[AnakChan]

This past weekend I had my 2nd attempt in listening to the Utopia off a current driven amp - thx to another head-fi member for bringing his Utopia whilst I left mine at home. I was listening to it via the Re-Leaf E1 and new E3-Hybrid amps.

It reaffirms me that current driven with the Utopia isn't a good pairing as the bass is unnaturally excessive. As Re-Leaf were debuting their new E3-hybrid that's current and voltage driven, this was easily tested/confirmed that voltage driven seems to produce a more "realistic" tonal signature.

If anyone else has a chance to try the Utopia on other branded current driven amp, it'll be interesting to hear your thoughts.

P.S. I know folks would usually recommend the likes of planar magnetic for current driven amps, but to Re-Leaf's credit, their current-driven amp drove the HD800 headphones pretty well.

 

[Svatopluk]

The output impedance may be too high for the Utopia. I had the same problem with excessive bass when I tried pairing the Utopia with the HDVA-600.

 

[AnakChan]

The output impedance may be too high for the Utopia. I had the same problem with excessive bass when I tried pairing the Utopia with the HDVA-600.

I raised that question to the Re-Leaf reps at the show. The response is that unlike voltage driven amps, impedance matching is less relevant with direct current drive amps.

Now I'm not technical enough to call him out on it. Just regurgitating what I hear.

Edit: Oh doing a bit of googling, I think I know why they say with current drive amps, impedance matching isn't a factor but I'll need to do a little bit more asking around in the backend.

 

[Svatopluk]

I never paid the current drive concept much attention but after some googling as well, it all sounds pretty interesting. Unfortunately it's past my bedtime so most of the information is going over my head.

 

[TimeLord]

@TimeLord Amazing "arsenal" of mobile stuff!

Not familiar with any of those.

So, Chord Mojo, HA-2SE (new model), and pick one of the rest that you like most...

Yeah, its"s been a long road on mobile gear and I'm still not done. I was hoping to have a Liquid Spark right about now, but it looks like it'll be a long wait on that and more pondering for mobile gear.

 

[JimL11]

Current drive amps have some theoretical advantages over voltage drive amps. In theory, current drive amps have an infinite output impedance, whereas voltage drive amps have a zero output impedance. For a dynamic driver, the force driving it is directly proportional to the current, so an amp whose output current is proportional to the input voltage should have an advantage.

However, AFAIK, there are no dynamic drivers which are specifically designed for flat frequency response (or its equivalent for headphones) using current drive. They are all designed for flat frequency response using voltage drive. Therefore, if a headphone sounds flat with a voltage drive amp, with a current drive amp, the frequency response curve will mirror the impedance curve. For dynamic drivers, which generally have a big impedance hump in the bass, the output from a current drive amp will sound bass heavy, which is exactly what AnakChan heard with the Utopias - the Utopias have an impedance of around 80 ohms, which rises to 320 ohms in the bass, so one would expect it so sound about 6 dB louder in the bass with a current drive amp compared to a voltage drive amp.

The HD800 has a bass and lower midrange peak up to about 600 ohm, but in the midrange it is somewhere over 350 ohms, so with a current drive amp it should have a broad increase in the mid-bass to lower midrange of 2-3 dB which would make it sound warmer. Note that this is assuming the current drive amp has an "infinite" impedance, e.g. at least 5-6 kilohm. If it has an impedance closer to 100 ohms, for example, the frequency response alteration would be about a 1 dB change, which would be a perceptible warming but not necessarily excessive.

OTOH the LCD-4, for example, has a flat impedance curve so would sound similar tonally whether driven by a voltage drive or current drive amp.

 

[rrahman]

Have yall seen the latest post on innerfidelity by bob katz?

Just curious what everyone's opinion is. I found it pretty eye opening and partially upsetting. I don't even own a Utopia, but I fear my Elear may suffer the same problems.

I still like the way my headphones sound, but disheartening cuz it effects resale and it makes it harder to relate my headphone experience with others.

 

[x RELIC x]

Have yall seen the latest post on innerfidelity by bob katz?

Just curious what everyone's opinion is. I found it pretty eye opening and partially upsetting. I don't even own a Utopia, but I fear my Elear may suffer the same problems.

I still like the way my headphones sound, but disheartening cuz it effects resale and it makes it harder to relate my headphone experience with others.

Certainly explains the different impressions you read by different people. Looking at the graphs I'd peg my August pair closer to Tyll's that he tested because if I had the ones that Bob tested I would have likely returned them promptly.

In the end I'm very surprised at the differences.

 

[Khragon]

Glad Tyll and Bob took the time to investigate. I'm not happy how both Focal and Audeze QC on these TOTL headphones, ones would expect pretty much identical measurement between L/R and batches of the headphones. My pair is purchased end of Nov. 2016, sounds good to me, but I'm afraid that if I need to get warranty service, I will end up with something inferior. Hope Focal measure each headphones and issue recall on the bad apples.

I will take my pair to the next meet to have them measure.

 

[Alu]

Glad Tyll and Bob took the time to investigate. I'm not happy how both Focal and Audeze QC on these TOTL headphones, ones would expect pretty much identical measurement between L/R and batches of the headphones. My pair is purchased end of Nov. 2016, sounds good to me, but I'm afraid that if I need to get warranty service, I will end up with something inferior. Hope Focal measure each headphones and issue recall on the bad apples.

I will take my pair to the next meet to have them measure.

I purchased my pair only last month or so, and I have to say that I loved them straight out of the box, compared to some other TOTL headphones that I found to be severely disappointing.
I don't feel like my pair has the issues that Bob mentioned, so I'm not sure whether it has anything to do with recent models being automatically more prone to this ridiculous variance.
The bass on these is one of the best things about it, which is why I was often surprised to read people thought they were lacking in that department.

I think it's beyond outrageous that this issue exists with a 4000 dollar product.

 

[lovethatsound]

I'm surprised nobody from focal has been on here yet to explain what action their taking,if any.

 

[paul2qute]

Certainly explains the different impressions you read by different people. Looking at the graphs I'd peg my August pair closer to Tyll's that he tested because if I had the ones that Bob tested I would have likely returned them promptly.

In the end I'm very surprised at the differences.

A proper depressing situation I think

 

[paul2qute]

Relic I can't reply to you in a private message, my phone won't let me do it with this new site, once the site is sorted I'll private message you about my thoughts using an amp mate

 

[thyname]

Guys: Does Utopia still sound good to you? If yes, does it matter what Innerfidelity says?

 

[Khragon]

Guys: Does Utopia still sound good to you? If yes, does it matter what Innerfidelity says?

Yes it does, but like I said if you return it for RMA, what you get back may not be the best sample.