"But I do agree that listening over a much longer period of time would show more of the minute differences in these fine integrated amps."
Hello pokey77-these amps were so close, that to REALLY discern the differences IMHO,I need to hear just 3-5 second "snippets" and IMMEDIATELY have the ability to switch to the other amp. Even though Kevin did a fine job of switching, it's just not fast enough.
My sonic memory just isn't that good.
On a side note: I'm discovering the PL HP really does need to be opened up to hear what a fine piece of equipment it is. I listened to that SRV cut at a very high level-3:00 o'clock, and my speakers really came alive. I played "Tin Pan Alley" from the record I purchased in 1984! WOW
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Thanks Kevin and enjoy your trip. I appreciate your throwing this together and also for changing up some of your approach at some of the suggestions. I think you really got a more interesting set of results than you might have otherwise (great call on the 3rd amp).
And for those who participated, thanks very much for your reports on your impressions...very interesting.
At the risk of sounding like a total KT150 fanboy (I may be!), I was interested to see how that variable might shake things out. I truly think it's a special combo with the PL amps AND the ARC amps...the PL HP in my case really went to another level.
However, I realize it's been a while since I've had the PL-provided EL34s in the amp, so I'm going to do my own comparison and go back to the EL34s that shipped with my HP for a few days and see how they sound again.
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@parsons
here are Kevins comments on EL34 vs. kt150 from Page 4 of this thread. "I use an HP at home with KT150's and it's amazing. But it's not night and day from a stock one with EL34's. It's a small nudge." |
So why is it that at the very same time, PL makes it sound as though it's auto-biasing and protection circuits are revolutionary? Even evolutionary?
The nexus of PrimaLuna is a man not happy with what's being made, who is very good at gathering engineering talent and looking at problems. Herman van den Dungen is that man. He also is the man created Kiseki, and created the Ah! Tjoeb CD player both of which have near cult status. My input come from being the complaint department for most every brand of tube audio made. When a poorly designed tube preamp with 27dB of gain goes through tubes, it's the tube dealer that has to explain it more than the company that made preamp. And we've re-tubed over 70,000 components since Upscale Audio opened over 20 years ago. Hence my involvement. Whether it's evolutionary or revolutionary..I can't say. I CAN say it's careful consideration of what IS possible. You are buying a fabulous statement product that will serve you well. Both the preamp and amp are beauties. I don't know if you said what you plan to do about speakers? |
pokey77--agreed, that comment and the Saturday event results prompted me to put the EL34s I had neatly foam wrapped in the cabinet back into my PL HP last night for a couple more hours of listening, and I have them playing right now again as I verbosely type.
Quite lovely, actually. I bought my PL HP used and don't really know if it was fully broken in when I was first listening to it, if my system synergy has changed, etc., I don't know...perhaps it sounded this good with EL34s from the beginning. My system hasn't changed that drastically in the 2 or so years, but I concur that the difference in sound is not that great (probably not as great as I imagined). The EL34s are even better than I remembered, and it's not that they weren't great when I got it, I just had the itch to try KT88s, KT120s, and KT150s because the amp let me, and they all sounded good to great to greater. The move up the KT "line" to 150s was fun (expensive, in retrospect) and each move removed a bit of things I didn't love with each move, and gave me more of the things I did love.
I think the EL34s simply feel a little softer in the lowest register, but not weak, and there is maybe the slightest loss of ultimate sparkle in cymbals, etc., with maybe the slightest shrinkage in soundstage. But overall they are a really lovely tube, with more drive and immediacy than I had remembered. And the tones and texture are absolutely gorgeous. I can see why people love this tube and see why it still ships in a number of the PL products--it's really a great sound.
I'm going to keep them in for a week or so before I go back to the 150s and see if my opinion changes again, but I agree that the changes are more subtle than I had originally remembered.
It just struck me that in some part of that driver tube upgrade journey I also swapped out the 12AU7s for something that was reported to be a better-sounding-than-shipped tube set (and were)--but that sends me back to this unfounded conclusion...as Kevin astutely called out earlier, the sound can change a lot with the two amplification pre-tubes. Perhaps that contributed as much to my improvements at the time as the upgrade to KT150s, and now going back to the EL34s that difference alone isn't that big?
I do maintain that the pre-section of the integrated, while great, is actually holding back the last ounces of amazingness that this amp alone is capable of. Put a really, really, really nice and transparent pre-amp in front of it through the HT bypass inputs and you will get more of what it's capable of. In my experience...YMMV. I make that point merely to suggest more experimentation in your own system.
The headphone amp is rarely mentioned, and that is a phenomenal addition to this amazing amp that probably doesn't get enough praise by itself. |
fsonicsmith, I agree that it would be very interesting to see the PL HP (or non-HP) against some of ARC's references and other brands', including the separates stacks obviously (in the reference lines).
I don't have an easy way to get my hands on really expensive amps other than buying them, so while I own a lot of very good to great amps, I'm in the territory where moving up in quality is a used car like investment...not an "experiment" I can make any longer. My local ARC dealer doesn't seem to have a way to get their reference amps and pres in for demo, oddly, even though I've expressed an interest and means to buy them if they are that much better. |
Kevin or anyone what were the driver and gain tubes used for this comparison? I assume stock Primaluna 12au7 for both the Premium and HP?
Personally I think the KT150 is a totally different animal than the EL34. The EL34 is a bit richer, doesn’t have the bass slam or quantity and doesn’t have the sparkle as the 150. Parson’s pretty much hits the nail on the head. I do have the Premium (non-HP) FYI. |
"You are buying a fabulous statement product that will serve you well. Both the preamp and amp are beauties. I don't know if you said what you plan to do about speakers? "
Come visit you and audition some Focals 😀 It could happen. I've been in the hobby for 40 years since at age 18 using my restaurant dishwashing job to buy Large Advents, a Sansuii 991(?) receiver and a BIC turntable. Then came constant upgrades particularly once out of law school. At age 30 or so I bought a pair of the original B&W Matrix 805's, a McCormack DNA.5 SE and a McCormack preamp (the passive buffered one whatever the model number might be). JPS Labs made a device called "Golden Flutes" that were powered by wall warts and went in between the amp and speakers to boost the bass response and I had those. Then came the MCAudio "Full Monty" upgrade following the shuttering of McCormack. Next I replaced the passive preamp with an Audio Prism Mantissa and then came Acoustic Zen Adagios when they were the budget hot item and then a NOS ARC VS110 (a well-to-do audiophile bought two with the second as a back-up and it sat in a closet for 7-8 years in its original packaging). With the digital player market in gear I tried a PC based music server and then upgraded to the much smaller and easier Aurender N100H with an Abbingdon DP777 dac. Then came a return to vinyl with too many tables and phono stages to list but I've settled down with a Manley Steelhead and two tables that sit on wall mounts flanking each side of my main equip rack-a VPI Prime with the Phoenix PS and tach and a fully restored Thorens TD124. My dad bought the Thorens in 1959 and after daily use when I was a kid my dad left it sitting idle for 25 years when CD's emerged in '84 or so. I had just read Art Dudley's piece on restoring a used TD124 and while visiting my parents one day I asked my dad if he still had the Thorens. I suspected it might be a 124 but was not sure. As soon as I saw it again after all that time I was happy as a clam-Dad was happy to give it to me-it no longer ran. I lusted for the ARC Ref 6 as soon as it came out-I never liked the looks of the toggles on ARC preamps. The ARC GS150 sure looks better than the Ref 150 SE but they are identical but for the chasis and meters (I confirmed with ARC) and the price differential.... Sorry for the long historical background.
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"anyone what were the driver and gain tubes used for this comparison? I assume stock Primaluna 12au7 for both the Premium and HP?"
samzx12-box stock tubes Kevn was hesitant to use KT150.Plumbing was Nordost Heimdall II. I think speaker cables were Valhalla
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Thanks tablejockey. Can't say I blame him for using KT150 as the HP version was running stock tubes. |
fsonicsmith you are da man. What a fun journey. Someone asked me today if I was ready to retire. Hell no. I'm having more fun now than ever. I still collect vintage receivers.
I'm going to be at the Focal factory in France next Tuesday and will be taking a few videos. I hear it's incredible. Which ones were you thinking about? |
I need either standmounts or small floorstanders. i have a dedicated room but its on the small side.
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Greetings all, As an amplifier manufacturer, I want to tread lightly on this topic. Please bear in mind that the following are my biases. Others clearly differ. Note that I didn’t have time to get through this entire thread, so perhaps some of this has been covered. I caught a few references to PCB vs. point to point however, and some misconceptions prompted my reply. Finally, I’d consider taking a look at VAC Amplification if you’re looking for a medium to high powered tube amplifier ( http://www.vac-amps.com/pages/statement.html). Begin rant … I’m a big fan of the turret board / tag strip construction technique. Designed correctly, it can have as short of a signal path as point to point, but with far more robust construction (immunity to shock and shipping damage), ease of maintenance, and sample to sample consistency. Know that (along with point to point) it’s much more expensive to manufacture, requiring more time and a skilled labor force, which I’ll expand on below. If carefully designed, the signal path can be as short as point to point, although many examples of this technique don’t reflect this (short signal path) as a priority of the designer. I can understand why, because it’s tedious work. It took me over 4 months to lay out our new NiWatt amplifier, achieving a total wire length on the positive side of the circuit of only 4” from input jack to speaker binding posts. Sometimes, longer isn’t better ;-) The term Point to point is freely bandied about by marketing departments. If you look at the Prima Luna site, you’ll note that their construction technique is in NO WAY point to point construction. It’s a mix of tag strip/turret board (I like that!) with quite a few printed circuit boards thrown in for good measure (meh!). I certainly prefer this construction to a pure PCB construction, but for my tastes, it’s not all the way “there”. In fairness to them, an amplifier as complex as the Prima Luna would be a nightmare to manufacture and service if it were fully point to point (or tag strip/turret board) construction. This calls into question whether this complex of a design has any sonic benefits vs. sonic costs ... a discussion for another day. The fact however, is that this is not point to point construction. Here’s a gut shot of their amplifier: http://www.primaluna-usa.com/dialogue-premium-hp-power-amplifier. This Wikipedia page has some photos of true point to point construction: https://en.wikipedia.org/wiki/Point-to-point_constructionHere’s an example of a beautifully executed turret board/tag strip construction (a Thoress phono stage): http://www.thoeress.com/images/thoeress-phono-enhancer-03.jpg. See the differences? Comment: I’d like to see a shorter signal path on the Thoress, as these “ladder” (parallel) component layouts tend to add quite a few more inches of wire into the equation, but I wanted to call out the elegance and robustness of the construction technique. As I mentioned above, you can achieve a short signal path with this technique, but it won’t look quite as neat as the Thoress. A couple of definitions and additional comments … Point to Point: All components are soldered to each other or to terminals (e.g. tube sockets, binding posts, input jacks, transformer terminals, etc.). An occasional wire is necessary on the hot side of the circuit (to bridge some longer distances), and some sort of ground bus (wire) is used on the negative side. Vintage components (i.e. Marantz, Scott, Fischer, etc.) are wired this way. Looking at them, the components appear to be a chaotic rat’s nest. There’s a lot to be said for this from a sonic perspective (parallel wires are your enemy). Duplicating the construction from sample to sample can be quite difficult however, and it requires a highly skilled labor force (expensive), because lead dressing differences (component and wire length and routing) can result in sample to sample sonic differences if attention isn’t paid to this. Tag Strip / Turret Board: This is the evolution of point to point and the precursor to circuit boards. It’s typically a mix of some point to point wiring combined with some form of “support” for many components by use of intermediate terminals or turrets to which some components are soldered. It’s typical of vintage guitar amplifier construction and can withstand the abuse of roadies throwing the gear around carelessly. The tags/turrets tend to fix the layout quite a bit more than point to point, so it’s quite a bit easier to maintain sample to sample layout and lead-dress consistency (less QC required on the back end than pure point to point). Circuit Board: We all know what this is. It’s the least expensive manufacturing technique, and you can get by with a much less skilled workforce. It offers lowest manufacturing cost (by far) and a better assurance of sample to sample consistency with less QC required at the back end. High quality circuit boards can withstand the abuse of parts replacement, but ask any tube amp tech which architecture he’d like to repair, and I’d expect them to say point to point or tag strip / turret board. The circuit board material (glass/epoxy) is inherently capacitive (a bad thing) and you can’t control the quality of your “wire” (the circuit traces). You can’t specify silver, 6-nines copper, etc. for your circuit board traces. Again, the above are my biases and by no means universally agreed upon. Rant off ... Cheers, Thom @ Galibier Design |
@thom_mackris
I noticed you said if looking for Med to High Power Tube Amp look at VAC. A lot of people can't afford VAC. What other company would you recommend looking at? Would Primaluna be a consideration?
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I noticed you said if looking for Med to High Power Tube Amp look at
VAC. A lot of people can't afford VAC. What other company would you
recommend looking at? Would Primaluna be a consideration?
I wish I could responsibly advise you on this. Most of my recent exposure has been to low power triode amplifiers - 2A3, 300B, 845 and such, and it's only serendipitous encounters with both Kevin Hayes and VAC in general that led me to bring them up. Indeed, they occupy more of the ARC price tier and not Prima Luna's. Prima Luna appears to make many intelligent design compromises (to meet a
price point), but without hearing them I'd hesitate to say, other than to recommend an audition. Cheers, Thom @ Galibier Design |
Thanks for the write up btw. Appreciate your time.
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"The
DiaLogue Seven is completely handwired,
point to point—and I’ve never seen
a better-built amp. Wires were neatly
trimmed and dressed, with no strand out
of place. I spent a long time trying to find
a single bad solder join, and could not:
Someone made this as if it mattered." - Art Dudley, Stereophile Magazine
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Art Dudley is one of the industries most experienced and respected writers.
And this was an earlier product before PrimaLuna added Silver-plated oxygen free copper wiring imported from Switzerland, Takman resistors, and Mundorf Mcap Evo Silver/Gold caps.
I don't think I need to address build quality. Or how they are built, or what "qualifies" as point to point. The most technically adept critics have all said it. If there is a better built amp, I'd like to hear about it. Only to applaud it as they exist I'm sure. The only contender I can think of off-hand is Atma-Sphere. Any others in that club, my hat's off to them! |
Thanks for the write up btw. Appreciate your time. You’re welcome @aniwolfe I don’t think I need to address build quality. Or how they are built, or what "qualifies" as point to point. I don’t mean to be a stickler, but respectfully Kevin, I think you do, since it’s in your advertising collateral. BTW, my philosophy (others may differ) is that if a component is inside the box, it's in the signal path. Then again, I also think that power cords make a difference ;-) None of this is meant to cast aspersions on what is very likely a fine product (I recommended its audition). Benefiting from offshore manufacture, the Prima Luna’s construction looks like that of an amplifier costing three times its price. My earlier post grew long, and I only implied another reason for PCB construction (apart from addressing circuit complexity) - to bring a product into a more affordable price class. If done intelligently, you can produce a very fine product. One such component using PCB construction (which I heartily endorse) is Keith Herron’s VTPH-2 phono stage. If it were entirely hand-wired, its price would likely triple. I’d love to hear Keith’s original breadboard prototype of this phono stage. I’ll bet it’s quite special. Congratulations on carrying a product with such value! Cheers, Thom @ Galibier Design |
Good posts Thom and you are most accurate and thoughtful in your posts. I am a big fan of 100% point to point and tag strip tube builds. Hard to find these anymore as you know. I also like no electrolytic caps in the power supply...only film. Yes, this can make for a larger chassis and increased cost, but I hear the difference.
The VAC gear is circuit board is it not?
I looked at at your site and did not see any pricing on your new 300b amp. I think it is due out soon. Looks very interesting.
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I don’t think I need to address build quality. Or how they are built, or what "qualifies" as point to point. I don’t mean to be a stickler, but respectfully Kevin, I think you do, since it’s in your advertising collateral.
What I meant is it's been well recognized in literally every PrimaLuna review that they are built better than most any tube brand on the market regardless of price. Most any brand. Most any price. It's been written about over and over by the most technically adept magazine reviewers. Dick Olsher, John Atkinson, Art Dudley, Herb Reichert, and many others. Hence our latest magazine ads called "Preamp Fairy Dust" and our suggestion to customers to use Google images before dropping a dime on ANY HiFi purchase. Tube amps and preamps are simple and benefit most from point to point construction. Having said that, there are some protection circuits we have that MUST be PCB. Adaptive AutoBias is a big, complex board but it's not in the signal path. Our CD players and soon to be released DAC will of course have some PCB's and some point to point. No way around that. Our upcoming phono stage will most likely be the same way. High end audio prices are arbitrary and in many cases have zero to do with engineering and build costs. Some big names charge as high a price as they can without losing sales, others that are new hope to build credibility by having a price so high it defies logic. Wow! It's expensive. It must be good. That, my friends, is the absolute truth.
I met with a manufacturer Tuesday that wants me to sell their product at Upscale. They have raised their prices 25-30% every time they come out with something new while internally they are cheaper by my parts count. I looked at them and asked "What's your next move? When does this stop?" Why not a small increase and better product?
There are others that see that in the long run our industry is not doing itself a favor, and they hold the line and still make a decent living at it. Quicksilver, Rogue, and a few others. Look at Klipsch Heritage speaker series as an example. They should be applauded and held up as a standard (FYI I don't sell them .... but I should) My wife Laura says I'm grumpier with my graying hair. She's probably right. I think I'll go yell at some kids to stay off my lawn. |
Your points are well taken, Kevin and I see that we’re basically counting angels on the head of a pin. I agree with you about the arbitrariness of pricing in many instances, and would love to see Prima Luna whup some of the big names (withheld to protect the guilty).
High end audio prices are arbitrary and in many cases have zero to do
with engineering and build costs. Some big names charge as high a price
as they can without losing sales, others that are new hope to build
credibility by having a price so high it defies logic. Wow! It's
expensive. It must be good. That, my friends, is the absolute truth. This is a touchy subject I’d rather stay away from, because it’s something that really makes me grumpy. Early in Galibier's history, we weren't taken seriously due to our value pricing. Of course, that was a time when we were learning the ropes - priced far too low to make a profit with our turntables. We had no clue as to the real cost of running a business ;-) Quicksilver is another one of those brands which should be applauded for their value. Some of it is a matter of Mike Sanders pricing fairly, and the rest of it is due to him being a master at procurement (cost containment). The VAC gear is circuit board is it not? Hi @grannyring, I know they use at least some turret boards in his construction. I haven’t peeked under the hood in a while however. Cheers, Thom @ Galibier Design |
I've been thinking of trying a pair of Klipsch Heritage Heresy IIIs (I have a pair of RELs so the 60hz low point bothers me not) which cost less than 2 grand a pair new (1500 or something "open box" shipped), they're made in the USA, and should be a great match for my Dennis Had Fire Bottle SEP "HO" (a HO...it's a HO) which has turned out to be the best sounding amp I've owned in 5 decades…a hand wired gem of an amp that cost around 1200 clams (actual clams, which I thought was a little strange), and is utterly a hand wired masterpiece of unobtainium (really…gotta grab 'em on Ebay when they show up, snooze you lose). |
Kevin,
When is the Primaluna's DAC coming out? What's the price range and how does it compare to PS directstream? Thx.
Allan
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our suggestion to customers to use Google images before dropping a dime on ANY HiFi purchase. With nothing but respect, I humbly disagree. Let me throw out two extremes. Back in the heyday of BAT, consumers IMHO were looking at the fancy round-cased transformers and impossibly complex circuits filled edge to edge with various parts and buying/perceiving based on the visual more than the audible. I don’t mean to comment that BAT was bad or overrated but instead on consumer behavior. The other extreme is this; https://www.stereophile.com/content/croft-acoustics-phono-integrated-integrated-amplifierIt looks humble/ugly, it has a paucity of parts, it does not measure well. But good heads/ears love the sound. I can’t think of a single other hobby in which-to such a large degree- the consumers buy with their eyes and not their ears/brains. Particularly with loudspeakers. I too am guilty. You can’t judge with your eyes. Period. |
I just heard from Kevin & company after they evaluated my PrimaLuna Prologue Premium integrated amp. They have judged it to be working perfectly. I sent it to them as my Klipsch La Scalla II speakers were making hum which is audible from 12 feet. These same speakers make no hum when connected to my BAT 300SE integrated. I'll conclude that the PL integrated is incompatible with the Klipsch (I'd like to hear from any Klipsch owners driving their classics with PL and no hum). Anyone interested in my PL integrated can drop me a line and I'll post it on Audiogon ASAP. Got my eye on a Pass XA30.8...
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Allan: The DAC is finished in prototyping. No ETA or any other info as yet. If anybody is looking for a PS Audio Directstream I had a brand new one that was purchased by a customer that two weeks later got transferred to Europe and we could not get the voltage switched in time and he had to buy a 230v. His unit is for sale I think but perhaps it got sold. He also had the new transport. Incredible opportunity. Thom_mackris : I like your thinking. What’s your take on Rogers then? Cathode bias, and I suspect they run the tubes hot. Yet they say this on their website. It's all true, except I've not seen a cathode bias amp with "the longest tube life". : - Auto Bias Circuit– For long tube life and ease of operation. Self Bias circuit for adjustment free operation and longest tube life. Customer does not need to adjust tube bias. As the tubes age, they adjust for bias changes automatically. The customer can change tubes at any time or replace a single tube rather than the full set of 4 and the amp will automatically re-bias for the change.
fsonicsmith: BAT makes some incredible products. The VK33SE, at $9995, is shockingly good. Look at the way they make their volume control with actual laddered resistors, dual-mono, toroidal transformers, transformer coupling, tube regulation, you name it. If you look at it and listen to it you will truly see how amazing it is. The problem BAT had was being "in vogue" as well as giving dealers a true safe haven to sell at retail, which others do real well. And the dealer margins weren’t that great in the first place. The behavior of dealers to that is what creates being "in vogue" Trust me on this folks. I’ve done this as a living for 40 years. Stripping away all that, the VK33SE at $9995 is amazing. No qualifications. But the original poster said it here in his original post. ARC was his dream. That always plays a part, and that’s fine. When I get back from my trip, I’d be down with doing another comparison. Somebody mentioned VAC. I know how the DiaLogue Premium compares to the Sigma 160i. But I don’t have one. I have the flagship Alpha Phi that we took on trade but it’s not current. Can somebody find a way to get one? Or a preamp/poweramp combo that is current? |
https://www.southampton.ac.uk/~apm3/diyaudio/Croft_top3.jpgHere's a pic I was looking for-look how the Wondercaps (I presume) are assembled askew-for the shortest possible signal path. Kevin-Art Dudley has a penchant for looking at what he considers to be good-value build quality and scoring points with readers as an audio consumer advocate. He loves to see simple casework and point-to-point-he does after all worship at the alter of Shindo and Garrard. I don't disagree with his particular viewpoint (pun) but it again ultimately means little. Look at Plinius. One look and you would think some designer thought he could forge a market with over-the-top casework and mediocre electronics but that would be a wrong assumption too. Getting again to the point, your gear IS built well and designed to give the buyer a very trouble-free tubed amp/preamp/integrated. Commendable stuff. But you can't pick good gear with your eyeballs. Watches-yes, audio gear no. Hey, it's a wonder Harbeth is still in business with their homely loudspeakers but obviously as soon as people hear them they get over any concerns that they are like "mom's idea of a nice girl with a good personality". |
I caved and put the KT150s back in after just under 3 days. It's all the loveliness of the EL34s, but at SCALE. Everything is just "more" of what the EL34s have. Soundstage is much much larger, bass is deeper and a little tighter. Sparkle a little more real on cymbals. No downside I can find, other than perhaps I'm in the first or second row of the presentation where I was more like 10th or 12th row with the EL34s, which is not a downside to me (preference), just a difference. |
I caved and put the KT150s back in after just under 3 days. It's all the loveliness of the EL34s, but at SCALE. Everything is just "more" of what the EL34s have. Soundstage is much much larger, bass is deeper and a little tighter. Sparkle a little more real on cymbals. No downside I can find, other than perhaps I'm in the first or second row of the presentation where I was more like 10th or 12th row with the EL34s, which is not a downside to me (preference), just a difference.
I think that is a perfect description. I do worry that guys get the impression that it's a REQUIREMENT in PL gear when it's obviously not. It's not huge. But real. I can also say that at the super low plate voltage and easy way they are biased they will go and go and go. I run the heck out of mine and after 2 years they measure 90% of new. One pair of 12AU7's can be similarly effective. |
fsonic, I don’t think upscale suggested buying amps by their looks. He set up a listening session comparing 2 PrimaLunas to an AR integrated that was more than twice the price of the PLs, after all. He invited everyone to attend. Those who did attend listened and selected the PrimaLunas as sounding better. A single listening session is not enough to determine which component will sound best in the long run, of course.
He also suggests that you look at build quality as part of your buying decision making process. Good advice, I think, but far from suggesting that you buy with your eyes. |
Thom_mackris : I like your thinking. What’s your take on Rogers then? Cathode bias, and I suspect they run the tubes hot. Yet they say this on their website. It’s all true, except I’ve not seen a cathode bias amp with "the longest tube life". :
- Auto Bias Circuit– For long tube life and ease of operation. Self Bias circuit for adjustment free operation and longest tube life. Customer does not need to adjust tube bias. As the tubes age, they adjust for bias changes automatically. The customer can change tubes at any time or replace a single tube rather than the full set of 4 and the amp will automatically re-bias for the change.
Hi Kevin (@upscaleaudio), The first box I look to check off when considering a product is reliability and ease of service. My earlier rant was partially based on this prerequisite. Obviously, great construction doesn’t mean you have a stable design, or good sound, but any component that doesn’t pass this test is immediately eliminated from further consideration. It’s a big trigger point for me. For a vacuum tube product, you should be able to go to any reliable tube vendor and pick up replacements that won’t blow up your gear. Others are free to disagree. People tend to forget that back in the day, vacuum tube gear wasn’t considered unreliable – when our “greatest generation” depended on military radios working reliably in the field because lives were at stake. Unfortunately, a segment of our industry has gone off the rails with respect to this, and it hurts all of us – the consumer as well as the manufacturer who honors this tradition. Some manufacturers will have you believe that a component being on the knife edge of instability is an entry point into the inner sanctum of world class sound – that theirs is a finely tuned, thoroughbred circuit and this is the price of admission. My opinion about this can’t be repeated in polite company. I haven’t had the opportunity to listen to any of Rogers’ products but it’s clear that he checks off this very important (to me) box. His thermal stress testing is impressive. One could conclude (correctly?) that his circuit designs are stable. Great engineering doesn’t necessarily mean great sound, but that’s what auditioning is about. Of course, cathode bias means that you run a slightly higher B+ in order to achieve the same plate to cathode voltage, but it’s the quiescent current in conjunction with the plate to cathode voltage (not plate to ground voltage, which includes the voltage drop of the cathode resistor) which sets the plate dissipation of the tube. I’ve never heard anyone relate tube life to choice of biasing (fixed vs. cathode), but rather to operating points (plate dissipation). This reliability pain point reminds me of a customer’s experience – something I think all too many people can’t or won’t admit to (a bit of Stockholm Syndrome, methinks) … I had a customer who was looking to break in a Hagerman Trumpet phono stage. Jim Hagerman used to supply a small, inverse RIAA circuit that also dropped the signal by 40dB. The idea was that you could run your digital source into this small board and then into your phono stage. Playing on repeat, you could quickly log 25-50 hours on your phono stage. He called me up to ask: “do I have to run my power amp in order to do this?” Well, his big amplifier (4 KT-88’s per side) had a penchant for blowing screen resistors, and every time he powered it up, he experienced angst. It’s that sort of thing that (in my opinion) is ruining the industry. People shouldn’t be afraid to power up their gear. This hobby is supposed to be fun. Now, it’s my turn to start chasing kids off my lawn ;-) Cheers, Thom @ Galibier Design |
Of course, cathode bias means that you run a slightly higher B+ in order to achieve the same plate to cathode voltage, but it’s the quiescent current in conjunction with the plate to cathode voltage (not plate to ground voltage, which includes the voltage drop of the cathode resistor) which sets the plate dissipation of the tube. I’ve never heard anyone relate tube life to choice of biasing (fixed vs. cathode), but rather to operating points (plate dissipation).
Many of the cathode bias amps I've seen come through here run hotter than hell. I think people are attracted to them being"auto bias" when they are "self bias" and the fact that so much power goes up in heat isn't well-known. This come back to you statement about tube amps not being considered a problem back in the day. Squeezing the last bit of dissipation out of a tube wasn't something that Marantz would have done in the old days. |
Hi Kevin (@upscaleaudio), John Atwood (One Electron, Artemis Labs, etc.) has a fairly concise commentary on some of the design considerations you mention (post #2 of this thread in DIYaudio: http://www.diyaudio.com/forums/tubes-valves/132233-fixed-vs-cathode-bias.html). I'm thinking that the hot running cathode-biased amps you've experienced were more of a design choice for maximum power than anything else. There are certainly different issues at play with a cathode biased amp from that of fixed bias. For example, the quality of the cathode resistor's bypass capacitor can have a noticeable effect on the amplifier's sound. Typically (due to the required value), they're electrolytics, although bypassing them with a high quality cap can work. I'm not arguing in favor of one technique over another, but one serendipitous attribute of cathode bias is that you might loose fewer (or no) parts if a tube shorts out (a plate or screen to cathode short). Of course you can build protection into a fixed bias amp to address this. I think the Prima Lunas do this. It's a nice feature. I think that sonic considerations for fixed/auto bias are more evident in guitar amps where the output stage is pushed very hard. At this point, the time constant in a cathode biased amplifier (the recovery time) John refers to in his post comes into play, and cathode biased guitar amps have a slightly softer edge to them as a result. My thinking about audio in general, is that as design architectures "mature" (move higher up the sonic food chain), their sound converges ... toward reality. And so it goes ... Cheers, Thom @ Galibier Design |
Hey folks I'm getting on a plane now and may be out of touch for a bit. My wife is cool and loves audio but I better be present if you know what I mean. Vacation time. |
Update for everyone and a great big thanks to Kevin,
Been listening to my ARC system for awhile now and no problems to report. Sounds great. Very impressed with the low noise floor of the preamp. I can turn down the volume to zero while music is playing and the sound goes to zero. Can't hear a thing. Back when I had the Vincent amp hooked up, I could not do that. You could still hear the music a little.
In a earlier post, Kevin stated he had a PS Audio Direct Stream Digital DAC for sale. I looked into that and could not believe all the great reviews about it. Watched videos on it when it was unveiled back in 2014. Was going to purchase the Sony HAP-Z1ES but could not pass up the incredible deal Kevin had on the PS Audio DAC. I knew at some point down the road I would go with an external DAC but figured it would be awhile before I could afford that option. With the price Kevin had on the PS Audio DAC, I couldn't pass on it. Kevin was very helpful in answering all my questions which helped me decide what to do. Thanks Kevin.
Anybody out there have any experience with that DAC? Some people say it compares to the dCS line of DACs.
FYI, PS Audio is planning on coming out with a new product this Fall to go along with that DAC. It will store digital files on a SSD and come with an app for use on a tablet to manage the music. They hope to unveil it at the Rocky Mountain Audio Fest this October. No word yet on what it will go for.
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Interesting to see this as I also have the Vivid 1.5 and am looking to upgrade amplifier. Presently have CARY SLI-80 Sig F1. Thinking of the Primaluna as well. Wondering if it is worth going to the Dialogue Premium HP with the standard EL34 vs the Dialogue Premium but putting in KT 150 tubes. The HP has 8 tubes, so it will be pricey when time to retube as compared to the regular premium with 4 output tubes. It does have significantly more power, and if it runs cooler, the tubes could last longer.
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Hey Skyhawk. I own a Primaluna Dialogue Premium HP Integrated Amplifier and I love it. I'm 57, an ex night club DJ of many years. I've loved Valve amps since I was a kid and I own a Leak Stereo 20 fully restored. Kevin Deal was reluctant initially to put his name to an amp that couldn't be made totally in the states! I live in Melbourne Victoria Australia by the way. The build quality of the Primaluna Dialogue Premium HP Integrated is beyond reproach. Point to point wiring, toroidal hand made transformers, an Alps motorised volume control, a remote control that weighs about half a kilo......it has everything. No printed circuit boards here and you have a switch on the side to select either EL34s or KT88, KT120 or KT150 tubes. It has 6 12AU7s for the input and 8 power tubes with fully ventilated sockets. They're mounted to the chassis so theres no flexing unlike circuit boards which will eventually fail. The big thing here is full automatic bias. No multi meters here. As the tubes age this circuit which is not in the signal path keeps the push pull mode in its perfect sweet spot which minimizes noise by at least 50% more. It has AC offset to kill unwanted mains noise. It also has hermetically sealed relays controlled by the selector knob to kill input crosstalk which can stand being switched open and closed 50 thousand times. The headphone socket is selected by another switch to stop the socket from being a weak link in the audio chain. The speaker binding posts have no hole to insert cable to improve sound quality and all RCA inputs are gold plated. I'm running a turntable but even though you could've had a preamp installed, I bought a Cambridge Audio preamp to keep the unit stock. Vinyl sound through this amp is stunning and CDs are clean and warm. If a tube fails, a red LED lights up telling you which tube is faulty. Replace it, turn the power back on and forget about bias adjustment! I'm running a pair of Wharfedale speakers and using the stock EL34s, this amplifier just sings whether it's Enya, Pink Floyd or dance music. It has a Home Theatre through selector and it handles this function well. It's a heavy amp 30 kilos, but there was no compromise on build quality......10 out of 10. You can get them as stereo power amps or mono blocks and boy they kick some serious arse. Primaluna have just released a 5AR4 tube rectified stereo preamp and even though I don't need one, I will be getting one as soon as I can order it. The only downside is that if you want to run KT150 tubes, you can't fit the protective cage over them because those tubes are too high but 88s or 120s provide plenty of power but you can use KT150s without the cage! Primaluna are a young company but man their gear makes you drool. Google their internal pictures. No cheap components here. I love my Primaluna amplifier. Both them and Macintosh are my favourite amps but the Primaluna Dialogue Premium HP Integrated wins hands down! Cheers Andrew Peter Collins, Melbourne Victoria Australia!
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@crwindy
Sorry to be 5 months late to respond to this thread again...you may have moved on and made your decisions. To me it was well worth the upgrade to KT150s and "upgraded" driver tubes from what was shipped with it. You can re-read a few of my posts from earlier in this thread where I tried to detail the improvements I heard. I tried the EL34s again--they're great--but I preferred the KT150s for all that they do well, and in my opinion, better than the EL34s. All is relative, and you're correct in that it's not a cheap upgrade. |
Hello there.
I personally have experience with the Prima Luna Dialogue pre amp.
Also with some Audio Research.
Bottom line is Prima Luna !
If you want to fill a big room with high volume go with Prima Luna Dialogue mono blocks added to the pre amp.
Other amp manufactures I would recommend is Krell- 200watts/ch ,or Conrad Johnson 200 watts/ch.
you will be impressed.
Don't overthink too much and enjoy.!
Happy Listening
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would agree with Pokey. Have 4 PL amps, as well as numerous copies of tube amps from other mfgrs.
The PLs sound good right out of the box, and as Kevin noted, all point to point wiring which you do not get with most of the US mfgrs. who use circuit boards to save on labor costs)
The PL amps offer a great starting point to cap upgrading tube rolling etc.
And the PL amps don't run the tubes right at the design limits so you are not replacing tubes every 6-12 months with a PL amp.
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I am far from an expert. When I was looking for an amplifier, I noticed that compared to the number of units sold, there are few used PL amplifiers out there.
Between that and discussion with Upscale Audio I took a plunge and got a Dialogue HP integrated.
I got the KT150 from the start.
I could not be happier.
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Guy, great forum. New to the industry, however my 85 year old dad is a veteran playing reel to reel parties in his day. His biggest complaint is that what he paid 250.00 for in his day is now 5k to 8k. That is a lot of inflation. Saying technology of the old day still relevant today. I like everyone wants to upgrade to a retirement system. With my Tannoy Turnberry GF and my Delphi-Oracle MKVI turntable maxed out with a HANA ML MC I too want the best sound and money value for my tube amp upgrade. Have the Cronus Magnum ii and have eliminated all thumping, humming, etc by moving my WiFi to different location. Volume all the way up, NO distortion! So in the spirit of finding my best integrated tube amp, I ran into Raven on the net and they offer a Free 45 day trial with no questions asked. If you don’t like you spend 40.00 to ship it back. Wish more people would offer this. In defense I do have a high end audio store around 30 miles away but they too only sell limited brands based on the market interests and their ability to invest. I will check out all the other brand mentioned and thanks for the honesty. In defense of Kevin (I live in New Orleans) who else spends the time to make these informational videos that are a great resource for education and information. The TANNOY speakers I purchased are a wonder upgrade from my Golden Ear Triton 2. The sound gets my heart into the music and I dance to that sound, a lot. Thanks Kevin, you give us a great bench mark no matter what we decide on.... Steve |
