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"Once you’ve heard the difference, you can’t unhear it"

Doug Schroeder - Soundstage!

“What we have here, my friends, is the valve equivalent of Viagra.."

Ken Kessler - HiFi News


Kinkless Tetrode Tube



General Characteristics

Plate dissipation (Max.)

40 W

Grid dissipation (Max.)

6 W



Heater – Voltage

6.3 V

Heater – Current

1.6 A

Maximum Ratings

Anode voltage

800 V

Screen grid voltage

600 V

Va, g2

600 V


200 V


35 W


6 W

Pa + g2

40 W


230 mA

Vh -k

200 V


250 °C


Factory Matched Quad

EAT Diamond KT88.jpg
EAT Diamond KT88.jpg

EAT 300B

Directly Heated Triode Tube



General Characteristics

Plate dissipation (Max.)

36 W


Oxide , directly heated



Heater – Voltage

5 V

Heater – Current

1.25 A

Other Ratings

Maximum Anode voltage

450 V


5 mA/V

Measured Value If

1.1 A

Amplification Factor



Factory Matched Pair

EAT Diamond KT88.jpg
EAT Diamond KT88.jpg

The Ultimate 300B from EAT 

New improved version. Sold as pair

"With EAT 300B tubes in the circuit, the amplifier's performance at the frequency extremes improved pretty drastically."

AV Guide

Built with high-temperature glass, huge carbonized black plates and gold-plated pins, these individually serial numbered, hand-made 300B are the best currently available 300B on the market.


Warranty Information
EAT will replace the tubes providing the following conditions for all customers:

The tubes have a warranty of 12 months or 2000 hours of use starting with the date of purchase. The purchase data must be written and stamped by the distributor/dealer within 21 days after purchase (registration).
In the event of failure of the tubes, EAT or distributors/dealers will do replacement
within valid warranty claims. The tubes must be returned with the original box and warranty certificate ( date of purchase stamp-registration and complete return form) and prepaid shipment, otherwise warranty will be void.
Warranty has not been voided due to improper handling


Proper Handling
Make sure that the electrical specifications of your amplifier are correct before using tubes in your circuit. Failure to follow the manufacturer's recommendations may result in damage to your amplifier or valves and automatically voids the warranty. Tubes should be used in accordance to the standard specs (see technical data sheet ) and not exceed the maximum levels.

EuroAudioTeam will not be liable for damage resulting from improper use of tubes in your amplifier. Abuse, accidental damage, or incorrect use of the tube will be determined by EAT. Only expert technicians can change the working points of the tube. Improper use of the tube or incorrect application of the tube to a circuit cannot be covered by our warranty.


Shipment and Packaging
Pack for shipping in the original box to prevent side shock. Insufficient packaging may cause broken pieces inside of the valve. Shipment costs will be covered by the buyer. Returned tubes must include warranty certificate ( registration), return form, and original package.


Burn-in Procedure
Valves need to be burned-in for 50-100 hours under the conditions described in the specifications. A correct burn-in will assure maximum lifetime and quality of sound. During burn-in, start with a low audio level and gradually increase the volume. Do not use stand-by mode during burn-in, and let the tubes cool down after each use. Burn in with noise tools, a burn-in cd, radio noise, or pink noise. Make sure the valves have enough air for proper circulation.


Do not overdrive or tap on a working tube. This will cause permanent filament damage.


... So what are reviewers saying ?


E.A.T. 300B





TONEAudio Magazine / EU Edition

Jeff Dorgay -  April 25, 2019

"If you are a lover of single ended triode amplifiers, no doubt you are familiar with the mighty 300B.


The mightiest of them all are the vintage Western Electric 300Bs, and then if you can find them, the reissued WE 300Bs that came out around 2005 or so. Only a few pairs of these were made and then the “new Western Electric” fell back into obscurity. I had a pair of those and they were pretty incredible, and I did spend some time with the NOS models when I had my WAVAC monoblocks. Never should have gotten rid of those. Oh well.


Today, the 300B amps have had a bit of a resurgence (and to some, they never went away – just like vinyl) but there are no incredible tubes to power them with. Having listened to more than my share of the current 300Bs, most manufacturers have settled on Electro Harmonix or JJ, because they are available. But don’t expect the 50,000-hour tube life of the NOS WE’s. Nope, these are 5,000 hour tubes on a good day. Most manufacturers have voiced around the current tubes, but that only goes so far. If you have the chance to experience the vintage 300Bs, you’ll freak out.


The vintage WE’s are so smooth, extended, and dynamic, you’ll swear you’re listening to an entirely different amplifier. However, with these tubes going as high as $6,000 a pair for an amazing set. And being 60-80 years old, there’s still a chance you can pull them out of the box and have them croak. I’m just not that much of a gambler.



Enter EAT

The European Audio Team has their own factory in the Czech Republic, and recently, they’ve started production on the famed 300B, providing tubes that are a clear cut above the mass-produced items that are available, bridging the gap between NOS and NEW. With no WAVAC on hand, they were kind enough to send me a matched set of four for my Nagra 300B amplifier that is a push/pull design, delivering about 25 watts per channel.

The EAT 300B also bridges the price gap, tipping the scale at $1,695 per matched pair. Not so bad if you have SET monoblocks, but it gets a bit spendy if you need four of em. Regardless, this is still way less cash out of pocket that the 2004 vintage WE’s or the really old originals.



The Sound

Going past the afford/not afford, will my partner kill me/will they not notice part of the decision tree, the EAT tubes provide a substantial increase in performance than the current offerings in the $500-$900 pair tubes from “the other guys.” And by increase, I mean that the EAT tubes are more neutral sounding than the other current tubes, honestly more extended at both ends of the frequency range.

Where the Nagra has exceptional bass control, due to its massive, tight tolerance output transformers that are wound in-house, the EAT tubes bring a nearly solid state like grip to the lowest frequencies. Using our 96db/1-watt sensitive Pure Audio Project HORN 15 speakers, it’s almost as if I’ve added a subwoofer. Whether listening to EDM/electronica tracks, or Led Zeppelin, the bass line is hitting me more in the chest than the Nagra does with the stock JJ tubes.


An equal level of excitement is had on the upper register as well. Stringed instruments take on a more three-dimensional quality, with more texture. Pick your favorite acoustic guitar piece that you know well, and you will be surprised at how much more real the strings sound while being played, as well as the overtones that hang in the air after the strings have been struck.


This is the stuff we all love 300B amplifiers for in the first place and the EAT tubes give you more of it.



In the end

At first the price tag might seem a bit prohibitive, but considering the care in manufacturing that goes into these tubes, I’m going to stick my neck out and bet that the EAT 300Bs will probably last a lot longer than the others. If that’s the case, then these are not so much more money out the door in the long run. And if you hate swapping tubes as much as I do, once you’ve settled on a sound, this will be indeed welcome.


There are so few 300B enthusiasts out in the field that have jumped off the cliff on these tubes, I can’t say that anyone’s experience backs up my own, yet. I highly recommend their 300Bs, and hope to give the KT88s a spin sooner than later."


Scott Markwell

" From the beginning, the superiority of the EAT 300Bs was easily evident.

With these tubes in the circuit,the amplifier's performance at the frequency extremes improved pretty drastically. Bass guitar (and especially an unamplified acoustic bass)gained in transient impact, definition, tautness, and harmonic structure.


Drums of all kinds, especially big kits in jazz or rock recordings, sound-ed crisper, more powerful, and more alive and present, all without added hardness or glare. High-frequency percussion, such as triangles, cymbals, castanets, and bells, all sounded cleaner, with more air around the notes and a longer decay.

The higher harmonics of all instruments were better delineated, and it was easier to separate instrumental timbres than before.


For the first several hours with the EATs, the soundstage was rather flat, and vocals seemed dynamically soft and lacking inexpressiveness. However, as the tubes ran in a bit,things improved and that old midrange magic came through in full and became seamlessly integrated with the rest of the spectrum.

The Viva's ability to convincingly render dynamic contrasts and sound powerfully has always been one of its strong suits.Interestingly, although the amplifier was putting out no more power than before, with the EATs installed it seemed to; it became considerably more dynamically alive, while at the same time more relaxed and in control.


The one fly in the ointment is that, for some people, these tubes will not sound the way they expect a 300B type to sound. The classic sonic signature of a 300B tube/amplifier is one of a voluptuous midrange, slightly plummy midbass (with not much, if any, real bass below 40Hz), and sweet, gently rolling highs that start to fade out at about 12kHz. The result is a warm, inviting sound that is rich in harmonics and velvety smooth,with really good dynamic contrasts at the soft end of the scale and up to about a double forte. With the EAT devices, however, the overall presentation is somewhat leaner, more transparent, better balanced, considerably more extended, and not as overtly warm as most other 300Bs.


The closest thing I have heard to these, as matter of fact, is a Russian 572 triode tube, another modern (recently invented) somewhat more powerful SET-type tube that has similar virtues and the same burden of not sound-ing like a "conventional" SET device. In contrast, the justly famous Western Electric 300Bs (the only real competition to the EAT 300Bs thatI have heard) cost considerably more per pair (and are currently no longer available) than the EATs and sound like the best possible "regular" 300B that you will ever hear; some traditionalists may well feel, in comparison,that the EAT design is not a "proper" sounding 300B.


At the end of the day,however, with these tubes, music is not artificially lovely or truncated infrequency response, and the EATs certainly do not pull any punches in terms of dynamic expansion. The EAT tubes sound, to my ear, more like music than any other 300Bs I have heard, and that is what swayed me in the end. I love 300B amplifiers that can play with the push-pull big boys in terms of low coloration, frequency extension, and dynamic expressiveness, but they are few and far between. Same goes for their tubes. There are a number of brands on the market today, and they vary widely in cost and quality. But none that I have heard play music as convincingly as these EATs. So, prospective buyers need to make the choice between real music and a somewhat ersatz representation thereof. I choose the former." 


E.A.T. KT88 Diamond






Chris Binns

"The EAT’s had an authority that seemed to enhance every aspect of the performance; the bass was firmer, deeper and much more articulate, the mid was more open and spacious, while the treble had detail and clarity that had not been there before. The overall increase in focus and transparency was remarkable.


Nigel suggested that it made the original tubes sound ‘shagged’ (which they weren’t), and the disappointment was intense when we returned to them. To put things in perspective, I had a set of Svetlana KT88’s that I have been recently using, and to date have been my choice of the readily available valves. Differences between them and the Electroharmonix were interesting but minor, while there was a similar leap in performance with the EAT’s in situ.


The acid test involved a set of original MO KT88’s that I have clung on to for many years, really to use as a comparison in such circumstances as this, and as such, I would say that they are about half way through there life. While they sounded pretty good, superior to the Svetlana’s and Electroharmonix, they could not manage the sheer exuberance and taughtness of the EAT’s. It did occur to me however, that while there had been a general consens us that the EAT’s were just‘better’ in every respect, the character of the MO’s was a shade more laid back and therefore less obviously impressive. Another comparison suggested that this was true, but they could not match the EAT’s for colour, texture and in particular, definition.


The next evaluation took place over a longer period using twelve of the EAT valves in the big amplifiers described earlier. The demands here are a little different from the Rogue amp as the valves are potentially pushed a bit harder with 550 Volts on the anodes, while matching seems to be an important criteria when it comes to absolute sound quality, and not just under static conditions. Using the EAT KT88’s in these proved to be every bit as dramatic as the previous session, perhaps even more so. While I have never been disappointed with the bottom end of these 250 Watt amplifiers, it has never been a match for something like the Bryston. The use of the EAT’s was startling in this respect, and the grip. and bite exerted on the loudspeaker was much improved, to the extent that the amplifier would go considerably louder into difficult and inefficient loudspeakers; once again the result was a better amplifier. Musically, it felt as if several layers had been removed,and the slight sense of vagueness that has always been there diminished to imperceptible levels, with a real improvement in definition, a factor facilitated by what looked to be extremely close matching of the valves. Going back to the Svetlana’s or Sovtek’s was very disappointing.


There is no doubt that the EAT valves are extremely good. The big question is that at the price of these tubes – multiple times the price of say, a Svetlana – are they worth it? Judging by what I have heard, the answer is very definitely, yes. On performance alone, I think the results speak for themselves, while the security of the warranty makes it a considerably safer investment.


So, you are looking for the best? Original MO KT88’s are still available – just barely – at highly elevated prices, and I reckon you might be able to get a supposedly unused pair on ebay. There will be no guarantee; they will almost certainly not be matched, and it’s unlikely they will sound as good as the EAT’s... Truly a worthy successor to the esteemed British king.


Hi Fi +

Roy Gregory

" However, what we have here is altogether more interesting. Sourced from the original Tesla factory inPrague, Euro Audio Team are offering a KT88 that claimsparity with the legendary MO Valve Company original (they also offer a couple of different 300B designs, but that’s a story for another day). Internally, the construction of the EAT KT88 appears identical to the MO version, while eachtube is reassuringly solid when handled.They come in matched pairs as standard,with quartets or larger groupings for a very small extra cost. They also carry an almost unheard of six-month warranty.


Sonically the results are absolutely superb, trouncing generally available examples and bettering even NOS MO samples (which will cost you rather more than EATs). Romantic they aren’t, but if you want power, transparency, grip, focus, detail and definition – all woven into a singularly convincing whole, then look no further.


What’s more, with KT88s (and the 6550 equivalents) generally being used in multiple arrays, quality and matching becomes even more important to an amplifier’s overall performance. Consistency and longevity appear good, with no failures so far (and we’ve tried!) which combined with the fantastic musical and sonic performance makes these valves a must own upgrade for everyone with an appropriate amplifier. Once again, they seem expensive until you hear the results, at which point purchase becomes a no-brainer.


Soundstage! Hi-Fi

Doug Schneider -  September 1, 2019




Are they worth it?


Outwardly, EAT’s KT88 Diamond tube doesn’t look as if it should cost $448.75 (actually, $1795/four). Sonically, it’s a different story. Eight KT88 Diamonds considerably improved the sound of my JE Audio VM60 monoblocks. The JEAs didn’t become completely different-sounding amps, but they sure sounded better than before.


What’s more, the level of improvement was far greater than any change of speaker cable, interconnect, or power cord I’ve ever tried. Still, was that improvement worth more than seven times the cost of my Gold Lions? In my opinion, it comes down to how in love you are with the sound of your tube amplification -- and if you have the money.


Be warned : If you fall down this rabbit hole, listen to the EAT KT88 Diamonds, like what you hear, but aren’t willing to pay the price, you might find yourself disappointed and frustrated -- once you’ve heard the difference, you can’t unhear it. That’s what’s happened to me. I’ve returned the KT88 Diamonds to Vana Ltd. But now that I know how much more my VM60s are capable of with these tubes, I desperately want them back."

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