End of my tether

Not well matched in the sense that the speakers are unusually 16ohm and highly efficient i.e. >100. To date I’ve interpreted that as only being an issue in the sense that the volume goes loud at 9 o clock onwards. I’ve had no sense the 202/200 have been struggling.

At present I’ve iPeng volume at near 100% and the 202 goes loud after mm of movement. That inclines me to drop the volume within iPeng to give me more travel on the 202 volume.

Forgive my ignorance on this but my assumption is that moving the DAC into high gain mode would then require me to lower the volume further in iPeng to obtain similar travel on the 202 volume?

I’m also assuming that resistors across my speaker connections could also assist?

I am not sure the efficiency tells you that much, other than average sound pressure per electrical power… it tells you not a lot about control. Amp power in Hi-Fi is probably more about control rather than pure sound pressure… if you were designing a PA system you might have different considerations.

16 ohms average impedance sounds quite high… remember with a power amp high impedances can be as hard as low impedances to drive… what you win on current you loose on voltage.
Also what is the impedance curve… that is the key thing to look at… at the frequencies you think are hot or lacking, is there an impedance resonance of some sort… remember nearly all speakers will have a variable impedance, and speakers with cross overs and reflex ports will have resonances of high and low impedances… it is these resonances that can make a speaker difficult to drive… not its efficiency.
All part of the considerations, but 16 ohms does sound high to me for speakers for a modern / direct coupled power amp.
Any way good luck, but in my opinion your amp should be able to drive your speakers at low levels with a full bodies and clear sound… as in normal dynamic programme material at regular volume there will be low levels with texture and tonality that should be accurately portrayed.

1 Like

I’ve no idea on the curve Simon. I’m aware 16ohm is high. My assumption is therefore that I’m not underpowered. These were designed to be driven by a low powered valve amp. Would I be in the ball park thinking about resistors to alter what the amp is presenting to the speakers?

Yes that would explain it… probably with an output transformer…
For a transistor/direct driven amp 16 ohms could lead to being underpowered, unless your amp has high voltage rails. High voltage rails are often used for more powerful amps…

Unfortunately adding resistors (in parallel) is unlikely to help … as we are dealing with impedances, and adding resistors may well affect how the cross over works.

You might want to look for a amp with high voltage lines.

My amp is the 202. I lack the technical knowledge to say what it has. I suppose the question is whether any harm can be done by high gain mode?

Putting your DAC into a high gain mode is unlikely to damage anything, as long as you are mindful of overall levels to power amp. Your NAC (202) can handle a wide range of input voltages before clipping,
It is unlikely to improve the situation though, if you are suffering with tonal accuracy on low level material… ie if you matched for low level, then high level would be too hot and artificial.

Noted. Thank you. Not really suffering on tonal accuracy so much as needing to crank it up to get the real deal.

Thoughts on resistors?

As said above … no not recommended at all and I can’t see how it would help… you want to keep the link between power amp and speakers and clean as possible.
If the limiting factor is lack of amp voltage… then I can’t see how resistors can possibly help… your component would need to be an inductor in series, or capacitor in parallel, to attenuate Hf, but that would potentially interfere with the amp output impedance and speaker cross over, and could make your amplifier unstable.

I would looking at better matching amp and speaker and that sounds like that means changing one or the other unfortunately.

Thanks again Simon. The advice is much appreciated. My inclination is to stay as I am at present and enjoy what is, at higher volumes, simply fantastic. Longer term it makes more sense to me to retain the amp and move to speakers of 4 to 12ohm.

Sounds a plan… as long as you are happy with it for the majority of time.

Yes. Was the tether lengthened, eventually? I kind of lost track…

2 Likes

Certainly am. It would be nice to have more presence/mids at low volume but I’m not going to stress about it when there’s a Christmas tree at one end of the living room likely screwing with the sound anyway until January.

Also, with two new boxes in the system I think that realistically I will need to (re)explore speaker positioning. Once that’s all been addressed I can think about what I want. I don’t see me moving to valve amps as a solution as they simply don’t do it for me. So, possibly a speaker change at some point.

In the meantime, back to ripping boxed sets and keeping an eye on my first backup.

1 Like

image
Pinched from Stereophile.

This is from the zuaudio website, and is illustrating the method of using Loading Resistors to match the speaker impedance to better match the load as seen by the amplifier in cases where the amplifier seems to want a better matching. There is a blog post that describs the issue:

This may be what Mike is refering to when he asks about matching resistors.

I have high impedance Rogers LS3/5a which are the 15 ohm versions, and the Rogers BBC Studio monitors (which were 25 ohm) have various taps on a transformer that change the impedance. At the time they were made high impedance speaker (16ohm) was common.

Just to help, not wishing to start anything…

Thank you for all the above @Yeti and @fergch. I’m not clear how I should be reading any of that. Is the suggestion that loading resistors could in fact help? If so, how do I deduce which ones?

From some elsewhere forums, people say that the only suitable amps for Zu speakers would be class A amps, like Nelson Pass. Apart of course tube amps.

Omen appears designed for solid state but right now I’d rather focus on whether I’ve options to improve the current mismatch/lack of warmth.

Hi @trickydickie, hope you are well, good Christmas was had etc? Hope youve been getting some time to enjoy some music too…

Quick question to this - can you give me an example of an album in Qobuz or in MusicBrainz where the CD booklets are available please?

Ive looked at several examples of albums that Ive either purchased direct from Qobuz as a download, or ones that I havent (Qobuz or in MusicBrainz), and I cant for the life of me find where I would be able to download the booklet.

Maybe Im being thick, or maybe Im just unlucky with the albums Im checking out!

ps. apologies for the thread drift @mikehughescq, hope this is OK

1 Like

Yes, all good here thanks, hope all is well with you too!

The example I posted above is Stacey Kent, Tenderly

Also, Silje Nergarrds album of the same name, Agnes Obel, Aventine (Bonus Track Edition).

On Musicbrainz try Melody Gardot, The Absence. The one with catalogue number 2792657.

1 Like

Unless I missed some posts, are you not using a TT2 as your DAC now Mike? To me your speakers are the perfect candidate to be driven directly off the TT2. I have driven Dynaudio excite 12’s off my TT2 with excellent results. Toonartist drove his PMC speakers directly off his TT2 for quite a while also, and neither one of these speakers are anywhere near as efficient as yours. Have you considered this route?

2 Likes