Icon Audio HP8/MP 3

[lauthoerer]

One thing I wanted to check with the group is a recommendation I was given by the seller of my unit who said: always use the impedance selector at minimum value whatever maybe your headphone impedance. This way you will drive the tubes correctly without any distortion.

While the sound implication should be the same for all owners (higher setting increases volume, tonal weight, dynamics - at the expense of a higher noise floor), does anyone have any knowledge of the technical implications?

I just played around with the settings and actually, putting it at “H” when using the HD820 brought the HP8 (almost?) on the level of the Euforia (weight and dynamics especially). I need to explore this a lot more, of course, also on the VC, but that was quite the revelation… so hope the advice given above can actually be ignored…

 

[StokeNewingtonJohn]

Would be curious about that as well, but I guess there’s next to no one who’s able to hear them side by side and also with the same tubes…

My particular SE model had a hum I just couldn’t get rid of in my system at the time. Now, with almost everything in my chain having changed, the “early standard” HP8 is dead silent and sounds already great with the original supplied tubes.

Here's a review of the SE which compares it with the original HP8. The originals don't come up much, though. People get very attached to them!

 

[JonT]

Here's a review of the SE which compares it with the original HP8. The originals don't come up much, though. People get very attached to them!

I like a lot of the brands Paul Rigby champions. But I struggle with his ridiculous cable reviews: “Swapping in the X created a boost in the 10-12k Hz region and improved timing on the ride cymbal. A haze was lifted from the oboe and my testicles descended by 15mm”.

 

[Pharmaboy]

Nope - but a valid point, of course!

I rolled through two sets of 6SN7s over the weekend and even the ones that had some “ambience” in the Euforia, had next to no background in the HP8. So not worried at all about this with the new (old) specimen.

A/B’d the two tube amps against each other and am quite astonished how close the HP8 comes up to the Euforia. Early indication puts the latter in front, though. But that’s at several times the cost!

In my review of the ZMF Aegis (wonderful tc-tube amp that's larger, employs more tubes, and costs more than the HP8) I compared it at length to my HP8/SE with the best tubes I had at that time. I was shocked how close the HP8 came.

The Aegis is truly next level, but the HP8 isn't far behind.

 

[JerseyD]

One thing I wanted to check with the group is a recommendation I was given by the seller of my unit who said: always use the impedance selector at minimum value whatever maybe your headphone impedance. This way you will drive the tubes correctly without any distortion.

While the sound implication should be the same for all owners (higher setting increases volume, tonal weight, dynamics - at the expense of a higher noise floor), does anyone have any knowledge of the technical implications?

I just played around with the settings and actually, putting it at “H” when using the HD820 brought the HP8 (almost?) on the level of the Euforia (weight and dynamics especially). I need to explore this a lot more, of course, also on the VC, but that was quite the revelation… so hope the advice given above can actually be ignored…

I find a higher impedance setting usually makes my ears happier (within the range of reasonable impedance for a given headphone).

 

[JerseyD]

Question about tube rolling. While I don’t have a ton of tubes in my arsenal, up until now I have mixed and matched, looking for a sound I like best (and then used it for all my headphones and music genres). It occurs to me now that better approaches would be to find which tube combo I prefer for a particular headphone and/or a particular music genre. What approach do you take?

 

[vsrrr]

I match to the headphone personally. And even then, I won’t always swap the tubes when I switch between headphones. Too much of a hassle. I can’t imagine switching tubes every time I switch genres!

My VC’s need different treatment than my AO’s, but I try to give each headphone what it needs to perform its best with any of my preferred genres.

 

[SoundMuzik67]

Same. Easier... much easier and if there is any "fine tuning" that may be needed... I'll swap out the cable.
But my AC has different needs than my VC or AOs.

 

[jonathan c]

Question about tube rolling. While I don’t have a ton of tubes in my arsenal, up until now I have mixed and matched, looking for a sound I like best (and then used it for all my headphones and music genres). It occurs to me now that better approaches would be to find which tube combo I prefer for a particular headphone and/or a particular music genre. What approach do you take?

... I go by headphone. I do not go by music genre per se because the recording techniques employed vary widely. Ideally, I would go by recording -- that is too great a hassle, even before considering tube warm-up time.

 

[lifeson]

One thing I wanted to check with the group is a recommendation I was given by the seller of my unit who said: always use the impedance selector at minimum value whatever maybe your headphone impedance. This way you will drive the tubes correctly without any distortion.

While the sound implication should be the same for all owners (higher setting increases volume, tonal weight, dynamics - at the expense of a higher noise floor), does anyone have any knowledge of the technical implications?

I just played around with the settings and actually, putting it at “H” when using the HD820 brought the HP8 (almost?) on the level of the Euforia (weight and dynamics especially). I need to explore this a lot more, of course, also on the VC, but that was quite the revelation… so hope the advice given above can actually be ignored…

I leave it on H now (for VC anyway) so that's 600 into 300 I guess. I suppose technically its not optimal to have output impedance higher than input impedance (or is that different depending on whether that is power or voltage transfer - I dunno, long time since I did this stuff) but it sounds better to me (yes weightier, fuller, better bass, warmer - maybe it's technically 'worse' but my ears like it and that's all I care about). I'm sure there's much more to it like certain freqs being changed. Isn't resistance done on a logarithmic scale anyway so 600 is not really double 300 ? Or am I now spewing nonsense

 

[jonathan c]

One thing I wanted to check with the group is a recommendation I was given by the seller of my unit who said: always use the impedance selector at minimum value whatever maybe your headphone impedance. This way you will drive the tubes correctly without any distortion.

While the sound implication should be the same for all owners (higher setting increases volume, tonal weight, dynamics - at the expense of a higher noise floor), does anyone have any knowledge of the technical implications?

I just played around with the settings and actually, putting it at “H” when using the HD820 brought the HP8 (almost?) on the level of the Euforia (weight and dynamics especially). I need to explore this a lot more, of course, also on the VC, but that was quite the revelation… so hope the advice given above can actually be ignored…

There is no electrical / physical harm to Icon Audio HP8 or to the headphone when trying out "L", "M", or "H" impedance setting. Just turn down the volume before impedance switching. Ideally and practically, high-Z headphones (Senn, ZMF @ 300 ohms) should use the "H" setting; low-Z headphones (Dan Clark Aeon 2 @ 13 ohms) should use the "L" setting. Experiment! Go with what sounds best (or even most amusing!).

 

[lauthoerer]

Cheers, guys.

Best sounding for the 300 Ω headphones (AC, VC, HD820) has definitely been the H setting, no doubt about it. However, no matter the tubes I've used, it also always increased the noise floor, which is more or less ignorable depending on the music and the amount of "quiet" sections... On L, there is practically no noise (even though there's some "distant ambiance" I would say), on M the floor is easy to ignore even though it's not "nothing". I can live with the "compromise" of using the M or H depending on my particular mood of the day, but was just wondering if it is the same with your units...

 

[vsrrr]

Cheers, guys.

Best sounding for the 300 Ω headphones (AC, VC, HD820) has definitely been the H setting, no doubt about it. However, no matter the tubes I've used, it also always increased the noise floor, which is more or less ignorable depending on the music and the amount of "quiet" sections... On L, there is practically no noise (even though there's some "distant ambiance" I would say), on M the floor is easy to ignore even though it's not "nothing". I can live with the "compromise" of using the M or H depending on my particular mood of the day, but was just wondering if it is the same with your units...

Between your three ZMF's, which one picks up the most noise? Least noise?

 

[jonathan c]

Cheers, guys.

Best sounding for the 300 Ω headphones (AC, VC, HD820) has definitely been the H setting, no doubt about it. However, no matter the tubes I've used, it also always increased the noise floor, which is more or less ignorable depending on the music and the amount of "quiet" sections... On L, there is practically no noise (even though there's some "distant ambiance" I would say), on M the floor is easy to ignore even though it's not "nothing". I can live with the "compromise" of using the M or H depending on my particular mood of the day, but was just wondering if it is the same with your units...

.... are you using a 12AX7 in front (V1)? Changing to a 12AT7 (60x gain vs 100x gain) may address the 'noise floor'.

 

[lauthoerer]

Changing to a 12AT7 (60x gain vs 100x gain) may address the 'noise floor'. [PS, I use 12AT7 only -- for more dynamic 'headroom'.]

It’s actually on your recommendation that I’m using a Brimar FootsCray 12AT7 CV455 KB/FB 1956

Between your three ZMF's, which one picks up the most noise? Least noise?

Will double check and report back in that. Tried the CC only once so far and didn’t like it. Stark contrast to how well the AC and VC benefit from the HP8. Have been doing more of a “musicality” check while rolling through my assorted 6SN7 tubes (sticking with the Raytheon JAN-CRP 6SN7GT VT-231 for now)… will do a more technical noise check one of these days…