Ear Yoshino HP4 (and comparison with EC Zana Deux S)

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Hi all,

@bazelio kindly asked me to make a comparison between the EAR (Yoshino) HP4 and EC Zana Deus S amplifiers. Both come from highly regarded amplifier designers, and have a following on SBAF and HF, though the ZDS has more fame, while the HP4 is seldom mentioned these days.

Part of this might be to do with the fewer HP4 in circulation, no doubt due to the huge price disparity – the HP4 retails for roughly 5500 USD while the ZDS is roughly half that. I was lucky to snap up an used one from HF, though I have to use a transformer for my local voltage requirements.

@purrin has covered the design of the ZDS in detail elsewhere on SBAF. I am no engineer, but the EAR HP4 runs what the designer calls “Enhanced Triode Mode” – which I do not quite understand, so I will quote the advertisement’s description (hopefully someone can explain this better than me?):

“After years of research, development and day-to-day manufacture with the EL519 series of pentode tubes, Tim de Paravicini has come up with a new and exciting Triode configuration. Conventional triode connected pentodes have the second grid tied to the anode, which results in a halfway compromise between a pentode and a triode. This neither has the efficiency of the pentode, nor the linearity of the triode. Tim de Paravicini's Enhanced Triode Mode (ETM) goes one step further, and creates a true, highly linear triode from a robust pentode tube.

Instead of driving the normal Grid One with signal, this is tied down to the cathode, and thus becomes an invisible, transparent element, and part of the cathode. Signal is fed into the tube's Grid Two, and in this configuration, Grid Three has no effect - it can either be connected to earth, or left floating. The ETM behaves like a true triode and is in fact more linear than the majority of directly heated triodes. Compared with the latter, it has the additional advantage of being a tough, more robust tube, capable of much longer operational life.”

Equipment:

PC -> Lynx AES16e -> Metrum Pavane (AES) -> EAR HP4 (XLR) -> Utopia

PC -> Lynx AES16e -> Metrum Pavane (AES) -> ZDS (RCA) -> Utopia

Both amplifiers are using their stock tubes.

Music used:

Symphony No 6 in F Major, Op. 68 “Pastoral”: I. Allergo (Beethoven)

· Instrument separation: ZDS was better with the violins to the side during crowded passages (I could discern them better), otherwise both had indistinguishably excellent separation with the instruments in the centre.

· Mids: Both had excellent clarity, and while the HP4 is slightly warmer and thicker, the ZDS had the better balance of clarity and body – please do not think the HP4 is thick and hazy like, say, the Vioelectric V200, I only noticed the HP4’s increased warmth after repeated A-B comparisons,

· Bass: The cellos were a little more flabby on the HP4, while the notes were tighter with a more realistic air on the ZDS.

· Soundstage: Both have good width and depth, but I feel the ZDS has the wider and deeper soundstage, such that, as I have mentioned in the Utopia thread, the Utopia and HD800’s soundstage become less disparate.

· Dynamics: Both have excellent micro and macrodynamics, but the ZDS, by virtue of the slamming tighter bass and better dynamic range, wins this – the HP4 by comparison sounds slightly more compressed in range.

Eine Kleine Nachtmusik in G major, K525: I. Allergo (Mozart)

· Bass: Both slam hard, but the ZDS slams deeper and tighter.

· Highs: Now this is the biggest, most noticeable, difference:

o ZDS extends further and retains clarity, where the violins at the start climb to “high C” are sharp and clear but not at all painful – an amazing feat with the Utopias, whereas it does hurt with the HD800 - in fact, the air is such that I am reminded of how it sounded like sitting in front of my violin teacher playing, and am reminded that violins naturally have bite at the higher notes!​

o By comparison, the HP4 is well extended but like a traditional tube amp, it rolls the highs gently such that the effect is that the music rolls along smoothly and non-fatiguing, but I miss a little bit of the energy.​

Tabi no Tochuu (Natsumi Kiyoura) – ending song of the anime “Spice and Wolf” (Season 1)

· One of my favourite songs with a female vocalist

· Vocals:

o Both amplifiers have excellent clarity and bring the mids a little forward, such that the vocalists are (only) slightly in front, which works well for this song (compare this to the Andromeda with my iPhone, where the vocalist is still clearly heard but not as forward in the music).​

o The ZDS again has an excellent balance of clarity and body to the voice – the HP4 is not as clear, but sounds, for want of a better word, a bit more euphoric and thicker.​

Derezzed (Daft Punk) – TRON: Legacy soundtrack

· I would have imagined this EDM to have fared better on solid state amplifiers, but here goes…

· Bass: Again the bass on the ZDS is slightly tighter, and slams just a little bit harder.

· Speed: Though I do not have a solid state comparison, I get the feeling that the ZDS fares better than the HP4, either because of its better dynamics and bass slam.

Nocturne No 15 in F Minor, Op 55 No 1 (Chopin) played by Claudio Arrau

Resolution: Both amplifiers resolve very well - I can clearly hear the pianist shuffling in his seat as he plays with either amplifier.

Summary (TL;DR):

· ZDS has better slightly better bass slam and better bass tightness, wider soundstage, better instrument separation at the periphery and treble extension and energy (is this the right word for the violin?), and a better balance of mid clarity and body.

· HP4 has thicker more seductive/euphoric mids, mild blurring at the edge of the soundstage and slightly slower with slightly less impact and dynamics.

· Both are excellent resolvers and have very good cohesive soundstages – in that sense, both are very musical, its just that I find the ZDS to portray violins more realistically at the risk of potentially being more fatiguing with prolonged listening, whereas the HP4 is seldom fatiguing.

· I find myself using the ZDS more than the HP4, though time will tell if this is merely “new toy syndrome” – my gut instinct is that the ZDS will ultimately replace the HP4 for me, however.

I can see how @drfinley mentioned at one of his posts at a SBAF meet that the HP4 is an excellent match for dynamics and indeed the HD800 – the slightly rolled off treble would have been an excellent synergy, and the bass slam from the HP4 is very good for a tube amplifier, its just that the ZDS does it better.

On the treble side, I can see why people say the HD800 treble with the ZDS would be fatiguing, whereas that is less of an issue for the HP4. Conversely I found the HP4 (on brief listens) to be a little too thick for the HD650.

NB: One caveat I should mention is that I’m using the Pavane and HP4 with a balanced transformer to convert my native 230V to 120V as both need 120V to work – I am unsure whether this transformer might be affecting the dynamic range of the HP4?

 

Thanks for the writeup! Have you done any tube rolling with either amp?

 

Alas I haven't had a chance yet! I have a pair of Sylvania 6SL7WGT I bought off eBay, but haven't used them yet.

 

I used the low setting for both when using the Utopia - the high Z setting for the HP4 made the sensation of compression (reduced micro dynamics and) worse and narrowed the soundstage a bit.

I admit I haven't tried the Utopias on the high setting for the ZDS.

 

Do you still have a HD800 to test with the amps?

 

I do indeed, and my impressions of the modded HD800 and Utopia are detailed on the Utopia thread:

http://www.superbestaudiofriends.org/index.php?posts/122257/

To summarise, though, I would have been happy with the modded HD800s and the ZDS had I not heard the Utopias with this amplifier, but now that I have, I can't really go back - the Utopias have better dynamics and resolution, smoother treble with no less extension and better bass slam with either amplifier.

 

The HP4 does not contain pentodes, triode strapped or otherwise. It uses 6SL7's which are high impedance triodes. The above quote must relate to a different product. The circuit uses an output transformer with a feedback winding to compensate for the high impedance of the tubes.

 

Thanks for the correction and for providing the schematics - I have indeed quoted the wrong EAR product!

 

@alucart Do you mind sharing the reason why you prefer the Pavane paired with the Zana over the Yggdrasil?

 

Yes, that's the EAR861.

 

My reasons for preferring the Pavane over the Yggdrasil in general were briefly discussed on the dedicated Pavane thread:

http://www.superbestaudiofriends.org/index.php?posts/70059/

To summarise, though, the Pavane is just as detailed, if not slightly less detailed, as the Yggdrasil but has slightly more body and better tonal balance, as well as a slightly larger soundstage - the best analogy mentioned here on SBAF is the Yggdrasil is like a photo with the sharpness dialed slightly up such that you can see slight edges with the detail, while the Pavane is no less detailed but appears more natural.

Admittedly, I have not heard the Yggdrasil with the ZDS - my Yggdrasil is currently switched off, and from what I have read, any fair comparison with the Pavane and ZDS would need to involve warming the Yggdrasil for some days =)

 

God, i miss the pavane. Are you the guy selling the HP4 on headfi?

 

Haha I thought you had moved onto (or perhaps beyond) the Chord Dave?

Alas I am not the gentleman selling the HP4 on HF but if the ad is old (like last year) then perhaps I did buy it off him.

 

I think my V12 may also be a pentode being run in ETM. Not sure, though.

Nice reviews, thanks. Can recognise some family resemblance in the sound with regards to my V12, which is a planar-only amp for me (no speakers).

 

I just tried rolling in the Sylvania 6SL7WGT brown bases, packed in 1958 from the packaging (but who really knows?).

Compared to stock Tung-Sol 6SL7, the treble seems slightly rolled off and less energetic, while the mids were slightly clearer. To my chargin, I preferred the stock tube, so back into storage the Sylvanias went...

 

How does the EAR HP4 compare to DNA's Stratus and Stellaris amps?