Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by TomB, Aug 6, 2018.
Is that due to the higher Ri for 12AX7 (62K) than AY7 (23K) and AT7 (11K)?
Yes. We increased the current in the tube and changed the output devices a bit from the T3, so it might be less of an issue now. I don't know as I never tested AX7's on the new design.
Is the loaner tour still going on for the T4? I would be very interested to hear for myself if SQ is better than my Kenzie.
For those of you who have pre-purchased, just a pic to let you know that we're getting closer to shipping - six T4s nearing completion:
Not finished yet, unfortunately, but a lot more progress:
These six T4 PCBs are 100% populated. A little cleaning, then they are ready for PT connections and casework assembly. (I miscounted on the parafeed caps for one of them, but those are arriving tomorrow or Tuesday.) I think they should all be ready next weekend.
.... is anyone else having workstation envy right now?
Spent the week with the ECP Torpedo 4 [thanks @TomB ], Feliks Euforia (2018 Revision), and Eddie Current Aficionado [thanks @BillOhio ]. I tried a massive shitload of headphones with each amp, but during the course of writing this comparative overview, here's the list of what I used -
LCD-2 (2010) w/ Eikon Pads
ZMF Auteur (Lambskin Perf Eikon Pads)
Focal Elear w/ Clear Pads (aka Elex)
Sennheiser HD800 (SDR, dust caps removed, copper cable) [thanks @brencho ]
Sennheiser HD580 (stock)
Fostex TH-X00 Ebony
Klipsch HP-3 (TP Modded)
Source - Schiit Eitr -> Violectric V800 (just got my M22B back from repair [thanks @Cspirou ], hasn't warmed up yet).
Pic for verification (sorry for awful quality) -
I'll just jump right to the chart -
For what it's worth, one point of difference on this chart doesn't equate to one degree of subjective difference (sometimes more and sometimes less). All of these amplifiers are incredible in terms of performance - none of them feel lacking in any of the qualities on the chart to my ears. Direct comparison just makes the relative differences easier to discern. With A/B, the differences between each were generally quite noticeable, but might be more subtle with more time between listens. Here are some miscellaneous points -
1. The Af has a dramatically noticeable lead in the qualities where it marks best, and is very close in the qualities it does not mark best.
2. "Warmth" is not thickness. I tend to think of warmth as some combination of tonal balance and saturation profile, though an exact definition doesn't really exist. Regardless, the Af is curiously slightly bright (not what I expected) but also not lean at all in terms of tonal density and harmonic richness.
3. T4 feels the quickest and tightest in terms of decay, but also feels the "darkest" in terms of the subjective FR slope it brings to many of the headphones used (even though the frequency extension is excellent on both ends). It is a very tight and controlled sounding amplifier, which is why I notice myself preferring it with headphones which already impart a sense of extended decay [Auteur + T4 was one of my favorite pairings of the week]. T4 is the least likely to become congested with extremely busy passages because of this. Pretty important for some of the genres I tend to listen to.
4. Euforia is the least technically adept amplifier, but also suits my laid-back sensibilities when the mood is right and reduces fatigue with headphones that tend to have treble issues. Makes HD800 listenable (I'm usually allergic), and gives Elex a nice downslope [also a highlight pairing]. The midrange is very thick, liquid, and rich compared to the other amps. Inoffensive and always pleasant... forgiving without giving up too much spatialization and dynamics.
Here were my favorite pairings for each of the headphones -
LCD-2 (2010) w/ Eikon Pads - Aficionado
Modded HE5LE - Aficionado -> GFA-555
Modded HE5 - Aficionado -> GFA-555
ZMF Auteur (Lambskin Perf Eikon Pads) - Torpedo 4
Focal Elear w/ Clear Pads (aka Elex) - Euforia
Sennheiser HD800 (stock) - Euforia // Aficionado (content dependent)
Sennheiser HD580 (stock) - Euforia (couldn't test with Af due to lack of balanced cable, but I bet that would be my preference)
Fostex TH-X00 Ebony - Torpedo 4
Klipsch HP-3 (TP Modded) - Aficionado
The Aficionado is completely in stock configuration, possibly aside from a few changed capacitors. Ask Bill. As far as I know all units have the stock tubes installed. Impressions of course could change with mods to either the headphones or the amplifiers, tube rolling, different source, etc. I could swing one way or another in terms of my favorite pairings, even though ZMF + T4 was always a winner, Focal + Euforia, and HFM + Af + 555 is probably the best I've ever heard, given my preferences.
Edit: it's been quite interesting comparing three very well-designed and implemented tube amplifiers of various topologies. I wonder if the differences I noticed are indicative of the general sonic results of each topology - Transformer-Coupled SET, OTL, Parafeed. From the impressions I've read here and elsewhere, it seems that may be the case. It's clear each amp has executed the general principles at play extremely well.
If you have any specific questions about synergies I'll do my best to answer in further detail. This post is just an overview. There are too many words to type... best left for in-person discussions with Friends.
Edit - Mods: Wasn't sure if I should post this here or in the Af thread. Move wherever feels appropriate.
Quick correction-- hd800 has sd resonator, no dust caps, and a copper cable.
Bill's AF has the copper/silver duelund caps, afair? I think I remember they listened to that one and one with jupiters and it was a wash.
In any case that only makes the t4 more impressive since its another 150 bucks + shipping on top for the jupiters.
Fwiw I think t4 works well with hd800 /600 since it's fairly smooth and a bit warm, same with Elex. Just throw in some Brimar yellow t or military Mullard.
@E_Schaaf on your graph it looks like the T4 has a wide, shallow stage. Or is the T4 shallow compared to Af only? This was an issue for me with T3. Could you or someone who may have heard both T3/4 comment how they compare in this respect. Thanks.
Seems like AF is the best all rounder. But it's also $1K more expensive than the other two. I heard the AF and it was indeed special. Thanks for the comparison.
I find T3 gains some real soundstage depth with better tubes. Stock tubes didn't do it any favors in that regard. Soundstage really opened up with better tubes. I wouldn't be surprised if T4 would react in the same manner.
T4 stage is very wide and the image is very clean as well (excellent separation - in fact the best in this regard of what I heard). Stage definitely isn't shallow in general, just compared to Af.
The Af stage starts inside the head and expands spherically in every direction.
If you're a photographer, here's an analogy - the Af has a depth of field like a 50mm lens shot full frame at f5.6 from a few meters away. Enough to clearly isolate and focus on the forefront (and the immediate context of the primary subject), but kind of feathered extremely smoothly and evenly to the nth degree going backward from there. The T4 sounds more like f8-f11. More is in focus, but the depth of field feels slightly flatter. Like there are planes of focus as opposed to a continuously morphing blend.
The Euforia is like f2.0 up close. Creamy diffusive bokeh, very pleasant and still presenting a sense of front-to-back space, but focus is slightly soft and nebulous.
But don't worry, T4 is not f22 on a point-and-shoot at infinity-focus level flat. Still very impressive.
So T4 is Stanley Kubrick and AF is Alfred Hitchcock?
Great, now I'll be afraid of my Af sneaking into the shower and stabbing me, thanks
I had a T3 for a while and tried all the recommended tubes to remedy the stage, nothing really did that much. IMO, EC amps excel at stage depth, in another league compared to T3. I was hoping to hear that T4 remedied that which it sounds like it did.
HD800 also compensates quite a bit, which is the HP I was using.
While I have met Tippi Hedren (and eaten brownies she baked), I'll take Kubrick.
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