For tube amps: how often do you switch triode to ultralinear?

I know that some amps can do this. I have tested it out and it doesn't seem to be a huge difference. Do you prefer one over the other or even switch between modes (if your amp allows)?

 

Depending on the circuit in question, it's could be a big difference in available output power and in the output impedance of the amp, so depending on the speakers you're using -- their efficiency and their impedance curve -- the audible difference driving the load can be more or less considerable.

 

Wondering if that should be a deciding factor in picking an amp (whether it can swap triode/ ultralinear)

 

I rarely ever change mine (in a Rogue Stereo 100) as a I found a while back I preferred triode mode overall. There's just more depth there that suits my ears. Try listening for days at a time with triode vs ultralinear to find your preference. A immediate difference in sound may not be obvious. I've tried switching back to ultralinear and don't like it, I'll switch back to triode. I suppose I've just gotten used to that triode sound! Also, vs my previous speakers, the Legacy Signature SE I have are more revealing of the differences between triode and ultralinear. It all depends. That said, I don't think a switch between the two modes should be a deciding factor on purchasing an amp.

 

Speakers play an important roll but also the way you decide to voice your amp with tube rolling.

I have a PrimaLuna Dialogue Integrated, and after "playing¨ with the UL/TR switch for a while, I decided to voice my amp so it would sound the way I like just in UL, and now it´s been more than 1,5 years since I last listened in TR mode. It´s just that when I switch, power decreases, soundstage decreases and dinamic range decreases as well, so, it´s a very easy choice to me.

I think I could voice it to sound better in TR, but of course I would still have less power, less dinamic range and a smaller soundstage. IMHO, it´s not that mids are better in TR, it´s that all the rest is worse, so it looks as if mids were better. Still, I´ve read from lots of people with an amp like mine, and much more better equipment that claim TR sounds better than UL.

 

Depends on what speakers you're going to be using. If the triode mode of whatever amp you're using is going to be like a 15 watt amp with a 1 or 1+ ohm output impedance, and you're going to try to use that to drive some nominal 4 ohm speakers that dip to 3 ohms or less in the low and low mid frequencies with a -30 or more degree phase angle, I don't think the triode mode will be very useful for you at all.

 

Of the speakers that I have heard so far, Vandersteen Treo CF top the list. Just to pick a number, I would prefer to stay at 75 watts or higher

 

If they have measurements like these -- Vandersteen Audio Treo loudspeaker Measurements -- they're very low efficiency but the impedance curve looks pretty darn friendly for a tube amp. Recommendation from the manufacturer is for minimum 40 watts, I'd look for something that delivers at least that in triode mode. I do scratch my head at the Primalunas with the UL vs. triode switching in that even in UL mode some at least seem to have really high output impedances -- like 5 or 8 ohms in UL, 4 ohms in triode. I'm not sure I'd want an amp with those kinds of impedances unless I was driving a speaker with a perfectly flat impedance, which is, like none. But that's all in the abstract. Still, I'd pick the amp based on the speaker you like and the best amp to drive it, or the amp you like and the best load for the amp more than based on features like a triode mode switch on a UL amp.

 

My Primaluna has both modes. Triode is quieter and maybe a little smoother. But in my room I need the power, so I go 100% UL with total satisfaction.

 

Thank you. and definitely speakers 1st. I could go tube pre and ss amp. Best of both worlds.... van alstine, rogue, etc...after deciding on speakers, but that gets into the other thread topic

 

when i had my last tube amp ultralinear was by far the default mode and i never used triode mode. in triode the power decrease was significant and the benefits were not noticeable.
triode might be of value with super high efficiency speakers e.g. high 90s and up where an ultra refined sound is required to reduce the issues of driving HE speakers with high power.
IMO the switch makes the amp flexible for different speakers but needs to be set according to the speakers you have or target.
in the case of the mentioned vandersterns the triode mode will most likely be useless.

 

My amp can be wired for either UL (stock) or triode, and uses different tubes for each, so not an easy switchover. I have two amps, one wired each way, and I much prefer running the triode amp with EL34 tubes versus UL with 6550, or the big KT120, even though I lose half the power, just sounds more natural. Eventually I'll sell the stock UL amp.

 

That would be the deciding factor for me—meaning, I think I’d avoid any amplifier that offered this feature. Unless we’re overlooking a pentode/tetrode whose optimal triode and UL operating points overlap? Otherwise, the concern is that one or the other of the operating modes is significantly challenged—or that maybe both modes are somewhat compromised.

Seems like a good amplifier is hard enough to design and execute. Not sure why we’d set the additional goal of building two amplifiers into one—especially when it ought to be a relatively straightforward decision between them. (I think the consensus advice would probably be, “triode if you’re able.”)

Don’t mean to stir up controversy or knock anyone’s amplifier choice. Just wanted to weigh in with the idea that this switching option might not be as penalty-free as it appears.

Good luck with the decision, @Glfrancis2

 

I have the Primaluna evo 400 integrated.
Utra Linear audibly has more top and bottom end extension than triode mode. Much better overall grip on the speakers.

 

I use mine strictly in Triode mode. The only difference to me is that Ultalinear is just louder/more power.

 

If ultralinear is set up properly (IOW the taps on the output transformer are set up properly) you should hear no difference other than power since the linearity will be the same.

The thing is, there's a bit of confusion about how ultralinear output transformers are to be designed. This is because there was a patent that created the concept and then everyone worked around the patent by placing the taps in a slightly different spot on the transformer which cause the result to be slightly less linear. Nowadays that patent is long expired but most transformer manufacturers still put the taps in the wrong place!

 

Crazy question then, who does it properly?

 

It's a crazy question by virtue of the word "properly" in an audio forum, regardless of topic.

Cheers,
Robert

 

Good question.
The patent of greatest interest was given to David Hafler who was with Acro at the time (later became Acrosound), a manufacturer of output transformers. The patent states that the correct position of the tap will depend on the tube type; for example a 6L6 does best with about 18% where a 6V6 is better with 5%.

I'd simply ask the manufacturer of the amp how they set up the taps. I've seen a lot of taps at 42%; this for amps using EL34s (similar to KT66). If Mr. Hafler is correct then 42% probably isn't.

 

Primaluna owner. On my system, triode usually sounds better with acoustic, folk or vocal centric music. Everything else sounds better with UL.

 

In the last 20 years, maybe twice, not really my flavor.

 

I used to greatly prefer triode mode through my Cary SLI-80HS into a pair of Forte III's. Although my current Leben CS-300xs exceedingly outperforms the Cary....at least to my ears.

 

Just discovered an amp (if I can handle the tube biasing). Should pair perfectly with the rogue rp7 that I dream about. rogue zues. 225 watts of tube power and does both triode and ultralinear

 

Once.

 

The power rating of a tube amp says so little (if anything) about amp/speaker synergy.