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Pass Aleph 3

Probably needs to substantially better the 303 to justify the ongoing cost.

That’s my view too, and in this particular system/room it just isn’t (so far). I can tell it is clearly a very, very good amp, but it is just too rigid, restrained and measured in this particular context. The 303 just sounds freer, more alive and up for it. It gets out of the way better. It’s no huge surprise as I’ve been aware for a long while that a really good 303 is a remarkably synergistic match with these Tannoys and it likes the Verdier preamp. I’ll leave the Pass in for at least another week before sticking the 303 back, but I’ll be surprised if I revise this opinion. I’m obviously not saying the 303 is a “better” amp, just that it’s particular strengths and weaknesses align almost perfectly with this system to my taste.

My suspicion, and I’ll obviously be putting this to the test, is the Pass may be stunning into the JR149s (and maybe the LA3/5As). I’d not be surprised if the rather dark, solid and very spacious sound along with superb detail, tonality etc will click far better in that context. It could well be one of those amps (like the classic Krells etc) that can make small speakers sound absolutely huge.
 
I’ve just confirmed the above. It occurred to me that given my preamp has two sets of outputs and there is room on the top shelf of the table for the 303 if I shift it across a bit so I can swap between power amps pretty fast (still need to adjust the gain settings in the preamp, so that’s got it’s lid off at present). Bottom line is the 303 suits this system way, way better. It isn’t even close. Just bigger, freer, more open, relaxed and alive. More real. The Pass wins in some areas, it is very, very clear and revealing, but it just sounds small, over-controlled, undynamic and dead the way many other solid state amps seem to in this system.

PS Again I am absolutely not saying the 303 is the better amp! I guarantee the reverse would be true by at least the same margin in other contexts. I never do absolutes, plus I’ve heard 303s sound bloody awful many times! I’m expecting it to be rather good with the mini-monitors and I’ll do that next week sometime.
 
The first time I saw an Aleph amp was at Jazz Big Boy in Tokyo (https://www.bento.com/rev/3043.html http://jazzbigboy.sakura.ne.jp/) - a jazz bar with huge JBLs. The owner heard I was into hifi and invited me to come around the bar and see the components. I think the pass amps were his most prized components. I guess he was running a pair as mono blocks (not sure TBH but there were two of them on the counter). Small and undynamic the system was certainly not - but I think that is down to system synergy as you say.

It may be the amps at Big Boy are these: https://www.stereophile.com/solidpoweramps/1197pass/index.html

Interestingly, that stereophile review also mentions a significant warm up time:
It isn't their harmonic balance that changed as the 1.2s warmed up, but their dimensional capabilities. There was a recurring moment, about 35 to 45 minutes from startup, when the image just blossomed—from decent solid-state soundstaging to "Oh my God; they just showed me the magic." Pass Aleph 0s also take at least 30 minutes to bloom, but their metamorphosis isn't nearly as dramatic.
 
Small and undynamic the system was certainly not - but I think that is down to system synergy as you say.

I’m sure it is capable of great things, I’d put money on it. I am very confident this is a good amp! I may also be thinking about the wrong end here, i.e. it may not like my preamps. I’d like to have a really good solid state pre to compare, I guess ideally one of Pass’s own, but all I have is the Verdier (which I really like in its usual context), the Audio Synthesis passives, and some vintage Quad kit (33 & 34) which is entirely unsuited due to gain structure. If it doesn’t impress upstairs with the mini-monitors next week I’ll certainly start to suspect I’ve got something it doesn’t like upstream. On paper the Verdier should be fine; the Pass has a 23k input impedance, same as the 303, and there is absolutely tons of gain available, but specs often don’t tell the whole story.
 
I think your Audio Synthesis is the go-to on that front,Tony - really quite good enough: the Aleph 3 input impedance is purely passive, because the input LTP that follows is a pair of mosfets -it's not like your 'pre-out' needs to supply any extra current whatsoever to compensate for ..something, not even a few uA of input bias current.

Intrigued to how this all works-out...
 
I think your Audio Synthesis is the go-to on that front,Tony - really quite good enough: the Aleph 3 input impedance is purely passive, because the input LTP that follows is a pair of mosfets -it's not like your 'pre-out' needs to supply any extra current whatsoever to compensate for ..something, not even a few uA of input bias current.

I’ll definitely be trying that first with the 149s & LS3/5As, it’s just the sensitivity thing that may be an issue, I suspect I’ll end up with the Audio Synthesis pretty well cranked as it was half open into the Tannoys with CD earlier and the mini-monitors are 10db or so less efficient.
 
ah.

Just checked the Pass aleph 3 manual I have states its gain is 20db (10 x voltage ); that is about 1/3rd of most power amps (c. 29dB, = approaching 30x input voltage).

But - first - don't be afraid of running the passive damn-nigh-on, even wide-open! If that goes loud-enough - that will be as good as anything gets.
 
It's an audiophile cliché that "synergy is everything", but clichés have staying power because they tend to be true.

I've recently chewed my way through a variety of pre-amps looking for one with the balance, drive and resolution to do the First Watt J2 the justice the hyperbole it attracts demands.

Today an AudioValve Eklipse arrived - (an annoyingly bodged-about one it turns out, contrary to the dealer's description) - but it works, and it is excellent. Gone are the proverbial veils, behind which lurked greatness, and the J2 is a different amp - superbly transparent, open, dynamic, extended, clean... I have never heard my system sound better, even the wonderful Puresound L300 / M845 combo lags behind a little - though, interestingly, the sound signature has a good deal in common.

I am not, I'm afraid, a fan of Tannoys, and I am fairly confident that this pre-power combo would probably highlight that brand's shortcomings rather than unearthing their best qualities.
 
An interesting thread Tony, impressed by the speed in which you recapped the amp.
I was interested in a pair of Pass DIY mono's in the classifieds, but for my speakers i think need they need a bit more power that the Pass's produced.
Pass uses Tannoy's for their final reference when making their amps so they should be a good match, it's also possible that the cheaper 303's are simply better!

Pass' Tannoy's

NelsonPassVisit2015-3.jpg
 
ah.

Just checked the Pass aleph 3 manual I have states its gain is 20db (10 x voltage ); that is about 1/3rd of most power amps (c. 29dB, = approaching 30x input voltage).

But - first - don't be afraid of running the passive damn-nigh-on, even wide-open! If that goes loud-enough - that will be as good as anything gets.
Yes a wide open passive pre is as direct as it gets.
 
I've recently chewed my way through a variety of pre-amps looking for one with the balance, drive and resolution to do the First Watt J2 the justice the hyperbole it attracts demands.

That’s interesting. I’m certainly not ruling out my issue being upstream of the Pass, though as stated the Verdier is a good match on paper at least, and has huge amounts of gain on tap (20db on its highest setting, which is way too loud in this context). One thing that occurred to me when reading the manual again is the big claims for the Aleph being almost unique in having only two gain stages is maybe a tad disingenuous if it just means it’s passing that buck upstream to the preamp!

I am not, I'm afraid, a fan of Tannoys, and I am fairly confident that this pre-power combo would probably highlight that brand's shortcomings rather than unearthing their best qualities.

Fair enough, and a lot of folk aren’t. What I love about my system as it is set up is it sounds massive, pretty much life-size on jazz etc, and it just has so much dynamic life and impact. Drums sound like drums, a bass guitar sounds like a bass guitar etc. Effortlessly. It is not however a detail system, it is more broad brush. If you want to hear a pin drop somewhere or analyse the reflections off the back wall of the studio then go upstairs and listen to the LS3/5As! It does what it does, and I really like what it does. It sounds how I remember the big main monitors in studios sounding, which is little surprise given that is what it is.

The Pass kind of ‘over-focused’ it, and it is far from the first solid state amp to do this. By bringing everything into sharp relief everything gets smaller and somehow the bass gets a bit lumpen and boomy where it wasn’t at all with the 303 or Stereo 20. I get that this is likely output impedance and damping factor, it makes sense and is well documented. These amps have higher than modern amounts, and the Monitor Golds would have been voiced expecting it as that what amps of their time were like. Both these vintage amps roll-off earlier too, so whilst that won’t be audible here they may possibly be sending less energy into the cabs. I assume the Pass keeps going right down into the subsonics.

The thing I really don’t understand is why it sounds darker. Drum kit metalwork is no longer as crisp, alive and dynamic, it is very clean, but far harder to pick up on the nuance of hits of differing velocity on different parts of cymbals, hi-hats etc. It has got squashed somehow, pulled back in the mix. Given in some ways I preferred the Audio Synthesis passive may well point to a preamp matching issue. I certainly felt the top end was a bit more alive and more in context with the passive. I won’t be giving up on it until I fully understand this and have tried a few more options. I have a friend who could pop round with a Conrad Johnson pre (PV10 IIRC), but I doubt that is hugely different to my Verdier.

Pass uses Tannoy's for their final reference when making their amps so they should be a good match, it's also possible that the cheaper 303's are simply better!

Interesting, I’d not seen that. 1,200 JFETs a channel is just bonkers, I need to read up on his thinking there. He is a fascinating designer. They are different Tannoys though, the HPD are certainly solid-state era. The Monitor Golds are kind of the crossover point between the valve era Silvers and Reds and everything that came later, but I do view them more as a valve-era speaker. All the classic Tannoys have a lot in common, but they did adapt to market changes and usage context.
 
The Pass' output impedance is a near-constant 0.1 Ohm, whereas the 303 is 0.3 Ohms in series with 2000 uF and some inductance. This alone is bound to sound very different, especially below 200Hz or so. What happens higher up depends then entirely on your speakers' impedance curve.

It would be interesting to hear what happens when tacking a 303-style impedance onto the Aleph's output. Just ensure that you use bipolar caps, or normal ones back-to-back.
 
Doesn't Nelson Pass use and rate his B1 Buffer Preamp? That might be an option to try.

I note the Stereophile review states "Note that the Aleph 3's low voltage gain makes it unsuitable for use with passive control units"
 
The various claims made by others for NP's stuff (and the minor personality-cult that's grown-up around him), tend to overlook the fact that his aim has chiefly been to wield a minimalistic approach to engineering to achieve a particular subjective result. Those choices will always exclude some listeners as much as they exclude some partnering equipment. Until I had the J2 in-place, I had little idea whether it would work for me or no. Then it took a little experimentation to match the pre - but I suspect plenty of conventional hybrid pres would sound not-dissimilar (AR, Aesthetix, VTL, BAT, &c &c), but the Audiovalve was the first to really tick the box.

We all have a notional 'perfect sound' in our heads, and from all that I've experienced over the years, that's clearly capable of being very - even, once, shockingly - different from person-to-person. I don't mean to knock Tannoys - they make a lot of people very happy, and well-matched with appropriate kit especially so - that just happens to be a combo I've not encountered.
 
The various claims made by others for NP's stuff (and the minor personality-cult that's grown-up around him), tend to overlook the fact that his aim has chiefly been to wield a minimalistic approach to engineering to achieve a particular subjective result. Those choices will always exclude some listeners as much as they exclude some partnering equipment. Until I had the J2 in-place, I had little idea whether it would work for me or no. Then it took a little experimentation to match the pre - but I suspect plenty of conventional hybrid pres would sound not-dissimilar (AR, Aesthetix, VTL, BAT, &c &c), but the Audiovalve was the first to really tick the box.

Good post Paul. FWLIW, I got spectacular results out of Jim's old Aleph 0 monos with an Audio Research LS25 (might have been an LS26 I can't remember). There was a lot to be said for giving everything half an hour to warm up before settling down to use it. It took a modern NP pre (XP20) and NP monos (XA100) to see off the Aleph/AR setup.

TLDR: Trying an AR or NP pre-amp is a decent plan.

EDITED to correct typo on the AR model numbers
 
The Pass' output impedance is a near-constant 0.1 Ohm, whereas the 303 is 0.3 Ohms in series with 2000 uF and some inductance. This alone is bound to sound very different, especially below 200Hz or so. What happens higher up depends then entirely on your speakers' impedance curve.

FWIW neither of my 303s are entirely stock. The one in the main system has been recapped etc and the coupling caps uprated to 4700uF. I don’t know what impact that has on the specs, but it is a very good sounding 303.

PS Next stage is to try the Pass with the 149s upstairs. My hunch is this will be a better match assuming I’ve enough gain, though the competition up there is very high, those little TL12 Plus monos are really good!
 
I’ve come to the conclusion I’ve gone as far as I need with the Tannoys, so I’ve lumped it upstairs and given it a couple of hours with the JR149s. The system is Marantz SA8005 SACD player, Audio Synthesis ProPassion, Pass & 149s. It makes sense up here (after its warmed up), surprisingly deep and powerful bass along with good scale and heft. Again a slightly dark balance, but that works in the positive here as I’ve ended up in a bit of a room null (pretty much centre of the room). It is a more weighty and muscular sound than the little Leaks, though whether it has their dynamic subtlety and lightness of touch I don’t know. Definitely good though, and fascinating to hear it become more free, liquid and spacious as it warms up (currently 48c). Gain is as expected marginal, with the AS set at 12db attenuation (i.e. three-quarters open) I get about 85db peaks from a typical CD and have to crank it round to about 7db to get the same from an SACD. I suspect I have some early classical CDs and some SACDs I could run out of travel, especially if I ever wanted more than a near-field context.

I think it is starting to make sense as a purchase, though I suspect there is a lot more as yet untapped potential. The initial idea was to effectively swap it for the Stereo 20 as since rebuilding the pair of TL12 Plus I don’t really need that duplication, they are so close to being the same thing why keep both? The TL12s win on looks, so I’ll keep them! The Pass would give me another entirely different choice now and again and will be an interesting amp to have knocking around. I suspect I now have three distinct systems; the Verdier, 303 and Lockwoods downstairs, the Pass and the 149s, and the TL12 Plus and LS3/5As. I will try the LS3/5As with the Pass, but I suspect their bass-bump will work against things where it works with the Leaks. I’ll certainly try it though. I’ll also try the Verdier up here when I can be bothered unhooking it. I’m far from convinced the passive is a good answer, though it does work well enough. It doesn’t sound undynamic or sat on. I’m listening to I Have The Room Above Her by Paul Motain on ECM and it sounds stunning, though in fairness it always does!
 
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The thing I really don’t understand is why it sounds darker. Drum kit metalwork is no longer as crisp, alive and dynamic, it is very clean, but far harder to pick up on the nuance of hits of differing velocity on different parts of cymbals, hi-hats etc. It has got squashed somehow, pulled back in the mix.


A couple of us have found the Pass sound rather uninvolving:
https://pinkfishmedia.net/forum/threads/first-watt-f5.236820/page-5#post-3891749

I would be wary of drawing conclusions, however I have built a few 2-stage (FET output) amps and they all seem to lack a bit of grunt and involvement. The ones that come to mind:
SKA GB150
Renardson MJR7 Mk5
Both the above are pretty good, better than my DIY Aleph, but still fail to stay in the system for long periods.

I think you have nailed the Aleph sound. It will be interesting to see if it prevails with the JR149s etc.

EDIT: Just read your post above.
 
EDIT: Just read your post above.

As ever synergy, synergy and synergy! Just before turning off for the night I turned the lights out with the aforementioned Motain album and it was just stunning. Just a huge believable sound with a lot of dynamic subtlety (genius-grade jazz drummer!). I don’t like the warming up thing at all, the rest of my kit sounds great from cold, but in this system when warm it is clearly something special.
 
An interesting thread Tony, impressed by the speed in which you recapped the amp.
I was interested in a pair of Pass DIY mono's in the classifieds, but for my speakers i think need they need a bit more power that the Pass's produced.
Pass uses Tannoy's for their final reference when making their amps so they should be a good match, it's also possible that the cheaper 303's are simply better!

Pass' Tannoy's

NelsonPassVisit2015-3.jpg
yes those monos are tempting but they are heavy . I have some f5 that are divine with my impulse and are surprisingly light to carry
 


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