Review: Tube Research Labs Dude Tube preamp


Category: Preamps

This review is on the Dude tube preamp made by Paul and Brian Weitzel of Tube Research Labs (TRL). I purchased this preamp some 7 months ago direct from TRL which is how they market and sell them. The price is $3500. The unit has 5 tubes total with one 6sn7 tube per channel.

I am not a technical person and can only comment that the unit is very heavy, all point to point wired and contains a forest of caps the size of Red Bull and Coke cans!

The Dude also benefits from TRL’s newly designed power supply which is something very special indeed. It comes with two sets of outputs and three inputs – all RCA. I think Paul can work out XLR’s if you desire, but you would have to ask him. My unit has special wooden knobs which I prefer over his high quality gold ones.

The unit is turned on by a breaker switch on the back on the unit. The Dude does not incorporate any fuses, simply the breaker, for improved sound. The chassis is well built and solid in terms of fit and finish. While it is not eye candy, the Dude offers a simple attractiveness.

I must have over 700 hours on my unit by now and it is fully burned it. I have found this preamp responds very well to tube rolling. This review is based on the use of RCA 6sn7 GT’s ,VT231 with smoked glass. I picked up 6 of these for $130 on Ebay and just love them in the Dude. Paul likes Raytheon NOS’s, but I have not tried them as yet.

I like female vocals, Christian contemporary, jazz, piano and acoustic guitar instrumentals as well as some small ensemble Classical. You can also read my review of the TRL Samson amps for more information of my musical tastes.

As you have noticed I have owned and heard many great preamps over the years. The Dude has far outclassed each of them in virtually every important performance area. I particularly liked the Audio Horizons and Tube Distinctions preamps on my list. The Dude simply recreates real music in my home well beyond these other fine units.

The level of transparency is utterly shocking. Details and musical lines previously hidden now come alive and my music sounds brand new to me. I was amazed at all the instruments and notes I was missing in my recordings. What a revelation and joy to me as one into this hobby for 30 years.

Right now I am listening to solo acoustic guitar by Phil Keaggy and am consistently astounded with the additional pic, string and guitar body sounds completely hidden before. The sting plucks are so much more distinctive with every molecule of nuance presented to my senses. This is true at even the lowest of volumes on my system. Magic my friends and I mean magic!

I have never known any preamp to dig as deep, taunt and powerful in the bass region as the Dude. Bass has incredible impact, drive and articulation. Easily the best bass I have yet to encounter in a preamp. This tube preamp will shatter your preconceptions of tube preamp bass performance. Bass is no longer this vague sort of deep running tone, but rather a distinct and articulate portion of the whole performance.

Tonality is so beautiful and right. Not a hint of listener fatigue to be found. The massive amount of detail is delivered with exquisite beauty, body and soul. Don’t we all want that? The Dude does both in a way I felt was not even attainable. Tonality is vitally important to me. Voices have weight when they should. Like the guitar work nuances mentioned above the human voice is rendered absolutely and completely naked before you. You will hear aspects of your favorite vocalist you have never heard before. More air, more texture, more nuance, more personality – just amazing.

The Dude sets the stage big, wide and deep. First time I have heard stage depth so profoundly obvious. I now get a sense of what some reviewers mean by 3D! Life sized performance is a consistent attribute of the music flowing from this preamp.

I like to listen to very loud music at times. I like the live scale it gives the recording. The Dude is always in control and supremely poised. Nothing, no part of the audio spectrum is ever out of balance or forced. I hear a new standard of performance in terms of effortless, uncompressed music.

My system seems to have infinite room filling abilities. This is very, very important to me. Even at very loud settings music must flow not attack! The Dude is a complete gentleman in this regard.

Highs seem to have no ceiling or cap as they extend smoothly and without any hint of hardness. I am very sensitive to bright or hard highs and will quickly box up a unit if I hear a trace of it. Yikes! The Dude is a smooth operator and does so without robbing music of the precious detail and air we desire.

Well, I could go on much longer as the Dude is a revelation to me. It is the heart and soul of my current system and really makes everything sound so real and right.

I hope my words were able to convey what I experience with The Dude.

Have fun!



Associated gear
Please see my member system.

PBN Montana EPX custom speakers
TRL Modified Sony CD player/battery
TRL Samson amps
Audio Horizons cable
TRL Cables
Star Sound Sistrum stands
Echo Buster room treatments
SVS PB 12 Plus/2

Similar products
I have owned or had these preamps in my home system.

Audio Horizons TP2.1 fully loaded
Joule LA100 MKIII
Conrad Johnson LS16 V2
Thor 1000 MK2
Tom Evans Vibe
Supratek Cortese
Supratek Syrah
Audio Note m5
Wavac PR-X1
Rowland Concerto
Cary SLP98
Aesthetix Calypso
Tube Distinctions SoulMate
Placette passive
Wright Sound WLA 12A
Aloia 11.01
Belles 21A
Rogue 99
128x128grannyring
Kudos to Grannyring for stating the obvious and keeping things real.

"If a minor mod is required to accept the new voltage, no matter how long it takes to make the change, it is not essentially a direct replacement. A direct replacement would be a simple tube swap IMO."

So you are arguing semantics? Me no understand the point of that...

The point is pretty simple but its clear you missed it. Not being argumentative, just stating that if a circuit mod is required it can't be considered a direct replacement. Think plug 'n play.

"I thought these forums were supposed to be about sharing information and experiences. Now we're talking about keeping things hush because we have concerns the price might go up if too many people know about it. Sounds like some type of exclusivity to me."

True enough, but what is the relevance to you? You don't own one, but I think you need one. It has been clinically proven to lower blood pressure. Owning the Dude has real health benefits....

Being that you're a doctor maybe you should write me a prescription for one. Better yet, enroll me in a clinical trial program. That way I get one for free.

In all seriousness I'm happy with what I have. If I know Paul The Dude isn't the end of the line either. I'm sure he'll be cooking up something even better in the future.

"I know a guy with a boat load of these tubes. He's going to be all smiles when he learns how valuable they're going to be."

My point exactly....

Actually I was being sarcastic. He developed a circuit for a 6SN7 based tube amp a while back. When I asked him why he didn't use the 12SN7 or one of those variants I knew all I had to know about these tubes and while they're still sitting around his shop collecting dust. Again, Grannyring's post keeps it real. There are lots of really good 6SN7 tubes that are inexpensive and that sound very good. I have some lying around here myself since one of my amps uses them. I also have some really nice NOS tubes that I didn't pay an arm and a leg for but should reap a nice ROI if I decided to sell them.
Good source for the Marconi tubes? What is the exact part number designation? Clear top, smoked glass, fringed rear window?

On the mounting, are there locations to add feet or would I have to drill and tap myself? Engineer and DIY'r so no fear here.
Marconi tubes come with a silver metal base or black base. I am speaking of the black base. No other designation needed.

Hard to find. Try Andy of Vintage Tube services.
Clio09 (Tony): Paul has heard from a number of TRL Family members that one or two of the well known tube vendors have raised their price upon word that Paul switched to the 12 volt variety. This kind of sucks. Unfortunately, such vendors are all that some guys have the time for. Myself, I've bought my 3rd RCA 12SX7 in less than 2 weeks on eBay. One was $4.99, another for $7.50, and a $15 "Buy it Now" for the third. You can also buy 12SN7's on eBay for less than $10. So there are less expensive means. Paul and I have a trip to Oregon lined up, and a friend there with several large boxes of NOS tubes, so we can replenish the TRL stock.

Grannyring (Bill): What do the plates look like? The Marconi branded 6SN7's that I've came across were made for Marconi by Sylvania, and have the Sylvania "T" style or triangle plates that are "V"ed as you look at them, from the front. I haven't seen any yet that aren't Sylvanias.

I haven't bought tubes from Andy in the past, but may give him a call on Monday. Thank you.
The only Marconi tubes I have seen or used are the black base ones with either white or red Marconi lettering on them. Both sound great.

I am not sure about the detail of build and must let one with more tech knowledge answer about plates etc...

Sorry