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  • Why You Should Buy Manufacturer Supplied Replacement Tubes

    And not from tube sellers.

    First, a little background. Recently I’ve been playing with different types of driver and phase splitter tubes on my conrad-johnson ART300 amplifiers. My amplifiers originally came with Russian Électro-Harmonix 6922s and recently a local cj dealer suggested experimenting with some NOS Phillips 7DJ8s. So I called cj and purchased a quartet of Phillips 7DJ8 tubes from them. The 7DJ8–following the appropriate burn-in time—proved better overall than the 6922s. Still I wanted to go back to the original EH6922s and check my results but the original Russian tubes had disappeared in the meantime. So I decided to buy some replacement tubes from Upscale Audio rather than paying the higher price charged by cj.

    Jump ahead a week or so and the new Upscale EH 6922/tubes arrived and were subbed for the Phillips 7DJ8s. Only one problem. Both amps were humming away. Plug the 7DJ8s in and no hum. After playing around, I was able to find two Russian tubes that didn’t cause hum and ran one 7DJ8 and one 6922 per amp. In the meantime, I reordered four of Kevin’s select stash 6922 to try. They arrived and the same thing happened. 3/4 resulted in hum.

    What in tarnation was going on?

    Jump ahead another month or so and I happened to run into Jeff Fischel of cj at CAF 2019 and told him about my problems. Jeff immediately looked me in the eyes and said, “why didn’t you buy the tubes from us?!?!” Of course I had no answer. Jeff continued on saying that their amplifiers could hum if either of the two triodes in the driver or phase splitter tube is/are microphonic. Now I know Upscale tests for microphonics but the results speak for themselves. For those who don’t know, cj and many other tube manufacturers not only test the tubes using tube testers but check their performance in a mock up circuit. Does the circuit meet its specs using these tubes or not? So what you are paying for when you buy tubes from a reputable manufacturer are among other things a controlled burn-in and actual testing in the actual circuit they will be used in. Reject rates can be pretty high too. I know years ago cj was rejecting 50% of the 12AU7s it was using. That’s scary.

    So I learned my lesson with luckily no damage other than to my bank account. Right now the Phillips 7DJ8s are back in but I will be auditioning Some GL 6922s (an alternative tube suggested by Jeff). And yes, the GL6922s will come from cj.

    PS. What were my reservations with the Phillips tubes? Yes, the Phillips were clearly more transparent, dynamic and open than the 6922s, Yet there was—I hear this trait too with the Phillips 12DW7s in my Doshi phonostage—an ever so slight brightness in the upper midrange area. Not oppressive and on balance still preferable to the 6922. But I‘m aware of it. (The 6922 was be a touch darker here.)
    Myles B. Astor, PhD, Administrator
    Senior Editor, Positive-Feedback.com
    ________________________________________

    -Magico S5 Mk.2 speakers with SPod feet
    -Goldmund Telos 280 stereo amp
    -Goldmund Mimesis 37S Nextgen preamplifier
    -Doshi V3.0 phonostage
    -VPI Vanquish direct-drive turntable
    -VPI 12-inch 3D Fat Boy dual pivot tonearm, VPI 12-inch 3D Fat Boy gimballed and SAT LM-12 arm
    -Lyra Atlas SL Lambda, Fuuga, vdh Colibri Master Signature, MutechHayabusa, MOFI Master Tracker, Sumiko Songbird cartridges
    -Technics RS1506 with Flux Magnetic heads, Doshi V3.0 tape stage (balanced)
    -Assorted cables including Transparent XL Gen. 5, Skogrand, Viero, Kubala-Sosna, Audience Au24SX, Genesis Advanced Technologies and Ensemble Power Cords
    -Accessories including Stillpoint Aperture panels, Cathedral Sound panels, Furutech NCF Nano AC receptacles; Silver Circle Tchaik 6 PLC, Symposium ISIS and SRA Craz racks, Audiodharma Cable Cooker, Symposium Ultra and assorted SRA platforms.

  • #2
    Tubes can be microphonic both acoustic and internal , but I don’t get why this makes them hum ? Do the tubes have shields to put over them ? As for a makers tubes to buy from yes they should know more about what’s better. Tube hum has many causes some can be the location of nearby devices radiating Emi or RFI. I had one my dacs hum and make odd noises. It was an environmental issue non related to the dac at all. It was a router 4 feet away it was a high power one.
    I also had a hum issue due Emi from a large psu transformer some 3 feet above another product. Some hum is also caused by imp mismatch in the stages I feel. Atmosphere help us here while I’m guessing with some experience I would love your engineering input here. Tubes have magic , and mysteries a very tough combination.
    analog stuff.
    otari mtr 10 2 track 1/4 made new by soren
    otari mtr 10 2 track 1/4 1/2 combo made new by soren
    sota sapphire used eminent tech ver 2 arm
    new sota nova table has magnetic levitation platter and full speed control and latest motor same arm as above
    thorens td124 sme ver 2 arm
    thorens td125 sme ver 2 arm
    kenwood direct drive sme ver 2 arm
    phono preamp Ml no 25 all re capped
    speakers cust infinity IRS V , new caps and LPS , magnets etc.
    mark levivson pre no 26 amps no 33
    digital three cust servers , win ser 2016 , AO
    Dacs lampi various

    Comment


    • #3
      Conducted the same experiment years ago.

      I have a stash of 12AT7's that are dead quiet. But they're not in my pre-amp now.

      I have some old GEC A2900 (12AT7 equivalents). Noisy as heck. Between tracks it's disturbing. They're in the phono section now. While the music is playing, glorious.

      Comment


      • #4
        Huh. Myles, I can understand what you’re saying, but I cannot say I’m willing to follow your advice I have a large stash of very high quality vintage vacuum tubes, and a tube tester. I know that any tubes I put in my amps aren’t going to cause actual problems before they go in, so there is no risk. And I know from experience that most of the time the current production Russian tubes supplied with tube gear are nowhere near as good as the better vintage tubes from the height of the tube manufacturing era. But I will say this - without a tube tester, I would never roll tubes.
        TAPE: Studer A807, A810; Revox B77 MkII; Tascam BR-20; Technics RS-1700; Pioneer RT-707, RT-909
        VINYL: Denon DP59-L/Benz LP-S MR/ModWright PH 9.0; Pioneer PL-50LII/Dynavector 20xH
        DIGITAL: Bryston SP-3, Marantz NA6006/Pioneer N-50, Schiit Bifrost
        SPEAKERS: B&W Nautilus 800, Pioneer DSS-9, Velodyne FSR-15
        AMPS: Cary SLP-05/Sunfire Signature 600, Pioneer SX-1980

        Comment


        • #5
          I think manufacturer sourced tubes are a safe bet. Many of them will go to much greater lengths than many re sellers.

          I know I drove the folks at Aesthetix crazy years back with my obsession for tube rolling. The issue is that manufacturers can not rely on NOS tubes as there are not enough of them for consistency and production.

          As to current production tubes and re sellers, I bet - for example- not many will test for current drawn per section for small signal tubes and they definitely can't test in a similar circuit like CJ did.

          H-K alignment and such in individual tubes could cause hum that wouldn't be picked up by re sellers.

          I have found , for me, that some NOS work the best for what I am trying to accomplish . An ordinary tube tester wont tell me enough that I need to know before I try in my Io.
          I invested in the tester below for small signal tubes of which the Io uses 24..or so.

          Is it worth it? ,, maybe not. I buy OS tubes in bulk and test them and sort and I invested in the machine. Maybe better just to pay the premium to a good re- seller. It used to be fun now its a chore some times



          Click image for larger version  Name:	IMG_1478.JPG Views:	6 Size:	135.2 KB ID:	128544
          Front end: Aesthetix Io Eclipse with 2 Power Supplies and Volume controls
          Brinkmann La Grange & RonT Tube Power supply with Kuzma 4-point ,FR64S, Brinkmann 12.1 , .Koetsu Jade Platinum,Koetsu Rosewood Signature Platinum, Lyra Atlas, Lyra Etna SL Goldfinger Statement, KLAUDIO RCM, HRSM3X
          Amps: Wyetech Topaz, Futterman H3 Quad II,Citation II, Marantz 8b, 5 ,2
          Pre-Amps:Marantz 7, Marantz Model 1 Consolette Pair
          Speakers: Quad ESL 57, Beveridge Model 3 DD amps, REL S/2 x 2
          Otari 5050BXII, DeHavilland 222

          Comment


          • #6
            I should add that companies such as ARC, VTL and CAT recommend buying tubes from them.
            Myles B. Astor, PhD, Administrator
            Senior Editor, Positive-Feedback.com
            ________________________________________

            -Magico S5 Mk.2 speakers with SPod feet
            -Goldmund Telos 280 stereo amp
            -Goldmund Mimesis 37S Nextgen preamplifier
            -Doshi V3.0 phonostage
            -VPI Vanquish direct-drive turntable
            -VPI 12-inch 3D Fat Boy dual pivot tonearm, VPI 12-inch 3D Fat Boy gimballed and SAT LM-12 arm
            -Lyra Atlas SL Lambda, Fuuga, vdh Colibri Master Signature, MutechHayabusa, MOFI Master Tracker, Sumiko Songbird cartridges
            -Technics RS1506 with Flux Magnetic heads, Doshi V3.0 tape stage (balanced)
            -Assorted cables including Transparent XL Gen. 5, Skogrand, Viero, Kubala-Sosna, Audience Au24SX, Genesis Advanced Technologies and Ensemble Power Cords
            -Accessories including Stillpoint Aperture panels, Cathedral Sound panels, Furutech NCF Nano AC receptacles; Silver Circle Tchaik 6 PLC, Symposium ISIS and SRA Craz racks, Audiodharma Cable Cooker, Symposium Ultra and assorted SRA platforms.

            Comment


            • Slowgeezr
              Slowgeezr commented
              Editing a comment
              I would also add BAT. I've bought tubes from them for my BAT gear.

          • #7
            Originally posted by MylesBAstor View Post
            I should add that companies such as ARC, VTL and CAT recommend buying tubes from them.
            Myles, Great topic!


            imo: most manufactures go to great lengths to test/match and weed out bad tubes for the customers and hence the Premium prices on their tubes. Why risk your expensive gear, to save a few bucks?


            has anyone noticed that some or maybe most Manufactures? don't recommend "Tube Rolling" because of the unknown testing or quality of tubes on the market?





            the late and very talented Roger Modjeski (RAM Labs) had great articles about Tubes on his website (highly recommend reading)



            also in this video he talks about "Tube Matching" Start video at 40:00 (whole video is very good)


            https://www.youtube.com/watch?v=1pU3jNquDUo






            Comment


            • #8
              Most manufacturers do not carry any where near the variety of vintage tubes that are available if you are interested in rolling tubes. If you just want to replace the ones supplied by the manufacturer I agree you might as well buy from them.

              Second, and hopefully I read Myles initial post correctly, but it seems like you were trying to find a good pair of EH 6922s. If so, in there lies your problem. Those tubes are really bad and unreliable. When I purchased my Modwright PH9.0 phono pre they were supplied with EH 6922s. They sounded horrible. Any vintage 6922 that I owned sounded better. Frankly, I find most of the new production Russian and Chinese tubes to be poor options.

              Speakers: Vandersteen Model 7s, 4 M&K ST-150Ts, 1 VCC-5; Amplification: 2 Vandersteen M7-HPAs, CI Audio D200 MKII, Ayre V-6xe; Preamp: Doshi Audio Line Stage v3.0; Phono Pre: Doshi Audio V3 Phono Pre; Analog: Wave Kinetics NVS; Durand Telos and SME 3012R Tonearms, Clearaudio Goldfinger Statement v2; Miyajima Madake, Miyajima Zero, Benz Micro LPS; Reel to Reel: Technics RS-1500; Doshi Tape Pre-Amp; Studer A810; Studer A812; Tascam BR-20; Multi-channel: Bryston SP-3; Digital: Custom PC> Lampizator Big 7 DAC

              Comment


              • #9
                I built one of the prototypes of his RTP-3C preamp for the late Allen Wright . I dug it out earlier this year (as I have been using the factory build RTP-3D for the last 10 years) to modify it for tape head duties. After modifying the EQ for tape and running it in, it burned up. I rebuilt pretty much the whole audio section and the B+ regulators, and found out that two of the heater regulators shorted to the ground plate, which caused the catastrophic failure. I then bought a bunch of EH6922 to test the preamp with, since I don't want to risk any NOS tubes. I have the George Kaye small signal tube tester, which tests for noise and microphony. To be fair, my experience with the new release EH6922 is that it is more consistent than most NOS 6922, especially if you buy these from Ebay. This is because a lot of rejected NOS tubes end up on Ebay. My stash of NOS tubes were bought more than 20 years ago, mainly from legacy distributors such as Langrex Supplies in the UK, so they were left over stock lying in distributor warehouses. Even so, unless you have highly selected tubes such as 7308, NOS could be a problem. All my 7308s however performed perfectly, and are great tubes for phono stages. 7DJ8s have 7V heaters. They might do OK with 6.3V when new, but when they age, the transconductance will quickly drop. If you use 7DJ8, you should change the heater voltage to 7V. This could be easily done if the heaters are regulated by something such as an LM317. Most heater supplies have enough voltage headroom to allow for this.
                And don't forget NOS tubes do lose their vacuum with time and oxygen gets in, which makes the tubes go noisy quickly when they are used. Remember to bake them in an oven to reactivate the getter before you test/use them.

                Comment


                • #10
                  I have to say this is one of the most head-scratching threads I’ve ever read here on AN. Forget eBay. There are lots of very trustworthy sellers of very high quality vintage vacuum tubes that perform tests before sending. Unless there is no more material in the getter (which would mean a lot of actual use and so not “NOS” but just “OS”, there is no issue with the vacuum of an older tube. I agree with Minches in that at least to my ears the EH6922 sounds pretty bad. The JAN Sylvania 6922’s I put in my phone stage were BOTH quieter and better sounding.
                  TAPE: Studer A807, A810; Revox B77 MkII; Tascam BR-20; Technics RS-1700; Pioneer RT-707, RT-909
                  VINYL: Denon DP59-L/Benz LP-S MR/ModWright PH 9.0; Pioneer PL-50LII/Dynavector 20xH
                  DIGITAL: Bryston SP-3, Marantz NA6006/Pioneer N-50, Schiit Bifrost
                  SPEAKERS: B&W Nautilus 800, Pioneer DSS-9, Velodyne FSR-15
                  AMPS: Cary SLP-05/Sunfire Signature 600, Pioneer SX-1980

                  Comment


                  • #11
                    Originally posted by adrianwu View Post
                    And don't forget NOS tubes do lose their vacuum with time and oxygen gets in, which makes the tubes go noisy quickly when they are used. Remember to bake them in an oven to reactivate the getter before you test/use them.
                    Never heard of baking tubes in the oven. Can you explain please.
                    Source: Kuzma XL DC/4Point 14 inch/CAR60; Phono: Zanden 1200 Mk3; Tuner: Magnum Dynalab MD-108T Signature; Line Stage: Zanden 3000 Mk2; Power amp: conrad-johnson ART monos; Speakers: AlsyVox Botticelli; Grounding: Tripoint Troy Elite NG/Emperor Mk2; Cable system: Cardas Clear Beyond; Stands: Finite Elemente Master Reference & Master Reference Heavy Duty; Power strip: Cardas Nautilus; Acoustics treatment: Svanå Miljöteknik AB (SMT);

                    Comment


                    • adrianwu
                      adrianwu commented
                      Editing a comment
                      You can read this thread here: https://www.diyaudio.com/forums/tube...dure-help.html
                      Someone in the thread said that the heaters will heat the tube when used. However, once the grid starts conducting, it immediately reacts with any residual oxygen present. Therefore, you want to heat the getters to remove the oxygen BEFORE the grid starts conducting. This procedure is detailed in Morgan Jones' book "Valve amplifiers". It might not be necessary if the NOS still has a good vacuum, but it could save some otherwise perfectly good tubes.
                      The member above said "Unless there is no more material in the getter (which would mean a lot of actual use and so not “NOS” but just “OS”, there is no issue with the vacuum of an older tube.". However, even if there is material left in the getter, which is almost always the case with NOS tubes, it would not help if the grid is allowed to interact with oxygen before the getter can absorb all the residual oxygen.

                  • #12
                    I’ve had some further thoughts on the subject.

                    I bought a quartet of GL6922 tubes from cj for my ART300 and had one fail at around 100 hours. This tube was probably, in retrospect, bad from the start. It crackled when first installed and I shut the amplifier down and reseated the tube. That seemed to take care of the issue then but it came back and then wouldn’t go away.

                    So two things. It seems the quality of today’s new tubes leaves a lot to be desired. I wonder what companies rejection rates are for these tubes? It seems once get past a bad tube or so then everything works fine for the lifetime of the tube.

                    Second, what exactly can we test for? Even when used in a circuit. That shows the circuit works but I don’t see how that relates to the tube’s lifetime. Conventional testers are worse. Even my George Kaye tester that uses a class A circuit. There are tubes you know are shot eg loss of dynamics that still test good on the tube tester.
                    Myles B. Astor, PhD, Administrator
                    Senior Editor, Positive-Feedback.com
                    ________________________________________

                    -Magico S5 Mk.2 speakers with SPod feet
                    -Goldmund Telos 280 stereo amp
                    -Goldmund Mimesis 37S Nextgen preamplifier
                    -Doshi V3.0 phonostage
                    -VPI Vanquish direct-drive turntable
                    -VPI 12-inch 3D Fat Boy dual pivot tonearm, VPI 12-inch 3D Fat Boy gimballed and SAT LM-12 arm
                    -Lyra Atlas SL Lambda, Fuuga, vdh Colibri Master Signature, MutechHayabusa, MOFI Master Tracker, Sumiko Songbird cartridges
                    -Technics RS1506 with Flux Magnetic heads, Doshi V3.0 tape stage (balanced)
                    -Assorted cables including Transparent XL Gen. 5, Skogrand, Viero, Kubala-Sosna, Audience Au24SX, Genesis Advanced Technologies and Ensemble Power Cords
                    -Accessories including Stillpoint Aperture panels, Cathedral Sound panels, Furutech NCF Nano AC receptacles; Silver Circle Tchaik 6 PLC, Symposium ISIS and SRA Craz racks, Audiodharma Cable Cooker, Symposium Ultra and assorted SRA platforms.

                    Comment


                    • #13
                      I guess my feeling is that if the tube’s parameters test good on a mutual transconductance tester, then after that it comes down to does the tube sound good in my system.
                      TAPE: Studer A807, A810; Revox B77 MkII; Tascam BR-20; Technics RS-1700; Pioneer RT-707, RT-909
                      VINYL: Denon DP59-L/Benz LP-S MR/ModWright PH 9.0; Pioneer PL-50LII/Dynavector 20xH
                      DIGITAL: Bryston SP-3, Marantz NA6006/Pioneer N-50, Schiit Bifrost
                      SPEAKERS: B&W Nautilus 800, Pioneer DSS-9, Velodyne FSR-15
                      AMPS: Cary SLP-05/Sunfire Signature 600, Pioneer SX-1980

                      Comment


                      • #14
                        My manufacturer doesn't offer a replcement tube package. But I did just go through a frustrating experience. And now I still have to find tubes
                        PAP Trio 10/Voxativ & PAP Trio 15 Horn speakers, Ampsandsound Casablanca monoblocks, First Sound Audio Mark 3SI Paramount preamp,
                        Mojo Audio Deja Vu server, Mojo Audio Mystique V3 DAC, The Linear Solution Ethernet Switch, Blue Jeans Ethernet cablling,
                        Akiko Corelli, Custom power strip direct wired to panel with OFC copper wire. Inakustik Ref Air 2404 Speaker cable. Genesis and Inakustik NF2404 Air Interconnects. ADDPower Symphony and Electraclear.

                        Comment


                        • #15
                          Year ago I made an investment. I bought an Amplitrex AT1000 tube tester. It tests at full power, and there's no avoiding the results. It gives exact figures, no 'interpretation'.

                          Brother King Rex, what tubes do you need? If you pay shipping both ways, I'll test what tubes you have during the Super Bowl halftime show?

                          Brother Billy

                          Comment


                          • MylesBAstor
                            MylesBAstor commented
                            Editing a comment
                            That was really nice of you to offer!

                          • Kingrex
                            Kingrex commented
                            Editing a comment
                            I PM Bill that Telefunkin work best for me. They are around $365 each at Upscale. I will pay a fair price for a pair. I have one replacement set and 1 I think I got hosed on. I need those tested. Never found a better tube for my preamp. I tried the usual Sieme s, Amprex and maybe 3 other makes. Those old NOS telefunkin are amazing in my setup.

                          • Cousinbilly
                            Cousinbilly commented
                            Editing a comment
                            I don't believe I have Tele's. Sorry.
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