Solo ULDE

Totally agree with you Bob...my little used LCD 3's may well be up for sale in the not too distant if you are interested

Speaking about headphone preferences, I have found that my 'cheap' little Grado SR325e sound quite well-behaved - quite wonderful with some kinds of music, actually - combined with the Solo ULDE. Makes me like it again a lot more, where first I had issues with its inclination towards trebble harshness (to my ears).

Edited by Fuzzy - 08 Dec 2016 at 10:45pm

Fuzzy wrote: Speaking about headphone preferences, I have found that my 'cheap' little Grado SR325e sound quite well-behaved - quite wonderful with some kinds of music, actually - combined with the Solo ULDE. Makes me like it again a lot more, where first I had issues with its inclination towards trebble harshness (to my ears).

"...where first I had issues with its inclination towards trebble harshness (to my ears)."

I've always been cautious about saying anything untoward about the sound of "worshipful" headphones, because there are places on the 'net that will troll you for it...

...but, having found this with some headphones even after considerable "burn-in" had caused me to explore ways in which such harshness could be controlled.

I had an idea that the driving impedance could have some influence, but "the forums" could only hark on about the impedance having to be zero (zero is impossible so perhaps they meant virtually zero?)

However, some headphones simply don't sound good with zero driving (source) impedance. Some are made to DIN standard (have a guess...) and the driving impedance is stated as 120 Ohms in the standards.

Quite a few won't behave using 120 Ohms. And so as a designer trying to cover all bases life gets difficult/interesting.

You start asking questions like "I wonder if they designed their headphones with one particular headphone amplifier?" and "what amp was it?"

And more recently this chap answered in a roundabout way my questions when talking about speaker box design: https://www.youtube.com/watch?v=1eD0VUb5BFo (thanks for the pointer Stefan)

The behaviour of speakers is dependent to a degree on driving impedance also known as damping factor, and not all speakers are designed for high damping factors and yet some are. Some are designed to do well with valve amps which have little damping and some are designed to do well with DC coupled solid state amps with tons of damping.

I guess it depends on the speaker designer's amp of choice.

And so it might well be the same with headphones???

Grado sold headphone amps too. It doesn't take a massive stretch of the imagination to conclude their headphones could have been developed with one of them.

That headphone amp has driving impedance, it is not zero, but looks that way to the forum type commentator because he cannot see a resistor. Its opamp contains one however, plus it also contains intrinsic resistance.

The ULDE took into consideration this resistance (impedance in AC terms), which also tended to bode well with quite a few other popular headphones. However, that isn't all the story, but it seems to have tamed the (dare I say) problem.