Eurotubes JJ EL84 & ECC83S

Review by Mark Starlin

JJ EL84 power tube

One of the reasons many players prefer tube amps is that they are dynamic. If you find their “sweet spot”, you can get a clean tone by playing softly (or turning down your guitar’s volume control) and then dig in to get distortion. Also, the distortion (or overdrive) is usually smoother and more musical than transistor or digital distortion. Since these qualities are obviously related to the tubes used in an amp, changing tubes can actually change the character and tone of your amp.

I recently purchased a Traynor Custom Valve 20 amplifier but wasn’t completely satisfied with the stock Sovtek tubes. I decided to “retube” the amp using a set of Eurotubes tubes. Here are my results.

The Project Amp

The Traynor Custom Valve 20 (YCV20) is 15 watt combo that comes stock with 3 Sovtek 12AX7A preamp tubes and 2 Sovtek EL84 power tubes. [You can read my review of the amp here.] The Sovtek tubes sounded good at cleaner settings but began breaking up quickly, and at higher gain settings, the resulting distortion was very brittle and harsh. They can crunch, but they cannot sing. I decided to try retubing the amp to see if I could get a better tone.

Eurotunes JJ ECC83S tube

After some research, I came upon a company called Eurotubes. Essentially, Eurotubes is Bob Pletka, a guitarist and tube enthusiast who acts as a distributor for JJ Electronic. JJ Electronic is a tube manufacturer located in the Slovak Republic with over 25 years experience manufacturing tubes. You can find out more about JJ Electronic on the Eurotubes website. Bob visited JJ Electronic on a trip to Europe and was so impressed with their tubes that he became a US distributor.

The Personal Touch

One of the advantages of dealing with a small company is customer service, and Bob provides the kind you just can’t get from large corporations. I sent Bob an email describing my situation and he responded with a very detailed recommendation. Below is the text of my email and Bob’s reply:

Hi Bob;

I just discovered Eurotubes, and I am intrigued. I recently purchased a Traynor YCV20 15 watt amp. It has a pair of Sovtek EL84 tubes and 3 12AX7 tubes (one for reverb, I believe). The overdrive/distortion is a little harsh for my tastes when cranked. Also, the amp has a bit of a hum when turned on. I was wondering if you could recommend some tubes that might not be so harsh and help reduce humming. It is a channel switching amp so I would like to keep the clean channel clean. I play a wide variety of styles from jazz to rock and bought the amp to use mainly for teaching and small gigs (miked and sent through a PA.) I typically play at moderate volume (4 or 5) and gain (4 or 5.) I use a Les Paul Custom and Strat with Kinman PUs. I am also currently looking at Jazz boxes, so I will want a good “clean” tone. I am willing to replace all the tubes in the amp.

Thank you.


Hi Mark:

Good description, I like details. The hum is more than likely the power tubes. Your YCV20 is cathode biased so I would go with a matched pair of the JJ EL84’s that are a #35. As for the preamp tubes I would go with three of the JJ ECC83S’s. This will fatten up the drive channel and warm up the clean channel. I would use a graded and balanced ECC83S in the phase splitter hole, which is the preamp tube that’s closest to the power tubes. This will eliminate any dead spots and really make the amp sing. The verb is not tube driven.



As you can see, Bob is both knowledgeable and helpful. I decided to retube the amp.

The Result

To put it simply, the results were stunning. I checked the clean channel first. Wow. The Eurotubes made my Sovteks sound like mud. The amount of detail brought out by the Eurotubes is very impressive. I felt like every nuance of my picking was transmitted through to the speakers. And even with the amount of detail they possess, they still have a “warm” tone.

The overdrive channel is where things got even better. The character of the Eurotubes is much different from the Sovteks. The Sovteks are “meaner” but they are also ugly when pushed too hard. The Eurotubes break up much more smoothly, giving you a huge “sweet spot.” And at high gain settings, the Sovtek brittleness is gone, replaced by smoother, singing tone. They don’t soar like 6L6 tubes, but they are very impressive EL84’s.

As far as the amp’s humming, retubing didn’t affect it either way. Since I heard the same hum on three different Traynor YCV20’s, I have concluded that it is inherent in the amp’s electronics.

The Torture Test

I play a regular Sunday night set for my church youth group that requires a wide variety of tones from clean to scream. I usually use my Boogie Mark II and a Les Paul Custom. After retubing the Traynor, I decide to put it to the test and used it for the gig.

We typically have an acoustic guitar, me on electric, bass, keyboards, and an electronic drum kit. As it turned out, the night I brought the Traynor, we had no acoustic guitar player and the drummer was using an acoustic kit. I was concerned about the 15 watt Traynor being able to hang with an acoustic drum kit but, surprisingly, I had no problems hearing myself (we also mic the amp and send it through the PA.)

Being the only guitar player, I had to cover a lot of ground from bright and clean, to crunchy power chords, to screaming leads. The Traynor loaded with new Eurotubes came through like a champ.

Final Thoughts

It is rare nowadays to get a great product, excellent customer service, and a fantastic price, but that is exactly what Eurotubes offers. The JJ EL84’s and JJ ECC83S’s sound great, and my Traynor sounds like a completely different (and much better) amp. If you are in the market for tubes, you owe it to yourself to check out Eurotubes. Tell Bob I sent you.

Reader Comments

Better Guitar encourages your input. Agree with this review? Think I’m crazy? If you have used Eurotubes EL84’s or ECC83S’s, email me your comments and I’ll post them below. The more opinions we have available, the better our buying decisions will be.

Darren Lee

Really like your site. I purchased a Blackstar Artisan 15 a while back. I can't remember exactly but I seem to remember that the stock tubes are all Electro Harmonix (except for 2 Sovteks). I think the analogy of tubes are a bit like strings is very true (you don't notice the degradation until you change them). My amp sounded fine - I normally like to have the gain on my Les Paul at about half way. It wasn't until someone plugged into my amp at a gig with their Strat with their gain set to 10 that my amp sounded muddy, brittle and harsh. I decided to change my tubes and what a difference! I purchased a set of JJs from Bob (on ebay) and they are articulate sounding, bell like even at times but they also roar.I've now got my gain set to 10 and the sustain is also great. How long these tubes last I am not sure. There is a debate about old tubes vs new and the length of time etc but for the moment I would certainly recommend these to anyone.

Jim McGeorge

Hi, I bought a Marshall JCM900 off of Craigslist after doing some home work on the amp. When I went to pick up the amp I played it but wasn't able to turn it up. The owner said that he only played it on the 50 watt setting (this head has a switch to change from 50 to 100 Watts). I bought it and took it home to run it through the ringer. The drive was aggressive but a little noisy — the clean breaking up and notes were falling off. I checked the and found a blown fuse, so I started to do some research. That's when I stumbled across Eurotubes. After reading all about tubes and biasing I took the back panel off my amp and found 3 Marshall ECC83 s and 4 6L6's. The 6L6's where mismatched there were 2 Sovtek in valves 2 and 3 and 2 Groove Tubes in valves 1 and 4. I know at the very least this amp needed to be re-tubed.

I called Bob (Eurotubes) and told him about the tubes and how I was unhappy with the tone and told him that I read that some people where talking about changing the 6L6 's for EL34s and he asked if I scoop my mids and I said yes. He said to stick with the JJ6L6's and the JJ ECC83S s so I ordered the JJ 6L6 and ECC83S s High Gain set and the 25.00 bias probe on Friday and got them on Monday, the turnaround was great. I re-watched the bias video and started to re-tube my amp. I cleaned the sockets and put the new tubes in and checked the plate voltage. The video said that the plate voltage was suppose to be between 430 to 480 mine was 516. I was a little worried but I followed the video and did the calculation to figure out the bias. Again the video said that the bias with the 6L6 tubes on my amp should be between 35 and 40 mine was at 7.5. I started to think I was doing something wrong, but I followed the video and adjusted the bias trim pot to make the bias 35, I noticed that this brought the volume way up on the amp. I then re-checked the plate voltage and it was at 480 like the video indicated. I waited 10 minutes and re-checked the bias and it was at 36. I left it there, the video said that it would just make it a little hotter, which I wanted.

I let the tubes cool, took the probe out and put the amp back together. When I plugged in my Les Paul I started with the clean and man was it clean and rich. I couldn't believe it was the same amp. I knew it would sound different but I was in awe. Then when I changed to the driven channel I was blown away. Great low end I didn't have to scoop the mids and the crunch was heavy but every note was crystal clear, amazing!! That's all I can say. And the volume was at least a third higher. I don't have to turn the amp up near as much. Thanks to Bob and Eurotubes I love this amp and IMO I think it sounds way better then my other guitarist's JCM800 with stock EL34s.

Noah Mackey

I play a Stratocaster with a Duncan Phat Cat P90 in the bridge, and a Duncan STR-1 (silver telecaster rhythm, vintage) in the middle position and no neck pup. This goes through a Mesa Nomad 45 212. I got the amp off ebay, it had Groove Tubes in it. When it came time to re-tube I did what Mesa says and got a quad of their EL84s, and right out of the box they sounded very fizzy. Good cleans but danky distortion. And, not to mention that one of them became red hot and the sticker mesa puts on their Sovteks actually melted and burned off. I thought my amp was on fire! Matched mesa quad in a mesa amp should not yield these results. I decided to look elsewhere for tubes. I found Eurotubes, exchanged some emails with a dude named Jay, and a week later had my full re-tube kit. I got the low gain, but there's still plenty of gain. It just gave it a cleaner overall effect. Every spec of that nasty fizz went away. I can get a super bright sound without the static, or I can get the darkest, warmest brown you've ever heard with ZERO mud. Punch, clarity, TONE! I love this company and will never buy tubes from anywhere else as long as I live, period. So stop right now, quit thinking "Uh, I dunno if these will be good tubes or not" because they will be.

Shawn Sudul

OK so earlier this year I retubed my Peavey XXX. I researched tubes and talked with Bob from Eurotubes and went with the 6L6 JJ's and the ECC83s. And it has been the worst experience! The sound I have has almost made me quit playing guitar. When I first got them replaced I noticed it didn't sound right. I emailed Bob and he made the suggestion to move my selection switch in the back to tight. Did it, no difference. I do use the distortion on the amp. I run through a pedal. And before I purchased the tubes I explained that. I took it back in to see if it was biased wrong and it was not. I took out the JJ pre amps and put back in 2 Groove tube and 2 Sovtek like I had before. I gained a small amount of sound back. I play death/thrash metal and ride the E a lot as well as palm mute and play lots of skips. I cannot play that style with these tubes. They are lifeless with no punch and have a white noise type of sound. And I get feedback from them when I am not even turned up to 1! There is no clarity at all. The clean even has a broken up sound. My $50 Peavey musician solid-state sounds better. I am on a tight budget and JJs have been the worst experience with sound I have had!

Bill from Woodland

I've been ordering from Bob for over a year now. Since I'm local, the first time I bought tubes from him I actually drove over to his business/house and picked them up. Since then I've purchased more amps and more tubes as well as a Weber attenuator, and without exception Bob's service has been top notch. Of course it helps that the JJ tubes are excellent but Bob's prices are great and his attention to detail is second to none. If you're even considering JJ tubes for your amp Eurotubes is the place to get them. Why would you pay more for the same tubes and get a lower level of customer service?

Will Spicer

Finding Bob Pletka was more than a breath of fresh air. I sent him a similar email to the one in the review (with fewer details) and recieved a 2 page email about all of the sonic nuances I could get from about 6 different tube configurations. I was blown away — this guy is willing to write me all of this and I haven't spent a dime? When I retubed with the prescribed configuration, it was religious. My AC30 was stunning — so stunning my wife could hear a difference — now, that proves that this isn't just a tone-snob-audiophile who swears this config is better than that. This was gospel truth, my amp sounded almost 80% richer, the gain was super-creamy musical, and the sensitivity of the amp's dynamics are just amazing. Spend your money with Bob — he's passionate about good tone from tube amps, his service is unbelievable, and the prices are awesome.

Rick Serna

I too re-tubed a New Peavey Classic 30 after only having it for one show and 4 or 5 practices. It was glitchy and scrambled in the low end with doubling in the drive mode. I tested it and found one bad Sovtech power tube and a microphonic driver tube. Replaced with a quad matched set of 6BQ5 / EL84 eq. and an ECC83S /12AX7 eq. driver. Same as your other's comments... Waaaah Hoooo!! This amp outperforms my Fender Hotrod Deluxe and Blues Junior. I will re tube with JJs for those too. I use hot-rodded Strats and Telies. Our tube tech locally is "Uncle Spot."


Yes, I must agree. JJ makes a great sounding tube and when it’s right there’s nothing better. Although, I have found the guys at Eurotube to be a bit snobby and combative. I called Bob with a microphonic tube issue and after insinuating my amp tech may be taking advantage of me, he did not offer me an acceptable remedy. Customer service is paramount in business and there's a lot of knowledge at Eurotubes but they need to work on their people skills. Patience goes a long way to building a good business relationship.

Nicholas Matthew

I took your advise and I loaded my Traynor 20 with tubes supplied by Eurotubes and I have to say that you were right on the money!!! Re-tubing the amp was the best money I have ever spent on gear!! Everything you said was true. Thank you for the good advice and keep up the good reviewing!


JJ tubes are the best. I’ve been buying JJ’s from Bob at Eurotubes for a couple of years now. The tubes are fantastic but Bob’s service is even better. He really knows his stuff. To back me up about JJ tubes, I recently bought Marshalls top of the line Hand Wired series amp. I bought the 1974X model which is the 18 watt 1x12 combo. Well guess what tubes Marshall puts in there? Right JJ’s. Every tube in there are JJ, (el84’s,12ax7 and rec tube) These are the best tubes, and did I mention they are cheap. Great tubes great service great advice

Mark Johnson

I have had a variety of el84 amps mostly Peavey, Marshall and my newest Laney VC30. I’ve been playing for 5 years, weekend warrior, I know what I want my amp to sound like. My first set of JJ’s I purchased from Bob were 4 EL84s and 3 ecc83s for my Classic 50 212 which was my first tube amp ever; graduating from the Transtube. I loved the sound but couldn’t explain how I wanted it to change, everyone I knew had Marshalls and the creamy sustain and smoothness was great, most of them had Svetlana tubes in em. On the Peavey website I learned of Eurotubes and that was the last time I let a Sovtek tube hold me back.

The JJs creaminess, sustain and increase in shear volume, the harmonics! The responsiveness was incredible! Man I thought I was Billy Gibbons at the next jam session making all the little split note screams, I played my amp for hours after installing the JJ’s.

I could go elsewhere for tubes, but you could not get the personalized service of Bob Pletka anywhere else, he loves talking tubes amps and equipment, and takes time for his customers, he makes you feel like you and your amp are the only ones on earth. All seven of my amps have JJ’s in them, all by Bob’s Eurotubes.

Charlie Molter

I have been playing 46 years, and I have complete sets of JJ’s from Bob in all my tube amps. My 1991 Peavey Classic 50 410, Ultra 112 combo, Bravo 112, for almost 3 years now. I have stated in the past and still, these are the best tubes I have ever used and Bob offers something unheard of in today’s World. That is excellent products, fast shipping and the friendliest service and most knowledgeable tube guru. I heard a difference immediately and I started playing better, because I love the sound, singing, from my amps. I am happy to call Bob my friend even though we live on opposite sides of the US. Want to love your amp again? Call Bob, just tell him your amp, guitar/s and playing style and what you want to hear. Your amp will thank you with Righteous tone.


Good review on the Traynor YVC 20 and Eurotube JJs. I bought the YCV 40 2x10 and was very impressed with it but I had read that the Sovteks were harsh and sterile. So I ordered some JJs from Bob at Eurotube (2-6L6 and 3-12AX7) and I noticed the same dramatic improvements. I toyed with plunking down big bucks for NOS tubes but I decided for $57 I’d try JJs. Good decision. Now I feel I have an amp that delivers any fantastic tone in any style I will ever want to play (blues, R&B, jazz).

Craig Kerns

I talked with Bob at Eurotubes and asked his recommendations for my Peavey Bravos ( 2 of them) and my Peavey Classic 20. While I was at it, I asked what he would recommend for my Digitech RP-7. The tubes he sent for the amps were perfect. Clear, clean, articulate. Overdrive was sooo nice. I play slide so the overdrive couldn’t be harsh. Bob hit it spot on! As for the RP-7, Bob sent an ECC83S with a gain of 120. I had to go back and reset my parameters. It definately gave my RP-7 horns and a tail! The friendliness, service, knowledge and price just can’t be beat. Bob is without a doubt the "Tube Guru". I recommend him to everyone.

Bud Bremner

This is Bud Bremner from Vancouver. I did a complete JJ tube re-fit on my Peavey Classic 30 using three ECC83S (12AX7’s) and four EL84’s. I’d heard many great things about the JJ tubes and so I’ve waited about two weeks to post this review to be sure I was not speaking out of emotion alone. Man, am I a convert! Homer Simpson would proclaim “WooHoo!”

I am so very pleased at my sound from this little amp with JJ tubes over the stock Sovtek tubes, there is now bite without harshness, grit without dirt! I can now pull back on my EQ settings to a more natural flat response with the JJ’s, there is more openness to the sound with little need to EQ it. My need for a distortion pedal now seems moot as I get a great natural tube overdrive with just the amp itself. Wow! Even my clean sound is sooo much nicer to listen to, and I loved my guitars before! My axe’s are a 21 year old Japanese made Squire Strat 62’ Re-issue and a new Ibanez AS-120 Semi Acoustic. I use the matching Peavey Classic 112E extension cab with my C30 and my band mates have to keep telling me to be quiet, I can’t seem to stop playing! Anytime I get in trouble I just tell them it’s the Eurotubes fault.

These tubes rule. I will use JJ’s from now on in any amp I may own but parting with this Classic 30 seems unlikely. Bob Pletka’s customer service has been just great and we all have appreciated the time he spent giving us pearls of wisdom.


  • JJ EL84
  • • Gold plated control grid for improved fidelity and a plate dissipation of up to 12 watts
  • • Manufactured by JJ Electronic in the Slovak Republic
  • JJ ECC83S
  • • Special grid plated by gold to reduce microphone interaction and noise
  • • Manufactured by JJ Electronic in the Slovak Republic
  • Positives
  • Excellent tone and detail; smooth overdrive; inexpensive.
  • Negatives
  • None.
  • Rating
  • Performance: 10
  • Sound Quality: 10
  • Construction: 10
  • Overall: 10
  • Ratings Key
  • 0 = Worthless
  • 10 = Excellent
  • Approximate Street Price
  • $45 - $55 for 2 EL84 and 3 ECC83S

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