Review: Tube Research Labs Dude Tube preamp

Category: Preamps


This is a review of Tube Research Labs’ (TRL) Dude pre-amp(MSRP $3500 and price paid). The Dude is beyond words and my new reference. Like any good evangelist, I want people to “hear” the good news. Hearing implies more than perception of sound. It involves an intuition or flashbulb impression that becomes a window to a new and previously unseen place. If you hear what I am saying, go and hear a Dude.

This review has three parts: 1) a brief audio biography (I like to know where people have been and what they have learned); 2) technical data (this is fairly skeletal. It is based more on gut instinct and less on engineering comprehension. I recommend calling TRL for further details); and 3) listening impressions (both general and particular. I have tried to anchor specific listening impressions around specific pieces of music. I have two reasons for doing this: first, I love music and want fellow audiophiles to experience these particular artists. I have greatly appreciated the music recommendations derived from all reviews read in the past and want to return the favor. Second, it focuses my mind in regards to the Dude’s salient attributes.

Audio prelude: My audio journey has been a relatively long one. It began during the summer of 1979 (6th grade) when I bought vintage KLH speakers from a University of Virginia grad student, along with a Technics receiver and Akai tape deck. Later, I “upgraded” to Bose 501s, a NAD receiver, and some thicker gauge RadioShack wire (sweet). In middle school, my musical tastes revolved around hard rock and heavy metal (Van Halen, Rush, Black Sabbath, etc). During High School, I had a friend who was an avid drummer (he later went on to study Ethnomusicology at Wesleyan), and he introduced me to African, drum based groups such as King Sunny Ade, along with the full spectrum of Reggae. In college, neohippy influences took hold, and I started listening to into the Allman Brothers Band, Dead, and a litany of other “jam” bands. Dave Matthews (at that time they were known as the Boyd Tinsley Band) used to play regularly in the basement of my frat (TKE), and at local bars.

My system remained unchanged through college. During the early years, I did not think of it as a “system.” Music was the sole focus (funny how becoming an audiophile can pervert priorities). Medical school and subsequent surgical training stunted my audio habit, and it was not until 1999/2000 that resurrection life sprang forth. I spent three years doing surgical research in Minnesota, and I suddenly had unstructured time again. I donated my system to my parents and then spent over 6 months “researching” equipment. This included perusing endless reviews and frequenting local HiFi shops and equipment dealers. It was a frustrating experience for two reasons. One, the reviews raised my expectation level and made me believe that there was an audio experience to be had that was quasi-religious (which is true). Two, I had listened to a lot of live music, and little of the equipment I heard sounded real IMO.

I eventually stumbled onto reviews about Merlin speakers. What I read stirred something inside of me. Beneath the verbiage, I heard a description of a phenomenon that defies words: music. The speakers were apparently “musical.” On a whim, I spoke to Bobby P. at Merlin and bought a pair of VSM-Ms site unseen. Bobby was kind enough to recommend gear that synergized with the Merlins, thus removing me from the pain of cobbling together a system a priori. This included Cardas Golden reference cords throughout, an Audible Illusions L1 line stage, a Belles 150A Hotrod stereo amp, a Pioneer DV-525 DVD player, and a Bel Canto 1.1 DAC. My new rig was wonderful and musical, and I was happy for over 7 years. Bobby was the consummate audio gentleman, tolerated my phone calls and stupid questions, and taught me a lot like the good audio father he is.

Unfortunately, I developed an evil itch that is apparently part of being an “audiophile.” I wanted to try something new, but this was not due to overt deficiencies in my rig. I spent months and months researching, listening, and gnashing my teeth. Fortunately, I discovered Intuitive Design within the context of an Audiogon thread for another speaker manufacturer. After a 2 month, in-home trial (thank you, James DaRossa), I bought ID Gamma Summits, Coordinate amps, and cabling, along with a Granite Audio 657 CDP. (As an aside, the Granite piece has pre-amp functionality, and used alone, it was better than some expensive pre-amps I demoed by a significant margin IMO). Once again, I had another musical and magical system. The only issue I experienced, and once again, this was my issue, was a growing irritation with CDs and the act of getting up and down to change them. A good audio friend had snagged a Sonos (thank you, Al Krantz), and the beauty and ease of that interface had me on the computer audio trail. I spent months researching and discovered an obscure French device called the Zardoz, by dbSystems, which is a highly modded (with proprietary engineering…not simply modded) Airtunes. With my Iphone, and a MAC Mini, I was in business. The only thing missing was a PRE-AMP, and this brings me into the present tense and the review at hand. Enter the Dude….

Technical data: (This section is less about data and more about historical background.) Paul Weitzel has been in audio for over 20 years. His primary focus historically had been hi end tube gear. What many people do not know about Paul is that he is an accomplished recording engineer. Working in the recording studio fueled his desire to tweak and improve the equipment. Like Dale Pitcher at Intuitive Design, Paul’s frame of reference sonically is the master tape, true blue analogue. When voicing his gear, master tapes are used. Regarding the recording equipment, one obvious area to improve was power supply. He wanted to design a power supply that would elicit a smooth, relaxed, “analogue” sound found in master tapes.

In terms of technical particulars, I will defer to TRL. I do know that Paul designed the Dude’s circuitry in its entirety. It is not derived from someone else’s circuit. There are no circuit boards, just point-to-point wiring with solid core copper. The signal path has been kept as simple as humanly possible. The power supply, which is the cornerstone of this device IMO, is tube-regulated. It has a three-tube regulator and one 6NS7 per channel. It handles high voltages and is very stable. I have 22uf Mundorf Supreme coupling caps in place (overkill, I know), and there is no oscillation whatsoever. That speaks to the profound stability of this power supply. The rest of the capacitors living in the Dude are, as Bill Dion noted, the size of Red Bull cans. Enough said.

Associated Gear:
Speakers: Intuitive Design Gamma Summits
Amplifiers: Intuitive Design Coordinate Monoblocks (housed in ID granite stands)
Source: Zardoz (WiFi receiver) fed by an Apple MAC Mini + Apple Time Capsule router
Cabling: Intuitive Design speaker wire, ICs, and power cords throughout
Isolation devices: Stillpoints on speakers and stands; Sistrum stands for Dude and Zardoz

Review: The Dude arrived in a large crate via BAX global. In terms of aesthetics, the Dude chassis, which is constructed from aluminum, has a retro, military look. My wife actually liked it (a surprise). The pre-amp itself is a boat. It measures 19 W x 16 L x 5 H (in) and weighs nearly 40 lbs. It does not come with feet or a remote. As a disclaimer, Paul Weitzel had so many TRL costumers of his uber expensive tube gear complain and substitute their own custom feet that he stopped putting them on, assuming Dude owners would do the same. I have my Dude on a Sistrum stand fed by one of Dale Pitcher’s low current reference power cords. The TRL boys do apparently make some mean, anaconda-like power cords for their gear upon request, which also sound marvelous (according to Bill Dion and others).

Due to the monster caps and solid core, copper wiring, break-in is rather long. My Dude is still not completely broken in at 5+ weeks, but time is of the essence, and I am spreading the good news while able. Right out of the box, I heard glimpses of the purported TRL sound, but things were a little tight and arthritic and the soundstage was contracted. At the 4-week mark, everything opened up, the soundstage lateralized and deepened beyond the confines of my room and even created the occasional wrap-around effect with sound to the right and left of my ears. The TRL “house sound” is relaxed and smooth, with diaphanous, see-through detail, combined with great dynamics and bass energy. You have a “live” sound that does not assault your ears in a pushy, aggressive, compressed, HiFi way. All the vibratory energy of live instruments is faithfully recreated. My good audio friend, David Hartwick, aka Interlochen, recently coined the terms EOA (envelope of ambience) and AEC (atmospheric enervation coefficient). These terms sound like pseudo-scientific, audiospeak, but do capture the essence of the phenomenon I am trying to convey. We are all after the auditory illusion of live music, and the Dude delivers IMO. Another important point to mention is that the Dude does not fatigue the ears with bad recordings. That is critical. Some systems I have heard, while very resolving, fatigue the ears. The Dude IS NOT in this category. Crappy CDs are actually listenable. If you want to ruminate more on this issue, go read the Stereophile article, “God in the nuances,” (, in which a group of German psychologists performed blinded listening experiments comparing solid state and tube systems with an emphasis on listener fatigue. Now enough with broad generalizations or impressions and onto listening particulars and listening vignettes.

1. Bill Evans, Waltz for Debby: recorded live at the Village Vanguard on June 25th, 1961, it is one of my favorite Jazz albums. I liken Bill Evans to a Mr. Rodgers within the jazz arena…he is able to take you through the neighborhood so to speak. In my previous system, I could hear the clink of glasses and the amorphous buzz of conversation in the background. Now, I am hearing background or ambient detail that I had not before. I can pick out someone sneezing, particular male and female voices in the audience, laughter (male and female), the opening and closing of a door, etc. The sense of space or place rather, and the details therein is simply stunning. As I mentioned before, I am a big, big fan of live music, and the Dude is able to capture the sonic ambience of specific venues beautifully. Love that.

2. Allman Brothers Band, Live at the Cow Palace, San Francisco, 12/31/1973: again, one of my favorite live recordings of theirs, not due to its pristine audio fidelity, but due to the performance. The Allman Brothers were/are virtuosos musically with their fusion of blues, southern rock, and jazz. Their seamless improvisation is/was as good as any jazz troupe I have seen or heard. At first glance, it seems like this sort of live performance shouldn’t be hard to reproduce. Wrong. In my experience, live recordings of “jam bands” can sound bright, splashy, and ill defined (and this is not simply a byproduct of bad recording but can be). Like the Grateful Dead, they seemed to often play simultaneously with multiple, interwoven lines and not simply interchangeable solo and backup roles. With the Dude, individual performers are well delineated. In one piece on Disc 2, titled “Drums,” which then trickles in to “Les Bres in A Minor,” two different drum kits were going simultaneously. You can hear exactly where they were on stage (which is very large and deep), the echoes of the drum strikes on the venue, and the great dynamics necessary to create lifelike drums, interspersed with the crowd shouting during quiet interludes. And then the bass guitar comes in out of nowhere with tangible echo and reverb. I never saw the Allmans live, let alone in 1973 in San Francisco, but now I am able to do so regularly. Righteous and amazing.

3. Danny Gatton, Redneck Jazz Explosion: I had the pleasure of seeing him live in Charlottesville, VA, in 1988. He is the best guitarist I have ever laid eyes on and it is incredibly sad that he is no longer with us. This album is a must. He teamed up with Buddy Emmons, a steel guitar maestro, and toured and later recorded this album in 1978 at the Cellar Door Club in DC. It is intricate, explosive, and complex. Again, the Dude lays it all out like you are there. Great depth, explosive dynamics, and a level of three-dimensional “detail” that was new to me. Killer. Absolutely killer, dude.

4. Michael Hedges, Beyond Boundaries Guitar Solos: another must for any red-blooded audiophile’s collection. A virtuoso guitarist (considered by many to be one of the best of the 20th century) and composer who sadly passed not too long ago as well. If you ever want to put your system to the test in terms of being able to create a true auditory hallucination, his music is ideal. Michael developed a style of play in which he finger slapped the strings, creating the illusion of multiple guitarists playing simultaneously. With the Dude, rich harmonic detail and a vibratory presence or “EOA” was elicited. I could literally feel the vibrations of his guitar in my chest. Madness.

5. Saint German, Tourist: another great album worth owning. Saint German, a pseudonym for French composer-producer Ludovic Navarre, samples a lot of Blue Note jazz, Latin music, etc into a kind of hip, hypnotic, urban, dance club type sound. One feature I must emphasize regarding the Dude is the incredible bass and dynamic range. Much of this album has deep bass notes and a sweeping dynamic range (stretched to the hilt by high energy flute) that can sound compressed. The Dude captures the pulsating nature of this music that puts you right at the club with Martini in hand.

Conclusions: The moral of this story is that the Dude pre-amp by Tube Research Labs is astonishingly good. It delivers performance -- megabuck performance -- at a reasonable price. Why is it so good you ask? I don’t know exactly, but I do believe it may have a lot to do with their proprietary power supply. You have heard the dictum: power supply, power supply, power supply. Anyway, don’t take my word for it. Go and listen. That may be a tad bit difficult as TRL is relatively obscure and does not have a dealer network. However, Paul and Brian Weitzel are accommodating, wonderful, and honest to a tee and will work with you. They have been a pleasure to deal with. I live in Charlotte, NC, and any phile in my neck of the woods is welcome to roll by for a listen. I must also emphasize the contributions of my associated gear (Intuitive Design speakers, cabling, amps and dbSystem’s Zardoz) all of which are stellar IMO. That being said, the Dude elevated the performance of my system substantially. I am a very, very happy man, and that is quite a statement for any perfectionist and neurotic audiophile to make. Please feel free to contact me at any time in the future to see if I am still on the TRL train. Generally speaking, people who own their gear become long-term costumers. Ciao.

Andrew J.L. Gear

Associated gear
Speakers: Intuitive Design Gamma Summits
Amps:Intuitive Design Coordinate Monoblock amplifiers
Cabling: Intuitive Design cabling
Source: dbSystems Zardoz
Isolation devices: Stillpoints and Sistrum stands

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Nice job!
Congratulations to The Big Lebowski, awesome review.

I'll say it again, you have a way with words and your review reflects this.

Your time for hopping off the merry-go-round and flavor-of-the-month club has arrived, way to go ***Dude*** !!
Outstanding review! Your mention of the "incredible bass and dynamic range" of this piece under listening vignette #5 is very highly appreciated, at least by me. My main "phobia" regarding tube amps or preamps has been the potentially anemic bass that such units can have. Given its other attributes (which you describe so eloquently), it sounds like a piece worthy of audition, even if doing so requires some effort.
Nice review Andrew. I will be eagerly awaiting mine.
Spot on review Andrew.

One section of your review really captures the essence of the Dude in both of our systems.

"You have a “live” sound that does not assault your ears in a pushy, aggressive, compressed, HiFi way. All the vibratory energy of live instruments is faithfully recreated."

I say a great big AMEN to your wonderful words here. Yes, the Dude is the MAN and brings music to life in my home also.

Very nice review indeed.

Thanks for the kind words guys and thanks Pat/Rx8man for sending me Bill/Grannyring's review in regards to TRL. I would NEVER have known about them otherwise. My hope is more people will get a chance to hear this pre-amp and other TRL offerings.

I would also like to thank Bill/Mdhoover for singing the Intuitive Design song. Again, I would have never known to look....
Enjoy the DUDE! I own a GTP-3, TRL early work and love it.
Expansive soundstage and effortless!
I had had the mistaken idea that this unit was closer to $5K, and I was STILL thinking of checking it out. At $3500, it's even MORE tempting. Thanks, "Dude." Even though I'm already satisfied......still......didn't regret upgrading to Chimera cables when I was also satisfied (already ecstatic, actually) Andrew, your testimony is VERY compelling. I called the company and they CAN do a remote but they don't like to. When I called and asked about it, he was cordial and said that they could do it, but I could sense his distaste at the prospect defiling his fine creation with an unnecessary "add-on" such as a remote volume control. Purists, those TRL "Dudes" are.
Bill, as I mentioned, I paid 3500. I believe TRL has some fancier chassis in the docket with laser etching, etc, that will push the price to around 4K??? As for the remote, I find that I dial it in to a certain level and just sit back. In the past, I would get up and down a lot to twiddle with the volume. Now, the soundstage, etc does not change much if at all with volume changes and thus I am less compelled to do so.

Himiguel, expansive and effortless are two good adjectives that I failed to use in describing the Dude. Good stuff. I am glad you are enjoying your GTP-3. Very kool.
Andrew thanks for the great pics especially the back. I like gear that has what is needed and no more and that is what I see on the Dude. Great work on the review. Thanks for taking the time to post the pics and the review.
Saygrr, thanks for the input. In regards to the aesthetics, my snotty, fashionista wife actually found the Dude attractive, a true shocker. Again, it looks like it was pulled out of a vintage submarine.
The cosmetics kind of reminds me of the Wytech Labs gear. Mine will sport purple heart knobs for the volume controls and brass knobs for the input selector and stereo/mono switch. These are carry overs from my TRL Pre-1.5. I'm also going to look into a custom face plate.
Well, I am at the 6 week mark and things continue to open up further (if that were possible). I believe the Dude is one of those pieces that matures even after months and months of use. I experienced that phenomenon with my Summit speakers.

I am now completely in the "rediscover my music collection*" mode which is a good place to be. I cannot emphasize that element enough in regards to the Dude. When your focus shifts from equipment analysis to music, things are as they should be. The irony is that well designed gear ultimately becomes invisible.

*rediscovered or discovered music worth checking out:

1. Patricia Barber, Live: a fortnight in France
2. Steve Davis, Quality of Silence
3. Richard Leo Johnson, Language
4. Miles Davis, Bitches Brew

Finally, in addition to Bill Dion, I wanted to thank Jack Seaton for waving the TRL flag. You hear their enthusiasm and it sounds sketchy and too good to be true, but it ain't. Thank you.
It's amazing just how much music has been there, all along, that we haven't heard, huh?
Fantastic review, Andrew. I've been anxiously waiting on my Dude for a few weeks now. The new chassis parts should be in this week then it's clear sailing from there.

Thanks for the review, makes me even more excited to listen to it.
Andrew if you don't mind what is the story on the db systems Zardoz? Any comparisons before purchasing an obsure item for your digital sound?

By the way outstanding job of describing your experience. Any career in writing for us mobsters in a more reputable venue?

Pm if you like and thanks.

Mintzar, you are in for a treat. If the jones becomes unbearable, please feel free to swing through Charlotte. My wife tolerates philes and won't lash out. She does get irritated when she is trapped in the car with me and I am jawing about audio.

Luis, thanks for asking about the Zardoz. I will reviewing that device shortly. I did not do head to head comparisons prior to was a gut decision. Previously, I owned the Granite Audio 657 CDP which was very, very good in its own right but grew tired of spinning CDs (lame Gen X). That being said, the Z is righteous (like the Dude) and people need to know about it and at least put it on the list while looking for digital gear.

Thank you for the kind words about the review. I have always enjoyed the process of writing. It flushed up a lot of audio memories, crazy conversations with philes, etc. Unfortunately, I am tired surgeon and have little in the tank for extracurricular activities such as review writing. I decided to write this review out of moral compulsion more than anything. I have a habit of finding obscure but noteworthy gear and felt it was time to flap my gums a little. That being said, I might consider it at some point in the future when my life is less insane.
I'm sure that being a surgeon keeps you busy enough however, it is a shame that you aren't a reviewer, Andrew. I'm looking forward to your review of the Zardoz as we have had inquiries about them from family members.
thanks Brian...

Keep up the good work....
I'm also getting a Dude in a couple weeks, that's being converted from an earlier TRL 1.5 battery powered version.

It has separate Left / Right 40+ step attenuators which will remain from the previous preamp set-up.

Please let us know your impressions after the Dude is in your company.
I had a fantastic time listening to Andrew's system last weekend. Absolutely fantastic music! I'm really looking forward to bringing some toys over to see where his expensive gizmos can be pushed! Thanks for the excellent hospitality, Andrew! It was a real pleasure!

I've had the Dude for over a month now and it never ceases to put a smile on my face. I'll be writing a review myself as I snatch myself away from the film I am shooting right now. But the Dude is beyond my high expectations.

I'm looking forward to your review of the Dude, however, you have piqued my interest. What film are you working on, or are you at liberty to say? Could it be The Big Lebowski sequel? :)

I'm also happy to hear that TRL family members are reaching out to each other. Toys are meant to be shared and it makes the journey all that much better. Enjoy!

The Dude abides!

I am actually working on an independent film for the next few months, but then will be working on a sci-fi/fantasy film out in LA after that -- which I can't say anything about. The film I am working on now is about a guy who wakes up completely naked in a cornfield and has to survive his way home. It's about how he gets clothes, what dangers he faces along the way, and how the heck he got there in the first place. It's a fun shoot.

I'm not sure that I can surpass the Coen Brothers' work on The Big Lebowski, though that'd be a great film to work on!
Chris Farley would have been my choice for the guy in the cornfield !

It's saddening he's not here anymore.
LOL, yeah, Chris Farley's physical comedy would add a lot to the role. Maybe it's time to watch Tommy Boy again?

Ryan: What an exciting life you lead. Looking forward to your review.

Pat: Your Dude is up and running. :) Sounding good, too.
I'll keep it short < Thanks Brian !
Hey Pat! I'm glad Brian is enjoying your Dude, Dude. (o: I hope he lets you hear it for yourself soon.
Awwww, Pat. You're supposed to say, " That's great, Brian!" I'm glad you're enjoying MY preamp." (o:
Now Sherod, you behave, or I'm gonna have you replace some caps !
I apologize for being slow to post the review! My shooting schedule is heavy right now and I haven't had a chance to breath much less listen to music this past week!

But hey, at least I'm housebroken.
I will agree with that statement. Ryan is indeed housebroken. He behaved well in front of my wife....
Ryan is housebroken? That's good to hear, that rug really ties the room together.
Confirming Andrew's Zardoz analysis. It's ability to decipher spatial information is uncanny. There is an abundance of image floating. Vertical spatial information rendering is the best I've heard by far: Some images fully 1.5 feet above the speakers -- not vague ghosts, but palpably formed instruments.

Tonality is also the finest I've encountered. It removes more plastic and digititis from CDs than any CD playing configuration I've encountered. The harmonic richness of well recorded piano is simply mezmerizing.

It has all the audiophile attributes we demand, BUT...most importantly: The Zardoz is a deeply musical instrument. It wraps and iron fist around your soul and

I am supremely critical and do not engage in hyperbole. It is my wish that every 'phile audition this piece. Unlikely, but such is its mastery of music.
I have the bad habit of emailing reviewers/thread masters on Audiogon about their sentiments about a piece of equipment after the fact. Shockingly, a high percentage of people who wax poetic about equipment later throw it into the Audiogon recycle bin not long after the initial review. I will answer my own question: NOT! The Dude is just as spectacular and musical today as it was over a year ago when I first purchased it.

I can offer a few observations:

1. Power cords: it is relatively impervious to power cords (relatively). Good cords will still make a modest difference, but not to the degree that I have experienced in other equipment. I believe that is a testament to the quality of the power supply.

2. Tubes: I was relatively happy with my NOS RCAs, but, being a scientist of sorts, I decided to roll away based on the suggestions of others. I tried the Raytheons (I do not think they were the real deal organ grade). They had great clarity and speed and detail, but were a tinge hot on the top in my system. I recently tried a NOS Tong Sol. That tube was warm and fat but was a little slow and lacked clarity and detail. I recently popped in Marconis, and they have a very nice sonic signature with better clarity than the Tong Sols and GE tubes, but I still have an itch. Gary "Glory" Anderson really likes the 12XS7s, and I may convert my unit to 12V from 6 and see how they sound. All that aside, my system is sounding very, very good with the Marconis in the chain.