FS: Tube Research Labs "DUDE" preamp - SOLD

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genjamon

FS: Tube Research Labs "DUDE" preamp - SOLD
« on: 4 Nov 2015, 10:01 pm »
*SOLD*

The Dude as been a central part of my system for almost three years.  It started what has turned out to be a long evolution in thoroughly upgrading my system from solid mid-fi to true high end sound.  It established a baseline for me in terms of what truly high end sound is, and has been the heart and soul of my system for the past years.  It's known as a value leader in the $5-7K price range.  I have compared it directly to Bent AVC, Tortuga-based passive, Dodd pre/buffer on battery supply, and Ed Schilling's The Truth LDR/buffer.  Some of these might have edged it out a tad in detail, but never even close in realism department. 

But I've upgraded to a Lampizator Big 7 DAC, and there's some kind of an impedance mismatch going on between these units, and as good as the Dude is as a preamp, the Big 7 has an unparalleled DAC magic going on and I have to let the Dude go at this point.  There isn't room for both in my life, unfortunately, even though I've considered keeping it for a second system - but geez that would be total overkill for TV watching duties!  I'll be going with the integrated tube pre in my Line Magnetic 518 for now, and exploring the Big 7's integrated volume control solution over time.  I really wish the impedance mis-match wasn't there, but it appears the Big 7's unique output tube design has created a bit of a rare situation here.

The Dude is a 6sn7 based preamp.  Has a massive power supply section larger than any amp I've ever owned.  This one also includes single volume control knob and remote control volume control.  The remote control system is outsourced from John Chapman - it's a completely independent motor structure tied to a high quality stepped attenuator, powered by its own power supply and completely electrically independent from the rest of the preamp.  It's about as purist as you can get in terms of adding remote control functionality.  Built like a complete tank - 80 pounds, 8.5" tall, 20" square.  It won't fit in all racks, so carefully evaluate that aspect.

This unit was built in 2011, and has had the Duelund signal capacitors installed.  I never heard it without them, but am told it's a big upgrade. 

Four inputs, two outputs.  All single-ended RCA.

Asking $SOLD plus shipping - less than half what it costs for a new one...  It will ship in the original plywood crate - pretty much bomb proof, but around 100 pounds for the full package.  It's just under the weight limit for Fedex and UPS, so doesn't need freight shipping though.  I'd estimate $150 shipping for most places in the US, but can get quotes. 

I'm also including some extra 6sn7 tubes with it - some National Unions I've used for a couple years, some CBS/Hytron, some KenRad, and a set of vintage 1950's Russian Foton 6sn7 equivalents that are still NIB.  I will also ship some extra rectifier tubes.  Probably at least $500 in tubes being included here.  The Dude is designed to run 24/7 and never be turned off, and it runs the tubes extremely lightly.  A set of 6sn7's should last 10 years or more, according to the manufacturer.  Even if he's off a bit, it's built for very long tube life for sure. 

Any questions, please ask!






« Last Edit: 5 Nov 2015, 11:31 pm by genjamon »

genjamon

Re: FS: Tube Research Labs "DUDE" preamp
« Reply #1 on: 4 Nov 2015, 10:46 pm »
No balance control.  The stepped attenuator handles both channels in parallel. 

genjamon

Re: FS: Tube Research Labs "DUDE" preamp
« Reply #2 on: 5 Nov 2015, 12:36 am »
The faceplate is right at 7.5". The main chassis is 7 1/16" - pretty much 7".  The footers should be reasonably easy to remove, but I think you'll need to access them internally to loosen them.

Big Red Machine

Re: FS: Tube Research Labs "DUDE" preamp
« Reply #3 on: 5 Nov 2015, 11:47 am »
Good call Bob. Love my Dude!

genjamon

Re: FS: Tube Research Labs "DUDE" preamp
« Reply #4 on: 5 Nov 2015, 05:33 pm »
Thanks BRM!

Bob, you have PM

genjamon

Re: FS: Tube Research Labs "DUDE" preamp - SOLD
« Reply #5 on: 14 Dec 2015, 03:51 am »
Hi Bob,

Interesting results. Especially since you've had the unit since early November and this is the first I'm hearing of the remote issues. I can't comment on the performance of this unit relative to your friend's Dude. This is the only one I've ever heard.  It might have been a better idea to PM or email me to discuss before posting this to the entire Audiocircle forum for all to read in perpetuity.

Regarding the remote control, yes I have replaced the batteries before. And yes, it just requires a small hex head to unscrew the end cap and slide the board out for battery replacement. I can't remember what kind of battery is required, but think it's either AAA or AA type, nothing highly specialized.

If you think there is a major difference in performance between the two units you've heard, you might want to give Paul W. a call to discuss. He might be able to walk you through some diagnostics to ensure the unit is working up to spec. I did this when I first purchased the unit several years ago, and I bet he would help you out.

If you'd like to discuss further, might I suggest we take this offline via PM, email, or even a phone call? I believe you have all three points of contact for me from our previous conversations.

Sorry you're having trouble.

~Ben

Bob Stark

Re: FS: Tube Research Labs "DUDE" preamp - SOLD
« Reply #6 on: 16 Dec 2015, 02:39 am »
Sorry Ben,  I erased all the old info so this was it.  Thank you about where the batteries are located.  I'm not upset at all.  If I get the DUDE to sounding as good as I think it can, I'll be keeping it.  If not, I'll be perfectly happy with the AI 3A and will save much money.

Bob

genjamon

Re: FS: Tube Research Labs "DUDE" preamp - SOLD
« Reply #7 on: 16 Dec 2015, 02:53 am »
Understood, Bob. Glad there are no hard feelings. If I were you I'd explore tube rolling in the power supply. To my knowledge those are the original rectifiers and such. It might be time for them to be replaced. Or there might be better NOS tubes to enhance the sound. Not sure if the unit you borrowed had been carefully tweaked in these ways or was using stock tubes. And again, contacting Paul W of TRL about double checking capacitor values and such in the unit might be a good idea.

Regards, Ben

Big Red Machine

Re: FS: Tube Research Labs "DUDE" preamp - SOLD
« Reply #8 on: 16 Dec 2015, 03:21 am »
If there is a "sound" issue, I'd start with the tubes right away. The rest of the preamp is built like steel. I have 6 sets of tubes for my Dude and can swing the sound many degrees loose to tight just with the output tubes. So maybe some rolling and you'll get there soon. :D

sfox7076

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Re: FS: Tube Research Labs "DUDE" preamp - SOLD
« Reply #9 on: 18 Dec 2015, 04:37 am »
What tubes does the Dude take?  I know 6SN7s are in it.  Can it take 12SN7s (it will starve the filament.  I prefer them in an octal preamp I have to 6SN7s because of the starved filament.