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  • Can anyone help me identify this tube?

    Hi all, quick question.

    Sweetwater had a good deal on an evh 5150 100S Stealth amplifier and I wanted to give it a shot. According to the sales rep the amp is a demo and is like new but was quickly returned by a customer because they didn't like the red channel so they put it back up for sale.

    Amp looks in great shape, and it sounded great too, but I think one of the tubes is bad. I just happened to look through the back and noticed one of the four tubes was dark, no lighted filament, cold to the touch.

    I opened the back and tried switching the tubes around, same thing that one tube is just dark. So i pulled it and took a pic. 2 things:

    #1 according to EVH's website, the 5150 100S uses Shuguang 6l6 tubes. According to some sales websites including sweetwater, the same amp is listed as using Wing C 6l6s, so I don't even know what tube it's supposed to have, which leads to...

    #2 This is the tube I pulled from the amp, it says groove tube. I'm not a tube expert, i just want to get whatever evh ships stock back in the amplifier. Are groove tubes generic tubes? I thought they were a type of Mesa Boogie tubes but there's no MESA logo on the tube. Pics below of the tubes. Can anyone tell me what type of tube this is so I can try to find them online, or, just let me know what was stock with this amp? I googled shuguang 6l6 tubes but apparently they're discontinued or something. If that's true how is EVH putting them into their amps.

    Anyway, sorry for all the questions, just frustrated because I took a chance on the demo and am bummed to find the bad tube. I feel like now I gotta check all the preamps just in case that guy who originally got it did a fudge job trying to replace everything.

    Even with 3 tubes though the thing sounds pretty great for my purposes haha

    20200618_231818 by james f, on Flickr

    20200618_231821 by james f, on Flickr

  • #2
    Re: Can anyone help me identify this tube?

    That's a Groove Tubes 6L6 of some sort. It's impossible to say for certain exactly what it is, because Groove Tubes buys from several manufacturers and then re-labels them for sale. That being said, there's a decent chance that it is a Shuguang 6L6 as that is one of the factories GT buys from. Do the other tubes in the amp match? If they don't I would suspect that the previous purchaser stole one of more of the factory tubes before returning it. It's worth a shot to give Sweetwater a call, if you're lucky they may send you extra tube(s). You also shouldn't run the amp with only 3 working tubes as class A/B amps are designed to work with pairs of tubes. If you want to run it on 2 tubes, make sure that the outer or inner pair of sockets is populated and use a speaker output with half the impedance of your cabinet (16 ohm cab on 8 ohm output for example).
    Originally posted by crusty philtrum
    And that's probably because most people with electric guitars seem more interested in their own performance rather than the effect on the listener ... in fact i don't think many people who own electric guitars even give a poop about the effect on a listener. Which is why many people play electric guitars but very very few of them are actually musicians.

    Comment


    • #3
      Re: Can anyone help me identify this tube?

      Originally posted by dystrust View Post
      That's a Groove Tubes 6L6 of some sort. It's impossible to say for certain exactly what it is, because Groove Tubes buys from several manufacturers and then re-labels them for sale. That being said, there's a decent chance that it is a Shuguang 6L6 as that is one of the factories GT buys from. Do the other tubes in the amp match? If they don't I would suspect that the previous purchaser stole one of more of the factory tubes before returning it. It's worth a shot to give Sweetwater a call, if you're lucky they may send you extra tube(s). You also shouldn't run the amp with only 3 working tubes as class A/B amps are designed to work with pairs of tubes. If you want to run it on 2 tubes, make sure that the outer or inner pair of sockets is populated and use a speaker output with half the impedance of your cabinet (16 ohm cab on 8 ohm output for example).
      Thank you for the info. Yes I won't use it until I have all 4 tubes working. I just wasn't aware it was bad before. And all tubes match each other, so I guess they must be the stock ones. I will try calling EVH tomorrow and see if they can give me anymore info.

      Comment


      • #4
        Re: Can anyone help me identify this tube?

        Groove tubes typically source the same brand for each type......so their 6V6S is a JJ for example.

        Groove Tubes is not a tube manufacturer. Learn more about Groove Tubes and purchase upgrades and replacement tubes to improve your tube amplifier!

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        • #5
          Re: Can anyone help me identify this tube?

          Originally posted by AlexR View Post
          Groove tubes typically source the same brand for each type......so their 6V6S is a JJ for example.

          https://www.thetubestore.com/tube-brands/groove-tubes
          I don't know exactly what you are saying here, but GT often has different brands of each tube type, and the suffix after the tube type tells you which brand it is. For instance, in your example they used "S" after 6V6 for "Slovak". They have/had a 6V6"R" which is Russian (probably the EH 6V6) and I've seen 6V6"C" (for Chinese). In some tubes they have more than one type from a brand, for example in 12AX7's they might have 3 different tubes from Sovtek, and they put "R", "R2", and "R3" after the tube type.
          Having said that, since GT sold out to Fender I don't think they carry as many different variations in their catalog as they used to, it seems they have cut the catalog down quite a bit now.
          Al

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          • #6
            Re: Can anyone help me identify this tube?

            Thank you for the replies all. I spoke to sweetwater customer support.

            Allegedly what it comes with are: https://www.sweetwater.com/store/det...es-medium-duet which she called wing C. IDK maybe they are the Shuguangs, it does say "Chinese High Power"

            They didn't have any in stock so they shipped me a quartet of these: https://www.sweetwater.com/store/det...medium-quartet

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            • #7
              Re: Can anyone help me identify this tube?

              Originally posted by dystrust View Post
              If you want to run it on 2 tubes, make sure that the outer or inner pair of sockets is populated and use a speaker output with half the impedance of your cabinet (16 ohm cab on 8 ohm output for example).
              This speaker impedance thing is often repeated, but the output tubes have nothing to do with speaker impedance.

              The output tubes have an impedance of around 6,000 ohms. They feed the primary side of the output transformer (which is a 6K winding).

              The secondary side of the transformer has taps in the winding at 4, 8, or 16 Ohms. You select the tap to match the speaker.

              Running the amp on the wrong impedance can either drive too much current through the secondary, since the corresponding speaker windings are not there, or make the amp work harder, by trying to get a quarter of the winds on the transformer (say the 4 Ohm tap) to drive 16 Ohms worth of windings on the speakers, for example.

              I don’t know where this idea came from, but you hear it a lot about Marshalls.

              All removing two tubes does is produce less power.


              Sent from my iPhone using Tapatalk

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              • #8
                Re: Can anyone help me identify this tube?

                Originally posted by DavidRavenMoon View Post
                This speaker impedance thing is often repeated, but the output tubes have nothing to do with speaker impedance.

                The output tubes have an impedance of around 6,000 ohms. They feed the primary side of the output transformer (which is a 6K winding).

                The secondary side of the transformer has taps in the winding at 4, 8, or 16 Ohms. You select the tap to match the speaker.

                Running the amp on the wrong impedance can either drive too much current through the secondary, since the corresponding speaker windings are not there, or make the amp work harder, by trying to get a quarter of the winds on the transformer (say the 4 Ohm tap) to drive 16 Ohms worth of windings on the speakers, for example.

                I don’t know where this idea came from, but you hear it a lot about Marshalls.

                All removing two tubes does is produce less power.


                Sent from my iPhone using Tapatalk
                Not only is it often repeated, you are the first in my experience to say it isn't true. Are you sure about this, I've heard it from just about every reliable source on tube amps?. How can they all be wrong?.
                Al

                Comment


                • #9
                  Re: Can anyone help me identify this tube?

                  Originally posted by Zombiwoof View Post
                  Not only is it often repeated, you are the first in my experience to say it isn't true. Are you sure about this, I've heard it from just about every reliable source on tube amps?. How can they all be wrong?.
                  Al
                  When you have an amp like a Mesa, that has the half power switch, it shuts two of the tube off. But it doesn’t change the impedance.

                  Watch this video, they are mostly rewiring the cabs and matching the impedance at the amp, but they discuss how the output transformer works. At the end of the video they are mismatching a Mesa amp. He discusses the output transformer again and how mismatching the transformer to the speakers can cause too much current to flow on both the primary and secondary side. The bigger problem is having the amp on like 16 and then into a 4 ohm load. That draws too much current.

                  On solid state power amps you can always go higher, but never lower. They don’t have output transformers. The output stage is directly coupled to the speakers. So if you ran a 500 watt 4 ohm SS amp into 8 ohms you will get about 350 watts. I’m using my Hartke LH500 as an example. 4 ohms is the minimum load. If you run into a 2 Ohm load you will fry the output stage. It will sink too much current and get hot.

                  So same problem as a tube amp, except for the transformer. And because of the transformer, on a tube amp you always get the rated power regardless of the speaker impedance.

                  I don’t know why it’s repeated so often. But you don’t need to do It. And as they show in the video, the Mesa changed volume from the mismatch, which changes the amount of current into the speaker load.





                  Sent from my iPhone using Tapatalk

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                  • #10
                    Re: Can anyone help me identify this tube?

                    First 6L6 is Chinese. Second Sweetwater sent you is Russian.
                    You'd be much better off buying tubes from a qualified tube vendor rather than SW.
                    GT/MESA & Ruby/ARS ect just relabeled tubes from Slovak, Russia & China.

                    You'd be much better cutting out the middleman and buying from Tube store/Tube Depot ect that test & match.

                    Ebay has some good vendors as well.
                    Last edited by JMP/HBE; 06-20-2020, 11:13 AM.

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                    • #11
                      Re: Can anyone help me identify this tube?

                      Originally posted by Zombiwoof View Post
                      Not only is it often repeated, you are the first in my experience to say it isn't true. Are you sure about this, I've heard it from just about every reliable source on tube amps?. How can they all be wrong?.
                      Al
                      You can't compare Mesa and Marshall directly in this case because the output transformer specs are so different. The Mesa transformer is significantly over-spec'd to avoid damage from the primary impedance mismatch created when pulling a pair of tubes. More detail here.
                      Last edited by dystrust; 06-20-2020, 01:23 PM. Reason: Typo.
                      Originally posted by crusty philtrum
                      And that's probably because most people with electric guitars seem more interested in their own performance rather than the effect on the listener ... in fact i don't think many people who own electric guitars even give a poop about the effect on a listener. Which is why many people play electric guitars but very very few of them are actually musicians.

                      Comment


                      • #12
                        Re: Can anyone help me identify this tube?

                        Thanks for all the info guys.

                        I actually contacted both EVH and Fender and funny enough neither of them could actually give me the exact stock tube model (although I did appreciate their speedy response, less than 12 hours for both).

                        They just gave a recommendation on what to buy as replacements.

                        As far as I can tell, I THINK the stock tubes are 6l6 CHP "high power" (8-10 rating), which you can't get anywhere. The only ones you can get are 6l6 CHP medium (4-7). I doubt it really makes much of a difference, but that's what i got as a backup set. I think it's the closest I'll ever get to the stock tubes.

                        And oh yeah for sure I'm not going to turn this thing on until all tubes are square.

                        Comment


                        • #13
                          Re: Can anyone help me identify this tube?

                          Originally posted by chillytouch View Post
                          Thanks for all the info guys.

                          I actually contacted both EVH and Fender and funny enough neither of them could actually give me the exact stock tube model (although I did appreciate their speedy response, less than 12 hours for both).

                          They just gave a recommendation on what to buy as replacements.

                          As far as I can tell, I THINK the stock tubes are 6l6 CHP "high power" (8-10 rating), which you can't get anywhere. The only ones you can get are 6l6 CHP medium (4-7). I doubt it really makes much of a difference, but that's what i got as a backup set. I think it's the closest I'll ever get to the stock tubes.

                          And oh yeah for sure I'm not going to turn this thing on until all tubes are square.
                          "High Power" is just a marketing term. You have run of the mill Chinese 6L6 Bro. TAD makes about the best Chinese 6L6 you can get. IDK why you're going to all these retail outlets like Fender/Sweetwater. They're just going to tell you what you want to hear & take you to the cleaners financially. EVH amps are made in Mexico, thats about all you need to know.

                          Comment


                          • #14
                            Re: Can anyone help me identify this tube?

                            Originally posted by JMP/HBE View Post
                            "High Power" is just a marketing term. You have run of the mill Chinese 6L6 Bro. TAD makes about the best Chinese 6L6 you can get. IDK why you're going to all these retail outlets like Fender/Sweetwater. They're just going to tell you what you want to hear & take you to the cleaners financially. EVH amps are made in Mexico, thats about all you need to know.
                            It sounded like the OP got this set of tubes as a warranty replacement from Sweetwater since they bought the amp as a demo in that condition. I hope they didn't cost anything or were at the very least discounted since the amp apparently shipped with 3 working tubes.
                            Originally posted by crusty philtrum
                            And that's probably because most people with electric guitars seem more interested in their own performance rather than the effect on the listener ... in fact i don't think many people who own electric guitars even give a poop about the effect on a listener. Which is why many people play electric guitars but very very few of them are actually musicians.

                            Comment


                            • #15
                              Re: Can anyone help me identify this tube?

                              Originally posted by dystrust View Post
                              It sounded like the OP got this set of tubes as a warranty replacement from Sweetwater since they bought the amp as a demo in that condition. I hope they didn't cost anything or were at the very least discounted since the amp apparently shipped with 3 working tubes.
                              Yeah Sweetwater shipped me a replacement quartet free of charge, but they're not the stock tubes. They're 6l6s, but not same type. That's really all I was wondering. I don't really care either way I'm sure they're similar, but I just was trying to find out why it was such a difficult feat to find the "Shuguang 6l6" tubes the item description comes with on retailer/evh sites. According to sweetwater the Groove Tube 6l6 CHP (Chinese high power) tubes are probably out of the shuguang factory which makes sense, but you can only buy the medium rated version (groove tubes rates it 4-7), whereas the ones that came out of my amp were 8. Don't get me wrong, I'm diving SO deep into this and I don't really care, I just more care because I don't understand why it's so hard to just get the same exact stock tube.

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