“I recently bought a Belles 22a preamp that had Siemens tubes (not the crappy stock tubes). It is a fabulous preamp, regardless of price. My dealer suggested the RT tubes for a little more emphasis on both the low and high frequencies. I bought them and the difference was anything but subtle, from the first note of the music. The increased "slam" on the lower bass notes was immediately apparent as was the extension on the upper end. I have fiddled around with interconnects and cables off and on for years, most often with no discernible different in sound (to my 60-year old ears), but this bit of tube rolling was a sonic wonder. The Seimens perhaps have a bit more emphasis on the mid-range, so if you are a bit vocal lover, they may not be preferred for you. I listen 99% to jazz ensemble music with few vocals and I very highly recommend these tubes. I couldn't be happy with this purchase. In fact, I am going to buy a couple extra pairs in case I live to be 90 years old!!! Upscale Audio is the real deal for tubes, don't waste your time on ebay with sellers with potentially questionable-quality tubes to try to save a couple of bucks... life is too short. I judge Upscale's prices to be extremely competitive. You buy from Upscale, you need not worry about the quality of their products. I don't mean to sound like a shrill for these guys, but in this audio world of less-than-scrupulous dealers, these guys clearly deserve a huge "shout out".”

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Posted 12 years ago

“Replaced my Telefunken smooth plates in my Jolida JD100A Tubed CD player, and Wow! These Mullard's are much more dynamic. Bass is rounder, treble is smooth after burn-in. And the midrange is typical Mullard....very real without being forward. These are my favorite's!”

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Posted 12 years ago

“If I could keep only one 12au7 tube to use in my EE Minimax preamp this RT 12au7WA would be it. Excellent across the board- superior soundstage depth, nice punch and detail, mildly euphonic with nice tone reproduction across the entire frequency spectrum. Beautifully balanced with solid bass and clear high end and synergizes well in the Minimax with the classic 1950's era CV4001, EZ90 and U78 rectifiers, and with any 12au7 you pair it with- from the overly euphonic RCA black plates to the flat response of a Mullard M8136, and no noise or distortion evident at all.”

1 Helpful Report

Posted 12 years ago

Charlie Arachy

Unverified Reviewer

“Been using the stock Tungsram 12au7's in my Linestage section of my Spirit 3 and though I was quite pleased,I felt I needed a little more openness and pase..The RT for Upscale Audio made a huge difference in Openness and that " Air " we all search for..Excellent Bass too..Excellent tube...”

2 Helpful Report

Posted 12 years ago

“This platinum grade jewel has been in service for two months. I like it so much I saved my loose change and purchased two additional in case they go away to never return. My KT-88 based VTA ST-120 amp shines from top to bottom with this tube in the center preamp position. You can hear deep into the mix with laser focused staging. Healthy bottom, accurate mids, well balanced yet airy top. The RT has plenty of gain, ultra-low distortion, and no noticable noise. I like all kinds of music this amp has never met its match with this tube stock - Radiotechique 12AU7WA preamp, Sylvania 5963 phase inverters, and Gold Lion KT-88s. Highly recommended if you are looking for some excitement!”

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Posted 12 years ago

“Well, until I received this tube, the Radiotechnique 12AU7 1965 version was my favorite ( see my review). However, this tube provides my system with the greatest depth of image, separation of instruments, and inner detail. Even quiet, instrumental sound images deep in the mix are highly articulated and palpable. I love that.”

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Posted 12 years ago

“In my humble Bob Latino ST-120 Amp (stereo KT-88 kit) my search for center tube preamp has ended with the RT 12AU7WA. Top end air and sparkle make cymbals, bells, or anything percussive very believable. The top is reminiscent of 12BH7s but without the sibilance or exaggeration associated with the ones I tried. Bass response full and deep. Midrange and vocals accurate. Very seductive 3D presentation but might be too much in some systems if you prefer neutral, dryer sound. But the coloration magic is why a purchased a tube based amp and the RT 12AU7WA delivers. Really makes my system come alive and sound its best!”

2 Helpful Report

Posted 12 years ago

“For anyone out there who owns the Hifiman EF5 amplifier, you know that the amp has amazing sound quality for the price that it's being offered at. But, the tone of it is usually described as being a bit too warm for certain kinds of music... Well now that issue has been solved because of this fantastic tube! This hasn't broken 50 hours of use with me yet, but I can already tell the difference and I can't wait to get some more burn in hours. The soundstage is just perfect for this amp and the highs, mids, bass, all work together excellently. Rock music finally has more to it, and music with large musical ensembles finally sound like there being played in the rooms that they were recorded in. I would highly recommend this tube, perhaps one day I'll try the premium version with the cryo treatment added to it just to see if there is a big difference in the sq.”

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Posted 12 years ago

Radiotechnique 12AU7 Platinum Grade / No Cryo Reviews