded cables, haha, it dawned on my that, at this point the weakest link is my speakers. They sound pretty good for bargain basement speakers if I listen to solo instruments, but they sound very muddy and have very little clarity for complex music, meaning: many instruments happening at once. (And they have relatively little bass, but I'm hoping to get a REL sub delivered today.)

My first thought was, okay, I just need to get some better speakers - these are $200 Polk Tsi200 bookshelf speakers btw. Then I remembered the "sensitivity" doctrine, which states that one of the main things you need to do for a low-power amp is look for higher-sensitivity speakers, so there's enough volume.

Impedance graph: But then I found people online saying, based on their own direct, personal experience, that sensitivity really does not matter very much with a tube amp, and that what really matters is the IMPEDANCE graph, over all the frequencies, and that the impedance not dip down too low anywhere. So what they recommend is first: mostly ignore the "sensitivity" rating, and then secondly, totally ignore the alleged "nominal impedance" and focus instead on the "minimum impedance", or the lowest level that it dips down, and if you must use a tube amp or a SET tube amp, rule out anything where the impedance dips down to 2 or 3 or 4 ohms, and ideally look for something several clicks higher. Here is a useful article I found about this from a website called DHT Rob.

So on this basis, the Encore might be one of the better speakers offered by GR Research for someone worried about impedance dips, because it looks like it dips down to 7.5 Ohms at the lowest. Does that sound right?

However, this is all theory. What I also greatly value is testimony from people's direct, first-hand experience. Can anyone comment on using a tube amp (or a SET tube amp) with Encore speakers?

A bit more about my setup. I'm new to sound systems, right? I got this GemTune X-1 amp a few years ago. It has a total of four tubes, including two EL34-type tubes, and it has 4 and 8 ohm speaker taps, and it weighs about 18 pounds. I think it's called a SET amp, which I believe is more fussy than other types of tube amp, in terms of speaker matching requirements. It allegedly puts out 8-10 watts per channel, but again, some people online say the low wattage isn't necessarily a problem if you have high-impedance speakers. It sounds absolutely HEAVENLY with a classical guitar solo or violin solo. But with many, many instruments playing at once, a big orchestra or rock music, it just gives up and smears everything. It does help, however, when I switch from the 8-ohm to the 4-ohm speaker taps on the amp, but then the overall volume decreases.

Some people even go so far as to suggest that an ideal speaker for a solid-state amp cannot really be excellent for a SET tube amp, and vice versa. I don't know enough about such things to know if that's true. It's possible that as I learn more about home sound systems, I will decide that I have to get a second, solid-state amp, and not rely solely on a SET tube amp for all kinds of music. But I hope I don't have to do that.

I love the way Danny explains things in his videos, and I'm excited about the possibility of getting one of his speaker pairs. Just want to make sure I know what I'm doing.

Anyway... any tube amp users out there, using Encore speakers? How does it work for you? What have you observed, and what do you recommend? Thank you for your time.

[VinceT]

I used a 40 watt push pull tube amp for a while. I liked my higher wattage 75-150 solid state better with my Encores. Then again my listening area is pretty big so I need more power.

You can play them with lower wattage amps, but to my understanding that works better in smaller rooms or more nearfield. So I guess it depends on your application.

[corndog71]

I have driven a pair of X-LS with a pair of 18 watt tube amps…
https://youtu.be/bJa_9mDHcWc

and a pair of 140 watt tube amps…
https://youtu.be/teZk3cf6lxs

They sound great with both. 

I’ve also driven them with A/V receivers and higher end electronics. 

That’s kind of the beauty of Danny’s designs.  The X-series will pretty much work with anything.  And the better the electronics, the better they will sound.

With an 8 watt tube amp you’re pretty much limited to near-field or desktop listening.  You might be able to fill a small room with music but you’re going to hit the limit of those 8 watts pretty quickly if you try to crank it.  I would suggest either finding more efficient speakers or getting a more powerful amp.

Do your homework before buying.  Tube amps are great and fun but they also come with several caveats.  If possible, see if you can try it before you buy it.  They can also be a lot of trouble.  Tubes do die eventually and need to be replaced. 

[Edward4]

Thanks for the comments everyone, and for the video links corndog71.

I just found again in my notes, a comment I found online a week or two ago, whereby someone claimed to get "plenty" of volume (and presumably no tube-distortion) with 83db sensitivity speakers that had a 7.5 ohm minimum impedance. In other words, implying that impedance is important for tube amps. The Encores are rated at 87db and seem to have about 7.5 ohm minimum impedance, so I'm guessing they might work well.

In other news, I tried listening to my current speakers again. Wow, they really make the cymbals on a jazz album sound like they were put into a blender. lol. It's just mush. It reminded me of Danny Ritchie's video where he describes what 50-cent capacitors do to a signal that is fed through them.

[fre11111]

I did with no success. I used a Cayin integrated and also with a Primaluna. I still like my Solidstate better overall. Dont get me wrong, they sound good with all of them.

Frederick

[fre11111]

.

[EdwardT]

I used a Decware 6watt SE34I to power my first set of Encores and it sounded great but the 6 watts ended up being too little output power for our room. Now I use a Decware CSP3 tube pre and a couple of Schiit Vidar mono blocks to drive our Encore towers and the end result is quite pleasing.

[mlundy57]

I've used a number of different ones from a 5wpc OddWatt PodWatt to a 70wpc Jolida 801A. The PodWatt, while fine with the Wedgies, didn't cut it with the Encores. My favoriate tube amp paring was with a 30wpc PrimaLuna Prologue 4. Though not with the stock tubes. With the stock tubes, the amp lacked detail and resolution to the point of being mediocre. After doing some research and following a suggestion from the person I got the amp from, I replaced the stock tubes with ones that provided the sound signature I was looking for. Result, all the tube goodness plus detail, resolution,  and imaging.

Point being an under powered tube amp is going to struggle with the Encores. However, while anything with 15-20 watts or more will have enough power, it may or may not give you the sound you are looking for. While it could be a design issue with the tube amp, it could just be tube selection.

[planet10]

Impedance graph: But then I found people online saying, based on their own direct, personal experience, that sensitivity really does not matter very much with a tube amp, and that what really matters is the IMPEDANCE graph, over all the frequencies, and that the impedance not dip down too low anywhere.

My first question is: What tube amplifier?

If the amplifier has high output impedance (ie most SE amplifiers, some PP), then the shape of the impedance curve will be added to some extent to the net response. Do note that given OPTs are tapped for nominal impedances, flat impedance is also helpful.

Low impedances needcurrent delivery, harder to do with a tube amp, so higher impedances don’t hurt.

the Encore might be one of the better speakers offered by GR Research for someone worried about impedance dips[/img]

From Danny’s site.



If your tube amlifier has a high R_out then you will hear that big bump at the XO.

Some people even go so far as to suggest that an ideal speaker for a solid-state amp cannot really be excellent for a SET tube amp, and vice versa.

Depends. On the amps and on the speakers. And a bunch of other stuff.

dave

[Hobbsmeerkat]

This is the actual impedance of the X-LS


I've updated the page to show the correct impedance graph.

The one in the previous post is the impedance of the X-CS.

[planet10]

The 30Ω 1kHz bump is still there, but now with a reflex impdance at the bottom and not as much rise. Means bass should be less problematic.

(in the case of a high R_out amplifier.

dave

[Edward4]

Planet10: The amp I'm using now is called a GemTune X-1. I got it about six years ago for about $260. It has two EL34-type tubes, which I upgraded to JJ brand E34L. The amp supposedly puts out 8 watts per channel; I am not sure what the output impedance is as I can't find my manual for it (if it even came with one! ha). It sounds surprisingly good with acoustic music, to my inexperienced ears anyway. It seems to have plenty of volume 99% of the time with my current cheap Polk TSi200 two-way speakers (rated at 89db sensitivity, and unknown impedance curve) - last time I played a record I turned the volume up to about 11-o'clock and that was plenty loud. I am using the 4-ohm output taps, instead of the 8-ohm taps, which I think lowered the volume, but also lowered the distortion issues. There DOES seem to be distortion sometimes with recordings that have bigger sound, more instruments playing at once. I assume it's because this draws too much current on the tubes.

Here's a comment from one person who allegedly bought this same model of amp: "I am driving NHT VT 2.4 towers. They have 88dB and 6 ohms impedance. They drive them very nicely, fill the room completely. The sound gets loud to the point of annoying neighbours. Personally, I cannot listen to music louder than this. However, if you are the kind of person that wants the music VERY loud, you should try a solid state amplifier with more power..."

I'd be open to upgrading this amp at some point. I do like the tube amp sound with acoustic music.

Ideally I would also like, someday, to figure out how to have a proper, high-quality, high-pass inline filter for the main speakers, since I just got a REL subwoofer. I'm thinking that if the bookshelf speakers are trying to play below 100 or 200Hz, maybe that's wasted electrical current that the amp would rather not spend. I believe this is what Danny Richie said recently in another thread. I guess tube amps simply don't have a lot of current to spend, so things like in-line filters and minimum-impedance speakers both can help to conserve the current, perhaps.

So the crossover is where the impedance curve tends to dip down?

Are the impedance curve spikes an issue for tube amps, or just the dips? Some people online say that SET tube amps want to see flat-impedance-curve speakers. Other people say they just want to see minimum-impedance speakers, meaning, ones with no big dips. I'm totally new to all this, so just learning.

[planet10]

I call those inexpensie amps “pre=built kits”. They sceam out for modification as soon as you get them, and way more than tube swap.

It is SE, typical power is about 5-6 watts in Pentode (maybe UL), output impedance will be high, how high depends on how much feedback they use to lower it. Without feedback an SE pentode is a current amplifier.

Where the volume contril sits is more about how much gain there is in the system, and almost nothign to do with how much power you are using up.

If the Encore is 87 dB, you will run out of juice about 97 dB, at most typical listening levels found in the home it is likely sufficient, but it will clip if you crank it.

dave

[Edward4]

I call those inexpensie amps “pre=built kits”. They sceam out for modification as soon as you get them, and way more than tube swap.

Hi Dave, so just out of curiosity, what would you consider modifying first if you acquired a cheap SET amp? Or what would you look for in a high-end SET amp? Which shortcoming screams out at you the loudest, so to speak?

I heard a rumor recently that the transformers in a SET amp tend to be one of the device's limiting factors in being able to delivery good sound (especially when there's a lot happening at once in the recording), and this person said he would like a SET amp which weighed at least 90 pounds, because the transformers have the potential to be more stable in that case. Wow.

[planet10]

The OPT is very important.

But you will have to live with them.

Many have circuits pinched from old US stuff and could be better. you have to know some circuit design, or get help from someone who doe (i lean on those guys even knowing a bit myself). Often there are extra connections that can go… ie on one the volume pot was mounted on a PCB and then 2 connectrs to where it fit in the circuit, direct wiring with solde rimproves things. But the biggest thing is that given it is a cheap mp it uses cheap parts.

You have chassis, iron, tube sockets. Everything else can be considered a playground.

dave

 

[Tyson]

I find that speakers with moderate sensitivity and box based designs do well with push pull amps vs. SET amps.

[planet10]

Tyson, that seems a generalization far off the mark.

dave

[Early B.]

OP -- don't overthink it. SET amps aren't designed to power low or moderate sensitivity speakers. Get rid of that cheap tube amp and buy a more robust amp. The next step will be to replace the Polk speakers with one of Danny's models.