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
Bug, I am using RCA 6sn7's from the late 40's that I got from Andy at Vintage Tube Services. I like them lots.

I want to give an update to my original Dude review as I now have a new Dude as mentioned above. Before I tell you how I feel about the new Dude let me share some of my Dude's custom features. Since my system pairs the Dude with a SS amp and Sound Lab M1 speakers, I wanted my new Dude to have more gain then my original Dude. My Sound Lab speakers and very inefficient, but sound so magnificent that they are worth all efforts to maximize their sound. My Dude has;

- 2 6sn7 tubes per side instead of one
- The extra capacitance that comes with this
- Duelund Alexander coupling caps (nothing to do with gain - just my preference)

So how does this new Dude differ? Well it shares the same Dudeness in terms of SOTA imaging and dynamics. The Dude is the champ in these areas. My new Dude also shares the same sense of ease and control I have always enjoyed. Here are the improvements I have experienced in my system.

1) Improved looks and overall fit and finish. Outstanding!
2) Dead quiet of any mechanical noise/hum/buzz or noise through the speakers. My first Dude was also quiet, but this new one is DEAD quiet. The blackest background I have yet to enjoy in my audio quest.
3) Improved feel, operation and volume adjustment with the new 45 step volume control. Love the over-sized metal knob. It is a joy to turn as it screams - high build quality and confidence.
4) Clarity is improved with a transparency I felt was not possible in audio gear. The Dude does this and NEVER sounds aggressive or hyper detailed. Rather, the Dude is composed, rich in texture and with gobs of natural tone. All of this while delivering utter transparency.
5) I find the bass is even more powerful and deep. Tight and fast, but with a fullness I also desire - no crave!

I am enjoying my new Dude to no end and feel very fortunate to have one. It is without a doubt the heart of my system and the ONE piece that brings everything together. IMHO it represents a value of astounding proportions. Why? Because I know my Dude is one of the finest sounding, looking and built audio pieces available and I have it in my home! I can actually afford one of the best now!

Ya, I'm over the top loving my music and don't mind telling Agoners how I really feel:-)
Would you think the dueling alexander caps are an upgrade that could be used to improve on stock dudes?
I don't know if I would call it an upgrade. Paul knows great sound and uses coupling caps that sound great in the Dude already. I happen to think Duelund caps are simply the very best one can use as wanted them. Mine cost $400 for the two and many might find this to costly.

IMHO I found the Duelund caps more to my liking with more body and weight and equal neutrality and clarity, I would say this is a very subjective thing, sort of like the tubes one likes to use...
Well, I decided to place the very best capacitor made into my Dude based on my positive experience with the Duelund Alexander caps. I purchased a set of the Duelund CAST caps. I will now state categorically that this is a major upgrade and has improved the sound of my Dude well beyond the place of the Alexander caps.

Understand they are very, very expensive caps and a set will cost the buyer over $1,000. However, Parts Connection has a sale for these at 66% off and I could not pass it up. I purchased two .22 uf caps and I am thrilled with the results.

How are they an improvement over the Alexander caps. The answer is in every single way from top to bottom. More natural and open sounding. These make all other caps sound rather noisy and mechanical in comparison. My speakers disappear more and instruments sound more real then ever.

On sale these caps cost me $400 and represent the single best upgrade I have encountered in audio.

I liked the caps so much that I purchased 4 more to go into my hybrid amp. The results have been just as fantastic!